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Barbosa ACC, Venceslau SS, Pereira IAC. DsrMKJOP is the terminal reductase complex in anaerobic sulfate respiration. Proc Natl Acad Sci U S A 2024; 121:e2313650121. [PMID: 38285932 PMCID: PMC10861901 DOI: 10.1073/pnas.2313650121] [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: 08/08/2023] [Accepted: 12/20/2023] [Indexed: 01/31/2024] Open
Abstract
Microbial dissimilatory sulfate reduction (DSR) is a key process in the Earth biogeochemical sulfur cycle. In spite of its importance to the sulfur and carbon cycles, industrial processes, and human health, it is still not clear how reduction of sulfate to sulfide is coupled to energy conservation. A central step in the pathway is the reduction of sulfite by the DsrAB dissimilatory sulfite reductase, which leads to the production of a DsrC-trisulfide. A membrane-bound complex, DsrMKJOP, is present in most organisms that have DsrAB and DsrC, and its involvement in energy conservation has been inferred from sequence analysis, but its precise function was so far not determined. Here, we present studies revealing that the DsrMKJOP complex of the sulfate reducer Archaeoglobus fulgidus works as a menadiol:DsrC-trisulfide oxidoreductase. Our results reveal a close interaction between the DsrC-trisulfide and the DsrMKJOP complex and show that electrons from the quinone pool reduce consecutively the DsrM hemes b, the DsrK noncubane [4Fe-4S]3+/2+ catalytic center, and finally the DsrC-trisulfide with concomitant release of sulfide. These results clarify the role of this widespread respiratory membrane complex and support the suggestion that DsrMKJOP contributes to energy conservation upon reduction of the DsrC-trisulfide in the last step of DSR.
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Affiliation(s)
- Ana C. C. Barbosa
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras2780-156, Portugal
| | - Sofia S. Venceslau
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras2780-156, Portugal
| | - Inês A. C. Pereira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras2780-156, Portugal
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2
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Dale-Evans AR, Robinson MJ, Lloyd-Laney HO, Gavaghan DJ, Bond AM, Parkin A. A Voltammetric Perspective of Multi-Electron and Proton Transfer in Protein Redox Chemistry: Insights From Computational Analysis of Escherichia coli HypD Fourier Transformed Alternating Current Voltammetry. Front Chem 2021; 9:672831. [PMID: 34195174 PMCID: PMC8238118 DOI: 10.3389/fchem.2021.672831] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 05/25/2021] [Indexed: 11/25/2022] Open
Abstract
This paper explores the impact of pH on the mechanism of reversible disulfide bond (CysS-SCys) reductive breaking and oxidative formation in Escherichia coli hydrogenase maturation factor HypD, a protein which forms a highly stable adsorbed film on a graphite electrode. To achieve this, low frequency (8.96 Hz) Fourier transformed alternating current voltammetric (FTACV) experimental data was used in combination with modelling approaches based on Butler-Volmer theory with a dual polynomial capacitance model, utilizing an automated two-step fitting process conducted within a Bayesian framework. We previously showed that at pH 6.0 the protein data is best modelled by a redox reaction of two separate, stepwise one-electron, one-proton transfers with slightly “crossed” apparent reduction potentials that incorporate electron and proton transfer terms (Eapp20 > Eapp10). Remarkably, rather than collapsing to a concerted two-electron redox reaction at more extreme pH, the same two-stepwise one-electron transfer model with Eapp20 > Eapp10 continues to provide the best fit to FTACV data measured across a proton concentration range from pH 4.0 to pH 9.0. A similar, small level of crossover in reversible potentials is also displayed in overall two-electron transitions in other proteins and enzymes, and this provides access to a small but finite amount of the one electron reduced intermediate state.
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Affiliation(s)
| | - Martin J Robinson
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Henry O Lloyd-Laney
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - David J Gavaghan
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Alan M Bond
- School of Chemistry, Monash University, Clayton, VIC, Australia
| | - Alison Parkin
- Department of Chemistry, University of York, Heslington, United Kingdom
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3
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Pignataro M, Rocco GD, Lancellotti L, Bernini F, Subramanian K, Castellini E, Bortolotti CA, Malferrari D, Moro D, Valdrè G, Borsari M, Monte FD. Electrochemical data on redox properties of human Cofilin-2 and its Mutant S3D. Data Brief 2020; 33:106345. [PMID: 33024804 PMCID: PMC7528206 DOI: 10.1016/j.dib.2020.106345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/15/2020] [Accepted: 09/18/2020] [Indexed: 10/26/2022] Open
Abstract
The reported data are related to a research paper entitled "Phosphorylated cofilin-2 is more prone to oxidative modifications on Cys39 and favors amyloid fibril formation" [1]. Info about the formation and redox properties of the disulfide bridge of a protein is quite difficult to obtain and only in a few cases was it possible to observe a cyclic voltammetry (CV) signal [2,3]. Human cofilin-2 contains two cysteines (Cys39 and Cys80) which can be oxidized in suitable conditions and form a disulfide bridge [1]. For this purpose, CV measurements were carried out on human cofilin-2 WT and its mutant S3D immobilized on a gold electrode coated by an anionic self-assembled monolayer (SAM), after a pre-oxidation time which was fundamental for observing a CV signal relating to the oxidation/reduction process of the disulfide bridge of the proteins. The data include CV curves obtained with and without electrochemical pre-oxidation and after oxidation with H2O2. In addition, the plot of the cathodic peak current vs. electrochemical pre-oxidation time and the pH dependence of the formal potential (E°') are reported. The data obtained by CV measurements were used to determine the time required to form the disulfide bridge for the immobilized proteins and, consequently, to observe the CV signal, to calculate the E°' values and analyse the pH dependence of E°'. The electrochemical data were provided which will be useful for further electrochemical investigations regarding proteins bearing disulfide bridge(s) or cysteines prone to oxidation.
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Affiliation(s)
- Marcello Pignataro
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, USA
| | - Giulia Di Rocco
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Lidia Lancellotti
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Fabrizio Bernini
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | | | - Elena Castellini
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | | | - Daniele Malferrari
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Daniele Moro
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
| | - Giovanni Valdrè
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
| | - Marco Borsari
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Federica Del Monte
- Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston, USA.,Department of Experimental, Diagnostic and Specialty Medicine (DIMES), School of Medicine, University of Bologna, Bologna, Italy
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4
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Pignataro M, Di Rocco G, Lancellotti L, Bernini F, Subramanian K, Castellini E, Bortolotti CA, Malferrari D, Moro D, Valdrè G, Borsari M, Del Monte F. Phosphorylated cofilin-2 is more prone to oxidative modifications on Cys39 and favors amyloid fibril formation. Redox Biol 2020; 37:101691. [PMID: 32863228 PMCID: PMC7472925 DOI: 10.1016/j.redox.2020.101691] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 08/06/2020] [Accepted: 08/17/2020] [Indexed: 02/01/2023] Open
Abstract
Cofilins are small protein of the actin depolymerizing family. Actin polymerization/depolymerization is central to a number of critical cellular physiological tasks making cofilin a key protein for several physiological functions of the cell. Cofilin activity is mainly regulated by phosphorylation on serine residue 3 making this post-translational modification key to the regulation of myofilament integrity. In fact, in this form, the protein segregates in myocardial aggregates in human idiopathic dilated cardiomyopathy. Since myofilament network is an early target of oxidative stress we investigated the molecular changes induced by oxidation on cofilin isoforms and their interplay with the protein phosphorylation state to get insight on whether/how those changes may predispose to early protein aggregation. Using different and complementary approaches we characterized the aggregation properties of cofilin-2 and its phosphomimetic variant (S3D) in response to oxidative stress in silico, in vitro and on isolated cardiomyocytes. We found that the phosphorylated (inactive) form of cofilin-2 is mechanistically linked to the formation of an extended network of fibrillar structures induced by oxidative stress via the formation of a disulfide bond between Cys39 and Cys80. Such phosphorylation-dependent effect is likely controlled by changes in the hydrogen bonding network involving Cys39. We found that the sulfide ion inhibits the formation of such structures. This might represent the mechanism for the protective effect of the therapeutic agent Na2S on ischemic injury.
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Affiliation(s)
- Marcello Pignataro
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, USA
| | - Giulia Di Rocco
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Lidia Lancellotti
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Fabrizio Bernini
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | | | - Elena Castellini
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | | | - Daniele Malferrari
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Daniele Moro
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
| | - Giovanni Valdrè
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
| | - Marco Borsari
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy.
| | - Federica Del Monte
- Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston, USA; Department of Experimental, Diagnostic and Specialty Medicine (DIMES), School of Medicine, University of Bologna, Bologna, Italy.
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5
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Adamson H, Robinson M, Bond PS, Soboh B, Gillow K, Simonov AN, Elton DM, Bond AM, Sawers RG, Gavaghan DJ, Parkin A. Analysis of HypD Disulfide Redox Chemistry via Optimization of Fourier Transformed ac Voltammetric Data. Anal Chem 2017; 89:1565-1573. [PMID: 28029041 DOI: 10.1021/acs.analchem.6b03589] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Rapid disulfide bond formation and cleavage is an essential mechanism of life. Using large amplitude Fourier transformed alternating current voltammetry (FTacV) we have measured previously uncharacterized disulfide bond redox chemistry in Escherichia coli HypD. This protein is representative of a class of assembly proteins that play an essential role in the biosynthesis of the active site of [NiFe]-hydrogenases, a family of H2-activating enzymes. Compared to conventional electrochemical methods, the advantages of the FTacV technique are the high resolution of the faradaic signal in the higher order harmonics and the fact that a single electrochemical experiment contains all the data needed to estimate the (very fast) electron transfer rates (both rate constants ≥ 4000 s-1) and quantify the energetics of the cysteine disulfide redox-reaction (reversible potentials for both processes approximately -0.21 ± 0.01 V vs SHE at pH 6). Previously, deriving such data depended on an inefficient manual trial-and-error approach to simulation. As a highly advantageous alternative, we describe herein an automated multiparameter data optimization analysis strategy where the simulated and experimental faradaic current data are compared for both the real and imaginary components in each of the 4th to 12th harmonics after quantifying the charging current data using the time-domain response.
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Affiliation(s)
- Hope Adamson
- Department of Chemistry, University of York , Heslington, York, YO10 5DD, United Kingdom
| | - Martin Robinson
- Department of Computer Science, University of Oxford , Wolfson Building, Parks Road, Oxford, OX1 3QD, United Kingdom
| | - Paul S Bond
- Department of Chemistry, University of York , Heslington, York, YO10 5DD, United Kingdom
| | - Basem Soboh
- Experimental Molecular Biophysics, Freie Universität Berlin , Arnimalle 14, 14195 Berlin, Germany
| | - Kathryn Gillow
- Mathematical Institute, Andrew Wiles Building, University of Oxford , Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, United Kingdom
| | - Alexandr N Simonov
- School of Chemistry and the ARC Centre of Excellence for Electromaterials Science, Monash University , Clayton, Victoria 3800, Australia
| | - Darrell M Elton
- School of Engineering and Mathematical Sciences, La Trobe University , Bundoora, Victoria 3086, Australia
| | - Alan M Bond
- School of Chemistry and the ARC Centre of Excellence for Electromaterials Science, Monash University , Clayton, Victoria 3800, Australia
| | - R Gary Sawers
- Institute for Biology/Microbiology, Martin Luther University Halle-Wittenberg , Halle (Saale), Germany
| | - David J Gavaghan
- Department of Computer Science, University of Oxford , Wolfson Building, Parks Road, Oxford, OX1 3QD, United Kingdom
| | - Alison Parkin
- Department of Chemistry, University of York , Heslington, York, YO10 5DD, United Kingdom
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6
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Protein Electrochemistry: Questions and Answers. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2016; 158:1-41. [DOI: 10.1007/10_2015_5016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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7
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Yenugudhati D, Prakash D, Kumar AK, Kumar RSS, Yennawar NH, Yennawar HP, Ferry JG. Structural and Biochemical Characterizations of Methanoredoxin from Methanosarcina acetivorans, a Glutaredoxin-Like Enzyme with Coenzyme M-Dependent Protein Disulfide Reductase Activity. Biochemistry 2015; 55:313-21. [PMID: 26684934 DOI: 10.1021/acs.biochem.5b00823] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Glutaredoxins (GRXs) are thiol-disulfide oxidoreductases abundant in prokaryotes, although little is understood of these enzymes from the domain Archaea. The numerous characterized GRXs from the domain Bacteria utilize a diversity of low-molecular-weight thiols in addition to glutathione as reductants. We report here the biochemical and structural properties of a GRX-like protein named methanoredoxin (MRX) from Methanosarcina acetivorans of the domain Archaea. MRX utilizes coenzyme M (CoMSH) as reductant for insulin disulfide reductase activity, which adds to the diversity of thiol protectants in prokaryotes. Cell-free extracts of M. acetivorans displayed CoMS-SCoM reductase activity that complements the CoMSH-dependent activity of MRX. The crystal structure exhibits a classic thioredoxin-glutaredoxin fold comprising three α-helices surrounding four antiparallel β-sheets. A pocket on the surface contains a CVWC motif, identifying the active site with architecture similar to GRXs. Although it is a monomer in solution, the crystal lattice has four monomers in a dimer of dimers arrangement. A cadmium ion is found within the active site of each monomer. Two such ions stabilize the N-terminal tails and dimer interfaces. Our modeling studies indicate that CoMSH and glutathione (GSH) bind to the active site of MRX similar to the binding of GSH in GRXs, although there are differences in the amino acid composition of the binding motifs. The results, combined with our bioinformatic analyses, show that MRX represents a class of GRX-like enzymes present in a diversity of methane-producing Archaea.
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Affiliation(s)
- Deepa Yenugudhati
- Department of Biochemistry and Molecular Biology, ‡Huck Institutes of Life Sciences, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Divya Prakash
- Department of Biochemistry and Molecular Biology, ‡Huck Institutes of Life Sciences, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Adepu K Kumar
- Department of Biochemistry and Molecular Biology, ‡Huck Institutes of Life Sciences, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - R Siva Sai Kumar
- Department of Biochemistry and Molecular Biology, ‡Huck Institutes of Life Sciences, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Neela H Yennawar
- Department of Biochemistry and Molecular Biology, ‡Huck Institutes of Life Sciences, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Hemant P Yennawar
- Department of Biochemistry and Molecular Biology, ‡Huck Institutes of Life Sciences, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - James G Ferry
- Department of Biochemistry and Molecular Biology, ‡Huck Institutes of Life Sciences, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
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8
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Wei Y, Li B, Prakash D, Ferry JG, Elliott SJ, Stubbe J. A Ferredoxin Disulfide Reductase Delivers Electrons to the Methanosarcina barkeri Class III Ribonucleotide Reductase. Biochemistry 2015; 54:7019-28. [PMID: 26536144 PMCID: PMC4697749 DOI: 10.1021/acs.biochem.5b01092] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two subtypes of class III anaerobic ribonucleotide reductases (RNRs) studied so far couple the reduction of ribonucleotides to the oxidation of formate, or the oxidation of NADPH via thioredoxin and thioredoxin reductase. Certain methanogenic archaea contain a phylogenetically distinct third subtype of class III RNR, with distinct active-site residues. Here we report the cloning and recombinant expression of the Methanosarcina barkeri class III RNR and show that the electrons required for ribonucleotide reduction can be delivered by a [4Fe-4S] protein ferredoxin disulfide reductase, and a conserved thioredoxin-like protein NrdH present in the RNR operon. The diversity of class III RNRs reflects the diversity of electron carriers used in anaerobic metabolism.
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Affiliation(s)
| | - Bin Li
- Department of Chemistry, Boston University , 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Divya Prakash
- Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - James G Ferry
- Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Sean J Elliott
- Department of Chemistry, Boston University , 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
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9
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Explorations of time and electrochemical potential: opportunities for fresh perspectives on signalling proteins. Biochem Soc Trans 2014; 42:47-51. [PMID: 24450626 DOI: 10.1042/bst20130256] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Apoptosis is triggered by an accumulation of ROS (reactive oxygen species) produced by proteins of the mitochondrial respiratory chain. The levels of ROS are controlled by the activities of mitochondrial redox proteins such as glutaredoxin 2 that help to modulate the susceptibility of a cell to apoptosis. However, once downstream events have resulted in the release of cytochrome c to the cytosol, it is widely considered that cell death is inevitable. Cytochrome c may promote its own release from mitochondria through interactions with the mitochondrial phospholipid cardiolipin (diphosphatidylglycerol). In the present article, spectroelectrochemistry of the cardiolipin complex of cytochrome c and protein film electrochemistry of glutaredoxin 2 are reviewed to illustrate how electrochemical methods provide insight into the properties of signalling proteins.
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10
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Scotcher J, Bythell BJ, Marshall AG. Unequivocal determination of site-specific protein disulfide bond reduction potentials by top-down FTICR MS: characterization of the N- and C-terminal redox-active sites in human thioredoxin 1. Anal Chem 2013; 85:9164-72. [PMID: 24040747 DOI: 10.1021/ac401850p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We report the reliable determination of equilibrium protein disulfide bond reduction potentials (E°') by isotope-coded cysteine alkylation coupled with top-down Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS). This technique enables multiple redox-active sites to be characterized simultaneously and unambiguously without the need for proteolysis or site-directed mutagenesis. Our model system was E. coli thioredoxin, and we determined E°' for its CGPC active-site disulfide as -280 mV in accord with literature values. E°' for the homologous disulfide in human thioredoxin 1 (Trx1) was determined as -281 mV, a value considerably more negative than the previously reported -230 mV. We also observed S-glutathionylation of Trx1 and localized that redox modification to Cys72; E°' for the intermolecular disulfide was determined as -186 mV. Intriguingly, that value corresponds to the intracellular glutathione/glutathione disulfide (GSH/GSSG) potential at the redox boundary between cellular differentiation and apoptosis.
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Affiliation(s)
- Jenna Scotcher
- National High Magnetic Field Laboratory, Florida State University , 1800 E. Paul Dirac Drive, Tallahassee, Florida 32310, United States
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11
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Cheng Z, Zhang J, Ballou DP, Williams CH. Reactivity of thioredoxin as a protein thiol-disulfide oxidoreductase. Chem Rev 2011; 111:5768-83. [PMID: 21793530 DOI: 10.1021/cr100006x] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Zhiyong Cheng
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-5606, USA
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12
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Abstract
This review focuses on thiol/disulfide redox switches that regulate heme binding to proteins and modulate their activities. The importance of redox switches in metabolic regulation and the general mechanism by which redox switches modulate activity are discussed. Methods are described to characterize heme-binding sites and to assess their physiological relevance. For thiol/disulfide interconversion to regulate activity of a system, the redox process must be reversible at the ambient redox potentials found within the cell; thus, methods (and their limitations) are discussed that can address the physiological relevance of a redox switch. We review recent results that define a mechanism for how thiol/disulfide redox switches that control heme binding can regulate the activities of an enzyme, heme oxygenase-2, and an ion channel, the BK potassium channel. The redox switches on these proteins are composed of different types of Cys-containing motifs that have opposite effects on heme affinity, yet have complementary effects on hypoxia sensing. Finally, a model is proposed to describe how the redox switches on heme oxygenase-2 and the BK channel form an interconnected system that is poised to sense oxygen levels in the bloodstream and to elicit the hypoxic response when oxygen levels drop below a threshold value.
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Affiliation(s)
- Stephen W Ragsdale
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0606, USA.
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13
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Barker KD, Eckermann AL, Sazinsky MH, Hartings MR, Abajian C, Georganopoulou D, Ratner MA, Rosenzweig AC, Meade TJ. Protein Binding and the Electronic Properties of Iron(II) Complexes: An Electrochemical and Optical Investigation of Outer Sphere Effects. Bioconjug Chem 2009; 20:1930-9. [DOI: 10.1021/bc900270a] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kylie D. Barker
- Departments of Chemistry, Biochemistry and Molecular and Cell Biology, Neurobiology and Physiology, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Amanda L. Eckermann
- Departments of Chemistry, Biochemistry and Molecular and Cell Biology, Neurobiology and Physiology, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Matthew H. Sazinsky
- Departments of Chemistry, Biochemistry and Molecular and Cell Biology, Neurobiology and Physiology, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Matthew R. Hartings
- Departments of Chemistry, Biochemistry and Molecular and Cell Biology, Neurobiology and Physiology, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Carnie Abajian
- Departments of Chemistry, Biochemistry and Molecular and Cell Biology, Neurobiology and Physiology, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Dimitra Georganopoulou
- Departments of Chemistry, Biochemistry and Molecular and Cell Biology, Neurobiology and Physiology, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Mark A. Ratner
- Departments of Chemistry, Biochemistry and Molecular and Cell Biology, Neurobiology and Physiology, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Amy C. Rosenzweig
- Departments of Chemistry, Biochemistry and Molecular and Cell Biology, Neurobiology and Physiology, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Thomas J. Meade
- Departments of Chemistry, Biochemistry and Molecular and Cell Biology, Neurobiology and Physiology, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208
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14
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SOAS: A free program to analyze electrochemical data and other one-dimensional signals. Bioelectrochemistry 2009; 76:141-7. [DOI: 10.1016/j.bioelechem.2009.02.010] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 02/25/2009] [Accepted: 02/27/2009] [Indexed: 11/19/2022]
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15
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Mitra S, Elliott SJ. Oxidative disassembly of the [2Fe-2S] cluster of human Grx2 and redox regulation in the mitochondria. Biochemistry 2009; 48:3813-5. [PMID: 19292455 DOI: 10.1021/bi900112m] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Mitochondrial Grx2 is a new member of the thioredoxin superfamily that has been found to bind a [2Fe-2S] cluster in a novel coordination motif at the interface of a homodimer, where cluster binding occurs via a catalytic cysteine residue and a molecule of GSH (per monomer). The (Grx2)(2)-[2Fe-2S] dimer is thought to undergo cluster destruction and monomerization in a redox-induced pathway of activation. In this report, we make use of protein film voltammetry (PFV) as a method to probe the stability of the Grx2-[2Fe-2S] cluster, using oxidative poises of varying potential and duration to probe the thermodynamic and kinetic stability of the cluster's electrochemical response. We find that the cluster signal is stable at positive potentials up to 0.5 V but that cluster destruction occurs readily when oxidative pulses in excess of this value are applied.
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Affiliation(s)
- Sanghamitra Mitra
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA
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16
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Léger C, Bertrand P. Direct Electrochemistry of Redox Enzymes as a Tool for Mechanistic Studies. Chem Rev 2008; 108:2379-438. [DOI: 10.1021/cr0680742] [Citation(s) in RCA: 594] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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