1
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M Meirovich M, Bachar O, Shemesh M, Cohen Y, Popik A, Yehezkeli O. Light-driven, bias-free nitrogenase-based bioelectrochemical cell for ammonia generation. Biosens Bioelectron 2024; 255:116254. [PMID: 38569252 DOI: 10.1016/j.bios.2024.116254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 03/12/2024] [Accepted: 03/25/2024] [Indexed: 04/05/2024]
Abstract
Nitrogen fixation is a key process that sustains life on Earth. Nitrogenase is the sole enzyme capable of fixing nitrogen under ambient conditions. Extensive research efforts have been dedicated to elucidating the enzyme mechanism and its artificial activation through high applied voltage, photochemistry, or strong reducing agents. Harnessing light irradiation to minimize the required external bias can lower the process's high energy investment. Herein, we present the development of photo-bioelectrochemical cells (PBECs) utilizing BiVO4/CoP or CdS/NiO photoanodes for nitrogenase activation toward N2 fixation. The constructed PBEC based on BiVO4/CoP photoanode requires minimal external bias (200 mV) and suppresses O2 generation that allows efficient activation of the nitrogenase enzyme, using glucose as an electron donor. In a second developed PBEC configuration, CdS/NiO photoanode was used, enabling bias-free activation of the nitrogenase-based cathode to produce 100 μM of ammonia at a faradaic efficiency (FE) of 12%. The ammonia production was determined by a commonly used fluorescence probe and further validated using 1H-NMR spectroscopy. The presented PBECs lay the foundation for biotic-abiotic systems to directly activate enzymes toward value-added chemicals by light-driven reactions.
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Affiliation(s)
- Matan M Meirovich
- Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, 3200003, Haifa, Israel
| | - Oren Bachar
- Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, 3200003, Haifa, Israel
| | - Mor Shemesh
- Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, 3200003, Haifa, Israel
| | - Yifat Cohen
- Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, 3200003, Haifa, Israel
| | - Alice Popik
- Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, 3200003, Haifa, Israel
| | - Omer Yehezkeli
- Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, 3200003, Haifa, Israel; Russell Berrie Nanotechnology Institute, Technion - Israel Institute of Technology, 3200003, Haifa, Israel; The Nancy and Stephen Grand Technion Energy Program, Technion - Israel Institute of Technology, 3200003, Haifa, Israel.
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2
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Yang J, Duan YF, Liu L. Crystal structure of the iron-sulfur cluster transfer protein ApbC from Escherichia coli. Biochem Biophys Res Commun 2024; 722:150167. [PMID: 38797154 DOI: 10.1016/j.bbrc.2024.150167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Accepted: 05/22/2024] [Indexed: 05/29/2024]
Abstract
Iron-sulfur (Fe-S) clusters are ubiquitous and are necessary to sustain basic life processes. The intracellular Fe-S clusters do not form spontaneously and many proteins are required for their biosynthesis and delivery. The bacterial P-loop NTPase family protein ApbC participates in Fe-S cluster assembly and transfers the cluster into apoproteins, with the Walker A motif and CxxC motif being essential for functionality of ApbC in Fe-S protein biogenesis. However, the structural basis underlying the ApbC activity and the motifs' role remains unclear. Here, we report the crystal structure of Escherichia coli ApbC at 2.8 Å resolution. The dimeric structure is in a W shape and the active site is located in the 2-fold center. The function of the motifs can be annotated by structural analyses. ApbC has an additional N-terminal domain that differs from other P-loop NTPases, possibly conferring its inherent specificity in vivo.
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Affiliation(s)
- Jingyu Yang
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China.
| | - Ya-Fei Duan
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China
| | - Lin Liu
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China
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3
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Maslać N, Cadoux C, Bolte P, Murken F, Gu W, Milton RD, Wagner T. Structural comparison of (hyper-)thermophilic nitrogenase reductases from three marine Methanococcales. FEBS J 2024. [PMID: 38696373 DOI: 10.1111/febs.17148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 01/17/2024] [Accepted: 04/17/2024] [Indexed: 05/04/2024]
Abstract
The nitrogenase reductase NifH catalyses ATP-dependent electron delivery to the Mo-nitrogenase, a reaction central to biological dinitrogen (N2) fixation. While NifHs have been extensively studied in bacteria, structural information about their archaeal counterparts is limited. Archaeal NifHs are considered more ancient, particularly those from Methanococcales, a group of marine hydrogenotrophic methanogens, which includes diazotrophs growing at temperatures near 92 °C. Here, we structurally and biochemically analyse NifHs from three Methanococcales, offering the X-ray crystal structures from meso-, thermo-, and hyperthermophilic methanogens. While NifH from Methanococcus maripaludis (37 °C) was obtained through heterologous recombinant expression, the proteins from Methanothermococcus thermolithotrophicus (65 °C) and Methanocaldococcus infernus (85 °C) were natively purified from the diazotrophic archaea. The structures from M. thermolithotrophicus crystallised as isolated exhibit high flexibility. In contrast, the complexes of NifH with MgADP obtained from the three methanogens are superposable, more rigid, and present remarkable structural conservation with their homologues. They retain key structural features of P-loop NTPases and share similar electrostatic profiles with the counterpart from the bacterial model organism Azotobacter vinelandii. In comparison to the NifH from the phylogenetically distant Methanosarcina acetivorans, these reductases do not cross-react significantly with Mo-nitrogenase from A. vinelandii. However, they associate with bacterial nitrogenase when ADP·AlF 4 - $$ {\mathrm{AlF}}_4^{-} $$ is added to mimic a transient reactive state. Accordingly, detailed surface analyses suggest that subtle substitutions would affect optimal binding during the catalytic cycle between the NifH from Methanococcales and the bacterial nitrogenase, implying differences in the N2-machinery from these ancient archaea.
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Affiliation(s)
- Nevena Maslać
- Microbial Metabolism Research Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Cécile Cadoux
- Department of Inorganic and Analytical Chemistry, Faculty of Sciences, University of Geneva, Switzerland
- National Centre of Competence in Research (NCCR) Catalysis, University of Geneva, Switzerland
| | - Pauline Bolte
- Microbial Metabolism Research Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Fenja Murken
- Microbial Metabolism Research Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Wenyu Gu
- Laboratory of Microbial Physiology and Resource Biorecovery, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédéral de Lausanne, Switzerland
| | - Ross D Milton
- Department of Inorganic and Analytical Chemistry, Faculty of Sciences, University of Geneva, Switzerland
- National Centre of Competence in Research (NCCR) Catalysis, University of Geneva, Switzerland
| | - Tristan Wagner
- Microbial Metabolism Research Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
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4
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Xie ZL, Jin WT, Zhou ZH. Analyses of the electronic structures of FeFe-cofactors compared with those of FeMo- and FeV-cofactors and their P-clusters. Dalton Trans 2024; 53:6529-6536. [PMID: 38299993 DOI: 10.1039/d3dt04126c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
The electronic structures of FeFe-cofactors (FeFe-cos) in resting and turnover states, together with their PN clusters from iron-only nitrogenases, have been calculated using the bond valence method, and their crystallographic data were reported recently and deposited in the Protein Data Bank (PDB codes: 8BOQ and 8OIE). The calculated results have also been compared with those of their homologous Mo- and V-nitrogenases. For FeFe-cos in the resting state, Fe1/2/4/5/6/7/8 atoms are prone to Fe3+, while the Fe3 atom shows different degrees of mixed valences. The results support that the Fe8 atom at the terminal positions of FeFe-cos possesses the same oxidation states as the Mo3+/V3+ atoms of FeMo-/FeV-cos. In the turnover state, the overall oxidation state of FeFe-co is slightly reduced than those in the resting species, and its electronic configuration is rearranged after the substitution of S2B with OH, compatible with those found in CO-bound FeV-co. Moreover, the calculations give the formal oxidation states of 6Fe2+-2Fe3+ for the electronic structures of PN clusters in Fe-nitrogenases. By the comparison of Mo-, V- and Fe-nitrogenases, the overall oxidation levels of 7Fe atoms (Fe1-Fe7) for both FeFe- and FeMo-cos in resting states are found to be higher than that of FeV-co. For the PN clusters in MoFe-, VFe- and FeFe-proteins, they all exhibit a strong reductive character.
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Affiliation(s)
- Zhen-Lang Xie
- State Key Laboratory of Physical Chemistry of Solid Surfaces and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
| | - Wan-Ting Jin
- College of Chemical and Material Engineering, Quzhou University, Quzhou, 324000, China
| | - Zhao-Hui Zhou
- State Key Laboratory of Physical Chemistry of Solid Surfaces and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
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5
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Badalyan A, Yang ZY, Seefeldt LC. A voltammetric study of nitrogenase MoFe-protein using low-potential electron transfer mediators. Bioelectrochemistry 2024; 155:108575. [PMID: 37738860 DOI: 10.1016/j.bioelechem.2023.108575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/28/2023] [Accepted: 09/16/2023] [Indexed: 09/24/2023]
Abstract
The molybdenum-iron protein (MoFeP), a component of the enzyme nitrogenase, catalyzes the reduction of an array of small molecules, including N2 to NH3. In microorganisms, during the catalytic cycle, MoFeP receives electrons from the obligate biological redox partner iron protein (FeP) in a process coupled to the hydrolysis of two MgATP per one electron transferred. Despite the favorable redox properties of the cofactors, the requirement of the MgATP hydrolysis significantly decreases the energy efficiency of MoFeP. Therefore, remarkable efforts have been devoted to electrochemically activating MoFeP without FeP and MgATP. Previously, MoFeP was adsorbed on an electrode surface and revealed a slow catalysis with and without electron transfer mediators. However, enzyme adsorption can cause conformational and structural changes in a fragile protein molecule and alter its catalytic activity. In this work, MoFeP was electrochemically studied in solution. Various electron transfer mediators with potentials ranging from -0.3 V to -1 V (vs. NHE) were examined with MoFeP using cyclic voltammetry. No significant catalytic activity of the MoFeP was observed with any of the tested mediators. This indicates that efficient electrochemical activation of MoFeP cannot be achieved exclusively by increasing the driving force between the MoFeP redox cofactors and an electron donor.
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Affiliation(s)
- Artavazd Badalyan
- Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, UT 84322, USA.
| | - Zhi-Yong Yang
- Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, UT 84322, USA
| | - Lance C Seefeldt
- Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, UT 84322, USA.
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6
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Schmidt FV, Schulz L, Zarzycki J, Prinz S, Oehlmann NN, Erb TJ, Rebelein JG. Structural insights into the iron nitrogenase complex. Nat Struct Mol Biol 2024; 31:150-158. [PMID: 38062208 PMCID: PMC10803253 DOI: 10.1038/s41594-023-01124-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 09/12/2023] [Indexed: 01/24/2024]
Abstract
Nitrogenases are best known for catalyzing the reduction of dinitrogen to ammonia at a complex metallic cofactor. Recently, nitrogenases were shown to reduce carbon dioxide (CO2) and carbon monoxide to hydrocarbons, offering a pathway to recycle carbon waste into hydrocarbon products. Among the three nitrogenase isozymes, the iron nitrogenase has the highest wild-type activity for the reduction of CO2, but the molecular architecture facilitating these activities has remained unknown. Here, we report a 2.35-Å cryogenic electron microscopy structure of the ADP·AlF3-stabilized iron nitrogenase complex from Rhodobacter capsulatus, revealing an [Fe8S9C-(R)-homocitrate] cluster in the active site. The enzyme complex suggests that the iron nitrogenase G subunit is involved in cluster stabilization and substrate channeling and confers specificity between nitrogenase reductase and catalytic component proteins. Moreover, the structure highlights a different interface between the two catalytic halves of the iron and the molybdenum nitrogenase, potentially influencing the intrasubunit 'communication' and thus the nitrogenase mechanism.
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Affiliation(s)
- Frederik V Schmidt
- Microbial Metalloenzymes Research Group, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Luca Schulz
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Jan Zarzycki
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Simone Prinz
- Central Electron Microscopy Facility, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Niels N Oehlmann
- Microbial Metalloenzymes Research Group, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Tobias J Erb
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Johannes G Rebelein
- Microbial Metalloenzymes Research Group, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
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7
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Warmack RA, Rees DC. Nitrogenase beyond the Resting State: A Structural Perspective. Molecules 2023; 28:7952. [PMID: 38138444 PMCID: PMC10745740 DOI: 10.3390/molecules28247952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 12/24/2023] Open
Abstract
Nitrogenases have the remarkable ability to catalyze the reduction of dinitrogen to ammonia under physiological conditions. How does this happen? The current view of the nitrogenase mechanism focuses on the role of hydrides, the binding of dinitrogen in a reductive elimination process coupled to loss of dihydrogen, and the binding of substrates to a binuclear site on the active site cofactor. This review focuses on recent experimental characterizations of turnover relevant forms of the enzyme determined by cryo-electron microscopy and other approaches, and comparison of these forms to the resting state enzyme and the broader family of iron sulfur clusters. Emerging themes include the following: (i) The obligatory coupling of protein and electron transfers does not occur in synthetic and small-molecule iron-sulfur clusters. The coupling of these processes in nitrogenase suggests that they may involve unique features of the cofactor, such as hydride formation on the trigonal prismatic arrangement of irons, protonation of belt sulfurs, and/or protonation of the interstitial carbon. (ii) Both the active site cofactor and protein are dynamic under turnover conditions; the changes are such that more highly reduced forms may differ in key ways from the resting-state structure. Homocitrate appears to play a key role in coupling cofactor and protein dynamics. (iii) Structural asymmetries are observed in nitrogenase under turnover-relevant conditions by cryo-electron microscopy, although the mechanistic relevance of these states (such as half-of-sites reactivity) remains to be established.
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Affiliation(s)
- Rebeccah A. Warmack
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Douglas C. Rees
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
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8
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Einsle O. On the Shoulders of Giants-Reaching for Nitrogenase. Molecules 2023; 28:7959. [PMID: 38138449 PMCID: PMC10745432 DOI: 10.3390/molecules28247959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 11/14/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023] Open
Abstract
Only a single enzyme system-nitrogenase-carries out the conversion of atmospheric N2 into bioavailable ammonium, an essential prerequisite for all organismic life. The reduction of this inert substrate at ambient conditions poses unique catalytic challenges that strain our mechanistic understanding even after decades of intense research. Structural biology has added its part to this greater tapestry, and in this review, I provide a personal (and highly biased) summary of the parts of the story to which I had the privilege to contribute. It focuses on the crystallographic analysis of the three isoforms of nitrogenases at high resolution and the binding of ligands and inhibitors to the active-site cofactors of the enzyme. In conjunction with the wealth of available biochemical, biophysical, and spectroscopic data on the protein, this has led us to a mechanistic hypothesis based on an elementary mechanism of repetitive hydride formation and insertion.
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Affiliation(s)
- Oliver Einsle
- Institute of Biochemistry, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg im Breisgau, Germany
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9
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Einsle O. Catalysis and structure of nitrogenases. Curr Opin Struct Biol 2023; 83:102719. [PMID: 37802004 DOI: 10.1016/j.sbi.2023.102719] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 09/03/2023] [Accepted: 09/06/2023] [Indexed: 10/08/2023]
Abstract
In providing bioavailable nitrogen as building blocks for all classes of biomacromolecules, biological nitrogen fixation is an essential process for all organismic life. Only a single enzyme, nitrogenase, performs this task at ambient conditions and with ATP as an energy source. The assembly of the complex iron-sulfur enzyme nitrogenase and its catalytic mechanism remains a matter of intense study. Recent progress in the structural analysis of the three known isoforms of nitrogenase-differentiated primarily by the heterometal in their active site cofactor-has revealed a degree of structural plasticity of these clusters that suggest two distinct binding sites for substrates and reaction intermediates. A mechanistic proposal based on this finding integrates most of the available experimental data. Furthermore, the first applications of high-resolution cryo-electron microscopy have highlighted further dynamic conformational changes. Structures obtained under turnover conditions support the proposed alternating half-site reactivity in the C2-symmetric nitrogenase complex.
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Affiliation(s)
- Oliver Einsle
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg im Breisgau, Germany.
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10
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Pellows LM, Willis MA, Ruzicka JL, Jagilinki BP, Mulder DW, Yang ZY, Seefeldt LC, King PW, Dukovic G, Peters JW. High Affinity Electrostatic Interactions Support the Formation of CdS Quantum Dot:Nitrogenase MoFe Protein Complexes. NANO LETTERS 2023; 23:10466-10472. [PMID: 37930772 DOI: 10.1021/acs.nanolett.3c03205] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
Nitrogenase MoFe protein can be coupled with CdS nanocrystals (NCs) to enable photocatalytic N2 reduction. The nature of interactions that support complex formation is of paramount importance in intermolecular electron transfer that supports catalysis. In this work we have employed microscale thermophoresis to examine binding interactions between 3-mercaptopropionate capped CdS quantum dots (QDs) and MoFe protein over a range of QD diameters (3.4-4.3 nm). The results indicate that the interactions are largely electrostatic, with the strength of interactions similar to that observed for the physiological electron donor. In addition, the strength of interactions is sensitive to the QD diameter, and the binding interactions are significantly stronger for QDs with smaller diameters. The ability to quantitatively assess NC protein interactions in biohybrid systems supports strategies for understanding properties and reaction parameters that are important for obtaining optimal rates of catalysis in biohybrid systems.
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Affiliation(s)
- Lauren M Pellows
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Mark A Willis
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99163, United States
| | - Jesse L Ruzicka
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Bhanu P Jagilinki
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - David W Mulder
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Zhi-Yong Yang
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Lance C Seefeldt
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Paul W King
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Gordana Dukovic
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Materials Science and Engineering, University of Colorado Boulder, Boulder, Colorado 80303, United States
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - John W Peters
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99163, United States
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
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11
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Tokmina-Lukaszewska M, Huang Q, Berry L, Kallas H, Peters JW, Seefeldt LC, Raugei S, Bothner B. Fe protein docking transduces conformational changes to MoFe nitrogenase active site in a nucleotide-dependent manner. Commun Chem 2023; 6:254. [PMID: 37980448 PMCID: PMC10657360 DOI: 10.1038/s42004-023-01046-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 10/30/2023] [Indexed: 11/20/2023] Open
Abstract
The reduction of dinitrogen to ammonia catalyzed by nitrogenase involves a complex series of events, including ATP hydrolysis, electron transfer, and activation of metal clusters for N2 reduction. Early evidence shows that an essential part of the mechanism involves transducing information between the nitrogenase component proteins through conformational dynamics. Here, millisecond time-resolved hydrogen-deuterium exchange mass spectrometry was used to unravel peptide-level protein motion on the time scale of catalysis of Mo-dependent nitrogenase from Azotobacter vinelandii. Normal mode analysis calculations complemented this data, providing insights into the specific signal transduction pathways that relay information across protein interfaces at distances spanning 100 Å. Together, these results show that conformational changes induced by protein docking are rapidly transduced to the active site, suggesting a specific mechanism for activating the metal cofactor in the enzyme active site.
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Affiliation(s)
| | - Qi Huang
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Luke Berry
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Hayden Kallas
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, USA
| | - John W Peters
- Institute of Biological Chemistry, The University of Oklahoma, Norman, OK, USA
| | - Lance C Seefeldt
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, USA
| | - Simone Raugei
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA.
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12
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Solomon JB, Liu YA, Górecki K, Quechol R, Lee CC, Jasniewski AJ, Hu Y, Ribbe MW. Heterologous expression of a fully active Azotobacter vinelandii nitrogenase Fe protein in Escherichia coli. mBio 2023; 14:e0257223. [PMID: 37909748 PMCID: PMC10746259 DOI: 10.1128/mbio.02572-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 09/27/2023] [Indexed: 11/03/2023] Open
Abstract
The functional versatility of the Fe protein, the reductase component of nitrogenase, makes it an appealing target for heterologous expression, which could facilitate future biotechnological adaptations of nitrogenase-based production of valuable chemical commodities. Yet, the heterologous synthesis of a fully active Fe protein of Azotobacter vinelandii (AvNifH) in Escherichia coli has proven to be a challenging task. Here, we report the successful synthesis of a fully active AvNifH protein upon co-expression of this protein with AvIscS/U and AvNifM in E. coli. Our metal, activity, electron paramagnetic resonance, and X-ray absorption spectroscopy/extended X-ray absorption fine structure (EXAFS) data demonstrate that the heterologously expressed AvNifH protein has a high [Fe4S4] cluster content and is fully functional in nitrogenase catalysis and assembly. Moreover, our phylogenetic analyses and structural predictions suggest that AvNifM could serve as a chaperone and assist the maturation of a cluster-replete AvNifH protein. Given the crucial importance of the Fe protein for the functionality of nitrogenase, this work establishes an effective framework for developing a heterologous expression system of the complete, two-component nitrogenase system; additionally, it provides a useful tool for further exploring the intricate biosynthetic mechanism of this structurally unique and functionally important metalloenzyme. IMPORTANCE The heterologous expression of a fully active Azotobacter vinelandii Fe protein (AvNifH) has never been accomplished. Given the functional importance of this protein in nitrogenase catalysis and assembly, the successful expression of AvNifH in Escherichia coli as reported herein supplies a key element for the further development of heterologous expression systems that explore the catalytic versatility of the Fe protein, either on its own or as a key component of nitrogenase, for nitrogenase-based biotechnological applications in the future. Moreover, the "clean" genetic background of the heterologous expression host allows for an unambiguous assessment of the effect of certain nif-encoded protein factors, such as AvNifM described in this work, in the maturation of AvNifH, highlighting the utility of this heterologous expression system in further advancing our understanding of the complex biosynthetic mechanism of nitrogenase.
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Affiliation(s)
- Joseph B. Solomon
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California, USA
- Department of Chemistry, University of California, Irvine, California, USA
| | - Yiling A. Liu
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California, USA
| | - Kamil Górecki
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California, USA
| | - Robert Quechol
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California, USA
| | - Chi Chung Lee
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California, USA
| | - Andrew J. Jasniewski
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California, USA
| | - Yilin Hu
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California, USA
| | - Markus W. Ribbe
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California, USA
- Department of Chemistry, University of California, Irvine, California, USA
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13
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Kang W. Unveiling Nature's Nitrogen-Fixing Secrets. Mol Cells 2023; 46:535-537. [PMID: 37691259 PMCID: PMC10495689 DOI: 10.14348/molcells.2023.0086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/12/2023] [Accepted: 06/13/2023] [Indexed: 09/12/2023] Open
Affiliation(s)
- Wonchull Kang
- Department of Chemistry and Integrative Institute of Basic Science, College of Natural Sciences, Soongsil University, Seoul 06978, Korea
- Department of Green Chemistry and Materials Engineering, Soongsil University, Seoul 06978, Korea
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14
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Maggiolo AO, Mahajan S, Rees DC, Clemons WM. Intradimeric Walker A ATPases: Conserved Features of A Functionally Diverse Family. J Mol Biol 2023; 435:167965. [PMID: 37330285 DOI: 10.1016/j.jmb.2023.167965] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 01/12/2023] [Indexed: 06/19/2023]
Abstract
Nucleoside-triphosphate hydrolases (NTPases) are a diverse, but essential group of enzymes found in all living organisms. NTPases that have a G-X-X-X-X-G-K-[S/T] consensus sequence (where X is any amino acid), known as the Walker A or P-loop motif, constitute a superfamily of P-loop NTPases. A subset of ATPases within this superfamily contains a modified Walker A motif, X-K-G-G-X-G-K-[S/T], wherein the first invariant lysine residue is essential to stimulate nucleotide hydrolysis. Although the proteins in this subset have vastly differing functions, ranging from electron transport during nitrogen fixation to targeting of integral membrane proteins to their correct membranes, they have evolved from a shared ancestor and have thus retained common structural features that affect their functions. These commonalities have only been disparately characterized in the context of their individual proteins systems, but have not been generally annotated as features that unite the members of this family. In this review, we report an analysis based on the sequences, structures, and functions of several members in this family that highlight their remarkable similarities. A principal feature of these proteins is their dependence on homodimerization. Since their functionalities are heavily influenced by changes that happen in conserved elements at the dimer interface, we refer to the members of this subclass as intradimeric Walker A ATPases.
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Affiliation(s)
- Ailiena O Maggiolo
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, United States
| | - Shivansh Mahajan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, United States
| | - Douglas C Rees
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, United States.
| | - William M Clemons
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, United States.
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15
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Abstract
The Fischer-Tropsch (FT) process converts a mixture of CO and H2 into liquid hydrocarbons as a major component of the gas-to-liquid technology for the production of synthetic fuels. Contrary to the energy-demanding chemical FT process, the enzymatic FT-type reactions catalyzed by nitrogenase enzymes, their metalloclusters, and synthetic mimics utilize H+ and e- as the reducing equivalents to reduce CO, CO2, and CN- into hydrocarbons under ambient conditions. The C1 chemistry exemplified by these FT-type reactions is underscored by the structural and electronic properties of the nitrogenase-associated metallocenters, and recent studies have pointed to the potential relevance of this reactivity to nitrogenase mechanism, prebiotic chemistry, and biotechnological applications. This review will provide an overview of the features of nitrogenase enzymes and associated metalloclusters, followed by a detailed discussion of the activities of various nitrogenase-derived FT systems and plausible mechanisms of the enzymatic FT reactions, highlighting the versatility of this unique reactivity while providing perspectives onto its mechanistic, evolutionary, and biotechnological implications.
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Affiliation(s)
- Yilin Hu
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine 92697-3900, USA
| | - Chi Chung Lee
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine 92697-3900, USA
| | - Mario Grosch
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine 92697-3900, USA
| | - Joseph B. Solomon
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA
| | - Wolfgang Weigand
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Markus W. Ribbe
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine 92697-3900, USA
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA
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16
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Utreja D. Sulfonamide functionalized silica nano-composite: characterization and fluorescence "turn-on" detection of Fe 3+ ions in aqueous samples. Photochem Photobiol Sci 2023:10.1007/s43630-023-00421-5. [PMID: 37186235 DOI: 10.1007/s43630-023-00421-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 04/10/2023] [Indexed: 05/17/2023]
Abstract
We have synthesized novel sulfonamide-based nano-composite (SAN) for selective and sensitive detection of Fe3+ ions in aqueous samples. Morphological characterization of SAN was carried out with TGA, FT-IR, UV-Vis, ninhydrin assay, FE-SEM, pXRD, BET, EDX, and elemental analysis. The sensing nature, effect of pH, sensor concentration and response time analysis were accomplished with the help of emission spectral studies and SAN was assessed as "turn-on" emission detector for the biologically important Fe3+ ions. Here, the LOD and LOQ were computed to be 26.68 nM and 88.93 nM, respectively, and it was found to be much lower than the permissible limit of Fe3+ ions in drinking water. The accuracy of the sensor (SAN) was determined by testing the aqueous samples spiked with known concentrations of Fe3+ ions and results demonstrated 98.00-99.66% recovery, which made SAN a reliable, selective and sensitive chemosensor for the quantification of Fe3+ ions in fully aqueous media.
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Affiliation(s)
- Divya Utreja
- Department of Chemistry, Punjab Agricultural University, Ludhiana, Punjab, 141004, India.
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17
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Martin Del Campo JS, Rigsbee J, Bueno Batista M, Mus F, Rubio LM, Einsle O, Peters JW, Dixon R, Dean DR, Dos Santos PC. Overview of physiological, biochemical, and regulatory aspects of nitrogen fixation in Azotobacter vinelandii. Crit Rev Biochem Mol Biol 2023; 57:492-538. [PMID: 36877487 DOI: 10.1080/10409238.2023.2181309] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Understanding how Nature accomplishes the reduction of inert nitrogen gas to form metabolically tractable ammonia at ambient temperature and pressure has challenged scientists for more than a century. Such an understanding is a key aspect toward accomplishing the transfer of the genetic determinants of biological nitrogen fixation to crop plants as well as for the development of improved synthetic catalysts based on the biological mechanism. Over the past 30 years, the free-living nitrogen-fixing bacterium Azotobacter vinelandii emerged as a preferred model organism for mechanistic, structural, genetic, and physiological studies aimed at understanding biological nitrogen fixation. This review provides a contemporary overview of these studies and places them within the context of their historical development.
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Affiliation(s)
| | - Jack Rigsbee
- Department of Chemistry, Wake Forest University, Winston-Salem, NC, USA
| | | | - Florence Mus
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Luis M Rubio
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Pozuelo de Alarcón, Spain
| | - Oliver Einsle
- Department of Biochemistry, University of Freiburg, Freiburg, Germany
| | - John W Peters
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Ray Dixon
- Department of Molecular Microbiology, John Innes Centre, Norwich, UK
| | - Dennis R Dean
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, USA
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18
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Ribbe MW, Górecki K, Grosch M, Solomon JB, Quechol R, Liu YA, Lee CC, Hu Y. Nitrogenase Fe Protein: A Multi-Tasking Player in Substrate Reduction and Metallocluster Assembly. Molecules 2022; 27:molecules27196743. [PMID: 36235278 PMCID: PMC9571451 DOI: 10.3390/molecules27196743] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/05/2022] [Accepted: 10/06/2022] [Indexed: 11/18/2022] Open
Abstract
The Fe protein of nitrogenase plays multiple roles in substrate reduction and metallocluster assembly. Best known for its function to transfer electrons to its catalytic partner during nitrogenase catalysis, the Fe protein is also a key player in the biosynthesis of the complex metalloclusters of nitrogenase. In addition, it can function as a reductase on its own and affect the ambient reduction of CO2 or CO to hydrocarbons. This review will provide an overview of the properties and functions of the Fe protein, highlighting the relevance of this unique FeS enzyme to areas related to the catalysis, biosynthesis, and applications of the fascinating nitrogenase system.
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Affiliation(s)
- Markus W. Ribbe
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA
- Correspondence: (M.W.R.); (Y.H.)
| | - Kamil Górecki
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA
| | - Mario Grosch
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA
| | - Joseph B. Solomon
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA
| | - Robert Quechol
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA
| | - Yiling A. Liu
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA
| | - Chi Chung Lee
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA
| | - Yilin Hu
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA
- Correspondence: (M.W.R.); (Y.H.)
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19
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Rutledge HL, Cook BD, Nguyen HPM, Herzik MA, Tezcan FA. Structures of the nitrogenase complex prepared under catalytic turnover conditions. Science 2022; 377:865-869. [PMID: 35901182 PMCID: PMC9949965 DOI: 10.1126/science.abq7641] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The enzyme nitrogenase couples adenosine triphosphate (ATP) hydrolysis to the multielectron reduction of atmospheric dinitrogen into ammonia. Despite extensive research, the mechanistic details of ATP-dependent energy transduction and dinitrogen reduction by nitrogenase are not well understood, requiring new strategies to monitor its structural dynamics during catalytic action. Here, we report cryo-electron microscopy structures of the nitrogenase complex prepared under enzymatic turnover conditions. We observe that asymmetry governs all aspects of the nitrogenase mechanism, including ATP hydrolysis, protein-protein interactions, and catalysis. Conformational changes near the catalytic iron-molybdenum cofactor are correlated with the nucleotide-hydrolysis state of the enzyme.
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Affiliation(s)
- Hannah L. Rutledge
- Department of Chemistry and Biochemistry, University of California San Diego, San Diego, CA 92093, USA
| | - Brian D. Cook
- Department of Chemistry and Biochemistry, University of California San Diego, San Diego, CA 92093, USA
| | - Hoang P. M. Nguyen
- Department of Chemistry and Biochemistry, University of California San Diego, San Diego, CA 92093, USA
| | - Mark A. Herzik
- Department of Chemistry and Biochemistry, University of California San Diego, San Diego, CA 92093, USA,Corresponding author. (FAT), (MAH)
| | - F. Akif Tezcan
- Department of Chemistry and Biochemistry, University of California San Diego, San Diego, CA 92093, USA,Corresponding author. (FAT), (MAH)
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20
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Abstract
Synthetic iron-sulfur cubanes are models for biological cofactors, which are essential to delineate oxidation states in the more complex enzymatic systems. However, a complete series of [Fe4S4]n complexes spanning all redox states accessible by 1-electron transformations of the individual iron atoms (n = 0-4+) has never been prepared, deterring the methodical comparison of structure and spectroscopic signature. Here, we demonstrate that the use of a bulky arylthiolate ligand promoting the encapsulation of alkali-metal cations in the vicinity of the cubane enables the synthesis of such a series. Characterization by EPR, 57Fe Mössbauer spectroscopy, UV-visible electronic absorption, variable-temperature X-ray diffraction analysis, and cyclic voltammetry reveals key trends for the geometry of the Fe4S4 core as well as for the Mössbauer isomer shift, which both correlate systematically with oxidation state. Furthermore, we confirm the S = 4 electronic ground state of the most reduced member of the series, [Fe4S4]0, and provide electrochemical evidence that it is accessible within 0.82 V from the [Fe4S4]2+ state, highlighting its relevance as a mimic of the nitrogenase iron protein cluster.
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21
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Analysis of the Ammonia Production Rates by Nitrogenase. Catalysts 2022. [DOI: 10.3390/catal12080844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Ammonia (NH3) is produced industrially by the Haber–Bosch process from dinitrogen (N2) and dihydrogen (H2) using high temperature and pressure with an iron catalyst. In contrast to the extreme conditions used in the Haber–Bosch process, biology has evolved nitrogenase enzymes, which operate at ambient temperature and pressure. In biological settings, nitrogenase requires large amounts of energy in the form of ATP, using at least 13 GJ ton−1 of ammonia. In 2016, Brown et al. reported ATP-free ammonia production by nitrogenase. This result led to optimism that the energy demands of nitrogenase could be reduced. More recent reports confirmed the ATP-free production of ammonia; however, the rates of reaction are at least an order of magnitude lower. A more detailed understanding of the role of ATP in nitrogenase catalysis is required to develop ATP-free catalytic systems with higher ammonia production rates. Finally, we calculated the theoretical maximal ammonia production rate by nitrogenase and compared it to currently used Haber–Bosch catalysts. Somewhat surprisingly, nitrogenase has a similar theoretical maximum rate to the Haber–Bosch catalysts; however, strategies need to be developed to allow the enzyme to maintain operation at its optimal rate.
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22
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Stripp ST, Duffus BR, Fourmond V, Léger C, Leimkühler S, Hirota S, Hu Y, Jasniewski A, Ogata H, Ribbe MW. Second and Outer Coordination Sphere Effects in Nitrogenase, Hydrogenase, Formate Dehydrogenase, and CO Dehydrogenase. Chem Rev 2022; 122:11900-11973. [PMID: 35849738 PMCID: PMC9549741 DOI: 10.1021/acs.chemrev.1c00914] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Gases like H2, N2, CO2, and CO are increasingly recognized as critical feedstock in "green" energy conversion and as sources of nitrogen and carbon for the agricultural and chemical sectors. However, the industrial transformation of N2, CO2, and CO and the production of H2 require significant energy input, which renders processes like steam reforming and the Haber-Bosch reaction economically and environmentally unviable. Nature, on the other hand, performs similar tasks efficiently at ambient temperature and pressure, exploiting gas-processing metalloenzymes (GPMs) that bind low-valent metal cofactors based on iron, nickel, molybdenum, tungsten, and sulfur. Such systems are studied to understand the biocatalytic principles of gas conversion including N2 fixation by nitrogenase and H2 production by hydrogenase as well as CO2 and CO conversion by formate dehydrogenase, carbon monoxide dehydrogenase, and nitrogenase. In this review, we emphasize the importance of the cofactor/protein interface, discussing how second and outer coordination sphere effects determine, modulate, and optimize the catalytic activity of GPMs. These may comprise ionic interactions in the second coordination sphere that shape the electron density distribution across the cofactor, hydrogen bonding changes, and allosteric effects. In the outer coordination sphere, proton transfer and electron transfer are discussed, alongside the role of hydrophobic substrate channels and protein structural changes. Combining the information gained from structural biology, enzyme kinetics, and various spectroscopic techniques, we aim toward a comprehensive understanding of catalysis beyond the first coordination sphere.
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Affiliation(s)
- Sven T Stripp
- Freie Universität Berlin, Experimental Molecular Biophysics, Berlin 14195, Germany
| | | | - Vincent Fourmond
- Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Institut Microbiologie, Bioénergies et Biotechnologie, CNRS, Aix Marseille Université, Marseille 13402, France
| | - Christophe Léger
- Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Institut Microbiologie, Bioénergies et Biotechnologie, CNRS, Aix Marseille Université, Marseille 13402, France
| | - Silke Leimkühler
- University of Potsdam, Molecular Enzymology, Potsdam 14476, Germany
| | - Shun Hirota
- Nara Institute of Science and Technology, Division of Materials Science, Graduate School of Science and Technology, Nara 630-0192, Japan
| | - Yilin Hu
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California 92697-3900, United States
| | - Andrew Jasniewski
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California 92697-3900, United States
| | - Hideaki Ogata
- Nara Institute of Science and Technology, Division of Materials Science, Graduate School of Science and Technology, Nara 630-0192, Japan.,Hokkaido University, Institute of Low Temperature Science, Sapporo 060-0819, Japan.,Graduate School of Science, University of Hyogo, Hyogo 678-1297, Japan
| | - Markus W Ribbe
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California 92697-3900, United States.,Department of Chemistry, University of California, Irvine, California 92697-2025, United States
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23
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Solomon JB, Tanifuji K, Lee CC, Jasniewski AJ, Hedman B, Hodgson KO, Hu Y, Ribbe MW. Characterization of a Nitrogenase Iron Protein Substituted with a Synthetic [Fe 4 Se 4 ] Cluster. Angew Chem Int Ed Engl 2022; 61:e202202271. [PMID: 35218104 PMCID: PMC9038695 DOI: 10.1002/anie.202202271] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Indexed: 11/08/2022]
Abstract
The Fe protein of nitrogenase plays multiple roles in substrate reduction and cluster maturation via its redox-active [Fe4 S4 ] cluster. Here we report the synthesis and characterization of a water-soluble [Fe4 Se4 ] cluster that is used to substitute the [Fe4 S4 ] cluster of the Azotobacter vinelandii Fe protein (AvNifH). Biochemical, EPR and XAS/EXAFS analyses demonstrate the ability of the [Fe4 Se4 ] cluster to adopt the super-reduced, all-ferrous state upon its incorporation into AvNifH. Moreover, these studies reveal that the [Fe4 Se4 ] cluster in AvNifH already assumes a partial all-ferrous state ([Fe4 Se4 ]0 ) in the presence of dithionite, where its [Fe4 S4 ] counterpart in AvNifH exists solely in the reduced state ([Fe4 S4 ]1+ ). Such a discrepancy in the redox properties of the AvNifH-associated [Fe4 Se4 ] and [Fe4 S4 ] clusters can be used to distinguish the differential redox requirements for the substrate reduction and cluster maturation of nitrogenase, pointing to the utility of chalcogen-substituted FeS clusters in future mechanistic studies of nitrogenase catalysis and assembly.
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Affiliation(s)
- Joseph B Solomon
- Department of Molecular Biology and Biochemistry, University of Califronia, Irvine, Irvine, CA 92697-3900, USA.,Department of Chemistry, University of California, Irvine, Irvine, CA 92697-2025, USA
| | - Kazuki Tanifuji
- Department of Molecular Biology and Biochemistry, University of Califronia, Irvine, Irvine, CA 92697-3900, USA.,Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Chi Chung Lee
- Department of Molecular Biology and Biochemistry, University of Califronia, Irvine, Irvine, CA 92697-3900, USA
| | - Andrew J Jasniewski
- Department of Molecular Biology and Biochemistry, University of Califronia, Irvine, Irvine, CA 92697-3900, USA
| | - Britt Hedman
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, USA
| | - Keith O Hodgson
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, USA.,Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Yilin Hu
- Department of Molecular Biology and Biochemistry, University of Califronia, Irvine, Irvine, CA 92697-3900, USA
| | - Markus W Ribbe
- Department of Molecular Biology and Biochemistry, University of Califronia, Irvine, Irvine, CA 92697-3900, USA.,Department of Chemistry, University of California, Irvine, Irvine, CA 92697-2025, USA
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24
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Solomon J, Tanifuji K, Lee CC, Jasniewski A, Hedman B, Hodgson K, Hu Y, Ribbe M. Characterization of a Nitrogenase Iron Protein Substituted with a Synthetic [Fe4Se4] Cluster. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | - Kazuki Tanifuji
- Kyoto University Institute for Chemical Research UNITED STATES
| | - Chi Chung Lee
- University of California Irvine Molecular Biology and Biochemistry UNITED STATES
| | - Andrew Jasniewski
- University of California Irvine Molecular Biology and Biochemistry UNITED STATES
| | - Britt Hedman
- Stanford University Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory UNITED STATES
| | | | - Yilin Hu
- University of California Irvine Molecular Biology and Biochemistry UNITED STATES
| | - Markus Ribbe
- Irvine Molecular Biology & Biochemistry 2236 McGaugh Hall 92697 Irvine UNITED STATES
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25
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Boncella AE, Sabo ET, Santore RM, Carter J, Whalen J, Hudspeth JD, Morrison CN. The expanding utility of iron-sulfur clusters: Their functional roles in biology, synthetic small molecules, maquettes and artificial proteins, biomimetic materials, and therapeutic strategies. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2021.214229] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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26
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Yuan C, Jin WT, Zhou ZH. Statistical analysis of PN clusters in Mo/VFe protein crystals using a bond valence method toward their electronic structures. RSC Adv 2022; 12:5214-5224. [PMID: 35425536 PMCID: PMC8981338 DOI: 10.1039/d1ra08507g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 01/26/2022] [Indexed: 11/21/2022] Open
Abstract
Iron valences of 129 P-clusters from FeMo/V proteins were analyzed using a bond valence method, supposing the existence of Fe3+ in a generally considered all-ferrous PN cluster in solution with excess reducing agent.
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Affiliation(s)
- Chang Yuan
- State Key Laboratory for Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
| | - Wan-Ting Jin
- State Key Laboratory for Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
| | - Zhao-Hui Zhou
- State Key Laboratory for Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
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27
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Bigness A, Vaddypally S, Zdilla MJ, Mendoza-Cortes JL. Ubiquity of cubanes in bioinorganic relevant compounds. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2021.214168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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28
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So M, Stiban J, Ciesielski GL, Hovde SL, Kaguni LS. Implications of Membrane Binding by the Fe-S Cluster-Containing N-Terminal Domain in the Drosophila Mitochondrial Replicative DNA Helicase. Front Genet 2021; 12:790521. [PMID: 34950192 PMCID: PMC8688847 DOI: 10.3389/fgene.2021.790521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 11/15/2021] [Indexed: 11/13/2022] Open
Abstract
Recent evidence suggests that iron-sulfur clusters (ISCs) in DNA replicative proteins sense DNA-mediated charge transfer to modulate nuclear DNA replication. In the mitochondrial DNA replisome, only the replicative DNA helicase (mtDNA helicase) from Drosophila melanogaster (Dm) has been shown to contain an ISC in its N-terminal, primase-like domain (NTD). In this report, we confirm the presence of the ISC and demonstrate the importance of a metal cofactor in the structural stability of the Dm mtDNA helicase. Further, we show that the NTD also serves a role in membrane binding. We demonstrate that the NTD binds to asolectin liposomes, which mimic phospholipid membranes, through electrostatic interactions. Notably, membrane binding is more specific with increasing cardiolipin content, which is characteristically high in the mitochondrial inner membrane (MIM). We suggest that the N-terminal domain of the mtDNA helicase interacts with the MIM to recruit mtDNA and initiate mtDNA replication. Furthermore, Dm NUBPL, the known ISC donor for respiratory complex I and a putative donor for Dm mtDNA helicase, was identified as a peripheral membrane protein that is likely to execute membrane-mediated ISC delivery to its target proteins.
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Affiliation(s)
- Minyoung So
- Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI, United States
| | - Johnny Stiban
- Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI, United States.,Department of Biology and Biochemistry, Birzeit University, Birzeit, Palestine
| | - Grzegorz L Ciesielski
- Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI, United States.,Institute of Biosciences and Medical Technology, University of Tampere, Tampere, Finland.,Department of Chemistry, Auburn University at Montgomery, Montgomery, AL, United States
| | - Stacy L Hovde
- Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI, United States
| | - Laurie S Kaguni
- Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI, United States.,Institute of Biosciences and Medical Technology, University of Tampere, Tampere, Finland
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29
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Meirovich MM, Bachar O, Nandi R, Amdursky N, Yehezkeli O. Tailoring Quantum Dot Sizes for Optimal Photoinduced Catalytic Activation of Nitrogenase. CHEMSUSCHEM 2021; 14:5410-5416. [PMID: 34612599 DOI: 10.1002/cssc.202101676] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 09/30/2021] [Indexed: 06/13/2023]
Abstract
Many efforts have been directed towards elucidating the nitrogenase structure, its biocatalytic activity, and methods to artificially activate it by external stimuli. Here, we investigated how semiconductor nanoparticles (NPs) with sizes ranging between 2.3-3.5 nm form nano-biohybrids with the nitrogenase enzyme and enable its photoinduced biocatalytic activity. We examined two homogenously synthesized quantum dots (QDs), CdS, CdSe, and two nitrogenase variants, the wild-type and a cysteine-mutated. We show that the cysteine-mutated variant does not enhance the hydrogen generation amounts, as compared with the wild type. Nevertheless, we show that the 2.3 nm-sized CdSe NPs facilitate an eightfold increase compared with larger CdSe NPs. The obtained results were investigated using electrochemical techniques, transmission electron microscopy, and further confirmed by time-resolved spectroscopic measurements, which allow us to determine the electron tranfer rate constant (kET ) of the different configurations.
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Affiliation(s)
- Matan M Meirovich
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, 3200003, Haifa, Israel
| | - Oren Bachar
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, 3200003, Haifa, Israel
| | - Ramesh Nandi
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, 3200003, Haifa, Israel
| | - Nadav Amdursky
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, 3200003, Haifa, Israel
| | - Omer Yehezkeli
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, 3200003, Haifa, Israel
- Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, 3200003, Haifa, Israel
- The Nancy and Stephen Grand Technion Energy Program, Technion-Israel Institute of Technology, 3200003, Haifa, Israel
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30
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Structural analysis of the reductase component AnfH of iron-only nitrogenase from Azotobacter vinelandii. J Inorg Biochem 2021; 227:111690. [PMID: 34929539 DOI: 10.1016/j.jinorgbio.2021.111690] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/29/2021] [Accepted: 12/03/2021] [Indexed: 11/20/2022]
Abstract
Biological nitrogen fixation, the conversion of atmospheric dinitrogen into bioavailable ammonium, is exclusively catalyzed by the enzyme nitrogenase that is present in nitrogen-fixing organisms, the diazotrophs. So far, three different nitrogenase variants, encoded in their corresponding, distinct gene clusters, have been found in nature. Each one of these consists of a catalytic dinitrogenase component and a unique, ATP-dependent reductase, the Fe protein. The three variant nitrogenases differ in the composition of the active site and contain either molybdenum, vanadium or only iron in the dinitrogenase component. Here we present the 2.0 Å resolution crystal structure of the ADP-bound reductase component AnfH of the iron-only nitrogenase from the model diazotroph Azotobacter vinelandii. A comparison of this structure with the ones reported for the two other Fe protein homologs NifH and VnfH in the ADP-bound state shows that all are adopting the same conformation. However, cross-reactivity assays with the three nitrogenase homologs revealed AnfH to be compatible with iron-only nitrogenase and to a lesser degree with the vanadium-containing enzyme, but not with molybdenum nitrogenase.
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31
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Ekta, Utreja D, Singh K, Sharma S. A Schiff‐Base Molecular Keypad LockandTurn‐On Sensor for Selective Detection of Fe
3+
with INHIBIT Logic Behaviour. ChemistrySelect 2021. [DOI: 10.1002/slct.202103730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Ekta
- Department of Chemistry Punjab Agricultural University Ludhiana 141004 India
| | - Divya Utreja
- Department of Chemistry Punjab Agricultural University Ludhiana 141004 India
| | - Kamaljit Singh
- Department of Chemistry Guru Nanak Dev University Amritsar 143004 India
| | - Sucheta Sharma
- Department of Biochemistry Punjab Agricultural University Ludhiana 141004 India
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32
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Moula G, Nagasaki A, Matsumoto T, Miehlich ME, Meyer K, Cramer RE, Tatsumi K. Synthesis of a Nitrogenase P
N
‐Cluster Model with [Fe
8
S
7
(μ‐S
thiolate
)
2
] Core from the All‐Ferric [Fe
4
S
4
(S
thiolate
)
4
] Cubane Synthon. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Golam Moula
- Research Center for Materials Science Nagoya University Furo-cho, Chikusa-ku Nagoya 464-8602 Japan
| | - Ayaka Nagasaki
- Research Center for Materials Science Nagoya University Furo-cho, Chikusa-ku Nagoya 464-8602 Japan
| | - Tsuyoshi Matsumoto
- Institute of Transformative Bio-Molecules (WPI-ITbM) Nagoya University Furo-cho, Chikusa-ku Nagoya 464-8601 Japan
| | - Matthias E. Miehlich
- Department of Chemistry and Pharmacy Inorganic Chemistry Friedrich-Alexander-University Erlangen-Nürnberg (FAU) Egerlandstrasse 1 91058 Erlangen Germany
| | - Karsten Meyer
- Department of Chemistry and Pharmacy Inorganic Chemistry Friedrich-Alexander-University Erlangen-Nürnberg (FAU) Egerlandstrasse 1 91058 Erlangen Germany
| | - Roger E. Cramer
- Department of Chemistry University of Hawaii Honolulu HI 96822 USA
| | - Kazuyuki Tatsumi
- Research Center for Materials Science Nagoya University Furo-cho, Chikusa-ku Nagoya 464-8602 Japan
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33
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Neumann F, Dobbek H. ATP Binding and a Second Reduction Enables a Conformationally Gated Uphill Electron Transfer. ACS Catal 2021. [DOI: 10.1021/acscatal.1c01038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Felix Neumann
- Institut für Biologie, Strukturbiologie/Biochemie, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany
| | - Holger Dobbek
- Institut für Biologie, Strukturbiologie/Biochemie, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany
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34
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Moula G, Nagasaki A, Matsumoto T, Miehlich ME, Meyer K, Cramer RE, Tatsumi K. Synthesis of a Nitrogenase P N -Cluster Model with [Fe 8 S 7 (μ-S thiolate ) 2 ] Core from the All-Ferric [Fe 4 S 4 (S thiolate ) 4 ] Cubane Synthon. Angew Chem Int Ed Engl 2021; 60:15792-15797. [PMID: 33928749 DOI: 10.1002/anie.202102369] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/31/2021] [Indexed: 11/06/2022]
Abstract
Constructing synthetic models of the nitrogenase PN -cluster has been a long-standing synthetic challenge. Here, we report an optimal nitrogenase PN -cluster model [{(TbtS)(OEt2 )Fe4 S3 }2 (μ-STbt)2 (μ6 -S)] (2) [Tbt=2,4,6-tris{bis(trimethylsilyl)methyl}phenyl] that is the closest synthetic mimic constructed to date. Of note is that two thiolate ligands and one hexacoordinated sulfide are connecting the two Fe4 S3 incomplete cubanes similar to the native PN -cluster, which has never been achieved. Cluster 2 has been characterized by X-ray crystallography and relevant physico-chemical methods. The variable temperature magnetic moments of 2 indicate a singlet ground state (S=0). The Mössbauer spectrum of 2 exhibits two doublets with an intensity ratio of 3:1, which suggests the presence of two types of iron sites. The synthetic pathway of the cluster 2 could indicate the native PN -cluster maturation process as it has been achieved from the Fe4 S4 cubane Fe4 S4 (STbt)4 (1).
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Affiliation(s)
- Golam Moula
- Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Ayaka Nagasaki
- Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Tsuyoshi Matsumoto
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
| | - Matthias E Miehlich
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Egerlandstrasse 1, 91058, Erlangen, Germany
| | - Karsten Meyer
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Egerlandstrasse 1, 91058, Erlangen, Germany
| | - Roger E Cramer
- Department of Chemistry, University of Hawaii, Honolulu, HI, 96822, USA
| | - Kazuyuki Tatsumi
- Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
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35
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Medina MS, Bretzing KO, Aviles RA, Chong KM, Espinoza A, Garcia CNG, Katz BB, Kharwa RN, Hernandez A, Lee JL, Lee TM, Lo Verde C, Strul MW, Wong EY, Owens CP. CowN sustains nitrogenase turnover in the presence of the inhibitor carbon monoxide. J Biol Chem 2021; 296:100501. [PMID: 33667548 PMCID: PMC8047169 DOI: 10.1016/j.jbc.2021.100501] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 01/28/2021] [Accepted: 03/01/2021] [Indexed: 11/28/2022] Open
Abstract
Nitrogenase is the only enzyme capable of catalyzing nitrogen fixation, the reduction of dinitrogen gas (N2) to ammonia (NH3). Nitrogenase is tightly inhibited by the environmental gas carbon monoxide (CO). Nitrogen-fixing bacteria rely on the protein CowN to grow in the presence of CO. However, the mechanism by which CowN operates is unknown. Here, we present the biochemical characterization of CowN and examine how CowN protects nitrogenase from CO. We determine that CowN interacts directly with nitrogenase and that CowN protection observes hyperbolic kinetics with respect to CowN concentration. At a CO concentration of 0.001 atm, CowN restores nearly full nitrogenase activity. Our results further indicate that CowN's protection mechanism involves decreasing the binding affinity of CO to nitrogenase's active site approximately tenfold without interrupting substrate turnover. Taken together, our work suggests CowN is an important auxiliary protein in nitrogen fixation that engenders CO tolerance to nitrogenase.
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Affiliation(s)
- Michael S Medina
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Kevin O Bretzing
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Richard A Aviles
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Kiersten M Chong
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Alejandro Espinoza
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Chloe Nicole G Garcia
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Benjamin B Katz
- Department of Chemistry, University of California, Irvine, Irvine, California, USA
| | - Ruchita N Kharwa
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Andrea Hernandez
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Justin L Lee
- Department of Chemistry, University of California, Irvine, Irvine, California, USA
| | - Terrence M Lee
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Christine Lo Verde
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Max W Strul
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Emily Y Wong
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Cedric P Owens
- Schmid College of Science and Technology, Chapman University, Orange, California, USA.
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36
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Mechanical coupling in the nitrogenase complex. PLoS Comput Biol 2021; 17:e1008719. [PMID: 33661889 PMCID: PMC7963043 DOI: 10.1371/journal.pcbi.1008719] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 03/16/2021] [Accepted: 01/18/2021] [Indexed: 11/19/2022] Open
Abstract
The enzyme nitrogenase reduces dinitrogen to ammonia utilizing electrons, protons, and energy obtained from the hydrolysis of ATP. Mo-dependent nitrogenase is a symmetric dimer, with each half comprising an ATP-dependent reductase, termed the Fe Protein, and a catalytic protein, known as the MoFe protein, which hosts the electron transfer P-cluster and the active-site metal cofactor (FeMo-co). A series of synchronized events for the electron transfer have been characterized experimentally, in which electron delivery is coupled to nucleotide hydrolysis and regulated by an intricate allosteric network. We report a graph theory analysis of the mechanical coupling in the nitrogenase complex as a key step to understanding the dynamics of allosteric regulation of nitrogen reduction. This analysis shows that regions near the active sites undergo large-scale, large-amplitude correlated motions that enable communications within each half and between the two halves of the complex. Computational predictions of mechanically regions were validated against an analysis of the solution phase dynamics of the nitrogenase complex via hydrogen-deuterium exchange. These regions include the P-loops and the switch regions in the Fe proteins, the loop containing the residue β-188Ser adjacent to the P-cluster in the MoFe protein, and the residues near the protein-protein interface. In particular, it is found that: (i) within each Fe protein, the switch regions I and II are coupled to the [4Fe-4S] cluster; (ii) within each half of the complex, the switch regions I and II are coupled to the loop containing β-188Ser; (iii) between the two halves of the complex, the regions near the nucleotide binding pockets of the two Fe proteins (in particular the P-loops, located over 130 Å apart) are also mechanically coupled. Notably, we found that residues next to the P-cluster (in particular the loop containing β-188Ser) are important for communication between the two halves.
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37
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Pence N, Lewis N, Alleman AB, Seefeldt LC, Peters JW. Revealing a role for the G subunit in mediating interactions between the nitrogenase component proteins. J Inorg Biochem 2020; 214:111273. [PMID: 33086169 DOI: 10.1016/j.jinorgbio.2020.111273] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 09/16/2020] [Accepted: 10/03/2020] [Indexed: 10/23/2022]
Abstract
Azotobacter vinelandii contains three forms of nitrogenase known as the Mo-, V-, and Fe-nitrogenases. They are all two-component enzyme systems, where the catalytic component, referred to as NifDK, VnfDGK, and AnfDGK, associates with the reductase component, the Fe protein or NifH, VnfH, and AnfH respectively. AnfDGK and VnfDGK have an additional subunit compared to NifDK, termed gamma or AnfG and VnfG, whose role is unknown. The expression of each nitrogenase is tightly regulated by metal availability, however it is known that there is crosstalk between the Mo- and V‑nitrogenases but the Fe‑nitrogenase components cannot support substrate reduction with its Mo‑nitrogenase counterparts. Here, docking models for the nitrogenase complexes were generated in ClusPro 2.0 based on the crystal structure of the Mo‑nitrogenase and refined using the HADDOCK 2.2 refinement interface to identify structural determinants that enable crosstalk between the Mo- and V‑nitrogenase but not the Fe‑nitrogenase. Differing salt bridge interactions were identified at the binding interface of each complex. Specifically, positively charged residues of VnfG enable complementary interactions with NifH and VnfH but not AnfH. Similarly, negatively charged residues of AnfG enable interactions with AnfH but not NifH or VnfH. A role for the G subunit is revealed where VnfG could be mediating crosstalk between the Mo- and V‑nitrogenases while the AnfG subunit on AnfDGK makes interactions with NifH and VnfH unfavorable, reducing competition with NifDK and funneling electrons to the most efficient nitrogenase.
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Affiliation(s)
- Natasha Pence
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, United States of America; Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, United States of America
| | - Nathan Lewis
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, United States of America
| | - Alexander B Alleman
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, United States of America
| | - Lance C Seefeldt
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322, United States of America
| | - John W Peters
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, United States of America.
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38
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Artificial, Photoinduced Activation of Nitrogenase Using Directed and Mediated Electron Transfer Processes. Catalysts 2020. [DOI: 10.3390/catal10090979] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Nitrogenase, a bacteria-based enzyme, is the sole enzyme that is able to generate ammonia by atmospheric nitrogen fixation. Thus, improved understanding of its utilization and developing methods to artificially activate it may contribute to basic research, as well as to the design of future artificial systems. Here, we present methods to artificially activate nitrogenase using photoinduced reactions. Two nitrogenase variants originating from Azotobacter vinelandii were examined using photoactivated CdS nanoparticles (NPs) capped with thioglycolic acid (TGA) or 2-mercaptoethanol (ME) ligands. The effect of methyl viologen (MV) as a redox mediator of hydrogen and ammonia generation was tested and analyzed. We further determined the NPs conductive band edges and their effect on the nitrogenase photoactivation. The nano-biohybrid systems comprising CdS NPs and nitrogenase were further imaged by transmission electron microscopy, visualizing their formation for the first time. Our results show that the ME-capped CdS NPs–nitrogenase enzyme biohybrid system with added MV as a redox mediator leads to a five-fold increase in the production of ammonia compared with the non-mediated biohybrid system; nevertheless, it stills lag behind the natural process rate. On the contrary, a maximal hydrogen generation amount was achieved by the αL158C MoFe-P and the ME-capped CdS NPs.
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39
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Li Q, Guo Z, Zhao X, Zhang T, Chen J, Wei Y. One-pot synthesis of 2,2'-dipicolylamine derived highly photoluminescent nitrogen-doped carbon quantum dots for Fe 3+ detection and fingermark detection. NANOTECHNOLOGY 2020; 31:335501. [PMID: 32357348 DOI: 10.1088/1361-6528/ab8f4b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The novel nitrogen-doped carbon quantum dots (N-CQDs) with high fluorescence quantum yield of 23.2% were successfully prepared via a simple hydrothermal reaction with citric acid and 2,2'-dipicolylamine. The as-prepared blue fluorescent N-CQDs had excellent water dispersibility, and showed pH and excitation-dependent emission behaviors. Noticeably, owing to the strong interaction between the residual 2,2'-dipicolylamine group on the surface of N-CQDs and Fe3+, the N-CQDs could be used as a turn off fluorescence probe for Fe3+ sensing through an electron transfer process. Moreover, the photoluminescent N-CQDs/poly(vinyl alcohol) film was further applied for latent fingermark imaging.
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Affiliation(s)
- Quan Li
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 3rd North East Road, Beijing, Chaoyang District 100029, People's Republic of China
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40
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Abstract
Nitrogenase is the only enzyme capable of reducing N2 to NH3. This challenging reaction requires the coordinated transfer of multiple electrons from the reductase, Fe-protein, to the catalytic component, MoFe-protein, in an ATP-dependent fashion. In the last two decades, there have been significant advances in our understanding of how nitrogenase orchestrates electron transfer (ET) from the Fe-protein to the catalytic site of MoFe-protein and how energy from ATP hydrolysis transduces the ET processes. In this review, we summarize these advances, with focus on the structural and thermodynamic redox properties of nitrogenase component proteins and their complexes, as well as on new insights regarding the mechanism of ET reactions during catalysis and how they are coupled to ATP hydrolysis. We also discuss recently developed chemical, photochemical, and electrochemical methods for uncoupling substrate reduction from ATP hydrolysis, which may provide new avenues for studying the catalytic mechanism of nitrogenase.
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Affiliation(s)
- Hannah L Rutledge
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
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41
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Van Stappen C, Decamps L, Cutsail GE, Bjornsson R, Henthorn JT, Birrell JA, DeBeer S. The Spectroscopy of Nitrogenases. Chem Rev 2020; 120:5005-5081. [PMID: 32237739 PMCID: PMC7318057 DOI: 10.1021/acs.chemrev.9b00650] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Indexed: 01/08/2023]
Abstract
Nitrogenases are responsible for biological nitrogen fixation, a crucial step in the biogeochemical nitrogen cycle. These enzymes utilize a two-component protein system and a series of iron-sulfur clusters to perform this reaction, culminating at the FeMco active site (M = Mo, V, Fe), which is capable of binding and reducing N2 to 2NH3. In this review, we summarize how different spectroscopic approaches have shed light on various aspects of these enzymes, including their structure, mechanism, alternative reactivity, and maturation. Synthetic model chemistry and theory have also played significant roles in developing our present understanding of these systems and are discussed in the context of their contributions to interpreting the nature of nitrogenases. Despite years of significant progress, there is still much to be learned from these enzymes through spectroscopic means, and we highlight where further spectroscopic investigations are needed.
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Affiliation(s)
- Casey Van Stappen
- Max Planck Institute for
Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Laure Decamps
- Max Planck Institute for
Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - George E. Cutsail
- Max Planck Institute for
Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Ragnar Bjornsson
- Max Planck Institute for
Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Justin T. Henthorn
- Max Planck Institute for
Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - James A. Birrell
- Max Planck Institute for
Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Serena DeBeer
- Max Planck Institute for
Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
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42
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Jasper J, Ramos JV, Trncik C, Jahn D, Einsle O, Layer G, Moser J. Chimeric Interaction of Nitrogenase-Like Reductases with the MoFe Protein of Nitrogenase. Chembiochem 2020; 21:1733-1741. [PMID: 31958206 PMCID: PMC7317204 DOI: 10.1002/cbic.201900759] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/17/2020] [Indexed: 11/24/2022]
Abstract
The engineering of transgenic organisms with the ability to fix nitrogen is an attractive possibility. However, oxygen sensitivity of nitrogenase, mainly conferred by the reductase component (NifH)2 , is an imminent problem. Nitrogenase-like enzymes involved in coenzyme F430 and chlorophyll biosynthesis utilize the highly homologous reductases (CfbC)2 and (ChlL)2 , respectively. Chimeric protein-protein interactions of these reductases with the catalytic component of nitrogenase (MoFe protein) did not support nitrogenase activity. Nucleotide-dependent association and dissociation of these complexes was investigated, but (CfbC)2 and wild-type (ChlL)2 showed no modulation of the binding affinity. By contrast, the interaction between the (ChlL)2 mutant Y127S and the MoFe protein was markedly increased in the presence of ATP (or ATP analogues) and reduced in the ADP state. Upon formation of the octameric (ChlL)2 MoFe(ChlL)2 complex, the ATPase activity of this variant is triggered, as seen in the homologous nitrogenase system. Thus, the described reductase(s) might be an attractive tool for further elucidation of the diverse functions of (NifH)2 and the rational design of a more robust reductase.
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Affiliation(s)
- Jan Jasper
- Institut für MikrobiologieTechnische Universität BraunschweigSpielmannstrasse 738106BraunschweigGermany
| | - José V. Ramos
- Institut für Pharmazeutische WissenschaftenPharmazeutische Biologie und BiotechnologieAlbert-Ludwigs-Universität FreiburgStefan-Meier-Str. 1979104FreiburgGermany
| | - Christian Trncik
- Institut für BiochemieAlbert-Ludwigs-Universität FreiburgAlbertstrasse 2179104FreiburgGermany
| | - Dieter Jahn
- Institut für MikrobiologieTechnische Universität BraunschweigSpielmannstrasse 738106BraunschweigGermany
| | - Oliver Einsle
- Institut für BiochemieAlbert-Ludwigs-Universität FreiburgAlbertstrasse 2179104FreiburgGermany
| | - Gunhild Layer
- Institut für Pharmazeutische WissenschaftenPharmazeutische Biologie und BiotechnologieAlbert-Ludwigs-Universität FreiburgStefan-Meier-Str. 1979104FreiburgGermany
| | - Jürgen Moser
- Institut für MikrobiologieTechnische Universität BraunschweigSpielmannstrasse 738106BraunschweigGermany
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43
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Affiliation(s)
- Oliver Einsle
- Institute for Biochemistry, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Douglas C. Rees
- Division of Chemistry and Chemical Engineering, Howard Hughes Medical Institute, California Institute of Technology, Pasadena California 91125, United States
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44
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Tanifuji K, Ohki Y. Metal–Sulfur Compounds in N2 Reduction and Nitrogenase-Related Chemistry. Chem Rev 2020; 120:5194-5251. [DOI: 10.1021/acs.chemrev.9b00544] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Kazuki Tanifuji
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, California 92697-3900, United States
| | - Yasuhiro Ohki
- Department of Chemsitry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
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45
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The Role of Fnr Paralogs in Controlling Anaerobic Metabolism in the Diazotroph Paenibacillus polymyxa WLY78. Appl Environ Microbiol 2020; 86:AEM.03012-19. [PMID: 32198173 DOI: 10.1128/aem.03012-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 02/28/2020] [Indexed: 11/20/2022] Open
Abstract
Fnr is a transcriptional regulator that controls the expression of a variety of genes in response to oxygen limitation in bacteria. Genome sequencing revealed four genes (fnr1, fnr3, fnr5, and fnr7) coding for Fnr proteins in Paenibacillus polymyxa WLY78. Fnr1 and Fnr3 showed more similarity to each other than to Fnr5 and Fnr7. Also, Fnr1 and Fnr3 exhibited high similarity with Bacillus cereus Fnr and Bacillus subtilis Fnr in sequence and structures. Both the aerobically purified His-tagged Fnr1 and His-tagged Fnr3 in Escherichia coli could bind to the specific DNA promoter. Deletion analysis showed that the four fnr genes, especially fnr1 and fnr3, have significant impacts on growth and nitrogenase activity. Single deletion of fnr1 or fnr3 led to a 50% reduction in nitrogenase activity, and double deletion of fnr1 and fnr3 resulted to a 90% reduction in activity. Genome-wide transcription analysis showed that Fnr1 and Fnr3 indirectly activated expression of nif (nitrogen fixation) genes and Fe transport genes under anaerobic conditions. Fnr1 and Fnr3 inhibited expression of the genes involved in the aerobic respiratory chain and activated expression of genes responsible for anaerobic electron acceptor genes.IMPORTANCE The members of the nitrogen-fixing Paenibacillus spp. have great potential to be used as a bacterial fertilizer in agriculture. However, the functions of the fnr gene(s) in nitrogen fixation and other metabolisms in Paenibacillus spp. are not known. Here, we found that in P. polymyxa WLY78, Fnr1 and Fnr3 were responsible for regulation of numerous genes in response to changes in oxygen levels, but Fnr5 and Fnr7 exhibited little effect. Fnr1 and Fnr3 indirectly or directly regulated many types of important metabolism, such as nitrogen fixation, Fe uptake, respiration, and electron transport. This study not only reveals the function of the fnr genes of P. polymyxa WLY78 in nitrogen fixation and other metabolisms but also will provide insight into the evolution and regulatory mechanisms of fnr in Paenibacillus.
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Jin WT, Yang M, Zhu SS, Zhou ZH. Bond-valence analyses of the crystal structures of FeMo/V cofactors in FeMo/V proteins. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2020; 76:428-437. [PMID: 32355039 DOI: 10.1107/s2059798320003952] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 03/18/2020] [Indexed: 12/15/2022]
Abstract
The bond-valence method has been used for valence calculations of FeMo/V cofactors in FeMo/V proteins using 51 crystallographic data sets of FeMo/V proteins from the Protein Data Bank. The calculations show molybdenum(III) to be present in MoFe7S9C(Cys)(HHis)[R-(H)homocit] (where H4homocit is homocitric acid, HCys is cysteine and HHis is histidine) in FeMo cofactors, while vanadium(III) with a more reduced iron complement is obtained for FeV cofactors. Using an error analysis of the calculated valences, it was found that in FeMo cofactors Fe1, Fe6 and Fe7 can be unambiguously assigned as iron(III), while Fe2, Fe3, Fe4 and Fe5 show different degrees of mixed valences for the individual Fe atoms. For the FeV cofactors in PDB entry 5n6y, Fe4, Fe5 and Fe6 correspond to iron(II), iron(II) and iron(III), respectively, while Fe1, Fe2, Fe3 and Fe7 exhibit strongly mixed valences. Special situations such as CO-bound and selenium-substituted FeMo cofactors and O(N)H-bridged FeV cofactors are also discussed and suggest rearrangement of the electron configuration on the substitution of the bridging S atoms.
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Affiliation(s)
- Wan Ting Jin
- State Key Laboratory for Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
| | - Min Yang
- State Key Laboratory for Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
| | - Shuang Shuang Zhu
- State Key Laboratory for Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
| | - Zhao Hui Zhou
- State Key Laboratory for Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
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Seefeldt LC, Yang ZY, Lukoyanov DA, Harris DF, Dean DR, Raugei S, Hoffman BM. Reduction of Substrates by Nitrogenases. Chem Rev 2020; 120:5082-5106. [PMID: 32176472 DOI: 10.1021/acs.chemrev.9b00556] [Citation(s) in RCA: 169] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Nitrogenase is the enzyme that catalyzes biological N2 reduction to NH3. This enzyme achieves an impressive rate enhancement over the uncatalyzed reaction. Given the high demand for N2 fixation to support food and chemical production and the heavy reliance of the industrial Haber-Bosch nitrogen fixation reaction on fossil fuels, there is a strong need to elucidate how nitrogenase achieves this difficult reaction under benign conditions as a means of informing the design of next generation synthetic catalysts. This Review summarizes recent progress in addressing how nitrogenase catalyzes the reduction of an array of substrates. New insights into the mechanism of N2 and proton reduction are first considered. This is followed by a summary of recent gains in understanding the reduction of a number of other nitrogenous compounds not considered to be physiological substrates. Progress in understanding the reduction of a wide range of C-based substrates, including CO and CO2, is also discussed, and remaining challenges in understanding nitrogenase substrate reduction are considered.
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Affiliation(s)
- Lance C Seefeldt
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Zhi-Yong Yang
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Dmitriy A Lukoyanov
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Derek F Harris
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Dennis R Dean
- Biochemistry Department, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Simone Raugei
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Brian M Hoffman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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Jasniewski AJ, Lee CC, Ribbe MW, Hu Y. Reactivity, Mechanism, and Assembly of the Alternative Nitrogenases. Chem Rev 2020; 120:5107-5157. [PMID: 32129988 DOI: 10.1021/acs.chemrev.9b00704] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Biological nitrogen fixation is catalyzed by the enzyme nitrogenase, which facilitates the cleavage of the relatively inert triple bond of N2. Nitrogenase is most commonly associated with the molybdenum-iron cofactor called FeMoco or the M-cluster, and it has been the subject of extensive structural and spectroscopic characterization over the past 60 years. In the late 1980s and early 1990s, two "alternative nitrogenase" systems were discovered, isolated, and found to incorporate V or Fe in place of Mo. These systems are regulated by separate gene clusters; however, there is a high degree of structural and functional similarity between each nitrogenase. Limited studies with the V- and Fe-nitrogenases initially demonstrated that these enzymes were analogously active as the Mo-nitrogenase, but more recent investigations have found capabilities that are unique to the alternative systems. In this review, we will discuss the reactivity, biosynthetic, and mechanistic proposals for the alternative nitrogenases as well as their electronic and structural properties in comparison to the well-characterized Mo-dependent system. Studies over the past 10 years have been particularly fruitful, though key aspects about V- and Fe-nitrogenases remain unexplored.
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Affiliation(s)
- Andrew J Jasniewski
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697-3900, United States
| | - Chi Chung Lee
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697-3900, United States
| | - Markus W Ribbe
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697-3900, United States.,Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Yilin Hu
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697-3900, United States
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Badalyan A, Yang ZY, Hu B, Luo J, Hu M, Liu TL, Seefeldt LC. An Efficient Viologen-Based Electron Donor to Nitrogenase. Biochemistry 2019; 58:4590-4595. [PMID: 31682410 DOI: 10.1021/acs.biochem.9b00844] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nitrogenase catalyzes the reduction of N2 to NH3, supporting all biological nitrogen fixation. Electron donors to this enzyme are ferredoxin or flavodoxin (in vivo) and sodium dithionite (in vitro). Features of these electron donors put a limit on spectrophotometric studies and electrocatalytic applications of nitrogenase. Although it is common to use methyl viologen as an electron donor for many low-potential oxidoreductases, decreased nitrogenase activity is observed with an increasing concentration of methyl viologen, limiting its utility under many circumstances. In this work, we suggest that this concentration-dependent decrease in activity can be explained by the formation of a dimer of the radical cation of methyl viologen (Me2V•+)2 at higher methyl viologen concentrations. In addition, viologens functionalized with positively and negatively charged groups were synthesized and studied using spectroscopy and cyclic voltammetry. A sulfonated viologen derivative, 1,1'-bis(3-sulfonatopropyl)-4,4'-bipyridinium radical {[(SPr)2V•]-}, was found to support full nitrogenase activity up to a mediator concentration of 3 mM, while the positively charged viologen derivative was not an efficient reductant of nitrogenase due to the high standard redox potential. The utility of [(SPr)2V•]- as an electron donor for nitrogenase was demonstrated by a simple, sensitive spectrophotometric assay for nitrogenase activity that can provide accurate values for the specific activity and turnover rate constant under argon. Under N2, the formation of ammonia was confirmed. Because of the observed full activity of nitrogenase and low overpotential, [(SPr)2V•]- should also prove to be valuable for nitrogenase electrocatalysis, including bioelectrosynthetic N2 reduction.
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Affiliation(s)
- Artavazd Badalyan
- Department of Chemistry and Biochemistry , Utah State University , 0300 Old Main Hill , Logan , Utah 84322 , United States
| | - Zhi-Yong Yang
- Department of Chemistry and Biochemistry , Utah State University , 0300 Old Main Hill , Logan , Utah 84322 , United States
| | - Bo Hu
- Department of Chemistry and Biochemistry , Utah State University , 0300 Old Main Hill , Logan , Utah 84322 , United States
| | - Jian Luo
- Department of Chemistry and Biochemistry , Utah State University , 0300 Old Main Hill , Logan , Utah 84322 , United States
| | - Maowei Hu
- Department of Chemistry and Biochemistry , Utah State University , 0300 Old Main Hill , Logan , Utah 84322 , United States
| | - T Leo Liu
- Department of Chemistry and Biochemistry , Utah State University , 0300 Old Main Hill , Logan , Utah 84322 , United States
| | - Lance C Seefeldt
- Department of Chemistry and Biochemistry , Utah State University , 0300 Old Main Hill , Logan , Utah 84322 , United States
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Van Stappen C, Thorhallsson AT, Decamps L, Bjornsson R, DeBeer S. Resolving the structure of the E 1 state of Mo nitrogenase through Mo and Fe K-edge EXAFS and QM/MM calculations. Chem Sci 2019; 10:9807-9821. [PMID: 32055350 PMCID: PMC6984330 DOI: 10.1039/c9sc02187f] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 09/03/2019] [Indexed: 11/21/2022] Open
Abstract
Biological nitrogen fixation is predominately accomplished through Mo nitrogenase, which utilizes a complex MoFe7S9C catalytic cluster to reduce N2 to NH3. This cluster requires the accumulation of three to four reducing equivalents prior to binding N2; however, despite decades of research, the intermediate states formed prior to N2 binding are still poorly understood. Herein, we use Mo and Fe K-edge X-ray absorption spectroscopy and QM/MM calculations to investigate the nature of the E1 state, which is formed following the addition of the first reducing equivalent to Mo nitrogenase. By analyzing the extended X-ray absorption fine structure (EXAFS) region, we provide structural insight into the changes that occur in the metal clusters of the protein when forming the E1 state, and use these metrics to assess a variety of possible models of the E1 state. The combination of our experimental and theoretical results supports that formation of E1 involves an Fe-centered reduction combined with the protonation of a belt-sulfide of the cluster. Hence, these results provide critical experiment and computational insight into the mechanism of this important enzyme.
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Affiliation(s)
- Casey Van Stappen
- Max-Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , NRW , Germany . ;
| | - Albert Thor Thorhallsson
- Max-Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , NRW , Germany . ;
| | - Laure Decamps
- Max-Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , NRW , Germany . ;
| | - Ragnar Bjornsson
- Max-Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , NRW , Germany . ;
| | - Serena DeBeer
- Max-Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , NRW , Germany . ;
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