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Hagel C, Blaum B, Friedrich T, Heider J. Characterisation of the redox centers of ethylbenzene dehydrogenase. J Biol Inorg Chem 2021; 27:143-154. [PMID: 34843002 PMCID: PMC8840923 DOI: 10.1007/s00775-021-01917-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/29/2021] [Indexed: 01/18/2023]
Abstract
Ethylbenzene dehydrogenase (EbDH), the initial enzyme of anaerobic ethylbenzene degradation from the beta-proteobacterium Aromatoleum aromaticum, is a soluble periplasmic molybdenum enzyme consisting of three subunits. It contains a Mo-bis-molybdopterin guanine dinucleotide (Mo-bis-MGD) cofactor and an 4Fe-4S cluster (FS0) in the α-subunit, three 4Fe-4S clusters (FS1 to FS3) and a 3Fe-4S cluster (FS4) in the β-subunit and a heme b cofactor in the γ-subunit. Ethylbenzene is hydroxylated by a water molecule in an oxygen-independent manner at the Mo-bis-MGD cofactor, which is reduced from the MoVI to the MoIV state in two subsequent one-electron steps. The electrons are then transferred via the Fe-S clusters to the heme b cofactor. In this report, we determine the midpoint redox potentials of the Mo-bis-MGD cofactor and FS1-FS4 by EPR spectroscopy, and that of the heme b cofactor by electrochemically induced redox difference spectroscopy. We obtained relatively high values of > 250 mV both for the MoVI-MoV redox couple and the heme b cofactor, whereas FS2 is only reduced at a very low redox potential, causing magnetic coupling with the neighboring FS1 and FS3. We compare the results with the data on related enzymes and interpret their significance for the function of EbDH.
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Affiliation(s)
- Corina Hagel
- Labor für Mikrobielle Biochemie and Synmikro Zentrum für Synthetische Mikrobiologie, Philipps Universität Marburg, 35043, Marburg, Germany
| | - Bärbel Blaum
- Institut für Biochemie, Albert-Ludwigs Universität, Albertstr. 21, 79104, Freiburg im Breisgau, Germany
| | - Thorsten Friedrich
- Institut für Biochemie, Albert-Ludwigs Universität, Albertstr. 21, 79104, Freiburg im Breisgau, Germany.
| | - Johann Heider
- Labor für Mikrobielle Biochemie and Synmikro Zentrum für Synthetische Mikrobiologie, Philipps Universität Marburg, 35043, Marburg, Germany.
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2
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Kalimuthu P, Wojtkiewicz AM, Szaleniec M, Bernhardt PV. Electrocatalytic Hydroxylation of Sterols by Steroid C25 Dehydrogenase from Sterolibacterium denitrificans. Chemistry 2018; 24:7710-7717. [PMID: 29573289 DOI: 10.1002/chem.201800616] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 03/22/2018] [Indexed: 12/20/2022]
Abstract
The electrochemically driven catalysis of the complex molybdoenzyme steroid C25 dehydrogenase (S25DH) from the β-Proteobacterium Sterolibacterium denitrificans is reported. S25DH catalyses the oxygen-independent regioselective hydroxylation of the tertiary C25 atom of sterols and also their derivatives. Cholest-4-en-3-one is a native substrate for S25DH, which produces 25-hydroxycholest-4-en-3-one as a product of catalytic turnover. Cholecalciferol (vitD3 ) is also a substrate. S25DH was immobilised on a modified gold working electrode with the co-adsorbent chitosan. The complexes ferricyanide ([Fe(CN)6 ]3- ) and ferrocenium methanol (FM+ ) are effective artificial electron acceptors from S25DH and act as mediators of electron transfer between the electrode and the enzyme. 2-Hydroxypropyl-β-cyclodextrin (HPCD) was employed as a sterol solubiliser, in addition to 2-methoxyethanol. The catalytic activity varied, depending upon the concentration of solubiliser in the reaction mixture. Parallel studies with [Fe(CN)6 ]3- as a chemical (as opposed to electrochemical) oxidant coupled to HPLC analysis show that S25DH is capable of oxidising both vitD3 and its less stable isomer, pre-vitD3 , and that the former substrate is stabilised by HPCD.
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Affiliation(s)
- Palraj Kalimuthu
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
| | - Agnieszka M Wojtkiewicz
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30 239, Krakow, Poland
| | - Maciej Szaleniec
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30 239, Krakow, Poland
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
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The H-bond network surrounding the pyranopterins modulates redox cooperativity in the molybdenum- bis PGD cofactor in arsenite oxidase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1353-1362. [DOI: 10.1016/j.bbabio.2016.05.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 05/12/2016] [Accepted: 05/16/2016] [Indexed: 11/19/2022]
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Heider J, Szaleniec M, Sünwoldt K, Boll M. Ethylbenzene Dehydrogenase and Related Molybdenum Enzymes Involved in Oxygen-Independent Alkyl Chain Hydroxylation. J Mol Microbiol Biotechnol 2016; 26:45-62. [PMID: 26960184 DOI: 10.1159/000441357] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Ethylbenzene dehydrogenase initiates the anaerobic bacterial degradation of ethylbenzene and propylbenzene. Although the enzyme is currently only known from a few closely related denitrifying bacterial strains affiliated to the Rhodocyclaceae, it clearly marks a universally occurring mechanism used for attacking recalcitrant substrates in the absence of oxygen. Ethylbenzene dehydrogenase belongs to subfamily 2 of the DMSO reductase-type molybdenum enzymes together with paralogous enzymes involved in the oxygen-independent hydroxylation of p-cymene, the isoprenoid side chains of sterols and even possibly n-alkanes; the subfamily also extends to dimethylsulfide dehydrogenases, selenite, chlorate and perchlorate reductases and, most significantly, dissimilatory nitrate reductases. The biochemical, spectroscopic and structural properties of the oxygen-independent hydroxylases among these enzymes are summarized and compared. All of them consist of three subunits, contain a molybdenum-bis-molybdopterin guanine dinucleotide cofactor, five Fe-S clusters and a heme b cofactor of unusual ligation, and are localized in the periplasmic space as soluble enzymes. In the case of ethylbenzene dehydrogenase, it has been determined that the heme b cofactor has a rather high redox potential, which may also be inferred for the paralogous hydroxylases. The known structure of ethylbenzene dehydrogenase allowed the calculation of detailed models of the reaction mechanism based on the density function theory as well as QM-MM (quantum mechanics - molecular mechanics) methods, which yield predictions of mechanistic properties such as kinetic isotope effects that appeared consistent with experimental data.
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Affiliation(s)
- Johann Heider
- Laboratory of Microbial Biochemistry, LOEWE Center for Synthetic Microbiology, Philipps University of Marburg, Marburg, Germany
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Leimkühler S, Iobbi-Nivol C. Bacterial molybdoenzymes: old enzymes for new purposes. FEMS Microbiol Rev 2015; 40:1-18. [PMID: 26468212 DOI: 10.1093/femsre/fuv043] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2015] [Indexed: 02/06/2023] Open
Abstract
Molybdoenzymes are widespread in eukaryotic and prokaryotic organisms where they play crucial functions in detoxification reactions in the metabolism of humans and bacteria, in nitrate assimilation in plants and in anaerobic respiration in bacteria. To be fully active, these enzymes require complex molybdenum-containing cofactors, which are inserted into the apoenzymes after folding. For almost all the bacterial molybdoenzymes, molybdenum cofactor insertion requires the involvement of specific chaperones. In this review, an overview on the molybdenum cofactor biosynthetic pathway is given together with the role of specific chaperones dedicated for molybdenum cofactor insertion and maturation. Many bacteria are involved in geochemical cycles on earth and therefore have an environmental impact. The roles of molybdoenzymes in bioremediation and for environmental applications are presented.
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Affiliation(s)
- Silke Leimkühler
- Institute of Biochemistry and Biology, Department of Molecular Enzymology, University of Potsdam, 14476 Potsdam, Germany
| | - Chantal Iobbi-Nivol
- The Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, CNRS, Aix Marseille Université, 13402 Marseille cedex 20, France
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Kalimuthu P, Heider J, Knack D, Bernhardt PV. Electrocatalytic Hydrocarbon Hydroxylation by Ethylbenzene Dehydrogenase from Aromatoleum aromaticum. J Phys Chem B 2015; 119:3456-63. [DOI: 10.1021/jp512562k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Palraj Kalimuthu
- School of Chemistry
and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Johann Heider
- Laboratory for
Microbial Biochemistry and Synmikro Center for Synthetic Microbiology, Philipps University Marburg, 35043 Marburg, Germany
| | - Daniel Knack
- Laboratory for
Microbial Biochemistry and Synmikro Center for Synthetic Microbiology, Philipps University Marburg, 35043 Marburg, Germany
| | - Paul V. Bernhardt
- School of Chemistry
and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
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Affiliation(s)
- Russ Hille
- Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
| | - James Hall
- Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
| | - Partha Basu
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, United States
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The prokaryotic Mo/W-bisPGD enzymes family: a catalytic workhorse in bioenergetic. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:1048-85. [PMID: 23376630 DOI: 10.1016/j.bbabio.2013.01.011] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 01/21/2013] [Accepted: 01/23/2013] [Indexed: 01/05/2023]
Abstract
Over the past two decades, prominent importance of molybdenum-containing enzymes in prokaryotes has been put forward by studies originating from different fields. Proteomic or bioinformatic studies underpinned that the list of molybdenum-containing enzymes is far from being complete with to date, more than fifty different enzymes involved in the biogeochemical nitrogen, carbon and sulfur cycles. In particular, the vast majority of prokaryotic molybdenum-containing enzymes belong to the so-called dimethylsulfoxide reductase family. Despite its extraordinary diversity, this family is characterized by the presence of a Mo/W-bis(pyranopterin guanosine dinucleotide) cofactor at the active site. This review highlights what has been learned about the properties of the catalytic site, the modular variation of the structural organization of these enzymes, and their interplay with the isoprenoid quinones. In the last part, this review provides an integrated view of how these enzymes contribute to the bioenergetics of prokaryotes. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems.
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Kong W, Dolhi JM, Chiuchiolo A, Priscu J, Morgan-Kiss RM. Evidence of form II RubisCO (cbbM) in a perennially ice-covered Antarctic lake. FEMS Microbiol Ecol 2012; 82:491-500. [PMID: 22703237 DOI: 10.1111/j.1574-6941.2012.01431.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 06/10/2012] [Accepted: 06/11/2012] [Indexed: 11/27/2022] Open
Affiliation(s)
- Weidong Kong
- Department of Microbiology; Miami University; Oxford; OH; USA
| | - Jenna M. Dolhi
- Department of Microbiology; Miami University; Oxford; OH; USA
| | - Amy Chiuchiolo
- Department of Land Resources and Environmental Sciences; Montana State University; Bozeman; MT; USA
| | - John Priscu
- Department of Land Resources and Environmental Sciences; Montana State University; Bozeman; MT; USA
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Nilsson T, Rova M, Smedja Bäcklund A. Microbial metabolism of oxochlorates: a bioenergetic perspective. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:189-97. [PMID: 22735192 DOI: 10.1016/j.bbabio.2012.06.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 06/05/2012] [Accepted: 06/15/2012] [Indexed: 11/28/2022]
Abstract
The microbial metabolism of oxochlorates is part of the biogeochemical cycle of chlorine. Organisms capable of growth using perchlorate or chlorate as respiratory electron acceptors are also interesting for applications in biotreatment of oxochlorate-containing effluents or bioremediation of contaminated areas. In this review, we discuss the reactions of oxochlorate respiration, the corresponding enzymes, and the relation to respiratory electron transport that can contribute to a proton gradient across the cell membrane. Enzymes specific for oxochlorate respiration are oxochlorate reductases and chlorite dismutase. The former belong to DMSO reductase family of molybdenum-containing enzymes. The heme protein chlorite dismutase, which decomposes chlorite into chloride and molecular oxygen, is only distantly related to other proteins with known functions. Pathways for electron transport may be different in perchlorate and chlorate reducers, but appear in both cases to be similar to pathways found in other respiratory systems. This article is part of a Special Issue entitled: Evolutionary aspects bioenergetic systems.
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Affiliation(s)
- Thomas Nilsson
- Karlstad University, Dept. Chemistry and Biomedical Sciences, SE-651 88 Karlstad, Sweden.
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12
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Low L, Ryan Kilmartin J, Paul V. B, Ulrike K. How are "Atypical" Sulfite Dehydrogenases Linked to Cell Metabolism? Interactions between the SorT Sulfite Dehydrogenase and Small Redox Proteins. Front Microbiol 2011; 2:58. [PMID: 21833314 PMCID: PMC3153034 DOI: 10.3389/fmicb.2011.00058] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 03/15/2011] [Indexed: 12/02/2022] Open
Abstract
Sulfite dehydrogenases (SDHs) are enzymes that catalyze the oxidation of the toxic and mutagenic compound sulfite to sulfate, thereby protecting cells from adverse effects associated with sulfite exposure. While some bacterial SDHs that have been characterized to date are able to use cytochrome c as an electron acceptor, the majority of these enzymes prefer ferricyanide as an electron acceptor and have therefore been termed "atypical" SDHs. Identifying the natural electron acceptor of these enzymes, however, is crucial for understanding how the "atypical" SDHs are integrated into cell metabolism. The SorT sulfite dehydrogenase from Sinorhizobium meliloti is a representative of this enzyme type and we have investigated the interactions of SorT with two small redox proteins, a cytochrome c and a Cu containing pseudoazurin, that are encoded in the same operon and are co-transcribed with the sorT gene. Both potential acceptor proteins have been purified and characterized in terms of their biochemical and electrochemical properties, and interactions and enzymatic studies with both the purified SorT sulfite dehydrogenase and components of the respiratory chain have been carried out. We were able to show for the first time that an "atypical" sulfite dehydrogenase can couple efficiently to a cytochrome c isolated from the same organism despite being unable to efficiently reduce horse heart cytochrome c, however, at present the role of the pseudoazurin in SorT electron transfer is unclear, but it is possible that it acts as an intermediate electron shuttle between. The SorT system appears to couple directly to the respiratory chain, most likely to a cytochrome oxidase.
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Affiliation(s)
- Louie Low
- School of Chemistry and Molecular Biosciences, Centre for Metals in Biology, The University of QueenslandSt. Lucia, QLD, Australia
| | - James Ryan Kilmartin
- School of Chemistry and Molecular Biosciences, Centre for Metals in Biology, The University of QueenslandSt. Lucia, QLD, Australia
| | - Bernhardt Paul V.
- School of Chemistry and Molecular Biosciences, Centre for Metals in Biology, The University of QueenslandSt. Lucia, QLD, Australia
| | - Kappler Ulrike
- School of Chemistry and Molecular Biosciences, Centre for Metals in Biology, The University of QueenslandSt. Lucia, QLD, Australia
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Bernhardt PV. Exploiting the versatility and selectivity of Mo enzymes with electrochemistry. Chem Commun (Camb) 2011; 47:1663-73. [DOI: 10.1039/c0cc03681a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Lowe EC, Bydder S, Hartshorne RS, Tape HLU, Dridge EJ, Debieux CM, Paszkiewicz K, Singleton I, Lewis RJ, Santini JM, Richardson DJ, Butler CS. Quinol-cytochrome c oxidoreductase and cytochrome c4 mediate electron transfer during selenate respiration in Thauera selenatis. J Biol Chem 2010; 285:18433-42. [PMID: 20388716 PMCID: PMC2881769 DOI: 10.1074/jbc.m110.115873] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 04/01/2010] [Indexed: 11/06/2022] Open
Abstract
Selenate reductase (SER) from Thauera selenatis is a periplasmic enzyme that has been classified as a type II molybdoenzyme. The enzyme comprises three subunits SerABC, where SerC is an unusual b-heme cytochrome. In the present work the spectropotentiometric characterization of the SerC component and the identification of redox partners to SER are reported. The mid-point redox potential of the b-heme was determined by optical titration (E(m) + 234 +/- 10 mV). A profile of periplasmic c-type cytochromes expressed in T. selenatis under selenate respiring conditions was undertaken. Two c-type cytochromes were purified ( approximately 24 and approximately 6 kDa), and the 24-kDa protein (cytc-Ts4) was shown to donate electrons to SerABC in vitro. Protein sequence of cytc-Ts4 was obtained by N-terminal sequencing and liquid chromatography-tandem mass spectrometry analysis, and based upon sequence similarities, was assigned as a member of cytochrome c(4) family. Redox potentiometry, combined with UV-visible spectroscopy, showed that cytc-Ts4 is a diheme cytochrome with a redox potential of +282 +/- 10 mV, and both hemes are predicted to have His-Met ligation. To identify the membrane-bound electron donors to cytc-Ts4, growth of T. selenatis in the presence of respiratory inhibitors was monitored. The specific quinol-cytochrome c oxidoreductase (QCR) inhibitors myxothiazol and antimycin A partially inhibited selenate respiration, demonstrating that some electron flux is via the QCR. Electron transfer via a QCR and a diheme cytochrome c(4) is a novel route for a member of the DMSO reductase family of molybdoenzymes.
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Affiliation(s)
- Elisabeth C. Lowe
- From the School of Biosciences, Centre for Biocatalysis, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Sarah Bydder
- the Department of Microbiology, La Trobe University, 3086 Victoria, Australia
| | - Robert S. Hartshorne
- the School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Hannah L. U. Tape
- From the School of Biosciences, Centre for Biocatalysis, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Elizabeth J. Dridge
- From the School of Biosciences, Centre for Biocatalysis, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Charles M. Debieux
- From the School of Biosciences, Centre for Biocatalysis, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Konrad Paszkiewicz
- From the School of Biosciences, Centre for Biocatalysis, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Ian Singleton
- the Institute for Research on Environment and Sustainability, University of Newcastle, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Richard J. Lewis
- the Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, United Kingdom, and
| | - Joanne M. Santini
- the Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - David J. Richardson
- the School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Clive S. Butler
- From the School of Biosciences, Centre for Biocatalysis, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
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Creevey NL, McEwan AG, Bernhardt PV. A mechanistic and electrochemical study of the interaction between dimethyl sulfide dehydrogenase and its electron transfer partner cytochrome c 2. J Biol Inorg Chem 2008; 13:1231-8. [DOI: 10.1007/s00775-008-0406-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Accepted: 06/28/2008] [Indexed: 11/29/2022]
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