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Almog N, Zgadzai O, Kuppusamy P, Zur Y, Baruch L, Machluf M, Blank A. Hand-held electron spin resonance scanner for subcutaneous oximetry using OxyChip. Magn Reson Med 2024; 92:430-439. [PMID: 38411265 PMCID: PMC11055674 DOI: 10.1002/mrm.30066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/07/2024] [Accepted: 02/08/2024] [Indexed: 02/28/2024]
Abstract
PURPOSE Electron spin resonance (ESR) is used to measure oxygen partial pressure (pO2) in biological media with many clinical applications. Traditional clinical ESR involves large magnets that encompass the subject of measurement. However, certain applications might benefit from a scanner operating within local static magnetic fields. Our group recently developed such a compact scanner for transcutaneous (surface) pO2 measurements of skin tissue. Here we extend this capability to subsurface (subcutaneous) pO2 measurements and verify it using an artificial tissue emulating (ATE) phantom. METHODS We introduce a new scanner, tailored for subcutaneous measurements up to 2 mm beneath the skin's surface. This scanner captures pulsed ESR signals from embedded approximate 1-mm oxygen-sensing solid paramagnetic implant, OxyChip. The scanner features a static magnetic field source, producing a uniform region outside its surface, and a compact microwave resonator, for exciting and receiving ESR signals. RESULTS ESR readings derived from an OxyChip, positioned approximately 1.5 mm from the scanner's surface, embedded in ATE phantom, exhibited a linear relation of 1/T2 versus pO2 for pO2 levels at 0, 7.6, 30, and 160 mmHg, with relative reading accuracy of about 10%. CONCLUSION The compact ESR scanner can report pO2 data in ATE phantom from an external position relative to the scanner. Implementing this scanner in preclinical and clinical applications for subcutaneous pO2 measurements is a feasible next phase for this development. This innovative design also has the potential to operate in conjunction with artificial skin graft for wound healing, combining therapeutic and pO2 diagnostic features.
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Affiliation(s)
- Nir Almog
- Schulich Faculty of Chemistry, Technion – Israel Institute of Technology, Haifa 32000, Israel
| | - Oleg Zgadzai
- Schulich Faculty of Chemistry, Technion – Israel Institute of Technology, Haifa 32000, Israel
| | - Periannan Kuppusamy
- Departments of Radiology, Radiation Oncology, and Medicine, Geisel School of Medicine, Dartmouth College, Lebanon, NH 03756, USA
| | - Yehonatan Zur
- Faculty of Biotechnology and Food Engineering, Technion – Israel Institute of Technology, Haifa 32000, Israel
| | - Limor Baruch
- Faculty of Biotechnology and Food Engineering, Technion – Israel Institute of Technology, Haifa 32000, Israel
| | - Marcelle Machluf
- Faculty of Biotechnology and Food Engineering, Technion – Israel Institute of Technology, Haifa 32000, Israel
| | - Aharon Blank
- Schulich Faculty of Chemistry, Technion – Israel Institute of Technology, Haifa 32000, Israel
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2
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Daplan E, Turin L. Free radical production induced by visible light in live fruit flies. J Photochem Photobiol B 2024; 255:112925. [PMID: 38703451 DOI: 10.1016/j.jphotobiol.2024.112925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/22/2024] [Accepted: 04/25/2024] [Indexed: 05/06/2024]
Abstract
Visible light triggers free radical production in alive and intact Drosophila melanogaster. We exposed fruit flies to red (613-631 nm), green (515-535 nm), and blue (455-475 nm) light while we monitored changes in unpaired electron content with an electron spin resonance spectrometer (ESR/EPR). The immediate response to light is a rapid increase in spin content lasting approximately 10 s followed by a slower, linear increase for approximately 170 s. When the light is turned off, the spin population promptly decays with a similar time course, though never fully returning to baseline. The magnitude and time course of the spin production depends on the wavelength of the light. Initially, we surmised that eumelanin might be responsible for the spin change because of its documented ability for visible light absorption and its highly stable free radical content. To explore this, we utilized different fruit fly strains with varying eumelanin content and clarified the relation of melanin types with the spin response. Our findings revealed that flies with darker cuticle have at least three-fold more unpaired electrons than flies with yellow cuticle. However, to our surprise, the increase in unpaired electron population by light was not drastically different amongst the genotypes. This suggests that light-induced free radical production may not exclusively rely on the presence of black melanin, but may instead be dependent on light effects on quinone-based cuticular polymers.
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Affiliation(s)
| | - Luca Turin
- University of Buckingham, United Kingdom
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3
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Veronesi G, Pérard J, Clémancey M, Gerez C, Duverger Y, Kieffer I, Barras F, Gambarelli S, Blondin G, Ollagnier de Choudens S. Multimodal Spectroscopic Analysis of the Fe-S Clusters of the as-Isolated Escherichia coli SufBC 2D Complex. Inorg Chem 2024; 63:8730-8738. [PMID: 38687645 DOI: 10.1021/acs.inorgchem.4c00304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Iron-sulfur (Fe-S) clusters are essential inorganic cofactors dedicated to a wide range of biological functions, including electron transfer and catalysis. Specialized multiprotein machineries present in all types of organisms support their biosynthesis. These machineries encompass a scaffold protein, on which Fe-S clusters are assembled before being transferred to cellular targets. Here, we describe the first characterization of the native Fe-S cluster of the anaerobically purified SufBC2D scaffold from Escherichia coli by XAS and Mössbauer, UV-visible absorption, and EPR spectroscopies. Interestingly, we propose that SufBC2D harbors two iron-sulfur-containing species, a [2Fe-2S] cluster and an as-yet unidentified species. Mutagenesis and biochemistry were used to propose amino acid ligands for the [2Fe-2S] cluster, supporting the hypothesis that both SufB and SufD are involved in the Fe-S cluster ligation. The [2Fe-2S] cluster can be transferred to ferredoxin in agreement with the SufBC2D scaffold function. These results are discussed in the context of Fe-S cluster biogenesis.
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Affiliation(s)
- Giulia Veronesi
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux, Grenoble F-38000, France
| | - Julien Pérard
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux, Grenoble F-38000, France
| | - Martin Clémancey
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux, Grenoble F-38000, France
| | - Catherine Gerez
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux, Grenoble F-38000, France
| | - Yohann Duverger
- Laboratoire de Chimie Bactérienne, UMR7243 Aix-Marseille Université CNRS, 31 Chemin Joseph Aiguier, Marseille 13009, France
| | - Isabelle Kieffer
- Univ. Grenoble Alpes, CNRS, IRD, Irstea, Météo France, OSUG, FAME, Grenoble 38000, France
| | - Frédéric Barras
- Institut Pasteur, Université de Paris, CNRS UMR 6047, Department of Microbiology, SAMe Unit, Paris 75724, France
| | - Serge Gambarelli
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, SyMMES, Grenoble F-38000, France
| | - Geneviève Blondin
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux, Grenoble F-38000, France
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4
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Jodts RJ, Ho MB, Reyes RM, Park YJ, Doan PE, Rosenzweig AC, Hoffman BM. Initial Steps in Methanobactin Biosynthesis: Substrate Binding by the Mixed-Valent Diiron Enzyme MbnBC. Biochemistry 2024; 63:1170-1177. [PMID: 38587906 DOI: 10.1021/acs.biochem.4c00011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
The MbnBC enzyme complex converts cysteine residues in a peptide substrate, MbnA, to oxazolone/thioamide groups during the biosynthesis of copper chelator methanobactin (Mbn). MbnBC belongs to the mixed-valent diiron oxygenase (MVDO) family, of which members use an Fe(II)Fe(III) cofactor to react with dioxygen for substrate modification. Several crystal structures of the inactive Fe(III)Fe(III) form of MbnBC alone and in complex with MbnA have been reported, but a mechanistic understanding requires determination of the oxidation states of the crystallographically observed Fe ions in the catalytically active Fe(II)Fe(III) state, along with the site of MbnA binding. Here, we have used electron nuclear double resonance (ENDOR) spectroscopy to determine such structural and electronic properties of the active site, in particular, the mode of substrate binding to the MV state, information not accessible by X-ray crystallography alone. The oxidation states of the two Fe ions were determined by 15N ENDOR analysis. The presence and locations of both bridging and terminal exogenous solvent ligands were determined using 1H and 2H ENDOR. In addition, 2H ENDOR using an isotopically labeled MbnA substrate indicates that MbnA binds to the Fe(III) ion of the cluster via the sulfur atom of its N-terminal modifiable cysteine residue, with displacement of a coordinated solvent ligand as shown by complementary 1H ENDOR. These results, which underscore the utility of ENDOR in studying MVDOs, provide a molecular picture of the initial steps in Mbn biosynthesis.
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Lewis NM, Kisgeropoulos EC, Lubner CE, Fixen KR. Characterization of ferredoxins involved in electron transfer pathways for nitrogen fixation implicates differences in electronic structure in tuning 2[4Fe4S] Fd activity. J Inorg Biochem 2024; 254:112521. [PMID: 38471286 DOI: 10.1016/j.jinorgbio.2024.112521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 03/03/2024] [Accepted: 03/05/2024] [Indexed: 03/14/2024]
Abstract
Ferredoxins (Fds) are small proteins which shuttle electrons to pathways like biological nitrogen fixation. Physical properties tune the reactivity of Fds with different pathways, but knowledge on how these properties can be manipulated to engineer new electron transfer pathways is lacking. Recently, we showed that an evolved strain of Rhodopseudomonas palustris uses a new electron transfer pathway for nitrogen fixation. This pathway involves a variant of the primary Fd of nitrogen fixation in R. palustris, Fer1, in which threonine at position 11 is substituted for isoleucine (Fer1T11I). To understand why this substitution in Fer1 enables more efficient electron transfer, we used in vivo and in vitro methods to characterize Fer1 and Fer1T11I. Electrochemical characterization revealed both Fer1 and Fer1T11I have similar redox transitions (-480 mV and - 550 mV), indicating the reduction potential was unaffected despite the proximity of T11 to an iron‑sulfur (FeS) cluster of Fer1. Additionally, disruption of hydrogen bonding around an FeS cluster in Fer1 by substituting threonine with alanine (T11A) or valine (T11V) did not increase nitrogenase activity, indicating that disruption of hydrogen bonding does not explain the difference in activity observed for Fer1T11I. Electron paramagnetic resonance spectroscopy studies revealed key differences in the electronic structure of Fer1 and Fer1T11I, which indicate changes to the high spin states and/or spin-spin coupling between the FeS clusters of Fer1. Our data implicates these electronic structure differences in facilitating electron flow and sets a foundation for further investigations to understand the connection between these properties and intermolecular electron transfer.
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Affiliation(s)
- Nathan M Lewis
- Department of Plant and Microbial Biology and the Biotechnology Institute, University of Minnesota, Minneapolis, MN, United States of America
| | | | - Carolyn E Lubner
- National Renewable Energy Laboratory, Golden, CO, United States of America.
| | - Kathryn R Fixen
- Department of Plant and Microbial Biology and the Biotechnology Institute, University of Minnesota, Minneapolis, MN, United States of America.
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Ghimire L, Waller E. Electron Paramagnetic Resonance (EPR) Biodosimetry with Human Teeth: A Crucial Technique for Acute and Chronic Exposure Assessment. Health Phys 2024; 126:322-338. [PMID: 38526251 DOI: 10.1097/hp.0000000000001822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
ABSTRACT Radiation exposure is a primary concern in emergency response scenarios and long-term health assessments. Accurate quantification of radiation doses is critical for informed decision-making and patient care. This paper reviews the dose reconstruction technique using both X- and Q-bands, with tooth enamel as a reliable dosimeter. Tooth enamel, due to its exceptional resistance to alteration over time, offers a unique opportunity for assessing both acute and chronic radiation exposures. This review delves into the principles underlying enamel dosimetry, the mechanism of radiation interactions, and dose retention in tooth enamel. We explore state-of-the-art analytical methods, such as electron paramagnetic resonance (EPR) spectroscopy, that accurately estimate low and high doses in acute and chronic exposure. Furthermore, we discuss the applicability of tooth enamel dosimetry in various scenarios, ranging from historical radiological incidents to recent nuclear events or radiological incidents. The ability to reconstruct radiation doses from dental enamel provides a valuable tool for epidemiological studies, validating the assessment of health risks associated with chronic exposures and aiding in the early detection and management of acute radiation incidents. This paper underscores the significance of tooth enamel as an essential medium for radiation dose reconstruction and its broader implications for enhancing radiation protection, emergency response, and public health preparedness. Incorporating enamel EPR dosimetry into standard protocols has the potential to transform the field of radiation assessment, ensuring more accurate and timely evaluations of radiation exposure and its associated risks.
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Affiliation(s)
- Lekhnath Ghimire
- Department of Energy and Nuclear Engineering, Faculty of Engineering and Applied Science, Ontario Tech University, Oshawa, ON, L1G 0C5, Canada, or email at
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Debus RJ, Oyala PH. Independent Mutation of Two Bridging Carboxylate Ligands Stabilizes Alternate Conformers of the Photosynthetic O 2-Evolving Mn 4CaO 5 Cluster in Photosystem II. J Phys Chem B 2024; 128:3870-3884. [PMID: 38602496 DOI: 10.1021/acs.jpcb.4c00829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
The O2-evolving Mn4CaO5 cluster in photosystem II is ligated by six carboxylate residues. One of these is D170 of the D1 subunit. This carboxylate bridges between one Mn ion (Mn4) and the Ca ion. A second carboxylate ligand is D342 of the D1 subunit. This carboxylate bridges between two Mn ions (Mn1 and Mn2). D170 and D342 are located on opposite sides of the Mn4CaO5 cluster. Recently, it was shown that the D170E mutation perturbs both the intricate networks of H-bonds that surround the Mn4CaO5 cluster and the equilibrium between different conformers of the cluster in two of its lower oxidation states, S1 and S2, while still supporting O2 evolution at approximately 50% the rate of the wild type. In this study, we show that the D342E mutation produces much the same alterations to the cluster's FTIR and EPR spectra as D170E, while still supporting O2 evolution at approximately 20% the rate of the wild type. Furthermore, the double mutation, D170E + D342E, behaves similarly to the two single mutations. We conclude that D342E alters the equilibrium between different conformers of the cluster in its S1 and S2 states in the same manner as D170E and perturbs the H-bond networks in a similar fashion. This is the second identification of a Mn4CaO5 metal ligand whose mutation influences the equilibrium between the different conformers of the S1 and S2 states without eliminating O2 evolution. This finding has implications for our understanding of the mechanism of O2 formation in terms of catalytically active/inactive conformations of the Mn4CaO5 cluster in its lower oxidation states.
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Affiliation(s)
- Richard J Debus
- Department of Biochemistry, University of California at Riverside, Riverside, California 92521, United States
| | - Paul H Oyala
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91106, United States
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8
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Kashnik AS, Baranov DS, Dzuba SA. Spatial Arrangement of the Drug Ibuprofen in a Model Membrane in the Presence of Lipid Rafts. J Phys Chem B 2024; 128:3652-3661. [PMID: 38576273 DOI: 10.1021/acs.jpcb.4c01507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
Many pharmaceutical drugs are known to interact with lipid membranes through nonspecific molecular interactions, which affect their therapeutic effect. Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) and one of the most commonly prescribed. In the presence of cholesterol, lipid bilayers can separate into nanoscale liquid-disordered and liquid-ordered structures, the latter known as lipid rafts. Here, we study spin-labeled ibuprofen (ibuprofen-SL) in the model membrane consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), and cholesterol in the molar ratio of (0.5-0.5xchol)/(0.5-0.5xchol)/xchol. Electron paramagnetic resonance (EPR) spectroscopy is employed, along with its pulsed version of double electron-electron resonance (DEER, also known as PELDOR). The data obtained indicate lateral lipid-mediated clustering of ibuprofen-SL molecules with a local surface density noticeably larger than that expected for random lateral distribution. In the absence of cholesterol, the data can be interpreted as indicating alternating clustering in two opposing leaflets of the bilayer. In the presence of cholesterol, for xchol ≥ 20 mol %, the results show that ibuprofen-SL molecules have a quasi-regular lateral distribution, with a "superlattice" parameter of ∼3.0 nm. This regularity can be explained by the entrapment of ibuprofen-SL molecules by lipid rafts known to exist in this system with the additional assumption that lipid rafts have a nanoscale substructure.
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Affiliation(s)
- Anna S Kashnik
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Denis S Baranov
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Sergei A Dzuba
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia
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Stehle J, Hülsmann M, Godt A, Drescher M, Azarkh M. Evaluation of Copper(II) Transfer between Amyloid-beta Peptides by Relaxation-Induced Dipolar Modulation Enhancement (RIDME). Chemphyschem 2024; 25:e202300928. [PMID: 38285014 DOI: 10.1002/cphc.202300928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 01/30/2024]
Abstract
In the brains of Alzheimer's disease patients, fibrillar aggregates containing amyloid-beta (Aβ) peptides are found, along with elevated concentrations of Cu(II) ions. The aggregation pathways of Aβ peptides can be modulated by Cu(II) ions and is determined by the formation and nature of the Cu(II)-Aβ complex. If spin-labeled, the Cu(II)-Aβ complex contains two dipolar coupled paramagnetic centers, the spin label and the Cu(II) ion. Measurement of the dipolar coupling between these paramagnetic centers by relaxation-induced dipolar modulation enhancement (RIDME) allows to monitor the complex formation and thus opens a way to follow the Cu(II) transfer between peptides if a mixture of wild-type and spin-labeled ones is used. We evaluate this approach for a specific Cu(II)-Aβ complex, the aggregation-inert Component II. The kinetics of the Cu(II) transfer can be resolved by performing RIDME in a time-dependent manner. A temporal resolution of seconds has been achieved, with the potential to reach milliseconds, using a rapid-freeze quench device to stop the Cu(II) transfer in solution after defined incubation times.
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Affiliation(s)
- Juliane Stehle
- Department of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstr. 10, 78457, Konstanz, Germany
| | - Miriam Hülsmann
- Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Adelheid Godt
- Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Malte Drescher
- Department of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstr. 10, 78457, Konstanz, Germany
| | - Mykhailo Azarkh
- Department of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstr. 10, 78457, Konstanz, Germany
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Bizet M, Byrne D, Biaso F, Gerbaud G, Etienne E, Briola G, Guigliarelli B, Urban P, Dorlet P, Kalai T, Truan G, Martinho M. Structural insights into the semiquinone form of human Cytochrome P450 reductase by DEER distance measurements between a native flavin and a spin labelled non-canonical amino acid. Chemistry 2024; 30:e202304307. [PMID: 38277424 DOI: 10.1002/chem.202304307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 01/28/2024]
Abstract
The flavoprotein Cytochrome P450 reductase (CPR) is the unique electron pathway from NADPH to Cytochrome P450 (CYPs). The conformational dynamics of human CPR in solution, which involves transitions from a "locked/closed" to an "unlocked/open" state, is crucial for electron transfer. To date, however, the factors guiding these changes remain unknown. By Site-Directed Spin Labelling coupled to Electron Paramagnetic Resonance spectroscopy, we have incorporated a non-canonical amino acid onto the flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) domains of soluble human CPR, and labelled it with a specific nitroxide spin probe. Taking advantage of the endogenous FMN cofactor, we successfully measured for the first time, the distance distribution by DEER between the semiquinone state FMNH• and the nitroxide. The DEER data revealed a salt concentration-dependent distance distribution, evidence of an "open" CPR conformation at high salt concentrations exceeding previous reports. We also conducted molecular dynamics simulations which unveiled a diverse ensemble of conformations for the "open" semiquinone state of the CPR at high salt concentration. This study unravels the conformational landscape of the one electron reduced state of CPR, which had never been studied before.
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Affiliation(s)
- Maxime Bizet
- Aix Marseille Univ, CNRS, Bioénergétique et Ingénierie des Protéines, IMM, 13402, Marseille, France
| | - Deborah Byrne
- Protein Expression Facility, Aix Marseille Univ, CNRS, IMM, 13402, Marseille, France
| | - Frédéric Biaso
- Aix Marseille Univ, CNRS, Bioénergétique et Ingénierie des Protéines, IMM, 13402, Marseille, France
| | - Guillaume Gerbaud
- Aix Marseille Univ, CNRS, Bioénergétique et Ingénierie des Protéines, IMM, 13402, Marseille, France
| | - Emilien Etienne
- Aix Marseille Univ, CNRS, Bioénergétique et Ingénierie des Protéines, IMM, 13402, Marseille, France
| | - Giuseppina Briola
- Aix Marseille Univ, CNRS, Bioénergétique et Ingénierie des Protéines, IMM, 13402, Marseille, France
| | - Bruno Guigliarelli
- Aix Marseille Univ, CNRS, Bioénergétique et Ingénierie des Protéines, IMM, 13402, Marseille, France
| | - Philippe Urban
- TBI, Université de Toulouse, CNRS, INRAE, INSA, 31077, Toulouse, France
| | - Pierre Dorlet
- Aix Marseille Univ, CNRS, Bioénergétique et Ingénierie des Protéines, IMM, 13402, Marseille, France
| | - Tamas Kalai
- Department of Organic and Medicinal Chemistry, Faculty of Pharmacy, University of Pécs, PO Box 99 Szigeti st. 12, H-7602 7624, Pécs, Hungary
| | - Gilles Truan
- TBI, Université de Toulouse, CNRS, INRAE, INSA, 31077, Toulouse, France
| | - Marlène Martinho
- Aix Marseille Univ, CNRS, Bioénergétique et Ingénierie des Protéines, IMM, 13402, Marseille, France
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Hinoshita M, Abe T, Sato A, Maeda Y, Takeyoshi M. Modified ESR-based photosafety test (ESR-PT) detecting singlet oxygen and free radical formation. J Appl Toxicol 2024; 44:651-662. [PMID: 38058230 DOI: 10.1002/jat.4569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 11/21/2023] [Accepted: 11/21/2023] [Indexed: 12/08/2023]
Abstract
The electron spin resonance-based photosafety test (ESR-PT) was modified using a new parameter, photoreactivity index (PRI), to detect singlet oxygen and free radical photoproducts simultaneously. With this modification, the modified ESR-PT is expected to reduce the number of false negative results due to chemicals producing free radical photoproducts other than singlet oxygen. The assay performance of the modified ESR-PT was evaluated using 56 chemicals, including hydrophobic chemicals. When using the PRI cutoff value of 2.0 in the modified ESR-PT, the accuracy relative to photosafety reference data was 91.1%, and the applicability (100%) was better than the other non-animal photosafety test. Among the chemicals producing positive results, bithionol, fenticlor, and doxycycline HCl were considered positive based on the detection of free radical photoproducts, suggesting that these three chemicals may have phototoxic or photoallergic potential via radical reactions. Additionally, this finding demonstrated the fundamental advantage of the modified ESR-PT using ESR spectroscopy, which can detect radicals selectively and quantitatively. Accordingly, the new parameter PRI is effective for photosafety evaluations based on not only singlet oxygen but also free radical photoproducts generated from chemicals. Therefore, the modified ESR-PT has a great potential for a photosafety test method applicable to various chemicals.
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Affiliation(s)
- Masumi Hinoshita
- CERI Osaka, Chemicals Evaluation and Research Institute, Osaka, Japan
| | - Takayuki Abe
- CERI Tokyo, Chemicals Evaluation and Research Institute, Tokyo, Japan
| | - Asako Sato
- Chemicals Assessment and Research Center, Chemicals Evaluation and Research Institute, Tokyo, Japan
| | - Yosuke Maeda
- Chemicals Assessment and Research Center, Chemicals Evaluation and Research Institute, Tokyo, Japan
| | - Masahiro Takeyoshi
- Chemicals Assessment and Research Center, Chemicals Evaluation and Research Institute, Tokyo, Japan
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Pierce BS, Schmittou AN, York NJ, Madigan RP, Nino PF, Foss FW, Lockart MM. Improved resolution of 3-mercaptopropionate dioxygenase active site provided by ENDOR spectroscopy offers insight into catalytic mechanism. J Biol Chem 2024; 300:105777. [PMID: 38395308 PMCID: PMC10966181 DOI: 10.1016/j.jbc.2024.105777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 02/13/2024] [Accepted: 02/15/2024] [Indexed: 02/25/2024] Open
Abstract
3-mercaptopropionate (3MPA) dioxygenase (MDO) is a mononuclear nonheme iron enzyme that catalyzes the O2-dependent oxidation of thiol-bearing substrates to yield the corresponding sulfinic acid. MDO is a member of the cysteine dioxygenase family of small molecule thiol dioxygenases and thus shares a conserved sequence of active site residues (Serine-155, Histidine-157, and Tyrosine-159), collectively referred to as the SHY-motif. It has been demonstrated that these amino acids directly interact with the mononuclear Fe-site, influencing steady-state catalysis, catalytic efficiency, O2-binding, and substrate coordination. However, the underlying mechanism by which this is accomplished is poorly understood. Here, pulsed electron paramagnetic resonance spectroscopy [1H Mims electron nuclear double resonance spectroscopy] is applied to validate density functional theory computational models for the MDO Fe-site simultaneously coordinated by substrate and nitric oxide (NO), (3MPA/NO)-MDO. The enhanced resolution provided by electron nuclear double resonance spectroscopy allows for direct observation of Fe-bound substrate conformations and H-bond donation from Tyr159 to the Fe-bound NO ligand. Further inclusion of SHY-motif residues within the validated model reveals a distinct channel restricting movement of the Fe-bound NO-ligand. It has been argued that the iron-nitrosyl emulates the structure of potential Fe(III)-superoxide intermediates within the MDO catalytic cycle. While the merit of this assumption remains unconfirmed, the model reported here offers a framework to evaluate oxygen binding at the substrate-bound Fe-site and possible reaction mechanisms. It also underscores the significance of hydrogen bonding interactions within the enzymatic active site.
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Affiliation(s)
- Brad S Pierce
- Department of Chemistry & Biochemistry, University of Alabama, Tuscaloosa, Alabama, USA.
| | - Allison N Schmittou
- Department of Chemistry & Biochemistry, University of Alabama, Tuscaloosa, Alabama, USA
| | - Nicholas J York
- Department of Chemistry & Biochemistry, University of Alabama, Tuscaloosa, Alabama, USA
| | - Ryan P Madigan
- Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, Texas, USA
| | - Paula F Nino
- Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, Texas, USA
| | - Frank W Foss
- Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, Texas, USA
| | - Molly M Lockart
- Department of Chemistry and Biochemistry, Samford University, Homewood, Alabama, USA.
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13
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Yi L, Jiang H, Ma Y, Zhu R, Zhang G, Ren Z. Highly efficient visible-light driven dye degradation via 0D BiVO 4 nanoparticles/2D BiOCl nanosheets p-n heterojunctions. Chemosphere 2024; 354:141658. [PMID: 38484995 DOI: 10.1016/j.chemosphere.2024.141658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 01/01/2024] [Accepted: 03/05/2024] [Indexed: 03/25/2024]
Abstract
The construction of hybrid heterojunction photocatalysts is an effective strategy to improve the utilization of photogenerated carriers and photocatalytic activity. To enhance the separation distance of photogenerated carriers and accelerate the effective separation at the heterojunction of the interface, a unique 0D-2D hierarchical nanostructured p-n heterojunction was successfully fabricated in this work. BiOCl (BOC) nanosheets (p-type) were in situ grown on BiVO4 (BVO) nanoparticles (n-type) using the microemulsion-calcination method for highly efficient visible-light-driven organic dye degradation. Compared with pure BVO (the degradation rate of rhodamine B (RhB): about 32.0% in 55 min, the mineralization rate: 24.9% in 120 min), the RhB degradation rate can reach about 99.5% in 55 min and the mineralization rate of 62.1% in 120 min by utilizing BVO/25%BOC heterojunction photocatalyst under visible light irradiation. Various characterizations demonstrate that the formation of BVO/BOC p-n heterojunction greatly facilitates photogenerated carriers separation efficiency. Meanwhile, the results of the scavenging experiments and electron spin resonance tests indicate that ·O2- and h+ are the prominent active species for Rh B degradation. In addition, possible degradation pathways for Rh B were proposed using LC-MS tests. This work proves that building low dimensional p-n heterojunction photocatalysts is a promising strategy for developing photocatalysts with high efficiency.
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Affiliation(s)
- Lian Yi
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China; Institute of Hydrogen and Fuel Cell, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China; International Joint Research Center for Persistent Toxic Substances, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China.
| | - Hongyi Jiang
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China; Institute of Hydrogen and Fuel Cell, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China; International Joint Research Center for Persistent Toxic Substances, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China.
| | - Yueyong Ma
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China; Institute of Hydrogen and Fuel Cell, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China; International Joint Research Center for Persistent Toxic Substances, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China.
| | - Rongshu Zhu
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China; Institute of Hydrogen and Fuel Cell, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China; International Joint Research Center for Persistent Toxic Substances, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China.
| | - Guan Zhang
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China.
| | - Zhaoyong Ren
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China; Institute of Hydrogen and Fuel Cell, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China; International Joint Research Center for Persistent Toxic Substances, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, PR China.
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14
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Bogdanov A, Frydman V, Seal M, Rapatskiy L, Schnegg A, Zhu W, Iron M, Gronenborn AM, Goldfarb D. Extending the Range of Distances Accessible by 19F Electron-Nuclear Double Resonance in Proteins Using High-Spin Gd(III) Labels. J Am Chem Soc 2024; 146:6157-6167. [PMID: 38393979 PMCID: PMC10921402 DOI: 10.1021/jacs.3c13745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/02/2024] [Accepted: 02/02/2024] [Indexed: 02/25/2024]
Abstract
Fluorine electron-nuclear double resonance (19F ENDOR) has recently emerged as a valuable tool in structural biology for distance determination between F atoms and a paramagnetic center, either intrinsic or conjugated to a biomolecule via spin labeling. Such measurements allow access to distances too short to be measured by double electron-electron resonance (DEER). To further extend the accessible distance range, we exploit the high-spin properties of Gd(III) and focus on transitions other than the central transition (|-1/2⟩ ↔ |+1/2⟩), that become more populated at high magnetic fields and low temperatures. This increases the spectral resolution up to ca. 7 times, thus raising the long-distance limit of 19F ENDOR almost 2-fold. We first demonstrate this on a model fluorine-containing Gd(III) complex with a well-resolved 19F spectrum in conventional central transition measurements and show quantitative agreement between the experimental spectra and theoretical predictions. We then validate our approach on two proteins labeled with 19F and Gd(III), in which the Gd-F distance is too long to produce a well-resolved 19F ENDOR doublet when measured at the central transition. By focusing on the |-5/2⟩ ↔ |-3/2⟩ and |-7/2⟩ ↔ |-5/2⟩ EPR transitions, a resolution enhancement of 4.5- and 7-fold was obtained, respectively. We also present data analysis strategies to handle contributions of different electron spin manifolds to the ENDOR spectrum. Our new extended 19F ENDOR approach may be applicable to Gd-F distances as large as 20 Å, widening the current ENDOR distance window.
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Affiliation(s)
- Alexey Bogdanov
- Department
of Chemical and Biological Physics, The
Weizmann Institute of Science, P.O. Box 26, Rehovot, 7610001, Israel
| | - Veronica Frydman
- Department
of Chemical Research Support, The Weizmann
Institute of Science, P.O. Box 26, Rehovot, 7610001, Israel
| | - Manas Seal
- Department
of Chemical and Biological Physics, The
Weizmann Institute of Science, P.O. Box 26, Rehovot, 7610001, Israel
| | - Leonid Rapatskiy
- Max
Planck Institute for Chemical Energy Conversion, 34-36 Stiftstraße, Mülheim an der Ruhr, 45470, Germany
| | - Alexander Schnegg
- Max
Planck Institute for Chemical Energy Conversion, 34-36 Stiftstraße, Mülheim an der Ruhr, 45470, Germany
| | - Wenkai Zhu
- Department
of Structural Biology, University of Pittsburgh, 4200 Fifth Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Mark Iron
- Department
of Chemical Research Support, The Weizmann
Institute of Science, P.O. Box 26, Rehovot, 7610001, Israel
| | - Angela M. Gronenborn
- Department
of Structural Biology, University of Pittsburgh, 4200 Fifth Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Daniella Goldfarb
- Department
of Chemical and Biological Physics, The
Weizmann Institute of Science, P.O. Box 26, Rehovot, 7610001, Israel
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15
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Santabarbara S, Agostini A, Petrova AA, Bortolus M, Casazza AP, Carbonera D. Chlorophyll triplet states in thylakoid membranes of Acaryochloris marina. Evidence for a triplet state sitting on the photosystem I primary donor populated by intersystem crossing. Photosynth Res 2024; 159:133-152. [PMID: 37191762 DOI: 10.1007/s11120-023-01023-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 04/27/2023] [Indexed: 05/17/2023]
Abstract
Photo-induced triplet states in the thylakoid membranes isolated from the cyanobacterium Acaryocholoris marina, that harbours Chlorophyll (Chl) d as its main chromophore, have been investigated by Optically Detected Magnetic Resonance (ODMR) and time-resolved Electron Paramagnetic Resonance (TR-EPR). Thylakoids were subjected to treatments aimed at poising the redox state of the terminal electron transfer acceptors and donors of Photosystem II (PSII) and Photosystem I (PSI), respectively. Under ambient redox conditions, four Chl d triplet populations were detectable, identifiable by their characteristic zero field splitting parameters, after deconvolution of the Fluorescence Detected Magnetic Resonance (FDMR) spectra. Illumination in the presence of the redox mediator N,N,N',N'-Tetramethyl-p-phenylenediamine (TMPD) and sodium ascorbate at room temperature led to a redistribution of the triplet populations, with T3 (|D|= 0.0245 cm-1, |E|= 0.0042 cm-1) becoming dominant and increasing in intensity with respect to untreated samples. A second triplet population (T4, |D|= 0.0248 cm-1, |E|= 0.0040 cm-1) having an intensity ratio of about 1:4 with respect to T3 was also detectable after illumination in the presence of TMPD and ascorbate. The microwave-induced Triplet-minus-Singlet spectrum acquired at the maximum of the |D|-|E| transition (610 MHz) displays a broad minimum at 740 nm, accompanied by a set of complex spectral features that overall resemble, despite showing further fine spectral structure, the previously reported Triplet-minus-Singlet spectrum attributed to the recombination triplet of PSI reaction centre,3 P 740 [Schenderlein M, Çetin M, Barber J, et al. Spectroscopic studies of the chlorophyll d containing photosystem I from the cyanobacterium Acaryochloris marina. Biochim Biophys Acta 1777:1400-1408]. However, TR-EPR experiments indicate that this triplet displays an eaeaea electron spin polarisation pattern which is characteristic of triplet sublevels populated by intersystem crossing rather than recombination, for which an aeeaae polarisation pattern is expected instead. It is proposed that the observed triplet, which leads to the bleaching of the P740 singlet state, sits on the PSI reaction centre.
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Affiliation(s)
- Stefano Santabarbara
- Photosynthesis Research Unit, Centro Studi Sulla Biologia Cellulare e Molecolare delle Piante, Consiglio Nazionale Delle Ricerche, Via Celoria 26, 20133, Milan, Italy.
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Via Bassini 15a, 20133, Milan, Italy.
| | - Alessandro Agostini
- Department of Chemical Sciences, Università di Padova, Via Marzolo 1, 35131, Padua, Italy
| | - Anastasia A Petrova
- Photosynthesis Research Unit, Centro Studi Sulla Biologia Cellulare e Molecolare delle Piante, Consiglio Nazionale Delle Ricerche, Via Celoria 26, 20133, Milan, Italy
- A. N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, Leninskye Gory 1 Building 40, Moscow, Russia, 119992
| | - Marco Bortolus
- Department of Chemical Sciences, Università di Padova, Via Marzolo 1, 35131, Padua, Italy
| | - Anna Paola Casazza
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Via Bassini 15a, 20133, Milan, Italy
| | - Donatella Carbonera
- Department of Chemical Sciences, Università di Padova, Via Marzolo 1, 35131, Padua, Italy.
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16
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Dodd EL, Le Brun NE. Probing the mechanism of the dedicated NO sensor [4Fe-4S] NsrR: the effect of cluster ligand environment. J Inorg Biochem 2024; 252:112457. [PMID: 38176366 DOI: 10.1016/j.jinorgbio.2023.112457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 12/11/2023] [Accepted: 12/16/2023] [Indexed: 01/06/2024]
Abstract
NsrR from Streptomyces coelicolor is a bacterial nitric oxide (NO) sensor/nitrosative stress regulator as its primary function, and has been shown to have differential response at low, mid, and high levels of NO. These must correspond to discrete structural changes at the protein-bound [4Fe-4S] cluster in response to stepwise nitrosylation of the cluster. We have investigated the effect of the monohapto carboxylate ligand in the site differentiated [4Fe-4S] cluster cofactor of the protein NsrR on modulating its reactivity to NO with a focus on indentifying mechanistic intermediates. We have prepared a synthetic model [4Fe-4S] cluster complex with tripodal ligand and one single site differentiated site occupied by either thiolate or carboxylate ligand. We report here the mechanistic details of sequential steps of nitrosylation as observed by ESI MS and IR spectroscopy. Parallel non-denaturing mass spectrometry analyses were performed using site-differentiated variants of NsrR with the native aspartic acid, cysteine, or alanine in the position of the forth ligand to the cluster. A mono-nitrosylated synthetic [4Fe-4S] cluster was observed for the first time in a biologically-relevant thiolate-based coordination environment. Combined synthetic and protein data give unprecedented clarity in the modulation of nitrosylation of a [4Fe-4S] cluster.
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Affiliation(s)
- Erin L Dodd
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
| | - Nick E Le Brun
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
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17
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Li Z, Feng X, Yuan K, Zhang XX. Identification of Binding Sites in Copper(II)-Peptide Complexes Using Infrared Spectroscopy. J Phys Chem B 2024; 128:1884-1891. [PMID: 38378490 DOI: 10.1021/acs.jpcb.4c00029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Complex formation of the copper(II) ion (CuII) with histidine (H) and H-containing peptides plays a crucial role in various metallo-enzymatic reactions. To elucidate the nature of coordinate bonding in CuII complexes, Fourier-transform infrared spectroscopy and 2D IR spectroscopy were employed to investigate the coordination geometries of CuII with diglycine, l-histidylglycine (HG), glycyl-l-histidine (GH), and glycylglycyl-l-histidine. The coordination of CuII to different peptide groups, including the peptide N- and C-termini, the amide group, and the imidazole of the H side chain, exhibits distinct spectral features. The derived molecular structure of the CuII-HG complex based on these spectral features significantly differs from that of CuII-GH, suggesting a preference of the N-terminus and the steric hindrance of the H side chain in CuII chelation.
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Affiliation(s)
- Zhenghangcheng Li
- School of Physics, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China
| | - Xueyu Feng
- School of Physics, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China
| | - Kaijun Yuan
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, P. R. China
| | - Xin-Xing Zhang
- School of Physics, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China
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18
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Hashemi Haeri H, Schneegans N, Eisenschmidt-Bönn D, Brandt W, Wittstock U, Hinderberger D. Characterization of the active site in the thiocyanate-forming protein from Thlaspi arvense (TaTFP) using EPR spectroscopy. Biol Chem 2024; 405:105-118. [PMID: 37586381 DOI: 10.1515/hsz-2023-0187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 07/19/2023] [Indexed: 08/18/2023]
Abstract
Glucosinolates are plant thioglucosides, which act as chemical defenses. Upon tissue damage, their myrosinase-catalyzed hydrolysis yields aglucones that rearrange to toxic isothiocyanates. Specifier proteins such as thiocyanate-forming protein from Thlaspi arvense (TaTFP) are non-heme iron proteins, which capture the aglucone to form alternative products, e.g. nitriles or thiocyanates. To resolve the electronic state of the bound iron cofactor in TaTFP, we applied continuous wave electron paramagnetic resonance (CW EPR) spectroscopy at X-and Q-band frequencies (∼9.4 and ∼34 GHz). We found characteristic features of high spin and low spin states of a d 5 electronic configuration and local rhombic symmetry during catalysis. We monitored the oxidation states of bound iron during conversion of allylglucosinolate by myrosinase and TaTFP in presence and absence of supplemented Fe2+. Without added Fe2+, most high spin features of bound Fe3+ were preserved, while different g'-values of the low spin part indicated slight rearrangements in the coordination sphere and/or structural geometry. We also examined involvement of the redox pair Fe3+/Fe2 in samples with supplemented Fe2+. The absence of any EPR signal related to Fe3+ or Fe2+ using an iron-binding deficient TaTFP variant allowed us to conclude that recorded EPR signals originated from the bound iron cofactor.
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Affiliation(s)
- Haleh Hashemi Haeri
- Martin Luther University Halle-Wittenberg, Institute of Chemistry, Von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - Nicola Schneegans
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, D-38106 Braunschweig, Germany
| | - Daniela Eisenschmidt-Bönn
- Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, D-06120 Halle (Saale), Germany
| | - Wolfgang Brandt
- Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, D-06120 Halle (Saale), Germany
| | - Ute Wittstock
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, D-38106 Braunschweig, Germany
| | - Dariush Hinderberger
- Martin Luther University Halle-Wittenberg, Institute of Chemistry, Von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
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19
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Ghebreamlak S, Stoian SA, Lees NS, Cronin B, Smith F, Ross MO, Telser J, Hoffman BM, Duin EC. The Active-Site [4Fe-4S] Cluster in the Isoprenoid Biosynthesis Enzyme IspH Adopts Unexpected Redox States during Ligand Binding and Catalysis. J Am Chem Soc 2024; 146:3926-3942. [PMID: 38291562 DOI: 10.1021/jacs.3c11674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
(E)-4-Hydroxy-3-methylbut-2-enyl diphosphate reductase, or IspH (formerly known as LytB), catalyzes the terminal step of the bacterial methylerythritol phosphate (MEP) pathway for isoprene synthesis. This step converts (E)-4-hydroxy-3-methylbut-2-enyl diphosphate (HMBPP) into one of two possible isomeric products, either isopentenyl diphosphate (IPP) or dimethylallyl diphosphate (DMAPP). This reaction involves the removal of the C4 hydroxyl group of HMBPP and addition of two electrons. IspH contains a [4Fe-4S] cluster in its active site, and multiple cluster-based paramagnetic species of uncertain redox and ligation states can be detected after incubation with reductant, addition of a ligand, or during catalysis. To characterize the clusters in these species, 57Fe-labeled samples of IspH were prepared and studied by electron paramagnetic resonance (EPR), 57Fe electron-nuclear double resonance (ENDOR), and Mössbauer spectroscopies. Notably, this ENDOR study provides a rarely reported, complete determination of the 57Fe hyperfine tensors for all four Fe ions in a [4Fe-4S] cluster. The resting state of the enzyme (Ox) has a diamagnetic [4Fe-4S]2+ cluster. Reduction generates [4Fe-4S]+ (Red) with both S = 1/2 and S = 3/2 spin ground states. When the reduced enzyme is incubated with substrate, a transient paramagnetic reaction intermediate is detected (Int) which is thought to contain a cluster-bound substrate-derived species. The EPR properties of Int are indicative of a 3+ iron-sulfur cluster oxidation state, and the Mössbauer spectra presented here confirm this. Incubation of reduced enzyme with the product IPP induced yet another paramagnetic [4Fe-4S]+ species (Red+P) with S = 1/2. However, the g-tensor of this state is commonly associated with a 3+ oxidation state, while Mössbauer parameters show features typical for 2+ clusters. Implications of these complicated results are discussed.
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Affiliation(s)
- Selamawit Ghebreamlak
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
| | - Sebastian A Stoian
- Department of Chemistry, University of Idaho, 875 Perimeter Drive, MS 2343 Moscow, Idaho 83844, United States
| | - Nicholas S Lees
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Bryan Cronin
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
| | - Forrest Smith
- Department of Drug Discovery & Development, Auburn University, 4306 Walker Building, Auburn, Alabama 36849, United States
| | - Matthew O Ross
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, 430 S. Michigan Avenue, Chicago, Illinois 60605, United States
| | - Brian M Hoffman
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Evert C Duin
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
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20
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Orzeł Ł, Drzewiecka-Matuszek A, Rutkowska-Zbik D, Krasowska A, Fiedor L, van Eldik R, Stochel G. Copper(II)-Assisted Degradation of Pheophytin a by Reactive Oxygen Species. Int J Mol Sci 2024; 25:1831. [PMID: 38339109 PMCID: PMC10855625 DOI: 10.3390/ijms25031831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/29/2024] [Accepted: 02/01/2024] [Indexed: 02/12/2024] Open
Abstract
The central ion Mg2+ is responsible for the differences between chlorophyll a and its free base in their reactivity toward metal ions and thus their resistance to oxidation. We present here the results of spectroscopic (electronic absorption and emission, circular dichroism, and electron paramagnetic resonance), spectroelectrochemical, and computational (based on density functional theory) investigations into the mechanism of pheophytin, a degradation that occurs in the presence of Cu ions and O2. The processes leading to the formation of the linear form of tetrapyrrole are very complex and involve the weakening of the methine bridge due to an electron withdrawal by Cu(II) and the activation of O2, which provides protection to the free ends of the opening macrocycle. These mechanistic insights are related to the naturally occurring damage to the photosynthetic apparatus of plants growing on metal-contaminated soils.
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Affiliation(s)
- Łukasz Orzeł
- Faculty of Chemistry, Jagiellonian University, 30-387 Cracow, Poland; (A.K.); (R.v.E.); (G.S.)
| | - Agnieszka Drzewiecka-Matuszek
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, 30-239 Cracow, Poland; (A.D.-M.); (D.R.-Z.)
| | - Dorota Rutkowska-Zbik
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, 30-239 Cracow, Poland; (A.D.-M.); (D.R.-Z.)
| | - Aneta Krasowska
- Faculty of Chemistry, Jagiellonian University, 30-387 Cracow, Poland; (A.K.); (R.v.E.); (G.S.)
| | - Leszek Fiedor
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Cracow, Poland;
| | - Rudi van Eldik
- Faculty of Chemistry, Jagiellonian University, 30-387 Cracow, Poland; (A.K.); (R.v.E.); (G.S.)
- Department of Inorganic and Coordination Chemistry, Nicolaus Copernicus University, 87-100 Torun, Poland
- Department of Chemistry add Pharmacy, University of Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Grażyna Stochel
- Faculty of Chemistry, Jagiellonian University, 30-387 Cracow, Poland; (A.K.); (R.v.E.); (G.S.)
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21
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Siegbahn PEM. Computational Model Study of the Experimentally Suggested Mechanism for Nitrogenase. J Phys Chem B 2024; 128:985-989. [PMID: 38237063 PMCID: PMC10839828 DOI: 10.1021/acs.jpcb.3c07675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/03/2024] [Accepted: 01/04/2024] [Indexed: 02/02/2024]
Abstract
The mechanism for N2 activation in the E4 state of nitrogenase was investigated by model calculations. In the experimentally suggested mechanism, the E4 state is obtained after four reductions to the ground state. In a recent theoretical study, results for a different mechanism have been found in excellent agreement with available Electron Paramagnetic Resonance (EPR) experiments for E4. The two hydrides in E4 leave as H2 concertedly with the binding of N2. The mechanism suggested differs from the experimentally suggested one by a requirement for four activation steps prior to catalysis. In the present study, the experimentally suggested mechanism is studied using the same methods as those used in the previous study on the theoretical mechanism. The computed results make it very unlikely that a structure obtained after four reductions from the ground state has two hydrides, and the experimentally suggested mechanism does therefore not agree with the EPR experiments for E4. Another structure with only one hydride is here suggested to be the one that has been observed to bind N2 after only four reductions of the ground state.
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Affiliation(s)
- Per E. M. Siegbahn
- Department of Organic Chemistry,
Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
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22
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Lasorsa A, Merzougui H, Cantrelle FX, Sicoli G, Dupré E, Hanoulle X, Belle V, Smet-Nocca C, Landrieu I. Magnetic resonance investigation of conformational responses of tau protein to specific phosphorylation. Biophys Chem 2024; 305:107155. [PMID: 38100856 DOI: 10.1016/j.bpc.2023.107155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 09/27/2023] [Accepted: 12/06/2023] [Indexed: 12/17/2023]
Abstract
Intrinsically disordered proteins (IDPs) are known to adopt many rapidly interconverting structures, making it difficult to pinpoint the specific conformational states that are relevant for their function. Tau is an important IDP, and its conformation is known to be affected by post-translational modifications (PTMs), such as phosphorylation. To investigate the effect of specific phosphorylation on full-length Tau's dynamic global conformation, we employed a combination of nuclear magnetic resonance-based paramagnetic relaxation interference methods and electron paramagnetic resonance spectroscopy. By reproducing the AT8 epitope, comprising exclusive phosphorylation at residues S202 and T205, we were able to identify conformations specific to phosphorylated Tau, which exhibited a tendency towards less compact states. These mechanistic details are of significance to understand the path leading from soluble Tau to the ordered structure of Tau fibers. This approach proved to be successful for studying the conformational changes of (phosphorylated) full-length Tau and can potentially be extended to the study of other IDPs that undergo various PTMs.
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Affiliation(s)
- Alessia Lasorsa
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands.; CNRS EMR9002 - BSI - Integrative Structural Biology, F-59000 Lille, France.; Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille U1167 - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, F-59000 Lille, France
| | - Hamida Merzougui
- CNRS EMR9002 - BSI - Integrative Structural Biology, F-59000 Lille, France.; Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille U1167 - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, F-59000 Lille, France
| | - François-Xavier Cantrelle
- CNRS EMR9002 - BSI - Integrative Structural Biology, F-59000 Lille, France.; Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille U1167 - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, F-59000 Lille, France
| | - Giuseppe Sicoli
- Univ. Lille, CNRS UMR 8516 - LASIRE - Laboratoire Avancé de Spectroscopie pour les Interactions, la Réactivité et l'Environnement, F-59000 Lille, France
| | - Elian Dupré
- CNRS EMR9002 - BSI - Integrative Structural Biology, F-59000 Lille, France.; Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille U1167 - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, F-59000 Lille, France
| | - Xavier Hanoulle
- CNRS EMR9002 - BSI - Integrative Structural Biology, F-59000 Lille, France.; Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille U1167 - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, F-59000 Lille, France
| | - Valérie Belle
- Aix Marseille Univ, CNRS, BIP - Bioénergétique et Ingénierie des Protéines, IMM, Marseille, France
| | - Caroline Smet-Nocca
- CNRS EMR9002 - BSI - Integrative Structural Biology, F-59000 Lille, France.; Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille U1167 - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, F-59000 Lille, France
| | - Isabelle Landrieu
- CNRS EMR9002 - BSI - Integrative Structural Biology, F-59000 Lille, France.; Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille U1167 - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, F-59000 Lille, France.
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23
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Reszczyńska E, Wiśniewska-Becker A, Duda M, Sęk A, Gruszecki WI, Hanaka A. The presence of free palmitic acid modulates the effects of lutein on structural and dynamic properties of lipid membranes. Arch Biochem Biophys 2024; 752:109883. [PMID: 38211638 DOI: 10.1016/j.abb.2024.109883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/15/2023] [Accepted: 01/08/2024] [Indexed: 01/13/2024]
Abstract
Free fatty acids, like palmitic acid (PA), and xanthophyll pigments, like lutein (LUT) are the natural membrane compounds in plants. To study the effect of PA on LUT and their organization, a model membrane of 1,2-dimyristoyl-sn-glycerol-3-phosphocholine (DMPC) enriched with 2 mol% PA and 1 mol% LUT was formed. Molecular mechanisms underlying the interaction between these two compounds were examined with application of molecular spectroscopy techniques, e.g., visible spectroscopy, electron paramagnetic resonance and Fourier transform infrared. We determined the monomeric/dimeric organization of LUT in the membrane. We proved that the presence of PA in the lipid phase facilitated and stabilized the formation of LUT structures in the membrane. Lutein with PA did not form strong molecular aggregates like H- and J-structures. We presented the simplified model membrane that could be a suitable representation of the physiological process of de-esterification of PA from LUT appearing in natural biomembranes in humans.
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Affiliation(s)
- Emilia Reszczyńska
- Department of Biochemistry and Molecular Biology, Medical University of Lublin, W. Chodźki 1 Street, 20-093, Lublin, Poland; Department of Plant Physiology and Biophysics, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 Street, 20-033, Lublin, Poland.
| | - Anna Wiśniewska-Becker
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7 Street, 30-387, Krakow, Poland
| | - Mariusz Duda
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7 Street, 30-387, Krakow, Poland
| | - Alicja Sęk
- Department of Biophysics, Faculty of Mathematics, Physics and Computer Science, Maria Curie-Skłodowska University, M. Curie-Skłodowska Square 1, 20-031, Lublin, Poland; The National Institute of Horticultural Research, Konstytucji 3 Maja 1/3 Street, 96-100, Skierniewice, Poland
| | - Wiesław I Gruszecki
- Department of Biophysics, Faculty of Mathematics, Physics and Computer Science, Maria Curie-Skłodowska University, M. Curie-Skłodowska Square 1, 20-031, Lublin, Poland
| | - Agnieszka Hanaka
- Department of Plant Physiology and Biophysics, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 Street, 20-033, Lublin, Poland
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24
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Killian MM, Brophy MB, Nolan EM, Brunold TC. Spectroscopic and computational investigations of Cobalt(II) binding to the innate immune protein human calprotectin. J Biol Inorg Chem 2024; 29:127-137. [PMID: 38233645 DOI: 10.1007/s00775-023-02034-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 10/30/2023] [Indexed: 01/19/2024]
Abstract
Human calprotectin (CP) is an innate immune protein that participates in the metal-withholding response to infection by sequestering essential metal nutrients from invading microbial pathogens. CP is comprised of S100A8 (α subunit, 10.8 kDa) and S100A9 (β subunit, 13.2 kDa). Two transition-metal binding sites of CP form at the S100A8/S100A9 dimer interface. Site 1 is a His3Asp motif comprised of His83 and His87 from the S100A8 subunit and His20 and Asp30 from the S100A9 subunit. Site 2 is an unusual hexahistidine motif composed of S100A8 residues His17 and His27 and S100A9 residues His91, His95, His103, and His105. In the present study, the His3Asp and His6 sites of CP were further characterized by utilizing Co2+ as a spectroscopic probe. Magnetic circular dichroism spectroscopy was employed in conjunction with electron paramagnetic resonance spectroscopy and density functional theory computations to characterize the Co2+-bound S100A8(C42S)/S100A9(C3S) CP-Ser variant and six site variants that allowed the His3Asp and His6 sites to be further probed. Our results provide new insight into the metal-binding sites of CP-Ser and the effect of amino acid substitutions on the structure of site 2.
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Affiliation(s)
- Michelle M Killian
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Megan B Brophy
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Elizabeth M Nolan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Thomas C Brunold
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA.
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25
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Kantesaria S, Tang X, Suddarth S, Pasek-Allen J, Namsrai BE, Goswitz A, Hintz M, Bischof J, Garwood M. A Low-Cost, Tabletop LOD-EPR System for Nondestructive Quantification of Iron Oxide Nanoparticles in Tissues. ACS Sens 2024; 9:262-271. [PMID: 38190731 DOI: 10.1021/acssensors.3c01898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
Iron oxide nanoparticles (IONPs) have wide utility in applications from drug delivery to the rewarming of cryopreserved tissues. Due to the complex behavior of IONPs (e.g., uneven particle distribution and aggregation), further developments and clinical translation can be accelerated by having access to a noninvasive method for tissue IONP quantification. Currently, there is no low-cost method to nondestructively track IONPs in tissues across a wide range of concentrations. This work describes the performance of a low-cost, tabletop, longitudinally detected electron paramagnetic resonance (LOD-EPR) system to address this issue in the field of cryopreservation, which utilizes IONPs for rewarming of rat kidneys. A low-cost LOD-EPR system is realized via simultaneous transmit and receive using MHz continuous-wave transverse excitation with kHz modulation, which is longitudinally detected at the modulation frequency to provide both geometric and frequency isolation. The accuracy of LOD-EPR for IONP quantification is compared with NMR relaxometry. Solution measurements show excellent linearity (R2 > 0.99) versus Fe concentration for both measurements on EMG308 (a commercial nanoparticle), silica-coated EMG308, and PEG-coated EMG308 in water. The LOD-EPR signal intensity and NMR longitudinal relaxation rate constant (R1) of water are affected by particle coating, solution viscosity, and particle aggregation. R1 remains linear but with a reduced slope when in cryoprotective agent (CPA) solution, whereas the LOD-EPR signal is relatively insensitive to this. R1 does not correlate well with Fe concentration in rat kidney sections (R2 = 0.3487), while LOD-EPR does (R2 = 0.8276), with a linear regression closely matching that observed in solution and CPA.
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Affiliation(s)
- Saurin Kantesaria
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Xueyan Tang
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Steven Suddarth
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Jacqueline Pasek-Allen
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Bat-Erdene Namsrai
- Department of Surgery, University of Minnesota, 420 Delaware Street SE, Minneapolis, Minnesota 55455, United States
| | - Arjun Goswitz
- Department of Mechanical Engineering, University of Minnesota, 111 Church St. SE, Minneapolis, Minnesota 55455, United States
| | - Mikaela Hintz
- Department of Mechanical Engineering, University of Minnesota, 111 Church St. SE, Minneapolis, Minnesota 55455, United States
| | - John Bischof
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Department of Mechanical Engineering, University of Minnesota, 111 Church St. SE, Minneapolis, Minnesota 55455, United States
| | - Michael Garwood
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, Minnesota 55455, United States
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26
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Usatov MS, Dobrynin SA, Polienko YF, Morozov DA, Glazachev YI, An’kov SV, Tolstikova TG, Gatilov YV, Bagryanskaya IY, Raizvikh AE, Bagryanskaya EG, Kirilyuk IA. Hydrophilic Reduction-Resistant Spin Labels of Pyrrolidine and Pyrroline Series from 3,4-Bis-hydroxymethyl-2,2,5,5-tetraethylpyrrolidine-1-oxyl. Int J Mol Sci 2024; 25:1550. [PMID: 38338825 PMCID: PMC10855552 DOI: 10.3390/ijms25031550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/18/2023] [Accepted: 12/24/2023] [Indexed: 02/12/2024] Open
Abstract
Highly resistant to reduction nitroxides open new opportunities for structural studies of biological macromolecules in their native environment inside living cells and for functional imaging of pH and thiols, enzymatic activity and redox status in living animals. 3,4-Disubstituted nitroxides of 2,2,5,5-tetraethylpyrrolidine and pyrroline series with a functional group for binding to biomolecules and a polar moiety for higher solubility in water and for more rigid attachment via additional coordination to polar sites were designed and synthesized. The EPR spectra, lipophilicities, kinetics of the reduction in ascorbate-containing systems and the decay rates in liver homogenates were measured. The EPR spectra of all 3,4-disubstituted pyrrolidine nitroxides showed additional large splitting on methylene hydrogens of the ethyl groups, while the spectra of similar pyrroline nitroxides were represented with a simple triplet with narrow lines and hyperfine structure of the nitrogen manifolds resolved in oxygen-free conditions. Both pyrrolidine and pyrroline nitroxides demonstrated low rates of reduction with ascorbate, pyrrolidines being a bit more stable than similar pyrrolines. The decay of positively charged nitroxides in the rat liver homogenate was faster than that of neutral and negatively charged radicals, with lipophilicity, rate of reduction with ascorbate and the ring type playing minor role. The EPR spectra of N,N-dimethyl-3,4-bis-(aminomethyl)-2,2,5,5-tetraethylpyrrolidine-1-oxyl showed dependence on pH with pKa = 3, ΔaN = 0.055 mT and ΔaH = 0.075 mT.
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Affiliation(s)
- Mikhail S. Usatov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
- Department of Natural Sciences, Novosibirsk State University, Pirogova Str. 1, Novosibirsk 630090, Russia
| | - Sergey A. Dobrynin
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Yuliya F. Polienko
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Denis A. Morozov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Yurii I. Glazachev
- Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Institutskaya 3, Novosibirsk 630090, Russia;
| | - Sergey V. An’kov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Tatiana G. Tolstikova
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Yuri V. Gatilov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Irina Yu. Bagryanskaya
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Arthur E. Raizvikh
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
- Department of Physics, Novosibirsk State University, Pirogova Str. 1, Novosibirsk 630090, Russia
| | - Elena G. Bagryanskaya
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Igor A. Kirilyuk
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
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27
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Kaur N, Singh P. A coronene diimide based radical anion for detection of picomolar H 2O 2: a biochemical assay for detection of picomolar glucose in aqueous medium. J Mater Chem B 2024; 12:1043-1051. [PMID: 38214029 DOI: 10.1039/d3tb02473c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Coronene diimide functionalized with 4-(2-nitrovinyl)phenyl (CDI 2) serves as a precursor for generating a stable radical anion (CDI 2˙-) using H2S as a reductant in 40% H2O-THF solution in the NIR region with stability up to >50 min. The optical, cyclic voltammetry (CV), current-voltage (I-V) and electron paramagnetic resonance (EPR) studies revealed the formation of the radical anion (CDI 2˙-). The addition of a strong oxidant NOBF4 quenches the radical anion (CDI 2˙-). The aggregation studies revealed that CDI 2 exists in the aggregated state in 40% H2O-THF solution, which points to the possibility of stabilization of the radical anion in the aggregates. The radical anion (CDI 2˙-) was explored for the detection of 58.27 pM H2O2 in aqueous medium with the naked eye colour change from green to light yellow. The biochemical assay involving the radical anion (CDI 2˙-) and glucose oxidase (GOx) enzyme can be used for the detection of 16 pM (UV-vis method) and 82.4 pM (fluorescence method) glucose. The naked eye colour change from green to light yellow (daylight) and a colorless non-fluorescent solution to a green fluorescent solution (365 nm) allow the detection of 1 nM glucose.
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Affiliation(s)
- Navdeep Kaur
- Department of Chemistry, UGC Centre for Advanced Studies-II, Guru Nanak Dev University, Amritsar 143001 (pb.), India.
| | - Prabhpreet Singh
- Department of Chemistry, UGC Centre for Advanced Studies-II, Guru Nanak Dev University, Amritsar 143001 (pb.), India.
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28
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Garaeva N, Fatkhullin B, Murzakhanov F, Gafurov M, Golubev A, Bikmullin A, Glazyrin M, Kieffer B, Jenner L, Klochkov V, Aganov A, Rogachev A, Ivankov O, Validov S, Yusupov M, Usachev K. Structural aspects of RimP binding on small ribosomal subunit from Staphylococcus aureus. Structure 2024; 32:74-82.e5. [PMID: 38000368 DOI: 10.1016/j.str.2023.10.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/18/2023] [Accepted: 10/30/2023] [Indexed: 11/26/2023]
Abstract
Ribosome biogenesis is an energy-intense multistep process where even minimal defects can cause severe phenotypes up to cell death. Ribosome assembly is facilitated by biogenesis factors such as ribosome assembly factors. These proteins facilitate the interaction of ribosomal proteins with rRNA and correct rRNA folding. One of these maturation factors is RimP which is required for efficient 16S rRNA processing and 30S ribosomal subunit assembly. Here, we describe the binding mode of Staphylococcus aureus RimP to the small ribosomal subunit and present a 4.2 Å resolution cryo-EM reconstruction of the 30S-RimP complex. Together with the solution structure of RimP solved by NMR spectroscopy and RimP-uS12 complex analysis by EPR, DEER, and SAXS approaches, we show the specificity of RimP binding to the 30S subunit from S. aureus. We believe the results presented in this work will contribute to the understanding of the RimP role in the ribosome assembly mechanism.
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Affiliation(s)
- Nataliia Garaeva
- Laboratory for Structural Analysis of Biomacromolecules, Federal Research Center «Kazan Scientific Center of Russian Academy of Sciences», Kazan 420111, Russian Federation; Laboratory of Structural Biology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan 420008, Russian Federation
| | - Bulat Fatkhullin
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR7104, INSERM U964, Université de Strasbourg, 67400 Illkirch, France; Institute of Protein Research RAS, 4 Institutskaya, Pushchino 142290, Russian Federation
| | - Fadis Murzakhanov
- Institute of Physics, Kazan Federal University, Kazan 420008, Russian Federation
| | - Marat Gafurov
- Institute of Physics, Kazan Federal University, Kazan 420008, Russian Federation
| | - Alexander Golubev
- Laboratory for Structural Analysis of Biomacromolecules, Federal Research Center «Kazan Scientific Center of Russian Academy of Sciences», Kazan 420111, Russian Federation
| | - Aydar Bikmullin
- Laboratory of Structural Biology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan 420008, Russian Federation
| | - Maxim Glazyrin
- Laboratory for Structural Analysis of Biomacromolecules, Federal Research Center «Kazan Scientific Center of Russian Academy of Sciences», Kazan 420111, Russian Federation
| | - Bruno Kieffer
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR7104, INSERM U964, Université de Strasbourg, 67400 Illkirch, France
| | - Lasse Jenner
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR7104, INSERM U964, Université de Strasbourg, 67400 Illkirch, France
| | - Vladimir Klochkov
- NMR Laboratory, Medical Physics Department, Institute of Physics, Kazan Federal University, Kazan 420008, Russian Federation
| | - Albert Aganov
- NMR Laboratory, Medical Physics Department, Institute of Physics, Kazan Federal University, Kazan 420008, Russian Federation
| | - Andrey Rogachev
- Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russian Federation; Joint Institute for Nuclear Research, Dubna 141980, Russian Federation
| | - Oleksandr Ivankov
- Joint Institute for Nuclear Research, Dubna 141980, Russian Federation
| | - Shamil Validov
- Laboratory for Structural Analysis of Biomacromolecules, Federal Research Center «Kazan Scientific Center of Russian Academy of Sciences», Kazan 420111, Russian Federation; Laboratory of Structural Biology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan 420008, Russian Federation
| | - Marat Yusupov
- Laboratory for Structural Analysis of Biomacromolecules, Federal Research Center «Kazan Scientific Center of Russian Academy of Sciences», Kazan 420111, Russian Federation; Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR7104, INSERM U964, Université de Strasbourg, 67400 Illkirch, France.
| | - Konstantin Usachev
- Laboratory for Structural Analysis of Biomacromolecules, Federal Research Center «Kazan Scientific Center of Russian Academy of Sciences», Kazan 420111, Russian Federation; Laboratory of Structural Biology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan 420008, Russian Federation.
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29
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Pei Y, Liu X, Cao M, Wang Z, Yang H. Heteroatom-modulated NiCo 2O 4 apparent energy activation of PMS for tetracycline removal: Mechanism and toxicity analysis. Environ Res 2024; 240:117571. [PMID: 37923107 DOI: 10.1016/j.envres.2023.117571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/25/2023] [Accepted: 10/28/2023] [Indexed: 11/07/2023]
Abstract
Heteroatom doping to reconfigure the electronic structure of heterogeneous catalysts is expected to lead to the development of advanced oxidation water purification materials with superior performance and greater stability. Herein, a series of catalysts with different elemental doping was developed by a simple and environmentally friendly one-step self-propagating combustion method to remove Tetracycline (TC). After S-doping, the normalized kinetic constant of TC was significantly increased from 30.49 to 159.41 min-1M-1 within 30 min, which is even higher than most recent heterogeneous catalysts. The prepared S-doped NiCo2O4 (NCO-S) exhibits an extremely promising catalytic performance for oxidation (92.8 %) and mineralization (65.9 %) of TC in a wide pH range (3-11). The resistance to interference is excellent for inorganic ions and even in real water samples. Quenching experiments, electron paramagnetic resonance (EPR), and electrochemical analyses demonstrated that the non-radical oxidation pathway, including electron transfer and 1O2, dominated the degradation process after S doping. It is speculated that possible intermediates and toxicological studies are discussed, finding that the overall degradation process is moving towards low toxicity to reveal prospects for large-scale applications. This work not only provides a way to remove TC, but may also inspire the design of more efficient and stable materials for water treatment and other applications.
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Affiliation(s)
- Yan Pei
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, Shihezi, China
| | - Xun Liu
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, Shihezi, China
| | - Mengbo Cao
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, Shihezi, China
| | - Zijun Wang
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, Shihezi, China.
| | - Hongbing Yang
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, Shihezi, China.
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30
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Rahmani-Manglano NE, Andersen ML, Guadix EM, García-Moreno PJ. Oxidative stability and oxygen permeability of oil-loaded capsules produced by spray-drying or electrospraying measured by electron spin resonance. Food Chem 2024; 430:136894. [PMID: 37544150 DOI: 10.1016/j.foodchem.2023.136894] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/22/2023] [Accepted: 07/13/2023] [Indexed: 08/08/2023]
Abstract
The oxidative stability and the oxygen permeability of oil-loaded capsules were investigated by Electron Spin Resonance (ESR). The capsules were produced by spray-drying or electrospraying in the monoaxial or coaxial configuration using glucose syrup as the encapsulating agent. ESR-spin trapping results showed that electrosprayed capsules oxidized faster and during the early stages of incubation, irrespective of the emitter configuration (monoaxial or coaxial), when compared to those produced by spray-drying. Furthermore, ESR oximetry showed that oxygen inside the spray-dried capsules reached equilibrium with the surrounding atmosphere significantly slower than the monoaxially electrosprayed capsules (i.e., ∼2h and ∼10 min, respectively). These findings have been attributed to the larger particle size of the spray-dried capsules influencing the oxygen diffusion area (i.e., lower surface-to-volume ratio) and diffusion path (i.e., thicker encapsulating wall for a fixed oil load). Together, the lower oxygen uptake reported for the spray-dried capsules correlated well with their higher oxidative stability.
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Affiliation(s)
| | - Mogens L Andersen
- Department of Food Science, University of Copenhagen, Copenhagen, Denmark
| | - Emilia M Guadix
- Department of Chemical Engineering, University of Granada, Granada, Spain
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31
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Wang B, Wang L, Cen W, Lyu T, Jarvis P, Zhang Y, Zhang Y, Han Y, Wang L, Pan G, Zhang K, Fan W. Exploring a chemical input free advanced oxidation process based on nanobubble technology to treat organic micropollutants. Environ Pollut 2024; 340:122877. [PMID: 37931673 DOI: 10.1016/j.envpol.2023.122877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 10/19/2023] [Accepted: 11/03/2023] [Indexed: 11/08/2023]
Abstract
Advanced oxidation processes (AOPs) are increasingly applied in water and wastewater treatment, but their energy consumption and chemical use may hinder their further implementation in a changing world. This study investigated the feasibility and mechanisms involved in a chemical-free nanobubble-based AOP for treating organic micropollutants in both synthetic and real water matrices. The removal efficiency of the model micropollutant Rhodamine B (RhB) by oxygen nanobubble AOP (98%) was significantly higher than for air (73%) and nitrogen nanobubbles (69%). The treatment performance was not significantly affected by pH (3-10) and the presence of ions (Ca2+, Mg2+, HCO3-, and Cl-). Although a higher initial concentration of RhB (10 mg/L) led to a slower treatment process when compared to lower initial concentrations (0.1 and 1 mg/L), the final removal performance reached a similar level (∼98%) between 100 and 500 min. The coexistence of organic matter (humic acid, HA) resulted in a much lower reduction (70%) in the RhB removal rate. Both qualitative and quantitative analysis of reactive oxygen species (ROSs) using fluorescent probe, electron spin resonance, and quenching experiments demonstrated that the contributions of ROSs in RhB degradation followed the order: hydroxyl radical (•OH) > superoxide radical (•O2-) > singlet oxygen (1O2). The cascade degradation reactions for RhB were identified which involve N-de-ethylation, hydroxylation, chromophore cleavage, opening-ring and final mineralisation processes. Moreover, the treatment of real water samples spiked with RhB, including natural lake water and secondary effluent from a sewage works, still showed considerable removals of the dye (75.3%-90.8%), supporting its practical feasibility. Overall, the results benefit future research and application of chemical free nanobubble-based AOP for water and wastewater treatment.
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Affiliation(s)
- Bangguo Wang
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Lijing Wang
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 101408, China.
| | - Wenxi Cen
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Tao Lyu
- School of Water, Energy and Environment, Cranfield University, College Road, Cranfield, Bedfordshire, MK43 0AL, United Kingdom
| | - Peter Jarvis
- School of Water, Energy and Environment, Cranfield University, College Road, Cranfield, Bedfordshire, MK43 0AL, United Kingdom
| | - Yang Zhang
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Yuanxun Zhang
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 101408, China; Yanshan Earth Critical Zone and Surface Fluxes Research Station, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Yinghui Han
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Lei Wang
- Research Centre for Eco-environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing, 100085, China
| | - Gang Pan
- School of Humanities, York St John University, Lord Mayor's Walk, York, North Yorkshire, YO31 7EX, United Kingdom; School of Chemical and Environmental Sciences, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Kaili Zhang
- Binzhou Institute of Technology, 8 Huanghe Road, Binzhou, 256606, China
| | - Wei Fan
- School of Environment, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
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32
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Hetzke T, Vogel M, Halbritter ALJ, Saha S, Suess B, Sigurdsson ST, Prisner TF. Simultaneous Localization of Two High Affinity Divalent Metal Ion Binding Sites in the Tetracycline RNA Aptamer with Mn 2+-Based Pulsed Dipolar EPR Spectroscopy. J Phys Chem Lett 2023; 14:11421-11428. [PMID: 38084602 DOI: 10.1021/acs.jpclett.3c02566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Mg2+ ions play an essential part in stabilizing the tertiary structure of nucleic acids. While the importance of these ions is well documented, their localization and elucidation of their role in the structure and dynamics of nucleic acids are often challenging. In this work, pulsed electron-electron double resonance spectroscopy (PELDOR, also known as DEER) was used to localize two high affinity divalent metal ion binding sites in the tetracycline RNA aptamer with high accuracy. For this purpose, the aptamer was labeled at different positions with a semirigid nitroxide spin label and diamagnetic Mg2+ was replaced with paramagnetic Mn2+, which did not alter the folding process or ligand binding. Out of the several divalent metal ion binding sites that are known from the crystal structure, two binding sites with high affinity were detected: one that is located at the ligand binding center and another at the J1/2 junction of the RNA.
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Affiliation(s)
- Thilo Hetzke
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Marc Vogel
- Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | | | - Subham Saha
- Department of Chemistry, Science Institute, University of Iceland, 107 Reykjavik, Iceland
| | - Beatrix Suess
- Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Snorri Th Sigurdsson
- Department of Chemistry, Science Institute, University of Iceland, 107 Reykjavik, Iceland
| | - Thomas F Prisner
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
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Omeiri J, Martin L, Usclat A, Cherrier MV, Nicolet Y. Maturation of the [FeFe]-Hydrogenase: Direct Transfer of the (κ 3 -cysteinate)Fe II (CN)(CO) 2 Complex B from HydG to HydE. Angew Chem Int Ed Engl 2023; 62:e202314819. [PMID: 37962296 DOI: 10.1002/anie.202314819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 11/15/2023]
Abstract
[FeFe]-hydrogenases efficiently catalyze the reversible oxidation of molecular hydrogen. Their prowess stems from the intricate H-cluster, combining a [Fe4 S4 ] center with a binuclear iron center ([2Fe]H ). In the latter, each iron atom is coordinated by a CO and CN ligand, connected by a CO and an azadithiolate ligand. The synthesis of this active site involves a unique multiprotein assembly, featuring radical SAM proteins HydG and HydE. HydG initiates the transformation of L-tyrosine into cyanide and carbon monoxide to generate complex B, which is subsequently transferred to HydE to continue the biosynthesis of the [2Fe]H -subcluster. Due to its instability, complex B isolation for structural or spectroscopic characterization has been elusive thus far. Nevertheless, the use of a biomimetic analogue of complex B allowed circumvention of the need for the HydG protein during in vitro functional investigations, implying a similar structure for complex B. Herein, we used the HydE protein as a nanocage to encapsulate and stabilize the complex B product generated by HydG. Using X-ray crystallography, we successfully determined its structure at 1.3 Å resolution. Furthermore, we demonstrated that complex B is directly transferred from HydG to HydE, thus not being released into the solution post-synthesis, highlighting a transient interaction between the two proteins.
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Affiliation(s)
- Juneina Omeiri
- Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France
| | - Lydie Martin
- Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France
| | - Anthony Usclat
- Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France
| | - Mickael V Cherrier
- Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France
| | - Yvain Nicolet
- Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France
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34
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Yang Z, Stein RA, Pink M, Madzelan P, Ngendahimana T, Rajca S, Wilson MA, Eaton SS, Eaton GR, Mchaourab HS, Rajca A. Cucurbit[7]uril Enhances Distance Measurements of Spin-Labeled Proteins. J Am Chem Soc 2023; 145:25726-25736. [PMID: 37963181 PMCID: PMC10961179 DOI: 10.1021/jacs.3c09184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
We report complex formation between the chloroacetamide 2,6-diazaadamantane nitroxide radical (ClA-DZD) and cucurbit[7]uril (CB-7), for which the association constant in water, Ka = 1.9 × 106 M-1, is at least 1 order of magnitude higher than the previously studied organic radicals. The radical is highly immobilized by CB-7, as indicated by the increase in the rotational correlation time, τrot, by a factor of 36, relative to that in the buffer solution. The X-ray structure of ClA-DZD@CB-7 shows the encapsulated DZD guest inside the undistorted CB-7 host, with the pendant group protruding outside. Upon addition of CB-7 to T4 Lysozyme (T4L) doubly spin-labeled with the iodoacetamide derivative of DZD, we observe the increase in τrot and electron spin coherence time, Tm, along with the narrowing of interspin distance distributions. Sensitivity of the DEER measurements at 83 K increases by a factor 4-9, compared to the common spin label such as MTSL, which is not affected by CB-7. Interspin distances of 3 nm could be reliably measured in water/glycerol up to temperatures near the glass transition/melting temperature of the matrix at 200 K, thus bringing us closer to the goal of supramolecular recognition-enabled long-distance DEER measurements at near physiological temperatures. The X-ray structure of DZD-T4L 65 at 1.12 Å resolution allows for unambiguous modeling of the DZD label (0.88 occupancy), indicating an undisturbed structure and conformation of the protein.
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Affiliation(s)
- Zhimin Yang
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Richard A. Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Maren Pink
- IUMSC, Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
| | - Peter Madzelan
- Department of Biochemistry and Redox Biology Center, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Thacien Ngendahimana
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Suchada Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Mark A. Wilson
- Department of Biochemistry and Redox Biology Center, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Sandra S. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Gareth R. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Hassane S. Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
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35
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Lundahl MN, Yang H, Broderick WE, Hoffman BM, Broderick JB. Pyruvate formate-lyase activating enzyme: The catalytically active 5'-deoxyadenosyl radical caught in the act of H-atom abstraction. Proc Natl Acad Sci U S A 2023; 120:e2314696120. [PMID: 37956301 PMCID: PMC10665898 DOI: 10.1073/pnas.2314696120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 10/03/2023] [Indexed: 11/15/2023] Open
Abstract
Enzymes of the radical S-adenosyl-l-methionine (radical SAM, RS) superfamily, the largest in nature, catalyze remarkably diverse reactions initiated by H-atom abstraction. Glycyl radical enzyme activating enzymes (GRE-AEs) are a growing class of RS enzymes that generate the catalytically essential glycyl radical of GREs, which in turn catalyze essential reactions in anaerobic metabolism. Here, we probe the reaction of the GRE-AE pyruvate formate-lyase activating enzyme (PFL-AE) with the peptide substrate RVSG734YAV, which mimics the site of glycyl radical formation on the native substrate, pyruvate formate-lyase. Time-resolved freeze-quench electron paramagnetic resonance spectroscopy shows that at short mixing times reduced PFL-AE + SAM reacts with RVSG734YAV to form the central organometallic intermediate, Ω, in which the adenosyl 5'C is covalently bound to the unique iron of the [4Fe-4S] cluster. Freeze-trapping the reaction at longer times reveals the formation of the peptide G734• glycyl radical product. Of central importance, freeze-quenching at intermediate times reveals that the conversion of Ω to peptide glycyl radical is not concerted. Instead, homolysis of the Ω Fe-C5' bond generates the nominally "free" 5'-dAdo• radical, which is captured here by freeze-trapping. During cryoannealing at 77 K, the 5'-dAdo• directly abstracts an H-atom from the peptide to generate the G734• peptide radical trapped in the PFL-AE active site. These observations reveal the 5'-dAdo• radical to be a well-defined intermediate, caught in the act of substrate H-atom abstraction, providing new insights into the mechanistic steps of radical initiation by RS enzymes.
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Affiliation(s)
- Maike N. Lundahl
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT59717
| | - Hao Yang
- Department of Chemistry, Northwestern University, Evanston, IL60208
| | - William E. Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT59717
| | - Brian M. Hoffman
- Department of Chemistry, Northwestern University, Evanston, IL60208
| | - Joan B. Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT59717
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36
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Khan F, Elgeti M, Grandfield S, Paz A, Naughton FB, Marcoline FV, Althoff T, Ermolova N, Wright EM, Hubbell WL, Grabe M, Abramson J. Membrane potential accelerates sugar uptake by stabilizing the outward facing conformation of the Na/glucose symporter vSGLT. Nat Commun 2023; 14:7511. [PMID: 37980423 PMCID: PMC10657379 DOI: 10.1038/s41467-023-43119-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 10/30/2023] [Indexed: 11/20/2023] Open
Abstract
Sodium-dependent glucose transporters (SGLTs) couple a downhill Na+ ion gradient to actively transport sugars. Here, we investigate the impact of the membrane potential on vSGLT structure and function using sugar uptake assays, double electron-electron resonance (DEER), electrostatic calculations, and kinetic modeling. Negative membrane potentials, as present in all cell types, shift the conformational equilibrium of vSGLT towards an outward-facing conformation, leading to increased sugar transport rates. Electrostatic calculations identify gating charge residues responsible for this conformational shift that when mutated reduce galactose transport and eliminate the response of vSGLT to potential. Based on these findings, we propose a comprehensive framework for sugar transport via vSGLT, where the cellular membrane potential facilitates resetting of the transporter after cargo release. This framework holds significance not only for SGLTs but also for other transporters and channels.
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Affiliation(s)
- Farha Khan
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, 49503, USA
| | - Matthias Elgeti
- Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
- Institute for Drug Discovery, Leipzig University Medical School, Leipzig, Germany.
| | - Samuel Grandfield
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Renaissance School of Medicine at Stony Brook University, Stony Brook, NY, 11794, USA
| | - Aviv Paz
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Hauptman-Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY, 14203, USA
| | - Fiona B Naughton
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Frank V Marcoline
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Thorsten Althoff
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Natalia Ermolova
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Ernest M Wright
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Wayne L Hubbell
- Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Michael Grabe
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, 94158, USA.
| | - Jeff Abramson
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
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37
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Tang Q, Sinclair M, Hasdemir HS, Stein RA, Karakas E, Tajkhorshid E, Mchaourab HS. Asymmetric conformations and lipid interactions shape the ATP-coupled cycle of a heterodimeric ABC transporter. Nat Commun 2023; 14:7184. [PMID: 37938578 PMCID: PMC10632425 DOI: 10.1038/s41467-023-42937-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/26/2023] [Indexed: 11/09/2023] Open
Abstract
Here we used cryo-electron microscopy (cryo-EM), double electron-electron resonance spectroscopy (DEER), and molecular dynamics (MD) simulations, to capture and characterize ATP- and substrate-bound inward-facing (IF) and occluded (OC) conformational states of the heterodimeric ATP binding cassette (ABC) multidrug exporter BmrCD in lipid nanodiscs. Supported by DEER analysis, the structures reveal that ATP-powered isomerization entails changes in the relative symmetry of the BmrC and BmrD subunits that propagates from the transmembrane domain to the nucleotide binding domain. The structures uncover asymmetric substrate and Mg2+ binding which we hypothesize are required for triggering ATP hydrolysis preferentially in one of the nucleotide-binding sites. MD simulations demonstrate that multiple lipid molecules differentially bind the IF versus the OC conformation thus establishing that lipid interactions modulate BmrCD energy landscape. Our findings are framed in a model that highlights the role of asymmetric conformations in the ATP-coupled transport with general implications to the mechanism of ABC transporters.
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Affiliation(s)
- Qingyu Tang
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Matt Sinclair
- Theoretical and Computational Biophysics Group, NIH Resource for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Hale S Hasdemir
- Theoretical and Computational Biophysics Group, NIH Resource for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Richard A Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Erkan Karakas
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, NIH Resource for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA.
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38
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Villarreal DG, Rao G, Tao L, Liu L, Rauchfuss TB, Britt RD. Characterizing the Biosynthesis of the [Fe(II)(CN)(CO) 2(cysteinate)] - Organometallic Product of the Radical-SAM Enzyme HydG by EPR and Mössbauer Spectroscopy. J Phys Chem B 2023; 127:9295-9302. [PMID: 37861415 DOI: 10.1021/acs.jpcb.3c05495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
[FeFe]-hydrogenases employ a catalytic H-cluster, consisting of a [4Fe-4S]H cluster linked to a [2Fe]H subcluster with CO, CN- ligands, and an azadithiolate bridge, which mediates the rapid redox interconversion of H+ and H2. In the biosynthesis of this H-cluster active site, the radical S-adenosyl-l-methionine (radical SAM, RS) enzyme HydG plays the crucial role of generating an organometallic [Fe(II)(CN)(CO)2(cysteinate)]- product that is en route to forming the H-cluster. Here, we report direct observation of this diamagnetic organometallic Fe(II) complex through Mössbauer spectroscopy, revealing an isomer shift of δ = 0.10 mm s-1 and quadrupole splitting of ΔEQ = 0.66 mm s-1. These Mössbauer values are a change from the starting values of δ = 1.15 mm s-1 and ΔEQ = 3.23 mm s-1 for the ferrous "dangler" Fe in HydG. These values of the observed product complex B are in good agreement with Mössbauer parameters for the low-spin Fe2+ ions in synthetic analogues, such as 57Fe Syn-B, which we report here. These results highlight the essential role that HydG plays in converting a resting-state high-spin Fe(II) to a low-spin organometallic Fe(II) product that can be transferred to the downstream maturase enzymes.
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Affiliation(s)
- David G Villarreal
- Department of Chemistry, University of California Davis, Davis, California 95616, United States
| | - Guodong Rao
- Department of Chemistry, University of California Davis, Davis, California 95616, United States
| | - Lizhi Tao
- Department of Chemistry, University of California Davis, Davis, California 95616, United States
| | - Liang Liu
- School of Chemical Sciences, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
| | - Thomas B Rauchfuss
- School of Chemical Sciences, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
| | - R David Britt
- Department of Chemistry, University of California Davis, Davis, California 95616, United States
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39
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Khan RH, Rotich NC, Morris A, Ahammad T, Baral B, Sahu ID, Lorigan GA. Probing the Structural Topology and Dynamic Properties of gp28 Using Continuous Wave Electron Paramagnetic Resonance Spectroscopy. J Phys Chem B 2023; 127:9236-9247. [PMID: 37856870 DOI: 10.1021/acs.jpcb.3c03679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Lysis of Gram-negative bacteria by dsDNA phages is accomplished through either the canonical holin-endolysin pathway or the pinholin-SAR endolysin pathway. During lysis, the outer membrane (OM) is disrupted, typically by two-component spanins or unimolecular spanins. However, in the absence of spanins, phages use alternative proteins called Disruptin to disrupt the OM. The Disruptin family includes the cationic antimicrobial peptide gp28, which is found in the virulent podophage φKT. In this study, EPR spectroscopy was used to analyze the dynamics and topology of gp28 incorporated into a lipid bilayer, revealing differences in mobility, depth parameter, and membrane interaction among different segments and residues of the protein. Our results indicate that multiple points of helix 2 and helix 3 interact with the phospholipid membrane, while others are solvent-exposed, suggesting that gp28 is a surface-bound peptide. The CW-EPR power saturation data and helical wheel analysis confirmed the amphipathic-helical structure of gp28. Additionally, course-grain molecular dynamics simulations were further used to develop the structural model of the gp28 peptide associated with the lipid bilayers. Based on the data obtained in this study, we propose a structural topology model for gp28 with respect to the membrane. This work provides important insights into the structural and dynamic properties of gp28 incorporated into a lipid bilayer environment.
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Affiliation(s)
- Rasal H Khan
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Nancy C Rotich
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Andrew Morris
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Tanbir Ahammad
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Binaya Baral
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Indra D Sahu
- Natural Science Division, Campbellsville University, Campbellsville, Kentucky 42718, United States
| | - Gary A Lorigan
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
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40
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Lisouskaya A, Schiemann O, Carmichael I. Unveiling the Mechanism of Photodamage to Sphingolipid Molecules via Laser Flash Photolysis and EPR. Photochem Photobiol 2023; 99:1400-1411. [PMID: 36943199 DOI: 10.1111/php.13804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 03/17/2023] [Indexed: 03/23/2023]
Abstract
Sphingolipids are involved in the maintenance of the skin barrier function and regulate cellular processes of keratinocytes. The work reported here is designed to uncover details of the mechanism of damage to such lipids by UV radiation. Our approach employs laser flash photolysis and electron paramagnetic resonance (EPR) spectrometry to explore the mechanism of the decay reactions, and to determine the associated kinetic parameters. To interpret our experiments, we computed both excitation energies and EPR parameters of radicals formed during photolysis. Employing the spin-trap EPR method confirmed the formation of both carbon- and nitrogen-centered radicals. Thus, we can conclude that the photodecomposition of sphingolipids and their analogues proceeds by Norrish type I reactions with the formation of both nitrogen-centered and alkyl radicals.
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Affiliation(s)
- Aliaksandra Lisouskaya
- Notre Dame Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana
- Clausius-Institute of Physical and Theoretical Chemistry, University of Bonn, Bonn, Germany
| | - Olav Schiemann
- Clausius-Institute of Physical and Theoretical Chemistry, University of Bonn, Bonn, Germany
| | - Ian Carmichael
- Notre Dame Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana
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Vigneshwaran S, Kim DG, Ko SO. Tuning of interfacial HGO@CLS nanohybrid S-scheme heterojunction with improved carrier separation and photocatalytic activity towards RhB degradation. Chemosphere 2023; 340:139914. [PMID: 37633616 DOI: 10.1016/j.chemosphere.2023.139914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/14/2023] [Accepted: 08/19/2023] [Indexed: 08/28/2023]
Abstract
Herein, we premeditated and invented the innovative hybrid photocatalyst 2D/2D CuLa2S4 on holey graphene oxide (HGO) (HGO@CLS) via the hydrothermal method. Electrochemical techniques demonstrate the action of HGO in the HGO@CLS photocatalyst as an effective medium for electron transfer. Combining bimetallic sulfides on porous HGO synergistically provides a higher negative conduction band edge (-0.141 V), greater photo response (10.8 mA/cm2), smaller charge transfer resistance (Rct = 1.79Ω), and lower photoluminescence (PL) spectral intensity. According to our research, the catalytic recitals are sped up when HGO is assimilated into CLS photocatalyst hetero-junction. Additionally, it lowers the reassimilation rate due to the combined mesh nanostructures and functionality of CLS and HGO. UV-Vis DRS, Mott-Schottky, PL, and Electrochemical impedance spectra (EIS) results manifested that the CuLa2S4/HGO makes the spatial separation competent and transference of charge carriers due to the photon irradiation and exhibits superior photocatalytic ability. Electron spin resonance (ESR) analysis confirmed that •OH and h+ were the predominant radical species responsible for Rhodamine B(RhB) degradation. Moreover, conceivable degradation ways of RhB were deduced according to the identified intermediates which are responsible for the degradation of recalcitrant products. To check the stability of the photocatalyst, revival tests were also carried out. Similarly, the oxidative byproducts created in the deprivation courses were looked at, and a thorough explanation for the mechanism of degradation was given.
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Affiliation(s)
- Sivakumar Vigneshwaran
- Environmental System Laboratory, Department of Civil Engineering, Kyung Hee University-Global Campus, 1732 Deogyong-daero, Giheung-Gu, Yongin-Si, Gyeonggi-Do 16705, Republic of Korea
| | - Do-Gun Kim
- Department of Environmental Engineering, Sunchon National University, 255 Jungang-ro, Suncheon, Jellanam-do, 57922, Republic of Korea
| | - Seok-Oh Ko
- Environmental System Laboratory, Department of Civil Engineering, Kyung Hee University-Global Campus, 1732 Deogyong-daero, Giheung-Gu, Yongin-Si, Gyeonggi-Do 16705, Republic of Korea.
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42
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Harada Y, Watari T, Nagano H, Suzuki T, Kunitomo K, Miyagami T, Aita T, Ishizuka K, Maebashi M, Harada T, Sakamoto T, Tomiyama S, Shimizu T. Diagnostic errors in uncommon conditions: a systematic review of case reports of diagnostic errors. Diagnosis (Berl) 2023; 10:329-336. [PMID: 37561056 DOI: 10.1515/dx-2023-0030] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 06/21/2023] [Indexed: 08/11/2023]
Abstract
OBJECTIVES To assess the usefulness of case reports as sources for research on diagnostic errors in uncommon diseases and atypical presentations. CONTENT We reviewed 563 case reports of diagnostic error. The commonality of the final diagnoses was classified based on the description in the articles, Orphanet, or epidemiological data on available references; the typicality of presentation was classified based on the description in the articles and the judgment of the physician researchers. Diagnosis Error Evaluation and Research (DEER), Reliable Diagnosis Challenges (RDC), and Generic Diagnostic Pitfalls (GDP) taxonomies were used to assess the factors contributing to diagnostic errors. SUMMARY AND OUTLOOK Excluding three cases in that commonality could not be classified, 560 cases were classified into four categories: typical presentations of common diseases (60, 10.7 %), atypical presentations of common diseases (35, 6.2 %), typical presentations of uncommon diseases (276, 49.3 %), and atypical presentations of uncommon diseases (189, 33.8 %). The most important DEER taxonomy was "Failure/delay in considering the diagnosis" among the four categories, whereas the most important RDC and GDP taxonomies varied with the categories. Case reports can be a useful data source for research on the diagnostic errors of uncommon diseases with or without atypical presentations.
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Affiliation(s)
- Yukinori Harada
- Department of Diagnostic and Generalist Medicine, Dokkyo Medical University, Shimotsuga-Gun, Japan
| | - Takashi Watari
- General Medicine Center, Shimane University Hospital, Izumo, Japan
| | - Hiroyuki Nagano
- Department of Healthcare Economics and Quality Management, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | | | - Kotaro Kunitomo
- National Hospital Organisation Kumamoto Medical Center, Kumamoto, Japan
| | | | - Tetsuro Aita
- Department of General Internal Medicine, Fukushima Medical University, Fukushima, Japan
| | - Kosuke Ishizuka
- Department of General Medicine, Yokohama City University School of Medicine, Yokohama, Japan
| | | | - Taku Harada
- Division of General Medicine, Nerima Hikarigaoka Hospital, Nerima-Ku, Tokyo
| | - Tetsu Sakamoto
- Department of Diagnostic and Generalist Medicine, Dokkyo Medical University, Shimotsuga-Gun, Japan
| | - Shusaku Tomiyama
- Department of Diagnostic and Generalist Medicine, Dokkyo Medical University, Shimotsuga-Gun, Japan
| | - Taro Shimizu
- Department of Diagnostic and Generalist Medicine, Dokkyo Medical University, Shimotsuga-Gun, Japan
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Kaur D, Ferlez B, Landry P, Biskup T, Weber S, Golbeck JH, Lakshmi KV, van der Est A. Electronic structure and energetics of a heterodimeric BChl g'/Chl a' special pair generated by exposure of Heliomicrobium modesticaldum to dioxygen. Phys Chem Chem Phys 2023; 25:26894-26905. [PMID: 37782629 DOI: 10.1039/d3cp03915c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Heliobacteria are anoxygenic phototrophs that have a Type I homodimeric reaction center containing bacteriochlorophyll g (BChl g). Previous experimental studies have shown that in the presence of light and dioxygen, BChl g is converted into 81-OH-chlorophyll aF (hereafter Chl aF), with an accompanying loss of light-driven charge separation. These studies suggest that the reaction center only loses the ability to transfer electrons once both BChl g' molecules of the P800 special pair have been converted to Chl aF'. The present work confirms that the partially converted BChl g'/Chl aF' special pair remains functional in samples exposed to dioxygen by demonstrating its presence using hyperfine couplings obtained from Q-band 1H ENDOR, 2D 14N HYSCORE and DFT methods. The DFT calculations of the BChl g'/BChl g' homodimeric primary donor, which are based on the recently published X-ray crystal structure, predict that the unpaired electron spin is equally delocalized over both BChl g' molecules and provide an excellent match to the experimental hyperfine couplings of the anaerobic samples. Exposure to dioxygen leads to substantial changes in the hyperfine interactions, indicative of greater localization of the unpaired electron spin. The measured hyperfine couplings are reproduced in the DFT calculations by replacing one of the BChl g' molecules of the primary donor with a Chl aF' molecule. The calculations reveal that the spin density becomes localized on BChl g' in the heterodimeric primary donor. Time-dependent DFT calculations demonstrate that conversion of either or both of the accessory BChl g molecules and/or one of the BChl g' molecules of P800 to Chl aF' results in minor effects on the energy of the charge-separated states. In contrast, if both of the BChl g' molecules of P800 are converted a large increase in the energy of the charge-separated state occurs. This suggests that the reaction center remains functional when only one half of the dimer is converted, however, conversion of both halves of the P800 dimer leads to loss of function.
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Affiliation(s)
- Divya Kaur
- Department of Chemistry, Brock University, St. Catharines, Ontario, L2S 3A1, Canada.
| | - Bryan Ferlez
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
| | - Patrick Landry
- Department of Chemistry and Chemical Biology and The 60 Baruch Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
| | - Till Biskup
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Stefan Weber
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - K V Lakshmi
- Department of Chemistry and Chemical Biology and The 60 Baruch Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
| | - Art van der Est
- Department of Chemistry, Brock University, St. Catharines, Ontario, L2S 3A1, Canada.
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Li W, Warncke K. Native and nonnative reactions in ethanolamine ammonia-lyase are actuated by different dynamics. Biophys J 2023; 122:3976-3985. [PMID: 37641402 PMCID: PMC10560697 DOI: 10.1016/j.bpj.2023.08.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 08/13/2023] [Accepted: 08/24/2023] [Indexed: 08/31/2023] Open
Abstract
We address the contribution of select classes of solvent-coupled configurational fluctuations to the complex choreography involved in configurational and chemical steps in an enzyme by comparing native and nonnative reactions conducted at different protein internal sites. The low temperature, first-order kinetics of covalent bond rearrangement of the cryotrapped substrate radical in coenzyme B12-dependent ethanolamine ammonia-lyase (EAL) from Salmonella enterica display a kink, or increase in slope, of the Arrhenius plot with decreasing temperature. The event is associated with quenching of a select class of reaction-actuating collective fluctuations in the protein hydration layer. For comparison, a nonnative, radical reaction of the protein interior cysteine sulfhydryl group with hydrogen peroxide (H2O2) is introduced by cryotrapping EAL in an aqueous H2O2 eutectic system. The low-temperature aqueous H2O2 protein hydration and mesodomain solvent phases surrounding cryotrapped EAL are characterized by using TEMPOL spin probe electron paramagnetic resonance spectroscopy, including a freezing transition of the eutectic phase that orders the protein hydration layer. Kinetics of the cysteine-H2O2 reaction in the EAL protein interior are monitored by DEPMPO spin trapping of hydroxyl radical product. In contrast to the native reaction, the linear Arrhenius relation for the nonnative cysteine-H2O2 reaction is maintained through the solvent-protein ordering transition. The nonnative reaction is coupled to the generic local, incremental fluctuations that are intrinsic to globular proteins. The comparative approach supports the proposal that select coupled solvent-protein configurational fluctuations actuate the native reaction, and suggests that select dynamical coupling contributes to the degree of catalysis in enzymes.
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Affiliation(s)
- Wei Li
- Department of Physics, Emory University, Atlanta, Georgia
| | - Kurt Warncke
- Department of Physics, Emory University, Atlanta, Georgia.
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45
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De Simone G, Monaca SD, Fattibene P, Bocedi A, Coletta M, Ascenzi P. Ferrous nitrosylated cytochrome c: The unusual strength of the proximal His18-Fe bond. J Inorg Biochem 2023; 247:112338. [PMID: 37549473 DOI: 10.1016/j.jinorgbio.2023.112338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/04/2023] [Accepted: 07/20/2023] [Indexed: 08/09/2023]
Abstract
NO binding to horse heart cytochrome c (hhcyt c) has been investigated as a function of pH by both optical absorption and EPR spectroscopies. Lowering pH from 3.5 to 1.5 induces: (i) a blue-shift of the maximum of the optical absorption spectrum in the Soret region from 415 to about 404 nm, and (ii) the appearance of a strong three hyperfine splitting in the gz region of the EPR spectrum. Both spectroscopic features indicate the cleavage of the proximal His18-Fe(II)-NO bond giving rise to the five-coordinated Fe(II)-NO species. By quantification of the relative weight for the six- and the five-coordinated component in the EPR spectra, the pKa value was determined. The apparent pKa of the proximal His Nε atom (1.8 ± 0.1) is unusually low for a ferrous nitrosylated form since in all investigated ferrous NO-bound heme-proteins the pKa value for the cleavage of the proximal His-Fe(II) bond ranges between 3.7 and 5.8. The pKa value of ferrous nitrosylated hhcyt c indicates that the strength of the proximal His18-Fe(II) bond (= 27.9 kJ/mol) is about 10-22 kJ/mol higher than that observed in all investigated heme-proteins. The strong coordination of the heme-Fe atom by His18 is extremely important to maintain the redox efficiency of cyt c and to keep apoptosis under control. This is a crucial point in tissues, such as retina, where apoptosis might trigger macular degenerative processes.
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Affiliation(s)
| | - Sara Della Monaca
- Servizio Grandi Strumentazioni and Core Facilities, Istituto Superiore di Sanità, 00185 Roma, Italy
| | - Paola Fattibene
- Servizio Grandi Strumentazioni and Core Facilities, Istituto Superiore di Sanità, 00185 Roma, Italy
| | - Alessio Bocedi
- Department of Chemical Sciences and Technologies, University of Roma "Tor Vergata", 00133 Roma, Italy
| | | | - Paolo Ascenzi
- Department of Sciences, Roma Tre University, 00146 Roma, Italy; Accademia Nazionale dei Lincei, 00165 Roma, Italy.
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46
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Berekute AK, Yu KP, Chuang YHB, Lin KYA. Novel visible-light-active P-g-CN-based α-Bi 2O 3/WO 3 ternary photocatalysts with a dual Z-scheme heterostructure for the efficient decomposition of refractory ultraviolet filters and environmental hormones: Benzophenones. Environ Res 2023; 234:116553. [PMID: 37406722 DOI: 10.1016/j.envres.2023.116553] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/24/2023] [Accepted: 07/02/2023] [Indexed: 07/07/2023]
Abstract
The ubiquitous and refractory benzophenone (BP)-type ultraviolet filters, which are also endocrine disruptors, were commonly detected in the aquatic matrix and could not be efficiently removed by conventional wastewater treatment processes, thus causing extensive concern. Herein, a novel ternary nanocomposite, P-g-CN/α-Bi2O3/WO3 (P-gBW), was successfully fabricated by mixing cocalcinated components and applied to the decomposition of BP-type ultraviolet filters. The dual-Z-scheme heterostructure of P-gBW enhances visible-light absorption, efficiently facilitates separation and mobility, and prolongs the lifetime of photoinduced charge carriers via double charge transfer mechanisms. The optimum 95 wt% P-gBW exhibited excellent photocatalytic activity, degrading 96% 4-hydroxy benzophenone (4HBP) within 150 min and 93% 2,2',4,4'-tetrahydroxybenzophenone (BP-2) within 100 min under visible-light illumination, respectively. The pseudo-first-order rate constant of 4HBP (1.15 h-1) was 6.8-, 3.1-, 3.3- and 2.2-fold higher than those of WO3, P-g-CN, α-Bi2O3, and P-g-CN/α-Bi2O3, respectively, while that of BP-2 (1.71 h-1) was 5.2-, 2.2-, 3.2- and 1.5-fold higher, respectively. The improved photocatalytic degradation was attributed to efficient photoinduced charge carrier separation and migration and prevented the recombination of electron holes, as verified by photoluminescence, transient photocurrent response, and electrochemical impedance spectroscopy. Trapping experiments, electron paramagnetic resonance, and band energy position indicated an efficient dual-Z-scheme heterostructure.
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Affiliation(s)
- Abiyu Kerebo Berekute
- International Ph.D. Program in Environmental Science and Technology, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan; Institute of Environmental and Occupational Health Sciences, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan; Department of Chemistry, College of Natural and Computational Sciences, Arba Minch University, Arbaminch, Ethiopia
| | - Kuo-Pin Yu
- International Ph.D. Program in Environmental Science and Technology, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan; Institute of Environmental and Occupational Health Sciences, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan.
| | - Yi-Hsueh Brad Chuang
- Institute of Environmental Engineering, National Yang Ming Chiao Tung University, Hsinchu City, 30010, Taiwan
| | - Kun-Yi Andrew Lin
- Department of Environmental Engineering and Innovation and Development Center of Sustainable Agriculture & Research Center of Sustainable Energy and Nano Technology, National Chung Hsing University, 250, Kuo-Kuang Road, Taichung, Taiwan
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Briggs C, Smith E, Vansandt J, Carr B, Loftin K, McDermott EG. PREVALENCE OF EHRLICHIA AND ANAPLASMA SPP. IN TICKS COLLECTED FROM CATTLE AND DEER IN ARKANSAS, USA. J Parasitol 2023; 109:530-536. [PMID: 37903502 DOI: 10.1645/23-53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2023] Open
Abstract
Bovine anaplasmosis, caused by Anaplasma marginale, is widespread in cattle in the southeast United States. The pathogen is biologically transmitted by Dermacentor spp. ticks, and mechanically transmitted by biting flies and via fomites. Despite high reported regional seroprevalence, Dermacentor spp. are rare on cattle in the southeast. To identify other putative An. marginale vectors, and to characterize cattle exposure to other tick-borne pathogens, we collected ticks from Arkansas cattle herds in 2020-2022. Recognizing that deer are important hosts for some of the same tick species that parasitize cattle, we also collected ticks from hunter-killed deer in the fall and winter of 2021. Ticks were screened for bacteria in the family Anaplasmataceae using qPCR. Positive samples were further amplified using a PCR assay targeting the groEL gene, and the resulting amplicons were sequenced for identification. A total of 3,794 ticks were collected, the majority of which were Amblyomma americanum. Amblyomma americanum was the most common species on cattle, and Ixodes scapularis was most common on deer. No ticks were positive for An. marginale, though Anaplasma phagocytophilum was detected in deer-collected I. scapularis, as well as in a single engorged Am. americanum from cattle. Amblyomma americanum from cattle were infected with Ehrlichia ewingii, Ehrilichia chaffeensis, and Panola Mountain Ehrlichia. Cattle in Arkansas are exposed to several ehrlichial pathogens and may also be exposed to An. phagocytophilum. The importance of these pathogens, particularly Panola Mountain Ehrlichia, in causing cattle disease in Arkansas deserves further study, as does the importance of mechanical transmission of An. marginale in bovine anaplasmosis epidemiology.
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Affiliation(s)
- Cierra Briggs
- Department of Entomology and Plant Pathology, University of Arkansas, Fayetteville, Arkansas 72701
| | - Elizabeth Smith
- Department of Entomology and Plant Pathology, University of Arkansas, Fayetteville, Arkansas 72701
| | - Jordan Vansandt
- Department of Entomology and Plant Pathology, University of Arkansas, Fayetteville, Arkansas 72701
| | - Brandon Carr
- Department of Entomology and Plant Pathology, University of Arkansas, Fayetteville, Arkansas 72701
| | - Kelly Loftin
- Department of Entomology and Plant Pathology, University of Arkansas, Fayetteville, Arkansas 72701
| | - Emily G McDermott
- Department of Entomology and Plant Pathology, University of Arkansas, Fayetteville, Arkansas 72701
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48
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Bogetti X, Bogetti A, Casto J, Rule G, Chong L, Saxena S. Direct observation of negative cooperativity in a detoxification enzyme at the atomic level by Electron Paramagnetic Resonance spectroscopy and simulation. Protein Sci 2023; 32:e4770. [PMID: 37632831 PMCID: PMC10503414 DOI: 10.1002/pro.4770] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 07/14/2023] [Accepted: 08/23/2023] [Indexed: 08/28/2023]
Abstract
The catalytic activity of human glutathione S-transferase A1-1 (hGSTA1-1), a homodimeric detoxification enzyme, is dependent on the conformational dynamics of a key C-terminal helix α9 in each monomer. However, the structural details of how the two monomers interact upon binding of substrates is not well understood and the structure of the ligand-free state of the hGSTA1-1 homodimer has not been resolved. Here, we used a combination of electron paramagnetic resonance (EPR) distance measurements and weighted ensemble (WE) simulations to characterize the conformational ensemble of the ligand-free state at the atomic level. EPR measurements reveal a broad distance distribution between a pair of Cu(II) labels in the ligand-free state that gradually shifts and narrows as a function of increasing ligand concentration. These shifts suggest changes in the relative positioning of the two α9 helices upon ligand binding. WE simulations generated unbiased pathways for the seconds-timescale transition between alternate states of the enzyme, leading to the generation of atomically detailed structures of the ligand-free state. Notably, the simulations provide direct observations of negative cooperativity between the monomers of hGSTA1-1, which involve the mutually exclusive docking of α9 in each monomer as a lid over the active site. We identify key interactions between residues that lead to this negative cooperativity. Negative cooperativity may be essential for interaction of hGSTA1-1 with a wide variety of toxic substrates and their subsequent neutralization. More broadly, this work demonstrates the power of integrating EPR distances with WE rare-events sampling strategy to gain mechanistic information on protein function at the atomic level.
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Affiliation(s)
- Xiaowei Bogetti
- Department of ChemistryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Anthony Bogetti
- Department of ChemistryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Joshua Casto
- Department of ChemistryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Gordon Rule
- Department of Biological SciencesCarnegie Mellon UniversityPittsburghPennsylvaniaUSA
| | - Lillian Chong
- Department of ChemistryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Sunil Saxena
- Department of ChemistryUniversity of PittsburghPittsburghPennsylvaniaUSA
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49
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Song G, Wu H, Jing J, Zhang X, Wang X, Li S, Zhou M. Insights into Electrochemical Dehalogenation by Non-Noble Metal Single-Atom Cobalt with High Efficiency and Low Energy Consumption. Environ Sci Technol 2023; 57:14482-14492. [PMID: 37699122 DOI: 10.1021/acs.est.3c06021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
It is critical to discover a non-noble metal catalyst with high catalytic activity capable of replacing palladium in electrochemical reduction. In this work, a highly efficient single-atom Co-N/C catalyst was synthesized with metal-organic frameworks (MOFs) as a precursor for electrochemical dehalogenation. X-ray absorption spectroscopy (XAS) revealed that Co-N/C exhibited a Co-N4 configuration, which had more active sites and a faster charge-transfer rate and thus enabled the efficient removal of florfenicol (FLO) at a wide pH, achieving a rate constant 3.5 and 2.1 times that of N/C and commercial Pd/C, respectively. The defluorination and dechlorination efficiencies were 67.6 and 95.6%, respectively, with extremely low Co leaching (6 μg L-1), low energy consumption (22.7 kWh kg-1), and high turnover frequency (TOF) (0.0350 min-1), demonstrating excellent dehalogenation performance. Spiking experiments and density functional theory (DFT) verified that Co-N4 was the active site and had the lowest energy barrier for forming atomic hydrogen (H*) (ΔGH*). Capture experiments, electron paramagnetic resonance (EPR), electrochemical tests, and in situ Fourier transform infrared (FTIR) proved that H* and direct electron transfer were responsible for dehalogenation. Toxicity assessment indicated that FLO toxicity decreased significantly after dehalogenation. This work develops a non-noble metal catalyst with broad application prospects in electrocatalytic dehalogenation.
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Affiliation(s)
- Ge Song
- Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
- Tianjin Advanced Water Treatment Technology International Joint Research Center, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Huizhong Wu
- Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
- Tianjin Advanced Water Treatment Technology International Joint Research Center, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Jiana Jing
- Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
- Tianjin Advanced Water Treatment Technology International Joint Research Center, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Xuyang Zhang
- Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
- Tianjin Advanced Water Treatment Technology International Joint Research Center, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Xuechun Wang
- Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
- Tianjin Advanced Water Treatment Technology International Joint Research Center, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Shuaishuai Li
- Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
- Tianjin Advanced Water Treatment Technology International Joint Research Center, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Minghua Zhou
- Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
- Tianjin Advanced Water Treatment Technology International Joint Research Center, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
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Sebők-Nagy K, Kóta Z, Kincses A, Fazekas ÁF, Dér A, László Z, Páli T. Spin-Label Electron Paramagnetic Resonance Spectroscopy Reveals Effects of Wastewater Filter Membrane Coated with Titanium Dioxide Nanoparticles on Bovine Serum Albumin. Molecules 2023; 28:6750. [PMID: 37836593 PMCID: PMC10574081 DOI: 10.3390/molecules28196750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 10/15/2023] Open
Abstract
The accumulation of proteins in filter membranes limits the efficiency of filtering technologies for cleaning wastewater. Efforts are ongoing to coat commercial filters with different materials (such as titanium dioxide, TiO2) to reduce the fouling of the membrane. Beyond monitoring the desired effect of the retention of biomolecules, it is necessary to understand what the biophysical changes are in water-soluble proteins caused by their interaction with the new coated filter membranes, an aspect that has received little attention so far. Using spin-label electron paramagnetic resonance (EPR), aided with native fluorescence spectroscopy and dynamic light scattering (DLS), here, we report the changes in the structure and dynamics of bovine serum albumin (BSA) exposed to TiO2 (P25) nanoparticles or passing through commercial polyvinylidene fluoride (PVDF) membranes coated with the same nanoparticles. We have found that the filtering process and prolonged exposure to TiO2 nanoparticles had significant effects on different regions of BSA, and denaturation of the protein was not observed, neither with the TiO2 nanoparticles nor when passing through the TiO2-coated filter membranes.
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Affiliation(s)
- Krisztina Sebők-Nagy
- Institute of Biophysics, Biological Research Centre Szeged, 6726 Szeged, Hungary; (K.S.-N.); (Z.K.); (A.K.); (A.D.)
| | - Zoltán Kóta
- Institute of Biophysics, Biological Research Centre Szeged, 6726 Szeged, Hungary; (K.S.-N.); (Z.K.); (A.K.); (A.D.)
| | - András Kincses
- Institute of Biophysics, Biological Research Centre Szeged, 6726 Szeged, Hungary; (K.S.-N.); (Z.K.); (A.K.); (A.D.)
| | - Ákos Ferenc Fazekas
- Department of Biosystems Engineering, Faculty of Engineering, University of Szeged, 6725 Szeged, Hungary; (Á.F.F.); (Z.L.)
| | - András Dér
- Institute of Biophysics, Biological Research Centre Szeged, 6726 Szeged, Hungary; (K.S.-N.); (Z.K.); (A.K.); (A.D.)
| | - Zsuzsanna László
- Department of Biosystems Engineering, Faculty of Engineering, University of Szeged, 6725 Szeged, Hungary; (Á.F.F.); (Z.L.)
| | - Tibor Páli
- Institute of Biophysics, Biological Research Centre Szeged, 6726 Szeged, Hungary; (K.S.-N.); (Z.K.); (A.K.); (A.D.)
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