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Verdejo-Torres O, Klein DC, Novoa-Aponte L, Carrazco-Carrillo J, Bonilla-Pinto D, Rivera A, Fitisemanu F, Jiménez-González ML, Flinn L, Pezacki AT, Lanzirotti A, Ortiz-Frade LA, Chang CJ, Navea JG, Blaby-Haas C, Hainer SJ, Padilla-Benavides T. Cysteine Rich Intestinal Protein 2 is a copper-responsive regulator of skeletal muscle differentiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.03.592485. [PMID: 38746126 PMCID: PMC11092763 DOI: 10.1101/2024.05.03.592485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Copper (Cu) is an essential trace element required for respiration, neurotransmitter synthesis, oxidative stress response, and transcriptional regulation. Imbalance in Cu homeostasis can lead to several pathological conditions, affecting neuronal, cognitive, and muscular development. Mechanistically, Cu and Cu-binding proteins (Cu-BPs) have an important but underappreciated role in transcription regulation in mammalian cells. In this context, our lab investigates the contributions of novel Cu-BPs in skeletal muscle differentiation using murine primary myoblasts. Through an unbiased synchrotron X-ray fluorescence-mass spectrometry (XRF/MS) metalloproteomic approach, we identified the murine cysteine rich intestinal protein 2 (mCrip2) in a sample that showed enriched Cu signal, which was isolated from differentiating primary myoblasts derived from mouse satellite cells. Immunolocalization analyses showed that mCrip2 is abundant in both nuclear and cytosolic fractions. Thus, we hypothesized that mCrip2 might have differential roles depending on its cellular localization in the skeletal muscle lineage. mCrip2 is a LIM-family protein with 4 conserved Zn2+-binding sites. Homology and phylogenetic analyses showed that mammalian Crip2 possesses histidine residues near two of the Zn2+-binding sites (CX2C-HX2C) which are potentially implicated in Cu+-binding and competition with Zn2+. Biochemical characterization of recombinant human hsCRIP2 revealed a high Cu+-binding affinity for two and four Cu+ ions and limited redox potential. Functional characterization using CRISPR/Cas9-mediated deletion of mCrip2 in primary myoblasts did not impact proliferation, but impaired myogenesis by decreasing the expression of differentiation markers, possibly attributed to Cu accumulation. Transcriptome analyses of proliferating and differentiating mCrip2 KO myoblasts showed alterations in mRNA processing, protein translation, ribosome synthesis, and chromatin organization. CUT&RUN analyses showed that mCrip2 associates with a select set of gene promoters, including MyoD1 and metallothioneins, acting as a novel Cu-responsive or Cu-regulating protein. Our work demonstrates novel regulatory functions of mCrip2 that mediate skeletal muscle differentiation, presenting new features of the Cu-network in myoblasts.
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Affiliation(s)
- Odette Verdejo-Torres
- Department of Molecular Biology and Biochemistry, Wesleyan University, CT, 06459. USA
| | - David C. Klein
- Department of Biological Sciences. University of Pittsburgh, Pittsburgh, PA. 15207. USA
| | - Lorena Novoa-Aponte
- Present address: Genetics and Metabolism Section, Liver Diseases Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD. USA
| | | | - Denzel Bonilla-Pinto
- Department of Molecular Biology and Biochemistry, Wesleyan University, CT, 06459. USA
| | - Antonio Rivera
- Department of Molecular Biology and Biochemistry, Wesleyan University, CT, 06459. USA
| | | | | | - Lyra Flinn
- Chemistry Department. Skidmore College, Saratoga Springs New York, 12866. USA
| | - Aidan T. Pezacki
- Department of Chemistry. University of California, Berkeley, California, 94720. USA
| | - Antonio Lanzirotti
- Center for Advanced Radiation Sources, The University of Chicago, Lemont, IL 60439. USA
| | | | - Christopher J. Chang
- Department of Chemistry. University of California, Berkeley, California, 94720. USA
- Department of Molecular and Cell Biology. University of California, Berkeley, California, 94720. USA
| | - Juan G. Navea
- Chemistry Department. Skidmore College, Saratoga Springs New York, 12866. USA
| | - Crysten Blaby-Haas
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA & DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA. USA
| | - Sarah J. Hainer
- Department of Biological Sciences. University of Pittsburgh, Pittsburgh, PA. 15207. USA
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Tada T, Mizuno Y, Shibata Y, Yasui H, Kuge Y. Application of copper (I) selective ligands for PET imaging of reactive oxygen species through metabolic trapping. Nucl Med Biol 2024; 134-135:108914. [PMID: 38733873 DOI: 10.1016/j.nucmedbio.2024.108914] [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: 10/17/2023] [Revised: 03/29/2024] [Accepted: 04/24/2024] [Indexed: 05/13/2024]
Abstract
INTRODUCTION Reactive oxygen species (ROS) are attractive targets for clinical PET imaging. In this study, we hypothesized that PET imaging of ROS would be possible by using chelating ligands (L) that form stable complexes with copper (I) but not with copper (II), based on metabolic trapping. Namely, when [64Cu][CuI(L)2]+ is oxidized by ROS, the oxidized complex will release [64Cu]Cu2+. Then, the released [64Cu]Cu2+ will be trapped inside the cell, resulting in PET signal depending on the redox potential of ROS. To examine the potential of this novel molecular design for ROS imaging, we synthesized copper (I) complexes with bicinchoninic acid (BCA) disodium salt and bathocuproinedisulfonic acid (BCS) disodium salt and evaluated their reactivity with several kinds of ROS. In addition, the cellular uptake of [64Cu][CuI(BCS)2]3- and the stability of [64Cu][CuI(BCS)2]3- in a biological condition were also evaluated. METHODS [64Cu]Cu2+ was reduced to [64Cu]Cu+ by ascorbic acid and coordinated with BCA and BCS in the acetate buffer to synthesize [64Cu][CuI(BCA)2]3- and [64Cu][CuI(BCS)2]3-. The radiochemical yields were determined by thin-layer chromatography (TLC). After [64Cu][CuI(BCS)2]3- was incubated with hydroxyl radical, lipid peroxide, superoxide, and hydrogen peroxide, the percentage of released [64Cu]Cu2+ from the parent complex was evaluated by TLC. HT-1080 human fibrosarcoma cells were treated with 0.1 % Dimethyl sulfoxide (control), imidazole ketone erastin (IKE), or IKE + ferrostatin-1 (Fer-1). Then, the uptake of [64Cu][CuI(BCS)2]3- to HT-1080 cells in each group was evaluated as %Dose/mg protein. Lastly, [64Cu][CuI(BCS)2]3- was incubated in human plasma, and its intact ratio was determined by TLC. RESULTS The radiochemical yield of [64Cu][CuI(BCS)2]3- (86 ± 1 %) was higher than that of [64Cu][CuI(BCA)2]3- (44 ± 3 %). [64Cu][CuI(BCA)2]3- was unstable and partially decomposed on TLC. After [64Cu][CuI(BCS)2]3- was reacted with hydroxyl radical, lipid peroxide, and superoxide, 67 ± 2 %, 44 ± 13 %, and 22 ± 3 % of total radioactivity was detected as [64Cu]Cu2+, respectively. On the other hand, the reaction with hydrogen peroxide did not significantly increase the ratio of [64Cu]Cu2+ (4 ± 1 %). These results suggest that [64Cu][CuI(BCS)2]3- could be used for detecting high-redox-potential ROS such as hydroxyl radical and lipid peroxide with high selectivity. The cellular uptake values of [64Cu][CuI(BCS)2]3- in the control, IKE, and Fer-1 group were 42 ± 2, 54 ± 2, and 47 ± 5 %Dose/mg protein (n = 3), respectively, suggesting the ROS specific uptake of [64Cu][CuI(BCS)2]3-. On the other hand, the intact ratio after the incubation of [64Cu][CuI(BCS)2]3- in human plasma was 9 ± 5 %. CONCLUSION PET imaging of ROS would be possible by using a copper (I) selective ligand, based on metabolic trapping. Although improvement of the membrane permeability and the stability of copper (I) complexes is required, the present results pave the way for the development of novel 64Cu-labeled complexes for PET imaging of ROS.
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Affiliation(s)
- Tetsuro Tada
- Graduate School of Biomedical Science and Engineering, Hokkaido University, Hokkaido 060-0815, Japan
| | - Yuki Mizuno
- Central Institute of Isotope Science, Hokkaido University, Hokkaido 060-0815, Japan; Global Center for Biomedical Science and Engineering, Hokkaido University, Hokkaido 060-0815, Japan.
| | - Yuki Shibata
- Central Institute of Isotope Science, Hokkaido University, Hokkaido 060-0815, Japan
| | - Hironobu Yasui
- Faculty of Veterinary Medicine, Hokkaido University, Hokkaido 060-0818, Japan; One Health Research Center, Hokkaido University, Hokkaido 060-0818, Japan
| | - Yuji Kuge
- Central Institute of Isotope Science, Hokkaido University, Hokkaido 060-0815, Japan; Global Center for Biomedical Science and Engineering, Hokkaido University, Hokkaido 060-0815, Japan
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Rulmont C, Stigliani JL, Hureau C, Esmieu C. Rationally Designed Cu(I) Ligand to Prevent CuAβ-Generated ROS Production in the Alzheimer's Disease Context. Inorg Chem 2024; 63:2340-2351. [PMID: 38243896 DOI: 10.1021/acs.inorgchem.3c02693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2024]
Abstract
In the context of Alzheimer's disease, copper (Cu) can be loosely bound to the amyloid-β (Aβ) peptide, leading to the formation of CuAβ, which can catalytically generate reactive oxygen species that contribute to oxidative stress. To fight against this phenomenon, the chelation therapy approach has been developed and consists of using a ligand able to remove Cu from Aβ and to redox-silence it, thus stopping the reactive oxygen species (ROS) production. A large number of Cu(II) chelators has been studied, allowing us to define and refine the properties required to design a "good" ligand, but without strong therapeutic outcomes to date. Those chelators targeted the Cu(II) redox state. Herein, we explore a parallel and relevant alternative pathway by designing a chelator able to target the Cu(I) redox state. To that end, we designed LH2 ([1N3S] binding set) and demonstrated that (i) it is perfectly able to extract Cu(I) from Cu(I)Aβ even in the presence of an excess of Zn(II) and (ii) it redox-silences the Cu, preventing the formation of ROS. We showed that LH2 that is sensitive to oxidation can efficiently replace the [Zn(II)L] complex without losing its excellent ability to stop the ROS production while increasing its resistance to oxidation.
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Affiliation(s)
- Clément Rulmont
- LCC-CNRS, Université de Toulouse, CNRS, Toulouse 31077, France
| | | | | | - Charlène Esmieu
- LCC-CNRS, Université de Toulouse, CNRS, Toulouse 31077, France
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Lu J, Liu X, Li X, Li H, Shi L, Xia X, He BL, Meyer TF, Li X, Sun H, Yang X. Copper regulates the host innate immune response against bacterial infection via activation of ALPK1 kinase. Proc Natl Acad Sci U S A 2024; 121:e2311630121. [PMID: 38232278 PMCID: PMC10823219 DOI: 10.1073/pnas.2311630121] [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: 07/09/2023] [Accepted: 11/22/2023] [Indexed: 01/19/2024] Open
Abstract
Copper is an essential trace element for the human body, and its requirement for optimistic immune functions has been recognized for decades. How copper is involved in the innate immune pathway, however, remains to be clarified. Here, we report that copper serves as a signal molecule to regulate the kinase activity of alpha-kinase 1 (ALPK1), a cytosolic pattern-recognition receptor (PRR), and therefore promotes host cell defense against bacterial infection. We show that in response to infection, host cells actively accumulate copper in the cytosol, and the accumulated cytosolic copper enhances host cell defense against evading pathogens, including intracellular and, unexpectedly, extracellular bacteria. Subsequently, we demonstrate that copper activates the innate immune pathway of host cells in an ALPK1-dependent manner. Further mechanistic studies reveal that copper binds to ALPK1 directly and is essential for the kinase activity of this cytosolic PRR. Moreover, the binding of copper to ALPK1 enhances the sensitivity of ALPK1 to the bacterial metabolite ADP-heptose and eventually prompts host cells to elicit an enhanced immune response during bacterial infection. Finally, using a zebrafish in vivo model, we show that a copper-treated host shows an increased production of proinflammatory cytokines, enhanced recruitment of phagosome cells, and promoted bacterial clearance. Our findings uncover a previously unrecognized role of copper in the modulation of host innate immune response against bacterial pathogens and advance our knowledge on the cross talk between cytosolic copper homeostasis and immune system.
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Affiliation(s)
- Jing Lu
- Guangdong Provincial Engineering Research Center of Molecular Imaging, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai519000, China
- Department of Gastroenterology, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai519000, China
| | - Xue Liu
- Guangdong Provincial Engineering Research Center of Molecular Imaging, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai519000, China
- Department of Chemistry, The University of Hong Kong, Hong Kong Special Administrative Region, China
- Guangdong-Hong Kong-Macao University Joint Laboratory of Interventional Medicine, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai519000, China
| | - Xinghua Li
- Department of Infectious Diseases, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai519000, China
| | - Hongyan Li
- Department of Chemistry, The University of Hong Kong, Hong Kong Special Administrative Region, China
- Chinese Academy of Sciences-The University of Hong Kong Joint Laboratory of Metallomics on Health and Environment, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Liwa Shi
- Guangdong Provincial Engineering Research Center of Molecular Imaging, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai519000, China
- Guangdong-Hong Kong-Macao University Joint Laboratory of Interventional Medicine, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai519000, China
| | - Xin Xia
- Guangdong Provincial Engineering Research Center of Molecular Imaging, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai519000, China
- Guangdong-Hong Kong-Macao University Joint Laboratory of Interventional Medicine, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai519000, China
| | - Bai-liang He
- Guangdong Provincial Engineering Research Center of Molecular Imaging, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai519000, China
- Guangdong-Hong Kong-Macao University Joint Laboratory of Interventional Medicine, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai519000, China
| | - Thomas F. Meyer
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin10117, Germany
- Laboratory of Infection Oncology, Institute of Clinical Molecular Biology, Christian Albrecht’s University of Kiel, University Hospital Schleswig Holstein, Kiel24105, Germany
| | - Xiaofeng Li
- Department of Gastroenterology, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai519000, China
| | - Hongzhe Sun
- Department of Chemistry, The University of Hong Kong, Hong Kong Special Administrative Region, China
- Chinese Academy of Sciences-The University of Hong Kong Joint Laboratory of Metallomics on Health and Environment, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Xinming Yang
- Guangdong Provincial Engineering Research Center of Molecular Imaging, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai519000, China
- Guangdong-Hong Kong-Macao University Joint Laboratory of Interventional Medicine, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai519000, China
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Kukoc-Modun L, Kraljevic T, Tsikas D, Spassov TG, Kolev SD. Determination of N-Acetyl-L-cysteine Ethyl Ester (NACET) by Sequential Injection Analysis. SENSORS (BASEL, SWITZERLAND) 2024; 24:312. [PMID: 38257405 PMCID: PMC10820985 DOI: 10.3390/s24020312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 12/25/2023] [Accepted: 12/30/2023] [Indexed: 01/24/2024]
Abstract
New sequential injection analysis (SIA) methods with optical sensing for the determination of N-acetyl-L-cysteine ethyl ester (NACET) have been developed and optimized. NACET is a potential drug and antioxidant with advantageous pharmacokinetics. The methods involve the reduction of Cu(II) in its complexes with neocuproine (NCN), bicinchoninic acid (BCA), and bathocuproine disulfonic acid (BCS) to the corresponding chromophoric Cu(I) complexes by the analyte. The absorbance of the Cu(I) complexes with NCN, BCA, and BCS was measured at their maximum absorbance wavelengths of 458, 562, and 483 nm, respectively. The sensing manifold parameters and experimental conditions were optimized for each of the Cu(II) complexes used. Under optimal conditions, the corresponding linear calibration ranges, limits of detection, and sampling rates were 8.0 × 10-6-2.0 × 10-4 mol L-1, 5.5 × 10-6 mol L-1, and 60 h-1 for NCN; 6.0 × 10-6-1.0 × 10-4 mol L-1, 5.2 × 10-6 mol L-1, and 60 h-1 for BCA; and 4.0 × 10-6-1.0 × 10-4 mol L-1, 2.6 × 10-6 mol L-1, and 78 h-1 for BCS. The Cu(II)-BCS complex was found to be best performing in terms of sensitivity and sampling rate. Usual excipients in pharmaceutical preparations did not interfere with NACET analysis.
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Affiliation(s)
- Lea Kukoc-Modun
- Department of Analytical Chemistry, Faculty of Chemistry and Technology, University of Split, Ruđera Boškovića 35, 21000 Split, Croatia
| | - Tomislav Kraljevic
- Department of Chemistry, Faculty of Science and Education, University of Mostar, Matice hrvatske bb, 88000 Mostar, Bosnia and Herzegovina;
| | - Dimitrios Tsikas
- Institute of Toxicology, Core Unit Proteomics, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany;
| | - Tony G. Spassov
- Faculty of Chemistry and Pharmacy, Sofia University “St. Kl. Ohridski”, 1 James Bourchier Blvd., 1164 Sofia, Bulgaria;
| | - Spas D. Kolev
- Faculty of Chemistry and Pharmacy, Sofia University “St. Kl. Ohridski”, 1 James Bourchier Blvd., 1164 Sofia, Bulgaria;
- School of Chemistry, The University of Melbourne, Melbourne, VIC 3010, Australia
- Department of Chemical Engineering, The University of Melbourne, Melbourne, VIC 3010, Australia
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6
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Yu Z, Blade G, Bouley BS, Dobrucki IT, Dobrucki LW, Mirica LM. Coordination Chemistry of Sulfur-Containing Bifunctional Chelators: Toward in Vivo Stabilization of 64Cu PET Imaging Agents for Alzheimer's Disease. Inorg Chem 2023; 62:20820-20833. [PMID: 38060375 DOI: 10.1021/acs.inorgchem.3c02929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
The broader utilization of 64Cu positron emission tomography (PET) imaging agents has been hindered by the unproductive demetalation induced by bioreductants. To advance the development of 64Cu-based PET imaging tracers for Alzheimer's Disease (AD), there is a need for novel ligand design strategies. In this study, we developed sulfur-containing dithiapyridinophane (N2S2) bifunctional chelators (BFCs) as well as all nitrogen-based diazapyridinophane (N4) BFCs to compare their abilities to chelate Cu and target Aβ aggregates. Through spectrophotometric titrations and electrochemical measurements, we have demonstrated that the N2S2-based BFCs exhibit >10 orders of magnitude higher binding affinity toward Cu(I) compared to their N4-based counterparts, while both types of BFCs exhibit high stability constants toward Cu(II). Notably, solid state structures for both Cu(II) and Cu(I) complexes supported by the two ligand frameworks were obtained, providing molecular insights into their copper chelating abilities. Aβ binding experiments were conducted to study the structure-affinity relationship, and fluorescence microscopy imaging studies confirmed the selective labeling of the BFCs and their copper complexes. Furthermore, we investigated the potential of these ligands for the 64Cu-based PET imaging of AD through radiolabeling and autoradiography studies. We believe our findings provide molecular insights into the design of bifunctional Cu chelators that can effectively stabilize both Cu(II) and Cu(I) and, thus, can have significant implications for the development of 64Cu PET imaging as a diagnostic tool for AD.
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Affiliation(s)
- Zhengxin Yu
- Department of Chemistry, Beckman Institute for Advanced Science and Technology, The Neuroscience Program, Carle Illinois College of Medicine, University of Illinois at Urbana─Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Glenn Blade
- Department of Chemistry, Beckman Institute for Advanced Science and Technology, The Neuroscience Program, Carle Illinois College of Medicine, University of Illinois at Urbana─Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Bailey S Bouley
- Department of Chemistry, Beckman Institute for Advanced Science and Technology, The Neuroscience Program, Carle Illinois College of Medicine, University of Illinois at Urbana─Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Iwona T Dobrucki
- Beckman Institute for Advanced Science and Technology, Department of Bioengineering, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
| | - Lawrence W Dobrucki
- Beckman Institute for Advanced Science and Technology, Department of Bioengineering, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
| | - Liviu M Mirica
- Department of Chemistry, Beckman Institute for Advanced Science and Technology, The Neuroscience Program, Carle Illinois College of Medicine, University of Illinois at Urbana─Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri 63110, United States
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7
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Han J. Copper trafficking systems in cells: insights into coordination chemistry and toxicity. Dalton Trans 2023; 52:15277-15296. [PMID: 37702384 DOI: 10.1039/d3dt02166a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
Transition metal ions, such as copper, are indispensable components in the biological system. Copper ions which primarily exist in two major oxidation states Cu(I) and Cu(II) play crucial roles in various cellular processes including antioxidant defense, biosynthesis of neurotransmitters, and energy metabolism, owing to their inherent redox activity. The disturbance in copper homeostasis can contribute to the development of copper metabolism disorders, cancer, and neurodegenerative diseases, highlighting the significance of understanding the copper trafficking system in cellular environments. This review aims to offer a comprehensive overview of copper homeostatic machinery, with an emphasis on the coordination chemistry of copper transporters and trafficking proteins. While copper chaperones and the corresponding metalloenzymes are thoroughly discussed, we also explore the potential existence of low-molecular-mass metal complexes within cellular systems. Furthermore, we summarize the toxicity mechanisms originating from copper deficiency or accumulation, which include the dysregulation of oxidative stress, signaling pathways, signal transduction, and amyloidosis. This perspective review delves into the current knowledge regarding the intricate aspects of the copper trafficking system, providing valuable insights into potential treatment strategies from the standpoint of bioinorganic chemistry.
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Affiliation(s)
- Jiyeon Han
- Department of Applied Chemistry, University of Seoul, Seoul 02504, Republic of Korea.
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8
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Zimmeter K, Vileno B, Platas-Iglesias C, Vinjamuri B, Sour A, Faller P. Derivatization of the Peptidic Xxx-Zzz-His Motif toward a Ligand with Attomolar Cu II Affinity under Maintaining High Selectivity and Fast Redox Silencing. Inorg Chem 2023. [PMID: 37269299 DOI: 10.1021/acs.inorgchem.3c00480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Cu chelation in biological systems is of interest as a tool to study the metabolism of this essential metal or for applications in the case of diseases with a systemic or local Cu overload, such as Wilson's or Alzheimer's disease. The choice of the chelating agent must meet several criteria. Among others, affinities and kinetics of metal binding and related metal selectivity are important parameters of the chelators to consider. Here, we report on the synthesis and characterization of Cu-binding properties of two ligands, L1 and L2, derivatives of the well-known peptidic CuII-binding motif Xxx-Zzz-His (also called ATCUN), where CuII is bound to the N-terminal amine, two amidates, and the imidazole. In either L, the N-terminal amine was replaced with a pyridine, and for L2, one amide was replaced with an amine compared to Xxx-Zzz-His. In particular, L2 showed several interesting features, including a CuII-binding affinity with a log KDapp = -16.0 similar to that of EDTA and stronger than all reported ATCUN peptides. L2 showed high selectivity for CuII over ZnII and other essential metal ions, even under the challenging conditions of the presence of human serum albumin. Further, L2 showed fast and efficient CuII redox silencing qualities and CuII-L2 was stable in the presence of mM GSH concentrations. Benefitting the fact that L2 can be easily elongated on its peptide part by standard SPPS to add other functions, L2 has attractive properties as a CuII chelator for application in biological systems.
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Affiliation(s)
- Katharina Zimmeter
- Institut de Chimie (UMR 7177), Université de Strasbourg, CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Bertrand Vileno
- Institut de Chimie (UMR 7177), Université de Strasbourg, CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Carlos Platas-Iglesias
- Departamento de Química Fundamental, Universidade da Coruña, Campus da Zapateira, Rúa da Fraga 10, 15008 A Coruña, Spain
| | - Bharath Vinjamuri
- Institut de Chimie (UMR 7177), Université de Strasbourg, CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Angélique Sour
- Institut de Chimie (UMR 7177), Université de Strasbourg, CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Peter Faller
- Institut de Chimie (UMR 7177), Université de Strasbourg, CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
- Institut Universitaire de France (IUF), 1 rue Descartes, 75231 Paris, France
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9
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Lee J, Dalton RA, Baslé A, Vita N, Dennison C. Important Structural Features of Thiolate-Rich Four-Helix Bundles for Cu(I) Uptake and Removal. Inorg Chem 2023; 62:6617-6628. [PMID: 37057906 PMCID: PMC10155185 DOI: 10.1021/acs.inorgchem.2c04490] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Indexed: 04/15/2023]
Abstract
A family of bacterial copper storage proteins (the Csps) possess thiolate-lined four-helix bundles whose cores can be filled with Cu(I) ions. The majority of Csps are cytosolic (Csp3s), and in vitro studies carried out to date indicate that the Csp3s from Methylosinus trichosporium OB3b (MtCsp3), Bacillus subtilis (BsCsp3), and Streptomyces lividans (SlCsp3) are alike. Bioinformatics have highlighted homologues with potentially different Cu(I)-binding properties from these characterized "classical" Csp3s. Determination herein of the crystal structure of the protein (RkCsp3) from the methanotroph Methylocystis sp. strain Rockwell with Cu(I) bound identifies this as the first studied example of a new subgroup of Csp3s. The most significant structural difference from classical Csp3s is the presence of only two Cu(I) sites at the mouth of the bundle via which Cu(I) ions enter and leave. This is due to the absence of three Cys residues and a His-containing motif, which allow classical Csp3s to bind five to six Cu(I) ions in this region. Regardless, RkCsp3 exhibits rapid Cu(I) binding and the fastest measured Cu(I) removal rate for a Csp3 when using high-affinity ligands as surrogate partners. New experiments on classical Csp3s demonstrate that their His-containing motif is not essential for fast Cu(I) uptake and removal. Other structural features that could be important for these functionally relevant in vitro properties are discussed.
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Affiliation(s)
- Jaeick Lee
- Biosciences Institute, Newcastle University, Newcastle
upon Tyne NE2 4HH, U.K.
| | - Rosemary A. Dalton
- Biosciences Institute, Newcastle University, Newcastle
upon Tyne NE2 4HH, U.K.
| | - Arnaud Baslé
- Biosciences Institute, Newcastle University, Newcastle
upon Tyne NE2 4HH, U.K.
| | - Nicolas Vita
- Biosciences Institute, Newcastle University, Newcastle
upon Tyne NE2 4HH, U.K.
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Yu J, Bacsa J, Fahrni CJ. Conformationally Preorganized High-Affinity Ligands for Copper Biology with Hinged and Rigid Thiophene Backbones. Inorg Chem 2023; 62:1287-1296. [PMID: 36661323 PMCID: PMC10118051 DOI: 10.1021/acs.inorgchem.2c03524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Copper-selective ligands are essential tools for probing the affinity of cuproproteins or manipulating the cellular copper availability. They also harbor significant potential as antiangiogenic agents in cancer therapy or as therapeutics to combat copper toxicity in Wilson's disease. To achieve the high Cu(I) affinities required for competing effectively with cellular cuproproteins, we recently devised a ligand design based on phosphine-sulfide-stabilized phosphine (PSP) donor motifs. Building on this design strategy, we integrated two PSP donors within preorganized ligand architectures composed of either a hinged bithiophene backbone (bithipPS) or a single rigid thiophene bridge (thipPS). Extensive characterization based on X-ray crystal structures, solution NMR data, spectrophotometric titrations, and electrochemical studies established that bithipPS adapts well to the coordination preferences of Cu(I) to form a discrete air-stable mononuclear Cu(I) complex with a dissociation constant of 4 zM. In contrast, the wider bite angle of thipPS introduces some strain upon Cu(I) coordination to yield an almost 10-fold lower affinity with a Kd of 35 zM. As revealed by ICP-MS and two-photon excitation microscopy studies with the Cu(I)-selective fluorescent probe crisp-17, both ligands are effective at removing cellular copper from live mouse fibroblasts with rapid kinetics. Altogether, the stability and redox properties of PSP-ligand-Cu(I) complexes can be effectively tuned by judicious balancing of their geometrical preorganization and conformational flexibility.
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Affiliation(s)
- Jiyao Yu
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332, United States
| | - John Bacsa
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332, United States
- X-ray Crystallography Center, Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Christoph J. Fahrni
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332, United States
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11
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Uzal-Varela R, Patinec V, Tripier R, Valencia L, Maneiro M, Canle M, Platas-Iglesias C, Esteban-Gómez D, Iglesias E. On the dissociation pathways of copper complexes relevant as PET imaging agents. J Inorg Biochem 2022; 236:111951. [PMID: 35963110 DOI: 10.1016/j.jinorgbio.2022.111951] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/15/2022] [Accepted: 07/27/2022] [Indexed: 02/07/2023]
Abstract
Several bifunctional chelators have been synthesized in the last years for the development of new 64Cu-based PET agents for in vivo imaging. When designing a metal-based PET probe, it is important to achieve high stability and kinetic inertness once the radioisotope is coordinated. Different competitive assays are commonly used to evaluate the possible dissociation mechanisms that may induce Cu(II) release in the body. Among them, acid-assisted dissociation tests or transchelation challenges employing EDTA or SOD are frequently used to evaluate both solution thermodynamics and the kinetic behavior of potential metal-based systems. Despite of this, the Cu(II)/Cu(I) bioreduction pathway that could be promoted by the presence of bioreductants still remains little explored. To fill this gap we present here a detailed spectroscopic study of the kinetic behavior of different macrocyclic Cu(II) complexes. The complexes investigated include the cross-bridge cyclam derivative [Cu(CB-TE1A)]+, whose structure was determined using single-crystal X-ray diffraction. The acid-assisted dissociation mechanism was investigated using HClO4 and HCl to analyse the effect of the counterion on the rate constants. The complexes were selected so that the effects of complex charge and coordination polyhedron could be assessed. Cyclic voltammetry experiments were conducted to investigate whether the reduction to Cu(I) falls within the window of common bioreducing agents. The most striking behavior concerns the [Cu(NO2Th)]2+ complex, a 1,4,7-triazacyclononane derivative containing two methylthiazolyl pendant arms. This complex is extremely inert with respect to dissociation following the acid-catalyzed mechanism, but dissociates rather quickly in the presence of a bioreductant like ascorbic acid.
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Affiliation(s)
- Rocío Uzal-Varela
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain
| | - Véronique Patinec
- Univ Brest, UMR-CNRS 6521 CEMCA, 6 avenue Victor le Gorgeu, 29238 Brest, France
| | - Raphaël Tripier
- Univ Brest, UMR-CNRS 6521 CEMCA, 6 avenue Victor le Gorgeu, 29238 Brest, France
| | - Laura Valencia
- Departamento de Química Inorgánica, Universidade de Vigo, Facultad de Ciencias, 36310 Pontevedra, Spain
| | - Marcelino Maneiro
- Departamento de Química Inorgánica, Universidade de Santiago de Compostela, Facultade de Ciencias, 27002 Lugo, Spain
| | - Moisés Canle
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain
| | - Carlos Platas-Iglesias
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain
| | - David Esteban-Gómez
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain.
| | - Emilia Iglesias
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain.
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12
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Novoa-Aponte L, Argüello JM. Unique underlying principles shaping copper homeostasis networks. J Biol Inorg Chem 2022; 27:509-528. [PMID: 35802193 PMCID: PMC9470648 DOI: 10.1007/s00775-022-01947-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/27/2022] [Indexed: 12/27/2022]
Abstract
Abstract Copper is essential in cells as a cofactor for key redox enzymes. Bacteria have acquired molecular components that sense, uptake, distribute, and expel copper ensuring that cuproenzymes are metallated and steady-state metal levels are maintained. Toward preventing deleterious reactions, proteins bind copper ions with high affinities and transfer the metal via ligand exchange, warranting that copper ions are always complexed. Consequently, the directional copper distribution within cell compartments and across cell membranes requires specific dynamic interactions and metal exchange between cognate holo-apo protein partners. These metal exchange reactions are determined by thermodynamic and kinetics parameters and influenced by mass action. Then, copper distribution can be conceptualized as a molecular system of singular interacting elements that maintain a physiological copper homeostasis. This review focuses on the impact of copper high-affinity binding and exchange reactions on the homeostatic mechanisms, the conceptual models to describe the cell as a homeostatic system, the various molecule functions that contribute to copper homeostasis, and the alternative system architectures responsible for copper homeostasis in model bacteria. Graphical Abstract ![]()
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Affiliation(s)
- Lorena Novoa-Aponte
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 60 Prescott St, Worcester, MA, 01605, USA.,Genetics and Metabolism Section, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, 20892, USA
| | - José M Argüello
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 60 Prescott St, Worcester, MA, 01605, USA.
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13
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Naletova I, Greco V, Sciuto S, Attanasio F, Rizzarelli E. Ionophore Ability of Carnosine and Its Trehalose Conjugate Assists Copper Signal in Triggering Brain-Derived Neurotrophic Factor and Vascular Endothelial Growth Factor Activation In Vitro. Int J Mol Sci 2021; 22:13504. [PMID: 34948299 PMCID: PMC8706131 DOI: 10.3390/ijms222413504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 12/11/2022] Open
Abstract
l-carnosine (β-alanyl-l-histidine) (Car hereafter) is a natural dipeptide widely distributed in mammalian tissues and reaching high concentrations (0.7-2.0 mM) in the brain. The molecular features of the dipeptide underlie the antioxidant, anti-aggregating and metal chelating ability showed in a large number of physiological effects, while the biological mechanisms involved in the protective role found against several diseases cannot be explained on the basis of the above-mentioned properties alone, requiring further research efforts. It has been reported that l-carnosine increases the secretion and expression of various neurotrophic factors and affects copper homeostasis in nervous cells inducing Cu cellular uptake in keeping with the key metal-sensing system. Having in mind this l-carnosine ability, here we report the copper-binding and ionophore ability of l-carnosine to activate tyrosine kinase cascade pathways in PC12 cells and stimulate the expression of BDNF. Furthermore, the study was extended to verify the ability of the dipeptide to favor copper signaling inducing the expression of VEGF. Being aware that the potential protective action of l-carnosine is drastically hampered by its hydrolysis, we also report on the behavior of a conjugate of l-carnosine with trehalose that blocks the carnosinase degradative activity. Overall, our findings describe a copper tuning effect on the ability of l-carnosine and, particularly its conjugate, to activate tyrosine kinase cascade pathways.
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Affiliation(s)
- Irina Naletova
- Institute of Crystallography, National Council of Research—CNR, Via Paolo Gaifami 18, 95126 Catania, Italy;
- National Inter-University Consortium Metals Chemistry in Biological Systems (CIRCMSB), Via Celso Ulpiani 27, 70126 Bari, Italy
| | - Valentina Greco
- Department of Chemical Sciences, University of Catania, Viale Andrea Doria 6, 95125 Catania, Italy; (V.G.); (S.S.)
| | - Sebastiano Sciuto
- Department of Chemical Sciences, University of Catania, Viale Andrea Doria 6, 95125 Catania, Italy; (V.G.); (S.S.)
| | - Francesco Attanasio
- Institute of Crystallography, National Council of Research—CNR, Via Paolo Gaifami 18, 95126 Catania, Italy;
| | - Enrico Rizzarelli
- Institute of Crystallography, National Council of Research—CNR, Via Paolo Gaifami 18, 95126 Catania, Italy;
- National Inter-University Consortium Metals Chemistry in Biological Systems (CIRCMSB), Via Celso Ulpiani 27, 70126 Bari, Italy
- Department of Chemical Sciences, University of Catania, Viale Andrea Doria 6, 95125 Catania, Italy; (V.G.); (S.S.)
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14
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Abstract
The functions, purposes, and roles of metallothioneins have been the subject of speculations since the discovery of the protein over 60 years ago. This article guides through the history of investigations and resolves multiple contentions by providing new interpretations of the structure-stability-function relationship. It challenges the dogma that the biologically relevant structure of the mammalian proteins is only the one determined by X-ray diffraction and NMR spectroscopy. The terms metallothionein and thionein are ambiguous and insufficient to understand biological function. The proteins need to be seen in their biological context, which limits and defines the chemistry possible. They exist in multiple forms with different degrees of metalation and types of metal ions. The homoleptic thiolate coordination of mammalian metallothioneins is important for their molecular mechanism. It endows the proteins with redox activity and a specific pH dependence of their metal affinities. The proteins, therefore, also exist in different redox states of the sulfur donor ligands. Their coordination dynamics allows a vast conformational landscape for interactions with other proteins and ligands. Many fundamental signal transduction pathways regulate the expression of the dozen of human metallothionein genes. Recent advances in understanding the control of cellular zinc and copper homeostasis are the foundation for suggesting that mammalian metallothioneins provide a highly dynamic, regulated, and uniquely biological metal buffer to control the availability, fluctuations, and signaling transients of the most competitive Zn(II) and Cu(I) ions in cellular space and time.
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Affiliation(s)
- Artur Krężel
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Wrocław 50-383, Poland
| | - Wolfgang Maret
- Departments of Biochemistry and Nutritional Sciences, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London SE1 9NH, U.K
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15
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Acquisition of ionic copper by the bacterial outer membrane protein OprC through a novel binding site. PLoS Biol 2021; 19:e3001446. [PMID: 34762655 PMCID: PMC8610252 DOI: 10.1371/journal.pbio.3001446] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 11/23/2021] [Accepted: 10/18/2021] [Indexed: 11/19/2022] Open
Abstract
Copper, while toxic in excess, is an essential micronutrient in all kingdoms of life due to its essential role in the structure and function of many proteins. Proteins mediating ionic copper import have been characterised in detail for eukaryotes, but much less so for prokaryotes. In particular, it is still unclear whether and how gram-negative bacteria acquire ionic copper. Here, we show that Pseudomonas aeruginosa OprC is an outer membrane, TonB-dependent transporter that is conserved in many Proteobacteria and which mediates acquisition of both reduced and oxidised ionic copper via an unprecedented CxxxM-HxM metal binding site. Crystal structures of wild-type and mutant OprC variants with silver and copper suggest that acquisition of Cu(I) occurs via a surface-exposed “methionine track” leading towards the principal metal binding site. Together with whole-cell copper quantitation and quantitative proteomics in a murine lung infection model, our data identify OprC as an abundant component of bacterial copper biology that may enable copper acquisition under a wide range of conditions. How do Gram-negative bacteria acquire copper? This study shows that the outer membrane protein OprC from Pseudomonas aeruginosa is abundant during infection and mediates highly selective acquisition of both copper redox states via an extracellular "methionine track" and an unprecedented near-irreversible binding site.
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16
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Novel Bifunctional [16]aneS 4-Derived Chelators for Soft Radiometals. Molecules 2021; 26:molecules26154603. [PMID: 34361752 PMCID: PMC8348053 DOI: 10.3390/molecules26154603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 07/24/2021] [Accepted: 07/26/2021] [Indexed: 11/16/2022] Open
Abstract
The field of targeted radionuclide therapy is rapidly growing, highlighting the need for wider radionuclide availability. Soft Lewis acid ions, such as radioisotopes of platinum, rhodium and palladium, are particularly underdeveloped. This is due in part to a lack of compatible bifunctional chelators. These allow for the practical bioconjugation to targeting vectors, in turn enabling radiolabeling. The [16]andS4 macrocycle has been reported to chelate a number of relevant soft metal ions. In this work, we present a procedure for synthesizing [16]andS4 in 45% yield (five steps, 12% overall yield), together with a selection of strategies for preparing bifunctional derivatives. An ester-linked N-hydroxysuccimide ester (NHS, seven steps, 4% overall yield), an ether-linked isothiocyanate (NCS, eight steps, 5% overall yield) and an azide derivative were prepared. In addition, a new route to a carbon-carbon linked carboxylic acid functionalized derivative is presented. Finally, a general method for conjugating the NHS and NCS derivatives to a polar peptide (octreotide) is presented, by dissolution in water:acetonitrile (1:1), buffered to pH 9.4 using borate. The reported compounds will be readily applicable in radiopharmaceutical chemistry, by facilitating the labeling of a range of molecules, including peptides, with relevant soft radiometal ions.
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17
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Principles and practice of determining metal-protein affinities. Biochem J 2021; 478:1085-1116. [PMID: 33710331 PMCID: PMC7959690 DOI: 10.1042/bcj20200838] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/05/2021] [Accepted: 02/11/2021] [Indexed: 01/02/2023]
Abstract
Metal ions play many critical roles in biology, as structural and catalytic cofactors, and as cell regulatory and signalling elements. The metal–protein affinity, expressed conveniently by the metal dissociation constant, KD, describes the thermodynamic strength of a metal–protein interaction and is a key parameter that can be used, for example, to understand how proteins may acquire metals in a cell and to identify dynamic elements (e.g. cofactor binding, changing metal availabilities) which regulate protein metalation in vivo. Here, we outline the fundamental principles and practical considerations that are key to the reliable quantification of metal–protein affinities. We review a selection of spectroscopic probes which can be used to determine protein affinities for essential biological transition metals (including Mn(II), Fe(II), Co(II), Ni(II), Cu(I), Cu(II) and Zn(II)) and, using selected examples, demonstrate how rational probe selection combined with prudent experimental design can be applied to determine accurate KD values.
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18
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The Two-Component System CopRS Maintains Subfemtomolar Levels of Free Copper in the Periplasm of Pseudomonas aeruginosa Using a Phosphatase-Based Mechanism. mSphere 2020; 5:5/6/e01193-20. [PMID: 33361129 PMCID: PMC7763554 DOI: 10.1128/msphere.01193-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Copper is a micronutrient required as cofactor in redox enzymes. When free, copper is toxic, mismetallating proteins and generating damaging free radicals. Two-component systems control periplasmic Cu+ homeostasis in Gram-negative bacteria. In characterized systems such as Escherichia coli CusRS, upon Cu+ binding to the periplasmic sensing region of CusS, a cytoplasmic phosphotransfer domain of the sensor phosphorylates the response regulator CusR. This drives the expression of efflux transporters, chaperones, and redox enzymes to ameliorate metal toxic effects. Here, we show that the Pseudomonas aeruginosa two-component sensor histidine kinase CopS exhibits a Cu-dependent phosphatase activity that maintains CopR in a nonphosphorylated state when the periplasmic Cu levels are below the activation threshold of CopS. Upon Cu+ binding to the sensor, the phosphatase activity is blocked and the phosphorylated CopR activates transcription of the CopRS regulon. Supporting the model, mutagenesis experiments revealed that the ΔcopS strain exhibits maximal expression of the CopRS regulon, lower intracellular Cu+ levels, and increased Cu tolerance compared to wild-type cells. The invariant phosphoacceptor residue His235 of CopS was not required for the phosphatase activity itself but was necessary for its Cu dependency. To sense the metal, the periplasmic domain of CopS binds two Cu+ ions at its dimeric interface. Homology modeling of CopS based on CusS structure (four Ag+ binding sites) clearly supports the different binding stoichiometries in the two systems. Interestingly, CopS binds Cu+/2+ with 3 × 10−14 M affinity, pointing to the absence of free (hydrated) Cu+/2+ in the periplasm. IMPORTANCE Copper is a micronutrient required as cofactor in redox enzymes. When free, copper is toxic, mismetallating proteins and generating damaging free radicals. Consequently, copper overload is a strategy that eukaryotic cells use to combat pathogens. Bacteria have developed copper-sensing transcription factors to control copper homeostasis. The cell envelope is the first compartment that has to cope with copper stress. Dedicated two-component systems control the periplasmic response to metal overload. This paper shows that the sensor kinase of the copper-sensing two-component system present in Pseudomonadales exhibits a signal-dependent phosphatase activity controlling the activation of its cognate response regulator, distinct from previously described periplasmic Cu sensors. Importantly, the data show that the system is activated by copper levels compatible with the absence of free copper in the cell periplasm. These observations emphasize the diversity of molecular mechanisms that have evolved in bacteria to manage the copper cellular distribution.
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Zengin H, Marsan H, Gürkan R. Selective extraction of Cu+ and Cu2+ ions from mushroom and lichen samples prior to analysis by micro-volume UV-Vis spectrophotometry: Application of a novel poly (SMIm)-Tris-Fe3O4 nanocomposite. J Food Compost Anal 2020. [DOI: 10.1016/j.jfca.2020.103539] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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20
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Shen T, Hu X, Liu Y, Zhang Y, Chen K, Xie S, Ke G, Song G, Zhang XB. Specific Core-Satellite Nanocarriers for Enhanced Intracellular ROS Generation and Synergistic Photodynamic Therapy. ACS APPLIED MATERIALS & INTERFACES 2020; 12:5403-5412. [PMID: 31916740 DOI: 10.1021/acsami.9b16934] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The deficiency of reactive oxygen species (ROS) is the main reason for the current poor efficiency of tumor photodynamic therapy (PDT). To solve this problem, a simple light-triggered core-satellite nanoplatform (UPSD@Au) has been developed by loading Au nanoparticles on the surface of mesoporous silica-coated upconversion nanoparticles. Small molecules DC50 (C17H14BrF2N3OS) and photosensitizer (silicon phthalocyanine dihydroxide, SPCD) were loaded into the silica shell to improve ROS production. Meanwhile, PDT can be triggered through facile near-infrared laser irradiation given the occurrence of a moderate photothermal transfer process between upconversion nanoparticles and Au. The reasonable increment in temperature induced by Au resulted in the timely release of DC50. The inhibition of copper transfer by DC50 results in reduced ROS scavenging and thus improves light-triggered ROS accumulation. Notably, the expression levels of the human copper-trafficking proteins Atox1 and CCS in cancerous cells exceed those in normal cells, and thus enhanced ROS accumulation effect was achieved in cancerous cells. In vitro and in vivo results demonstrate that the synergism between DC50 and SPCD coloaded in the UPSD@Au nanoplatform increases the efficiency of PDT. The UPSD@Au platform represents an efficient codelivery method for hydrophobic small molecules and improves sensitization to specific cancer therapy.
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Affiliation(s)
- Tingting Shen
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics , Hunan University , Changsha 410082 , China
| | - Xiaoxiao Hu
- College of Life Sciences, Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, Aptamer Engineering Center of Hunan Province , Hunan University , Changsha , Hunan 410082 , China
| | - Yongchao Liu
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics , Hunan University , Changsha 410082 , China
| | - Yu Zhang
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
| | - Kun Chen
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics , Hunan University , Changsha 410082 , China
| | - Sitao Xie
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics , Hunan University , Changsha 410082 , China
| | - Guoliang Ke
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics , Hunan University , Changsha 410082 , China
| | - Guosheng Song
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics , Hunan University , Changsha 410082 , China
| | - Xiao-Bing Zhang
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics , Hunan University , Changsha 410082 , China
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21
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Saeedifard F, Morgan MT, Bacsa J, Fahrni CJ. Preorganized PSP Ligands Yield Monomeric Cu(I) Complexes with Subzeptomolar Cu(I) Dissociation Constants. Inorg Chem 2019; 58:13631-13638. [PMID: 31124662 DOI: 10.1021/acs.inorgchem.9b00965] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Unraveling the function of biological copper (Cu) requires tools that can selectively recognize and manipulate this trace nutrient within the complex chemical environment of biological systems. Increasing evidence suggests that cells maintain an exchangeable pool of Cu(I) that is buffered in the high zeptomolar to low attomolar range. While mixed amine-thioether donors have been commonly employed for the design of Cu(I)-selective ligands and probes, their dissociation constants are limited to the pico- to femtomolar range. To address this challenge, we combined our previously devised phosphine sulfide-stabilized phosphine donor motifs with a rigid 1,2-phenylene or 1,8-naphthylene ligand backbone. The resulting ligands, phenPS and naphPS, bind Cu(I) with a 1:1 complex stoichiometry and offer dissociation constants of 0.6 and 0.8 zM, respectively. Concluding from the crystal structures of the free and Cu(I)-bound ligands, the 1,2-phenylene-bridged ligand phenPS provides a high degree of structural preorganization to accommodate the Cu(I) center without large conformational changes, while the 1,8-naphthylene-bridged ligand revealed significant out-of-plane distortions in both the free and Cu(I)-bound states. Both ligands were accessed by palladium-catalyzed cross-coupling reactions from the corresponding arylhalides under mild conditions, an approach that could be readily expanded toward the design of other ligands and probes.
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Affiliation(s)
- Farzaneh Saeedifard
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience , Georgia Institute of Technology , 901 Atlantic Drive , Atlanta , Georgia 30332 , United States
| | - M Thomas Morgan
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience , Georgia Institute of Technology , 901 Atlantic Drive , Atlanta , Georgia 30332 , United States
| | - John Bacsa
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience , Georgia Institute of Technology , 901 Atlantic Drive , Atlanta , Georgia 30332 , United States.,X-ray Crystallography Center, Department of Chemistry , Emory University , 1515 Dickey Drive , Atlanta , Georgia 30322 , United States
| | - Christoph J Fahrni
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience , Georgia Institute of Technology , 901 Atlantic Drive , Atlanta , Georgia 30332 , United States
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22
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Ratiometric two-photon microscopy reveals attomolar copper buffering in normal and Menkes mutant cells. Proc Natl Acad Sci U S A 2019; 116:12167-12172. [PMID: 31160463 DOI: 10.1073/pnas.1900172116] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Copper is controlled by a sophisticated network of transport and storage proteins within mammalian cells, yet its uptake and efflux occur with rapid kinetics. Present as Cu(I) within the reducing intracellular environment, the nature of this labile copper pool remains elusive. While glutathione is involved in copper homeostasis and has been assumed to buffer intracellular copper, we demonstrate with a ratiometric fluorescent indicator, crisp-17, that cytosolic Cu(I) levels are buffered to the vicinity of 1 aM, where negligible complexation by glutathione is expected. Enabled by our phosphine sulfide-stabilized phosphine (PSP) ligand design strategy, crisp-17 offers a Cu(I) dissociation constant of 8 aM, thus exceeding the binding affinities of previous synthetic Cu(I) probes by four to six orders of magnitude. Two-photon excitation microscopy with crisp-17 revealed rapid, reversible increases in intracellular Cu(I) availability upon addition of the ionophoric complex CuGTSM or the thiol-selective oxidant 2,2'-dithiodipyridine (DTDP). While the latter effect was dramatically enhanced in 3T3 cells grown in the presence of supplemental copper and in cultured Menkes mutant fibroblasts exhibiting impaired copper efflux, basal Cu(I) availability in these cells showed little difference from controls, despite large increases in total copper content. Intracellular copper is thus tightly buffered by endogenous thiol ligands with significantly higher affinity than glutathione. The dual utility of crisp-17 to detect normal intracellular buffered Cu(I) levels as well as to probe the depth of the labile copper pool in conjunction with DTDP provides a promising strategy to characterize perturbations of cellular copper homeostasis.
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23
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Rosario-Cruz Z, Eletsky A, Daigham NS, Al-Tameemi H, Swapna GVT, Kahn PC, Szyperski T, Montelione GT, Boyd JM. The copBL operon protects Staphylococcus aureus from copper toxicity: CopL is an extracellular membrane-associated copper-binding protein. J Biol Chem 2019; 294:4027-4044. [PMID: 30655293 PMCID: PMC6422080 DOI: 10.1074/jbc.ra118.004723] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 01/08/2019] [Indexed: 12/22/2022] Open
Abstract
As complications associated with antibiotic resistance have intensified, copper (Cu) is attracting attention as an antimicrobial agent. Recent studies have shown that copper surfaces decrease microbial burden, and host macrophages use Cu to increase bacterial killing. Not surprisingly, microbes have evolved mechanisms to tightly control intracellular Cu pools and protect against Cu toxicity. Here, we identified two genes (copB and copL) encoded within the Staphylococcus aureus arginine-catabolic mobile element (ACME) that we hypothesized function in Cu homeostasis. Supporting this hypothesis, mutational inactivation of copB or copL increased copper sensitivity. We found that copBL are co-transcribed and that their transcription is increased during copper stress and in a strain in which csoR, encoding a Cu-responsive transcriptional repressor, was mutated. Moreover, copB displayed genetic synergy with copA, suggesting that CopB functions in Cu export. We further observed that CopL functions independently of CopB or CopA in Cu toxicity protection and that CopL from the S. aureus clone USA300 is a membrane-bound and surface-exposed lipoprotein that binds up to four Cu+ ions. Solution NMR structures of the homologous Bacillus subtilis CopL, together with phylogenetic analysis and chemical-shift perturbation experiments, identified conserved residues potentially involved in Cu+ coordination. The solution NMR structure also revealed a novel Cu-binding architecture. Of note, a CopL variant with defective Cu+ binding did not protect against Cu toxicity in vivo Taken together, these findings indicate that the ACME-encoded CopB and CopL proteins are additional factors utilized by the highly successful S. aureus USA300 clone to suppress copper toxicity.
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Affiliation(s)
- Zuelay Rosario-Cruz
- From the Department of Biochemistry and Microbiology, Rutgers, the State University of New Jersey, New Brunswick, New Jersey 08901
| | - Alexander Eletsky
- the Department of Chemistry, State University of New York at Buffalo and Northeast Structural Genomics Consortium, Buffalo, New York 14260, and
| | - Nourhan S Daigham
- the Department of Molecular Biology and Biochemistry, Center for Advanced Biotechnology and Medicine, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854
| | - Hassan Al-Tameemi
- From the Department of Biochemistry and Microbiology, Rutgers, the State University of New Jersey, New Brunswick, New Jersey 08901
| | - G V T Swapna
- the Department of Molecular Biology and Biochemistry, Center for Advanced Biotechnology and Medicine, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854
| | - Peter C Kahn
- From the Department of Biochemistry and Microbiology, Rutgers, the State University of New Jersey, New Brunswick, New Jersey 08901
| | - Thomas Szyperski
- the Department of Chemistry, State University of New York at Buffalo and Northeast Structural Genomics Consortium, Buffalo, New York 14260, and
| | - Gaetano T Montelione
- the Department of Molecular Biology and Biochemistry, Center for Advanced Biotechnology and Medicine, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854,
- the Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854
| | - Jeffrey M Boyd
- From the Department of Biochemistry and Microbiology, Rutgers, the State University of New Jersey, New Brunswick, New Jersey 08901,
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24
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Straw ML, Chaplin AK, Hough MA, Paps J, Bavro VN, Wilson MT, Vijgenboom E, Worrall JAR. A cytosolic copper storage protein provides a second level of copper tolerance in Streptomyces lividans. Metallomics 2019; 10:180-193. [PMID: 29292456 DOI: 10.1039/c7mt00299h] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Streptomyces lividans has a distinct dependence on the bioavailability of copper for its morphological development. A cytosolic copper resistance system is operative in S. lividans that serves to preclude deleterious copper levels. This system comprises of several CopZ-like copper chaperones and P1-type ATPases, predominantly under the transcriptional control of a metalloregulator from the copper sensitive operon repressor (CsoR) family. In the present study, we discover a new layer of cytosolic copper resistance in S. lividans that involves a protein belonging to the newly discovered family of copper storage proteins, which we have named Ccsp (cytosolic copper storage protein). From an evolutionary perspective, we find Ccsp homologues to be widespread in Bacteria and extend through into Archaea and Eukaryota. Under copper stress Ccsp is upregulated and consists of a homotetramer assembly capable of binding up to 80 cuprous ions (20 per protomer). X-ray crystallography reveals 18 cysteines, 3 histidines and 1 aspartate are involved in cuprous ion coordination. Loading of cuprous ions to Ccsp is a cooperative process with a Hill coefficient of 1.9 and a CopZ-like copper chaperone can transfer copper to Ccsp. A Δccsp mutant strain indicates that Ccsp is not required under initial copper stress in S. lividans, but as the CsoR/CopZ/ATPase efflux system becomes saturated, Ccsp facilitates a second level of copper tolerance.
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Affiliation(s)
- Megan L Straw
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK.
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25
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Young TR, Wedd AG, Xiao Z. Evaluation of Cu(i) binding to the E2 domain of the amyloid precursor protein - a lesson in quantification of metal binding to proteins via ligand competition. Metallomics 2019; 10:108-119. [PMID: 29215101 DOI: 10.1039/c7mt00291b] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The extracellular domain E2 of the amyloid precursor protein (APP) features a His-rich metal-binding site (denoted as the M1 site). In conjunction with surrounding basic residues, the site participates in interactions with components of the extracellular matrix including heparins, a class of negatively charged polysaccharide molecules of varying length. This work studied the chemistry of Cu(i) binding to APP E2 with the probe ligands Bcs, Bca, Fz and Fs. APP E2 forms a stable Cu(i)-mediated ternary complex with each of these anionic ligands. The complex with Bca was selected for isolation and characterization and was demonstrated, by native ESI-MS analysis, to have the stoichiometry E2 : Cu(i) : Bca = 1 : 1 : 1. Formation of these ternary complexes is specific for the APP E2 domain and requires Cu(i) coordination to the M1 site. Mutation of the M1 site was consistent with the His ligands being part of the E2 ligand set. It is likely that interactions between the negatively charged probe ligands and a positively charged patch on the surface of APP E2 are one aspect of the generation of the stable ternary complexes. Their formation prevented meaningful quantification of the affinity of Cu(i) binding to the M1 site with these probe ligands. However, the ternary complexes are disrupted by heparin, allowing reliable determination of a picomolar Cu(i) affinity for the E2/heparin complex with the Fz or Bca probe ligands. This is the first documented example of the formation of stable ternary complexes between a Cu(i) binding protein and a probe ligand. The ready disruption of the complexes by heparin identified clear 'tell-tale' signs for diagnosis of ternary complex formation and allowed a systematic review of conditions and criteria for reliable determination of affinities for metal binding via ligand competition. This study also provides new insights into a potential correlation of APP functions regulated by copper binding and heparin interaction.
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Affiliation(s)
- Tessa R Young
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
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26
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Saito Y, Nishikawa M, Tsubomura T. Water-soluble copper( i) complexes bearing 2,2′-bicinchoninic acid dipotassium salt with red-light absorption and repeatable colour change upon freezing operation. NEW J CHEM 2019. [DOI: 10.1039/c8nj05147j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The repeatable colour change upon freezing–melting operation of a water solution of a Cu(i) complex is found. Efficient red light absorption is also one of the advantages of this complex.
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Affiliation(s)
- Yuma Saito
- Department of Materials and Life Science
- Seikei University
- Tokyo
- Japan
| | | | - Taro Tsubomura
- Department of Materials and Life Science
- Seikei University
- Tokyo
- Japan
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27
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Crawford CL, Dalecki AG, Narmore WT, Hoff J, Hargett AA, Renfrow MB, Zhang M, Kalubowilage M, Bossmann SH, Queern SL, Lapi SE, Hunter RN, Bao D, Augelli-Szafran CE, Kutsch O, Wolschendorf F. Pyrazolopyrimidinones, a novel class of copper-dependent bactericidal antibiotics against multi-drug resistant S. aureus. Metallomics 2019; 11:784-798. [DOI: 10.1039/c8mt00316e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Pyrazolopyrimidinones traffic copper into S. aureus, depleting ATP and altering essential ion concentrations, resulting in the death of the bacteria.
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Affiliation(s)
| | - Alex G. Dalecki
- Department of Medicine
- University of Alabama at Birmingham
- Birmingham
- USA
| | | | - Jessica Hoff
- Department of Medicine
- University of Alabama at Birmingham
- Birmingham
- USA
| | - Audra A. Hargett
- Department of Biochemistry and Molecular Genetics
- University of Alabama at Birmingham
- Birmingham
- USA
| | - Matthew B. Renfrow
- Department of Biochemistry and Molecular Genetics
- University of Alabama at Birmingham
- Birmingham
- USA
| | - Man Zhang
- Department of Chemistry
- Kansas State University
- Manhattan
- USA
| | | | | | - Stacy L. Queern
- Department of Radiology
- University of Alabama at Birmingham
- Birmingham
- USA
- Department of Chemistry
| | - Suzanne E. Lapi
- Department of Radiology
- University of Alabama at Birmingham
- Birmingham
- USA
- Department of Chemistry
| | - Robert N. Hunter
- Department of Chemistry
- Drug Discovery Division
- Southern Research
- Birmingham
- USA
| | - Donghui Bao
- Department of Chemistry
- Drug Discovery Division
- Southern Research
- Birmingham
- USA
| | | | - Olaf Kutsch
- Department of Medicine
- University of Alabama at Birmingham
- Birmingham
- USA
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28
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Kardos J, Héja L, Simon Á, Jablonkai I, Kovács R, Jemnitz K. Copper signalling: causes and consequences. Cell Commun Signal 2018; 16:71. [PMID: 30348177 PMCID: PMC6198518 DOI: 10.1186/s12964-018-0277-3] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 09/24/2018] [Indexed: 12/18/2022] Open
Abstract
Copper-containing enzymes perform fundamental functions by activating dioxygen (O2) and therefore allowing chemical energy-transfer for aerobic metabolism. The copper-dependence of O2 transport, metabolism and production of signalling molecules are supported by molecular systems that regulate and preserve tightly-bound static and weakly-bound dynamic cellular copper pools. Disruption of the reducing intracellular environment, characterized by glutathione shortage and ambient Cu(II) abundance drives oxidative stress and interferes with the bidirectional, copper-dependent communication between neurons and astrocytes, eventually leading to various brain disease forms. A deeper understanding of of the regulatory effects of copper on neuro-glia coupling via polyamine metabolism may reveal novel copper signalling functions and new directions for therapeutic intervention in brain disorders associated with aberrant copper metabolism.
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Affiliation(s)
- Julianna Kardos
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok körútja 2, Budapest, 1117 Hungary
| | - László Héja
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok körútja 2, Budapest, 1117 Hungary
| | - Ágnes Simon
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok körútja 2, Budapest, 1117 Hungary
| | - István Jablonkai
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok körútja 2, Budapest, 1117 Hungary
| | - Richard Kovács
- Institute of Neurophysiology, Charité-Universitätsmedizin, Berlin, Germany
| | - Katalin Jemnitz
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok körútja 2, Budapest, 1117 Hungary
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29
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Wall RJ, Moniz S, Thomas MG, Norval S, Ko EJ, Marco M, Miles TJ, Gilbert IH, Horn D, Fairlamb AH, Wyllie S. Antitrypanosomal 8-Hydroxy-Naphthyridines Are Chelators of Divalent Transition Metals. Antimicrob Agents Chemother 2018; 62:e00235-18. [PMID: 29844044 PMCID: PMC6105827 DOI: 10.1128/aac.00235-18;e00235-18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 05/18/2018] [Indexed: 08/22/2023] Open
Abstract
The lack of information regarding the mechanisms of action (MoA) or specific molecular targets of phenotypically active compounds can prove a barrier to their development as chemotherapeutic agents. Here, we report the results of our orthogonal genetic, molecular, and biochemical studies to determine the MoA of a novel 7-substituted 8-hydroxy-1,6-naphthyridine (8-HNT) series that displays promising activity against Trypanosoma brucei and Leishmania donovani High-throughput loss-of-function genetic screens in T. brucei highlighted two probable zinc transporters associated with resistance to these compounds. These transporters localized to the parasite Golgi apparatus. Directed by these findings, the role of zinc and other divalent cations in the MoA of these compounds was investigated. 8-HNT compounds were found to directly deplete intracellular levels of Zn2+, while the addition of exogenous Zn2+ and Fe2+ reduced the potency of compounds from this series. Detailed biochemical analyses confirmed that 8-HNT compounds bind directly to a number of divalent cations, predominantly Zn2+, Fe2+, and Cu2+, forming 2:1 complexes with one of these cations. Collectively, our studies demonstrate transition metal depletion, due to chelation, as the MoA of the 8-HNT series of compounds. Strategies to improve the selectivity of 8-HNT compounds are discussed.
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Affiliation(s)
- Richard J Wall
- Wellcome Trust Centre for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Sonia Moniz
- Wellcome Trust Centre for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Michael G Thomas
- Wellcome Trust Centre for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Suzanne Norval
- Wellcome Trust Centre for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Eun-Jung Ko
- Wellcome Trust Centre for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Maria Marco
- Diseases of the Developing World, GlaxoSmithKline, Madrid, Spain
| | - Timothy J Miles
- Diseases of the Developing World, GlaxoSmithKline, Madrid, Spain
| | - Ian H Gilbert
- Wellcome Trust Centre for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - David Horn
- Wellcome Trust Centre for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Alan H Fairlamb
- Wellcome Trust Centre for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Susan Wyllie
- Wellcome Trust Centre for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, United Kingdom
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30
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Antitrypanosomal 8-Hydroxy-Naphthyridines Are Chelators of Divalent Transition Metals. Antimicrob Agents Chemother 2018; 62:AAC.00235-18. [PMID: 29844044 PMCID: PMC6105827 DOI: 10.1128/aac.00235-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 05/18/2018] [Indexed: 12/25/2022] Open
Abstract
The lack of information regarding the mechanisms of action (MoA) or specific molecular targets of phenotypically active compounds can prove a barrier to their development as chemotherapeutic agents. Here, we report the results of our orthogonal genetic, molecular, and biochemical studies to determine the MoA of a novel 7-substituted 8-hydroxy-1,6-naphthyridine (8-HNT) series that displays promising activity against Trypanosoma brucei and Leishmania donovani High-throughput loss-of-function genetic screens in T. brucei highlighted two probable zinc transporters associated with resistance to these compounds. These transporters localized to the parasite Golgi apparatus. Directed by these findings, the role of zinc and other divalent cations in the MoA of these compounds was investigated. 8-HNT compounds were found to directly deplete intracellular levels of Zn2+, while the addition of exogenous Zn2+ and Fe2+ reduced the potency of compounds from this series. Detailed biochemical analyses confirmed that 8-HNT compounds bind directly to a number of divalent cations, predominantly Zn2+, Fe2+, and Cu2+, forming 2:1 complexes with one of these cations. Collectively, our studies demonstrate transition metal depletion, due to chelation, as the MoA of the 8-HNT series of compounds. Strategies to improve the selectivity of 8-HNT compounds are discussed.
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31
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Morgan MT, Yang B, Harankhedkar S, Nabatilan A, Bourassa D, McCallum AM, Sun F, Wu R, Forest CR, Fahrni CJ. Stabilization of Aliphatic Phosphines by Auxiliary Phosphine Sulfides Offers Zeptomolar Affinity and Unprecedented Selectivity for Probing Biological Cu I. Angew Chem Int Ed Engl 2018; 57:9711-9715. [PMID: 29885022 PMCID: PMC6105516 DOI: 10.1002/anie.201804072] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/01/2018] [Indexed: 01/06/2023]
Abstract
Full elucidation of the functions and homeostatic pathways of biological copper requires tools that can selectively recognize and manipulate this trace nutrient within living cells and tissues, where it exists primarily as CuI . Buffered at attomolar concentrations, intracellular CuI is, however, not readily accessible to commonly employed amine and thioether-based chelators. Herein, we reveal a chelator design strategy in which phosphine sulfides aid in CuI coordination while simultaneously stabilizing aliphatic phosphine donors, producing a charge-neutral ligand with low-zeptomolar dissociation constant and 1017 -fold selectivity for CuI over ZnII , FeII , and MnII . As illustrated by reversing ATP7A trafficking in cells and blocking long-term potentiation of neurons in mouse hippocampal brain tissue, the ligand is capable of intercepting copper-dependent processes. The phosphine sulfide-stabilized phosphine (PSP) design approach, which confers resistance towards protonation, dioxygen, and disulfides, could be readily expanded towards ligands and probes with tailored properties for exploring CuI in a broad range of biological systems.
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Affiliation(s)
- M. Thomas Morgan
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
| | - Bo Yang
- Prof. Dr. C.R. Forest, Dr. B. Yang G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology 315 Ferst Drive, Atlanta, GA 30332, USA,
| | - Shefali Harankhedkar
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
| | - Arielle Nabatilan
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
| | - Daisy Bourassa
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
| | - Adam M. McCallum
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
| | - Fangxu Sun
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
| | - Ronghu Wu
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
| | - Craig R. Forest
- Prof. Dr. C.R. Forest, Dr. B. Yang G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology 315 Ferst Drive, Atlanta, GA 30332, USA,
| | - Christoph J. Fahrni
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
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32
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Morgan MT, Yang B, Harankhedkar S, Nabatilan A, Bourassa D, McCallum AM, Sun F, Wu R, Forest CR, Fahrni CJ. Stabilization of Aliphatic Phosphines by Auxiliary Phosphine Sulfides Offers Zeptomolar Affinity and Unprecedented Selectivity for Probing Biological Cu
I. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201804072] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- M. Thomas Morgan
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
| | - Bo Yang
- G. W. Woodruff School of Mechanical Engineering Georgia Institute of Technology 315 Ferst Drive Atlanta GA 30332 USA
| | - Shefali Harankhedkar
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
| | - Arielle Nabatilan
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
| | - Daisy Bourassa
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
| | - Adam M. McCallum
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
| | - Fangxu Sun
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
| | - Ronghu Wu
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
| | - Craig R. Forest
- G. W. Woodruff School of Mechanical Engineering Georgia Institute of Technology 315 Ferst Drive Atlanta GA 30332 USA
| | - Christoph J. Fahrni
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
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33
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He M, Hu Q, Mei Y, Zhou B, Kong J, Zhang X. Metal-to-Ligand Charge-Transfer-based Visual Detection of Alkaline Phosphatase Activity. ANAL SCI 2018. [PMID: 29526903 DOI: 10.2116/analsci.34.341] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The ability to directly detect alkaline phosphatase (ALP) activity in undiluted serum samples is of great importance for clinical diagnosis. In this work, we report the use of the distinctive metal-to-ligand charge-transfer (MLCT) absorption properties of the Cu(BCA)2+ (BCA = bicinchoninic acid) reporter for the visual detection of ALP activity. In the presence of ALP, the substrate ascorbic acid 2-phosphate (AAP) can be enzymatically hydrolyzed to release ascorbic acid (AA), which in turn reduces Cu2+ to Cu+. Subsequently, the complexation of Cu+ with the BCA ligand generates the chromogenic Cu(BCA)2+ reporter, accompanied by a color change of colorless-to-purple of the solution with a sharp absorption band at 562 nm. The underlying MLCT-based mechanism has been demonstrated on the basis of density functional theory (DFT) calculations. Needless of any sequential multistep operations and elaborately designed colorimetric probe, the proposed MLCT-based method allows for a fast and sensitive visual detection of ALP activity within a broad linear range of 20 - 200 mU mL-1 (R2 = 0.999), with a detection limit of 1.25 mU mL-1. The results also indicate that it is highly selective and has great potential for the screening of ALP inhibitors in drug discovery. More importantly, it shows a good analytical performance for the direct detection of the endogenous ALP levels of undiluted human serum samples. Owing to the prominent simplicity and practicability, it is reasonable to conclude that the proposed MLCT-based method has a high application prospect in clinical diagnosis.
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Affiliation(s)
- Minhui He
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology
| | - Qiong Hu
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology
| | - Yaqi Mei
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology
| | - Baojing Zhou
- School of Chemical Engineering, Nanjing University of Science and Technology
| | - Jinming Kong
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology
| | - Xueji Zhang
- Chemistry Department, College of Arts and Sciences, University of South Florida
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34
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Chen D, Wang X, He Y, Kai T, Li Z, Xiang J, Jiang D, Zhou F. Studies of Electrode Reactions and Coordination Geometries of Cu(I) and Cu(II) Complexes with Bicinchoninic Acid. ELECTROANAL 2018. [DOI: 10.1002/elan.201700741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Dinglong Chen
- College of Chemistry and Chemical Engineering; Central South University, Changsha; Hunan 410008 P. R. China
| | - Xiaoying Wang
- College of Chemistry and Chemical Engineering; Central South University, Changsha; Hunan 410008 P. R. China
| | - Yonghui He
- Key Laboratory of Chemistry in Ethnic Medicine Resource, State Ethnic Affairs Commission & Ministry of Education; Yunnan Minzu University; Kunming 650031 P. R. China
| | - Tianhan Kai
- Department of Chemistry and Biochemistry; California State University, Los Angeles; Los Angeles CA 90032
| | - Zhiqiang Li
- Department of Chemistry and Biochemistry; California State University, Los Angeles; Los Angeles CA 90032
| | - Juan Xiang
- College of Chemistry and Chemical Engineering; Central South University, Changsha; Hunan 410008 P. R. China
| | - Dianlu Jiang
- Department of Chemistry and Biochemistry; California State University, Los Angeles; Los Angeles CA 90032
| | - Feimeng Zhou
- Department of Chemistry and Biochemistry; California State University, Los Angeles; Los Angeles CA 90032
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35
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Mei Y, Hu Q, Zhou B, Zhang Y, He M, Xu T, Li F, Kong J. Fluorescence quenching based alkaline phosphatase activity detection. Talanta 2018; 176:52-58. [DOI: 10.1016/j.talanta.2017.07.095] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/24/2017] [Accepted: 07/31/2017] [Indexed: 01/15/2023]
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36
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Shinde RG, Khan AA, Kunwar A, Tripathi VS, Barik A. Fluorescence “off” and “on” signalling of esculetin in the presence of copper and thiol: a possible implication in cellular thiol sensing. Photochem Photobiol Sci 2018; 17:1197-1205. [DOI: 10.1039/c8pp00157j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The fluorescence intensity of esculetin was drastically reduced in the presence of a copper ion, which was regenerated in the presence of GSH. The copper–esculetin system was able to detect GSH in a cellular model.
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Affiliation(s)
- Rupali G. Shinde
- Department of Chemistry
- Savitribai Phule Pune University
- Pune 411007
- India
- Radiation and Photochemistry Division
| | - Ayesha A. Khan
- Department of Chemistry
- Savitribai Phule Pune University
- Pune 411007
- India
| | - Amit Kunwar
- Radiation and Photochemistry Division
- Bhabha Atomic Research Centre
- Mumbai 400085
- India
| | - V. S. Tripathi
- Radiation and Photochemistry Division
- Bhabha Atomic Research Centre
- Mumbai 400085
- India
| | - Atanu Barik
- Radiation and Photochemistry Division
- Bhabha Atomic Research Centre
- Mumbai 400085
- India
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37
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Helsel ME, White EJ, Razvi SZA, Alies B, Franz KJ. Chemical and functional properties of metal chelators that mobilize copper to elicit fungal killing of Cryptococcus neoformans. Metallomics 2017; 9:69-81. [PMID: 27853789 DOI: 10.1039/c6mt00172f] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A panel of iron (Fe) and copper (Cu) chelators was screened for growth inhibitory activity against the fungal pathogen Cryptococcus neoformans. Select bidentate metal-binding ligands containing mixed O,S or O,N donor atoms were identified as agents that induce cell killing in a Cu-dependent manner. Conversely, structurally similar ligands with O,O donor atoms did not inhibit C. neoformans growth regardless of Cu status. Studies of Cu(ii) and Cu(i) binding affinity, lipophilicity, and growth recovery assays of Cu-import deficient cells identified lipophilicity of thermodynamically stable CuIIL2 complexes as the best predictor of antifungal activity. These same complexes induce cellular hyperaccumulation of Zn and Fe in addition to Cu. The results described here present the utility of appropriate metal-binding ligands as potential antifungal agents that manipulate cellular metal balance as an antimicrobial strategy.
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Affiliation(s)
- Marian E Helsel
- Department of Chemistry, Duke University, French Family Science Center, 124 Science Drive, 22708, Durham, NC, USA.
| | - Elizabeth J White
- Department of Chemistry, Duke University, French Family Science Center, 124 Science Drive, 22708, Durham, NC, USA.
| | - Sayyeda Zeenat A Razvi
- Department of Chemistry, Duke University, French Family Science Center, 124 Science Drive, 22708, Durham, NC, USA.
| | - Bruno Alies
- Department of Chemistry, Duke University, French Family Science Center, 124 Science Drive, 22708, Durham, NC, USA.
| | - Katherine J Franz
- Department of Chemistry, Duke University, French Family Science Center, 124 Science Drive, 22708, Durham, NC, USA.
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38
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Morgan MT, Nguyen LAH, Hancock HL, Fahrni CJ. Glutathione limits aquacopper(I) to sub-femtomolar concentrations through cooperative assembly of a tetranuclear cluster. J Biol Chem 2017; 292:21558-21567. [PMID: 29101230 DOI: 10.1074/jbc.m117.817452] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/27/2017] [Indexed: 11/06/2022] Open
Abstract
The tripeptide glutathione (GSH) is a crucial intracellular reductant and radical scavenger, but it may also coordinate the soft Cu(I) cation and thereby yield pro-oxidant species. The GSH-Cu(I) interaction is thus a key consideration for both redox and copper homeostasis in cells. However, even after nearly four decades of investigation, the nature and stability of the GSH-Cu(I) complexes formed under biologically relevant conditions remain controversial. Here, we revealed the unexpected predominance of a tetranuclear [Cu4(GS)6] cluster that is sufficiently stable to limit the effective free aquacopper(I) concentration to the sub-femtomolar regime. Combined spectrophotometric-potentiometric titrations at biologically realistic GSH/Cu(I) ratios, enabled by our recently developed Cu(I) affinity standards and corroborated by low-temperature phosphorescence studies, established cooperative assembly of [Cu4(GS)6] as the dominant species over a wide pH range, from 5.5 to 7.5. Our robust model for the glutathione-Cu(I) equilibrium system sets a firm upper limit on the thermodynamic availability of intracellular copper that is 3 orders of magnitude lower than previously estimated. Taking into account their ability to catalyze the production of deleterious superoxide, the formation of Cu(I)-glutathione complexes might be avoided under normal physiological conditions. The actual intracellular Cu(I) availability may thus be regulated a further 3 orders of magnitude below the GSH/Cu(I) affinity limit, consistent with the most recent affinity determinations of Cu(I) chaperones.
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Affiliation(s)
- M Thomas Morgan
- From the School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Lily Anh H Nguyen
- From the School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Haylie L Hancock
- From the School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Christoph J Fahrni
- From the School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332
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39
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Wu Z, Fan H, Satyavolu NSR, Wang W, Lake R, Jiang JH, Lu Y. Imaging Endogenous Metal Ions in Living Cells Using a DNAzyme-Catalytic Hairpin Assembly Probe. Angew Chem Int Ed Engl 2017; 56:8721-8725. [PMID: 28557357 PMCID: PMC5814595 DOI: 10.1002/anie.201703540] [Citation(s) in RCA: 149] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/03/2017] [Indexed: 12/16/2022]
Abstract
DNAzymes are a promising platform for metal ion detection, and a few DNAzyme-based sensors have been reported to detect metal ions inside cells. However, these methods required an influx of metal ions to increase their concentrations for detection. To address this major issue, the design of a catalytic hairpin assembly (CHA) reaction to amplify the signal from photocaged Na+ -specific DNAzyme to detect endogenous Na+ inside cells is reported. Upon light activation and in the presence of Na+ , the NaA43 DNAzyme cleaves its substrate strand and releases a product strand, which becomes an initiator that trigger the subsequent CHA amplification reaction. This strategy allows detection of endogenous Na+ inside cells, which has been demonstrated by both fluorescent imaging of individual cells and flow cytometry of the whole cell population. This method can be generally applied to detect other endogenous metal ions and thus contribute to deeper understanding of the role of metal ions in biological systems.
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Affiliation(s)
- Zhenkun Wu
- State Key Laboratory of Chemeo/Bio-Sensing and Chemometrics Institute of Chemical Biology and Nanomedicine and College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Huanhuan Fan
- State Key Laboratory of Chemeo/Bio-Sensing and Chemometrics Institute of Chemical Biology and Nanomedicine and College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | | | - WenJing Wang
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- State Key Laboratory of Analytical Chemistry for Life Science and School of Chemistry & Chemical Engineering, Nanjing University, N, anjing, 210093, P. R. China
| | - Ryan Lake
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Jian-Hui Jiang
- State Key Laboratory of Chemeo/Bio-Sensing and Chemometrics Institute of Chemical Biology and Nanomedicine and College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
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40
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Wu Z, Fan H, Satyavolu NSR, Wang W, Lake R, Jiang JH, Lu Y. Imaging Endogenous Metal Ions in Living Cells Using a DNAzyme-Catalytic Hairpin Assembly Probe. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201703540] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Zhenkun Wu
- State Key Laboratory of Chemeo/Bio-Sensing and Chemometrics Institute of Chemical Biology and Nanomedicine and College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 P. R. China
- Department of Chemistry; University of Illinois at Urbana-Champaign; Urbana Illinois 61801 USA
| | - Huanhuan Fan
- State Key Laboratory of Chemeo/Bio-Sensing and Chemometrics Institute of Chemical Biology and Nanomedicine and College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 P. R. China
- Department of Chemistry; University of Illinois at Urbana-Champaign; Urbana Illinois 61801 USA
| | | | - WenJing Wang
- Department of Chemistry; University of Illinois at Urbana-Champaign; Urbana Illinois 61801 USA
- State Key Laboratory of Analytical Chemistry for Life Science and School of Chemistry & Chemical Engineering; Nanjing University, N; anjing 210093 P. R. China
| | - Ryan Lake
- Department of Chemistry; University of Illinois at Urbana-Champaign; Urbana Illinois 61801 USA
| | - Jian-Hui Jiang
- State Key Laboratory of Chemeo/Bio-Sensing and Chemometrics Institute of Chemical Biology and Nanomedicine and College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 P. R. China
| | - Yi Lu
- Department of Chemistry; University of Illinois at Urbana-Champaign; Urbana Illinois 61801 USA
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41
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Liebsch F, Aurousseau MRP, Bethge T, McGuire H, Scolari S, Herrmann A, Blunck R, Bowie D, Multhaup G. Full-length cellular β-secretase has a trimeric subunit stoichiometry, and its sulfur-rich transmembrane interaction site modulates cytosolic copper compartmentalization. J Biol Chem 2017. [PMID: 28637867 DOI: 10.1074/jbc.m117.779165] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The β-secretase (BACE1) initiates processing of the amyloid precursor protein (APP) into Aβ peptides, which have been implicated as central players in the pathology of Alzheimer disease. BACE1 has been described as a copper-binding protein and its oligomeric state as being monomeric, dimeric, and/or multimeric, but the native cellular stoichiometry has remained elusive. Here, by using single-molecule fluorescence and in vitro cross-linking experiments with photo-activatable unnatural amino acids, we show that full-length BACE1, independently of its subcellular localization, exists as trimers in human cells. We found that trimerization requires the BACE1 transmembrane sequences (TMSs) and cytoplasmic domains, with residues Ala463 and Cys466 buried within the trimer interface of the sulfur-rich core of the TMSs. Our 3D model predicts that the sulfur-rich core of the trimeric BACE1 TMS is accessible to metal ions, but copper ions did not trigger trimerization. The results of functional assays of endogenous BACE1 suggest that it has a role in intracellular copper compartmentalization by transferring cytosolic copper to intracellular compartments, while leaving the overall cellular copper concentration unaltered. Adding to existing physiological models, our results provide novel insight into the atypical interactions between copper and BACE1 and into its non-enzymatic activities. In conclusion, therapeutic Alzheimer disease prevention strategies aimed at decreasing BACE1 protein levels should be regarded with caution, because adverse effects in copper homeostasis may occur.
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Affiliation(s)
- Filip Liebsch
- From the Integrated Program in Neuroscience, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Mark R P Aurousseau
- the Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Tobias Bethge
- the Institut für Chemie und Biochemie, Freie Universität Berlin, 14195 Berlin, Germany
| | - Hugo McGuire
- the Department of Physics, Université de Montréal, Montreal, Quebec H3C 3J7, Canada, and
| | - Silvia Scolari
- the Institut für Biologie, Humboldt Universität zu Berlin, 10115 Berlin, Germany
| | - Andreas Herrmann
- the Institut für Biologie, Humboldt Universität zu Berlin, 10115 Berlin, Germany
| | - Rikard Blunck
- the Department of Physics, Université de Montréal, Montreal, Quebec H3C 3J7, Canada, and
| | - Derek Bowie
- From the Integrated Program in Neuroscience, McGill University, Montreal, Quebec H3G 0B1, Canada.,the Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Gerd Multhaup
- From the Integrated Program in Neuroscience, McGill University, Montreal, Quebec H3G 0B1, Canada, .,the Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada
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42
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Niu Y, Wang J, Zhang C, Chen Y. Rapid determination of trace copper in animal feed based on micro-plate colorimetric reaction and statistical partitioning correction. Food Chem 2017; 221:1406-1414. [DOI: 10.1016/j.foodchem.2016.11.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 10/27/2016] [Accepted: 11/02/2016] [Indexed: 12/11/2022]
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43
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Chung R, Vo A, Hein JE. Copper-Catalyzed Hydrogen/Iodine Exchange in Terminal and 1-Iodoalkynes. ACS Catal 2017. [DOI: 10.1021/acscatal.6b03515] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Ryan Chung
- Department
of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Anh Vo
- Department
of Chemistry and Chemical Biology, University of California, Merced, Merced, California 95343, United States
| | - Jason E. Hein
- Department
of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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44
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Vita N, Landolfi G, Baslé A, Platsaki S, Lee J, Waldron KJ, Dennison C. Bacterial cytosolic proteins with a high capacity for Cu(I) that protect against copper toxicity. Sci Rep 2016; 6:39065. [PMID: 27991525 PMCID: PMC5171941 DOI: 10.1038/srep39065] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 11/16/2016] [Indexed: 01/23/2023] Open
Abstract
Bacteria are thought to avoid using the essential metal ion copper in their cytosol due to its toxicity. Herein we characterize Csp3, the cytosolic member of a new family of bacterial copper storage proteins from Methylosinus trichosporium OB3b and Bacillus subtilis. These tetrameric proteins possess a large number of Cys residues that point into the cores of their four-helix bundle monomers. The Csp3 tetramers can bind a maximum of approximately 80 Cu(I) ions, mainly via thiolate groups, with average affinities in the (1–2) × 1017 M−1 range. Cu(I) removal from these Csp3s by higher affinity potential physiological partners and small-molecule ligands is very slow, which is unexpected for a metal-storage protein. In vivo data demonstrate that Csp3s prevent toxicity caused by the presence of excess copper. Furthermore, bacteria expressing Csp3 accumulate copper and are able to safely maintain large quantities of this metal ion in their cytosol. This suggests a requirement for storing copper in this compartment of Csp3-producing bacteria.
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Affiliation(s)
- Nicolas Vita
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Gianpiero Landolfi
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Arnaud Baslé
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Semeli Platsaki
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Jaeick Lee
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Kevin J Waldron
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Christopher Dennison
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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45
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Hu Q, Zhou B, Li F, Kong J, Zhang X. Turn-On Colorimetric Platform for Dual Activity Detection of Acid and Alkaline Phosphatase in Human Whole Blood. Chem Asian J 2016; 11:3040-3045. [PMID: 27615725 DOI: 10.1002/asia.201601006] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/07/2016] [Indexed: 01/28/2023]
Abstract
The activity detection of acid phosphatase (ACP) and alkaline phosphatase (ALP) is of great importance to the diagnosis and prognosis of related diseases. In this work, we report for the first time a turn-on colorimetric platform for the activity detection of ACP and ALP, by exploiting Cu(BCDS)22- (BCDS=bathocuproinedisulfonate) as the probe. The presence of ACP or ALP dephosphorylates the substrate ascorbic acid 2-phosphate to produce ascorbic acid, which then reduces Cu(BCDS)22- into Cu(BCDS)23- , leading to a turn-on spectral absorption at 484 nm and a dramatic color change of the solution from colorless to orange-red. The underlying metal-to-ligand charge-transfer mechanism has been demonstrated by quantum mechanical computations. This platform allows a rapid, sensitive readout of ACP and ALP activities within the dynamic range from 0 to 220 mU ml-1 . In addition, it is highly immune to false-positive results and also highly selective. More importantly, it is applicable in the presence of human serum and even whole blood samples. These results demonstrate that our platform holds great potential in clinical practices and in the point-of-care analysis.
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Affiliation(s)
- Qiong Hu
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Baojing Zhou
- School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Feng Li
- American Advanced Nanotechnology, Houston, TX, 77459, USA
| | - Jinming Kong
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Xueji Zhang
- Chemistry Department, College of Arts and Sciences, University of South Florida, Tampa, FL, 33620-4202, USA
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46
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Nakajima T, Kawasaki Y, Kure B, Tanase T. Homo‐ and Heterodinuclear Rh and Ir Complexes Supported by SN
n
Mixed‐Donor Ligands (
n
= 2–4): Stereochemistry and Coordination‐Site‐Exchange Reactions of Cp*M (M = Rh, Ir) Units. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201600722] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Takayuki Nakajima
- Department of Chemistry Faculty of Science Nara Women's University Kitauoya‐nishi‐machi 630‐8506 Nara Japan
| | - Yuki Kawasaki
- Department of Chemistry Faculty of Science Nara Women's University Kitauoya‐nishi‐machi 630‐8506 Nara Japan
| | - Bunsho Kure
- Department of Chemistry Faculty of Science Nara Women's University Kitauoya‐nishi‐machi 630‐8506 Nara Japan
| | - Tomoaki Tanase
- Department of Chemistry Faculty of Science Nara Women's University Kitauoya‐nishi‐machi 630‐8506 Nara Japan
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47
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Johnson DK, Stevenson MJ, Almadidy ZA, Jenkins SE, Wilcox DE, Grossoehme NE. Stabilization of Cu(I) for binding and calorimetric measurements in aqueous solution. Dalton Trans 2016; 44:16494-505. [PMID: 26327397 DOI: 10.1039/c5dt02689j] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Conditions have been developed for the comproportionation reaction of Cu(2+) and copper metal to prepare aqueous solutions of Cu(+) that are stabilized from disproportionation by MeCN and other Cu(+)-stabilizing ligands. These solutions were then used in ITC measurements to quantify the thermodynamics of formation of a set of Cu(+) complexes (Cu(I)(MeCN)3(+), Cu(I)Me6Trien(+), Cu(I)(BCA)2(3-), Cu(I)(BCS)2(3-)), which have stabilities ranging over 15 orders of magnitude, for their use in binding and calorimetric measurements of Cu(+) interaction with proteins and other biological macromolecules. These complexes were then used to determine the stability and thermodynamics of formation of a 1 : 1 complex of Cu(+) with the biologically important tri-peptide glutathione, GSH. These results identify Me6Trien as an attractive Cu(+)-stabilizing ligand for calorimetric experiments, and suggest that caution should be used with MeCN to stabilize Cu(+) due to its potential for participating in unquantifiable ternary interactions.
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Affiliation(s)
- Destinee K Johnson
- Department of Chemistry, Physics and Geology, Winthrop University, Rock Hill, SC 27933, USA.
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48
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DiSpirito AA, Semrau JD, Murrell JC, Gallagher WH, Dennison C, Vuilleumier S. Methanobactin and the Link between Copper and Bacterial Methane Oxidation. Microbiol Mol Biol Rev 2016; 80:387-409. [PMID: 26984926 PMCID: PMC4867365 DOI: 10.1128/mmbr.00058-15] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Methanobactins (mbs) are low-molecular-mass (<1,200 Da) copper-binding peptides, or chalkophores, produced by many methane-oxidizing bacteria (methanotrophs). These molecules exhibit similarities to certain iron-binding siderophores but are expressed and secreted in response to copper limitation. Structurally, mbs are characterized by a pair of heterocyclic rings with associated thioamide groups that form the copper coordination site. One of the rings is always an oxazolone and the second ring an oxazolone, an imidazolone, or a pyrazinedione moiety. The mb molecule originates from a peptide precursor that undergoes a series of posttranslational modifications, including (i) ring formation, (ii) cleavage of a leader peptide sequence, and (iii) in some cases, addition of a sulfate group. Functionally, mbs represent the extracellular component of a copper acquisition system. Consistent with this role in copper acquisition, mbs have a high affinity for copper ions. Following binding, mbs rapidly reduce Cu(2+) to Cu(1+). In addition to binding copper, mbs will bind most transition metals and near-transition metals and protect the host methanotroph as well as other bacteria from toxic metals. Several other physiological functions have been assigned to mbs, based primarily on their redox and metal-binding properties. In this review, we examine the current state of knowledge of this novel type of metal-binding peptide. We also explore its potential applications, how mbs may alter the bioavailability of multiple metals, and the many roles mbs may play in the physiology of methanotrophs.
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Affiliation(s)
- Alan A DiSpirito
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, USA
| | - Jeremy D Semrau
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - J Colin Murrell
- Earth and Life Systems Alliance, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
| | - Warren H Gallagher
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, Wisconsin, USA
| | - Christopher Dennison
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Stéphane Vuilleumier
- Department of Microbiology, Genomics and the Environment, UMR 7156 UNISTRA-CNRS, Université de Strasbourg, Strasbourg, France
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49
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50
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Yang Y, Ibrahim AA, Hashemi P, Stockdill JL. Real-Time, Selective Detection of Copper(II) Using Ionophore-Grafted Carbon-Fiber Microelectrodes. Anal Chem 2016; 88:6962-6. [DOI: 10.1021/acs.analchem.6b00825] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Yuanyuan Yang
- Department
of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Ahmad A. Ibrahim
- Department
of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Parastoo Hashemi
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Jennifer L. Stockdill
- Department
of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
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