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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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Photoferrotrophy and phototrophic extracellular electron uptake is common in the marine anoxygenic phototroph Rhodovulum sulfidophilum. THE ISME JOURNAL 2021; 15:3384-3398. [PMID: 34054125 PMCID: PMC8528915 DOI: 10.1038/s41396-021-01015-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 05/07/2021] [Accepted: 05/12/2021] [Indexed: 02/03/2023]
Abstract
Photoferrotrophy allows anoxygenic phototrophs to use reduced iron as an electron donor for primary productivity. Recent work shows that freshwater photoferrotrophs can use electrons from solid-phase conductive substances via phototrophic extracellular electron uptake (pEEU), and the two processes share the underlying electron uptake mechanism. However, the ability of marine phototrophs to perform photoferrotrophy and pEEU, and the contribution of these processes to primary productivity is largely unknown. To fill this knowledge gap, we isolated 15 new strains of the marine anoxygenic phototroph Rhodovulum sulfidophilum on electron donors such as acetate and thiosulfate. We observed that all of the R. sulfidophilum strains isolated can perform photoferrotrophy. We chose strain AB26 as a representative strain to study further, and find that it can also perform pEEU from poised electrodes. We show that during pEEU, AB26 transfers electrons to the photosynthetic electron transport chain. Furthermore, systems biology-guided mutant analysis shows that R. sulfidophilum AB26 uses a previously unknown diheme cytochrome c protein, which we call EeuP, for pEEU but not photoferrotrophy. Homologs of EeuP occur in a range of widely distributed marine microbes. Overall, these results suggest that photoferrotrophy and pEEU contribute to the biogeochemical cycling of iron and carbon in marine ecosystems.
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Duarte AG, Barbosa ACC, Ferreira D, Manteigas G, Domingos RM, Pereira IAC. Redox loops in anaerobic respiration - The role of the widespread NrfD protein family and associated dimeric redox module. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148416. [PMID: 33753023 DOI: 10.1016/j.bbabio.2021.148416] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 02/25/2021] [Accepted: 03/11/2021] [Indexed: 02/06/2023]
Abstract
In prokaryotes, the proton or sodium motive force required for ATP synthesis is produced by respiratory complexes that present an ion-pumping mechanism or are involved in redox loops performed by membrane proteins that usually have substrate and quinone-binding sites on opposite sides of the membrane. Some respiratory complexes include a dimeric redox module composed of a quinone-interacting membrane protein of the NrfD family and an iron‑sulfur protein of the NrfC family. The QrcABCD complex of sulfate reducers, which includes the QrcCD module homologous to NrfCD, was recently shown to perform electrogenic quinone reduction providing the first conclusive evidence for energy conservation among this family. Similar redox modules are present in multiple respiratory complexes, which can be associated with electroneutral, energy-driven or electrogenic reactions. This work discusses the presence of the NrfCD/PsrBC dimeric redox module in different bioenergetics contexts and its role in prokaryotic energy conservation mechanisms.
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Affiliation(s)
- Américo G Duarte
- Instituto de Tecnologia Química e Biológica António Xavier/Universidade Nova de Lisboa, Av. da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal.
| | - Ana C C Barbosa
- Instituto de Tecnologia Química e Biológica António Xavier/Universidade Nova de Lisboa, Av. da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal
| | - Delfim Ferreira
- Instituto de Tecnologia Química e Biológica António Xavier/Universidade Nova de Lisboa, Av. da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal
| | - Gonçalo Manteigas
- Instituto de Tecnologia Química e Biológica António Xavier/Universidade Nova de Lisboa, Av. da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal
| | - Renato M Domingos
- Instituto de Tecnologia Química e Biológica António Xavier/Universidade Nova de Lisboa, Av. da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal
| | - Inês A C Pereira
- Instituto de Tecnologia Química e Biológica António Xavier/Universidade Nova de Lisboa, Av. da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal.
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4
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Zuccarello L, Berthomieu C, Boussac A, Brubach JB, Díaz-Moreno I, Díaz Quintana AJ, Hienerwadel R. Protonation of the Cysteine Axial Ligand Investigated in His/Cys c-Type Cytochrome by UV-Vis and Mid- and Far-IR Spectroscopy. J Phys Chem Lett 2020; 11:4198-4205. [PMID: 32364390 DOI: 10.1021/acs.jpclett.0c01016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
His/Cys coordination was recently found in several c-type cytochromes, which could act as sensors, in electron transport or in regulation. Toward a better understanding of Cys function and reactivity in these cytochromes, we compare cytochrome c6 (c6wt) from the cyanobacterium Nostoc PCC 7120 with its Met58Cys mutant. We probe the axial ligands and heme properties by combining visible and mid- to far-FTIR difference spectroscopies. Cys58 determines the strong negative redox potential and pH dependence of M58C (EmM58C = -375 mV, versus Emc6wt = +339 mV). Mid-IR (notably Cys ν(SH), His ν(C5N1), heme δ(CmH)) and far-IR (ν(Fe(II)-His), ν(His-Fe(III)-Cys)) markers of the heme and ligands show that Cys58 remains a strong thiolate ligand of reduced Met58Cys at alkaline pH, while it is protonated at pH 7.5, is stabilized by a strong hydrogen bonding interaction, and weakly interacts with Fe(II). These data provide a benchmark for further analysis of c-type cytochromes with natural His/Cys coordination.
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Affiliation(s)
- Lidia Zuccarello
- CEA, CNRS, Aix Marseille Univ., BIAM, Interactions Protéine Métal UMR 7265, 13108 Saint Paul-Lez-Durance, France
- Aix Marseille Univ., CEA, CNRS, BIAM, Luminy Genetics and Biophysic of Plants, UMR 7265, 13288 Marseille Cedex, France
| | - Catherine Berthomieu
- CEA, CNRS, Aix Marseille Univ., BIAM, Interactions Protéine Métal UMR 7265, 13108 Saint Paul-Lez-Durance, France
| | - Alain Boussac
- I2BC, UMR CNRS 9198, CEA Saclay, 91191 Gif-sur-Yvette, France
| | - Jean-Blaise Brubach
- Synchrotron SOLEIL, AILES Beamline, L'Orme des Merisier, Saint-Aubin, BP 48, F-91192 Gif-sur-Yvette Cedex, France
| | - Irene Díaz-Moreno
- Instituto de Investigaciones Químicas (IIQ), Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla - Consejo Superior de Investigaciones Científicas (CSIC), Avda. Américo Vespucio 49, Sevilla 41092, Spain
| | - Antonio J Díaz Quintana
- Instituto de Investigaciones Químicas (IIQ), Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla - Consejo Superior de Investigaciones Científicas (CSIC), Avda. Américo Vespucio 49, Sevilla 41092, Spain
| | - Rainer Hienerwadel
- Aix Marseille Univ., CEA, CNRS, BIAM, Luminy Genetics and Biophysic of Plants, UMR 7265, 13288 Marseille Cedex, France
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5
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Akram M, Reimann J, Dietl A, Menzel A, Versantvoort W, Kartal B, Jetten MSM, Barends TRM. A nitric oxide-binding heterodimeric cytochrome c complex from the anammox bacterium Kuenenia stuttgartiensis binds to hydrazine synthase. J Biol Chem 2019; 294:16712-16728. [PMID: 31548310 DOI: 10.1074/jbc.ra119.008788] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 09/17/2019] [Indexed: 01/17/2023] Open
Abstract
Anaerobic ammonium oxidation (anammox) is a microbial process responsible for significant nitrogen loss from the oceans and other ecosystems. The redox reactions at the heart of anammox are catalyzed by large multiheme enzyme complexes that rely on small cytochrome c proteins for electron shuttling. Among the most highly abundant of these cytochromes is a unique heterodimeric complex composed of class I and class II c-type cytochromes called NaxLS, which has distinctive biochemical and spectroscopic properties. Here, we present the 1.7 Å resolution crystal structure of this complex from the anammox organism Kuenenia stuttgartiensis (KsNaxLS). The structure reveals that the heme irons in each subunit exhibit a rare His/Cys ligation, which, as we show by substitution, causes the observed unusual spectral properties. Unlike its individual subunits, the KsNaxLS complex binds nitric oxide (NO) only at the distal heme side, forming 6cNO adducts. This is likely due to steric immobilization of the proximal heme-binding motifs upon complex formation, a finding that may be of functional relevance, because NO is an intermediate in the central anammox metabolism. Pulldown experiments with K. stuttgartiensis cell-free extract showed that the KsNaxLS complex binds specifically to one of the central anammox enzyme complexes, hydrazine synthase, which uses NO as one of its substrates. It is therefore possible that the KsNaxLS complex plays a role in binding the volatile NO to retain it in the cell for transfer to hydrazine synthase. Alternatively, we propose that KsNaxLS may shuttle electrons to this enzyme complex.
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Affiliation(s)
- Mohd Akram
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Heidelberg 69120, Germany
| | - Joachim Reimann
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Nijmegen 6525AJ, The Netherlands
| | - Andreas Dietl
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Heidelberg 69120, Germany
| | - Andreas Menzel
- Coherent X-ray Scattering Group, Paul Scherrer Institute, WLGA/223, Villigen 5232, Switzerland
| | - Wouter Versantvoort
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Nijmegen 6525AJ, The Netherlands
| | - Boran Kartal
- Microbial Physiology Group, Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany
| | - Mike S M Jetten
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Nijmegen 6525AJ, The Netherlands
| | - Thomas R M Barends
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Heidelberg 69120, Germany
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6
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Jenner LP, Kurth JM, van Helmont S, Sokol KP, Reisner E, Dahl C, Bradley JM, Butt JN, Cheesman MR. Heme ligation and redox chemistry in two bacterial thiosulfate dehydrogenase (TsdA) enzymes. J Biol Chem 2019; 294:18002-18014. [PMID: 31467084 PMCID: PMC6879331 DOI: 10.1074/jbc.ra119.010084] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/26/2019] [Indexed: 01/04/2023] Open
Abstract
Thiosulfate dehydrogenases (TsdAs) are bidirectional bacterial di-heme enzymes that catalyze the interconversion of tetrathionate and thiosulfate at measurable rates in both directions. In contrast to our knowledge of TsdA activities, information on the redox properties in the absence of substrates is rather scant. To address this deficit, we combined magnetic CD (MCD) spectroscopy and protein film electrochemistry (PFE) in a study to resolve heme ligation and redox chemistry in two representative TsdAs. We examined the TsdAs from Campylobacter jejuni, a microaerobic human pathogen, and from the purple sulfur bacterium Allochromatium vinosum. In these organisms, the enzyme functions as a tetrathionate reductase and a thiosulfate oxidase, respectively. The active site Heme 1 in both enzymes has His/Cys ligation in the ferric and ferrous states and the midpoint potentials (Em) of the corresponding redox transformations are similar, −185 mV versus standard hydrogen electrode (SHE). However, fundamental differences are observed in the properties of the second, electron transferring, Heme 2. In C. jejuni, TsdA Heme 2 has His/Met ligation and an Em of +172 mV. In A. vinosum TsdA, Heme 2 reduction triggers a switch from His/Lys ligation (Em, −129 mV) to His/Met (Em, +266 mV), but the rates of interconversion are such that His/Lys ligation would be retained during turnover. In summary, our findings have unambiguously assigned Em values to defined axial ligand sets in TsdAs, specified the rates of Heme 2 ligand exchange in the A. vinosum enzyme, and provided information relevant to describing their catalytic mechanism(s).
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Affiliation(s)
- Leon P Jenner
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Julia M Kurth
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich Wilhelms Universität Bonn, D-53115 Bonn, Germany
| | - Sebastian van Helmont
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich Wilhelms Universität Bonn, D-53115 Bonn, Germany
| | - Katarzyna P Sokol
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Erwin Reisner
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Christiane Dahl
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich Wilhelms Universität Bonn, D-53115 Bonn, Germany
| | - Justin M Bradley
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Julea N Butt
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Myles R Cheesman
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
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7
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Paquete CM, Rusconi G, Silva AV, Soares R, Louro RO. A brief survey of the "cytochromome". Adv Microb Physiol 2019; 75:69-135. [PMID: 31655743 DOI: 10.1016/bs.ampbs.2019.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Multihaem cytochromes c are widespread in nature where they perform numerous roles in diverse anaerobic metabolic pathways. This is achieved in two ways: multihaem cytochromes c display a remarkable diversity of ways to organize multiple hemes within the protein frame; and the hemes possess an intrinsic reactive versatility derived from diverse spin, redox and coordination states. Here we provide a brief survey of multihaem cytochromes c that have been characterized in the context of their metabolic role. The contribution of multihaem cytochromes c to dissimilatory pathways handling metallic minerals, nitrogen compounds, sulfur compounds, organic compounds and phototrophism are described. This aims to set the stage for the further exploration of the vast unknown "cytochromome" that can be anticipated from genomic databases.
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8
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Motomura T, Suga M, Hienerwadel R, Nakagawa A, Lai TL, Nitschke W, Kuma T, Sugiura M, Boussac A, Shen JR. Crystal structure and redox properties of a novel cyanobacterial heme protein with a His/Cys heme axial ligation and a Per-Arnt-Sim (PAS)-like domain. J Biol Chem 2017; 292:9599-9612. [PMID: 28428249 DOI: 10.1074/jbc.m116.746263] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 04/17/2017] [Indexed: 01/05/2023] Open
Abstract
Photosystem II catalyzes light-induced water oxidation leading to the generation of dioxygen indispensable for sustaining aerobic life on Earth. The Photosystem II reaction center is composed of D1 and D2 proteins encoded by psbA and psbD genes, respectively. In cyanobacteria, different psbA genes are present in the genome. The thermophilic cyanobacterium Thermosynechococcus elongatus contains three psbA genes: psbA1, psbA2, and psbA3, and a new c-type heme protein, Tll0287, was found to be expressed in a strain expressing the psbA2 gene only, but the structure and function of Tll0287 are unknown. Here we solved the crystal structure of Tll0287 at a 2.0 Å resolution. The overall structure of Tll0287 was found to be similar to some kinases and sensor proteins with a Per-Arnt-Sim-like domain rather than to other c-type cytochromes. The fifth and sixth axial ligands for the heme were Cys and His, instead of the His/Met or His/His ligand pairs observed for most of the c-type hemes. The redox potential, E½, of Tll0287 was -255 ± 20 mV versus normal hydrogen electrode at pH values above 7.5. Below this pH value, the E½ increased by ≈57 mV/pH unit at 15 °C, suggesting the involvement of a protonatable group with a pKred = 7.2 ± 0.3. Possible functions of Tll0287 as a redox sensor under microaerobic conditions or a cytochrome subunit of an H2S-oxidizing system are discussed in view of the environmental conditions in which psbA2 is expressed, as well as phylogenetic analysis, structural, and sequence homologies.
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Affiliation(s)
- Taiki Motomura
- From the Department of Picobiology, Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan.,the Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Michihiro Suga
- the Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Rainer Hienerwadel
- the Laboratoire de Génétique et Biophysique des Plantes, UMR 7265, CNRS-CEA-Aix-Marseille Université, Faculté des Sciences de Luminy, 13288 Marseille, France
| | - Akiko Nakagawa
- the Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.,the Proteo-Science Research Center, Ehime University, Ehime 790-8577, Japan
| | - Thanh-Lan Lai
- iBiTec-S, SB2SM, CNRS UMR 9198, CEA Saclay, 91191 Gif-sur-Yvette, France, and
| | - Wolfgang Nitschke
- the Laboratoire de Bioénergétique et Ingénierie des Protéines, CNRS UMR 7281, 13402 Marseille Cedex 20, France
| | - Takahiro Kuma
- the Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Miwa Sugiura
- the Proteo-Science Research Center, Ehime University, Ehime 790-8577, Japan
| | - Alain Boussac
- iBiTec-S, SB2SM, CNRS UMR 9198, CEA Saclay, 91191 Gif-sur-Yvette, France, and
| | - Jian-Ren Shen
- From the Department of Picobiology, Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan, .,the Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
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9
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Grabarczyk DB, Chappell PE, Eisel B, Johnson S, Lea SM, Berks BC. Mechanism of thiosulfate oxidation in the SoxA family of cysteine-ligated cytochromes. J Biol Chem 2015; 290:9209-21. [PMID: 25673696 PMCID: PMC4423706 DOI: 10.1074/jbc.m114.618025] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Indexed: 11/23/2022] Open
Abstract
Thiosulfate dehydrogenase (TsdA) catalyzes the oxidation of two thiosulfate molecules to form tetrathionate and is predicted to use an unusual cysteine-ligated heme as the catalytic cofactor. We have determined the structure of Allochromatium vinosum TsdA to a resolution of 1.3 Å. This structure confirms the active site heme ligation, identifies a thiosulfate binding site within the active site cavity, and reveals an electron transfer route from the catalytic heme, through a second heme group to the external electron acceptor. We provide multiple lines of evidence that the catalytic reaction proceeds through the intermediate formation of a S-thiosulfonate derivative of the heme cysteine ligand: the cysteine is reactive and is accessible to electrophilic attack; cysteine S-thiosulfonate is formed by the addition of thiosulfate or following the reverse reaction with tetrathionate; the S-thiosulfonate modification is removed through catalysis; and alkylating the cysteine blocks activity. Active site amino acid residues required for catalysis were identified by mutagenesis and are inferred to also play a role in stabilizing the S-thiosulfonate intermediate. The enzyme SoxAX, which catalyzes the first step in the bacterial Sox thiosulfate oxidation pathway, is homologous to TsdA and can be inferred to use a related catalytic mechanism.
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Affiliation(s)
- Daniel B Grabarczyk
- From the Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom and
| | - Paul E Chappell
- the Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom
| | - Bianca Eisel
- From the Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom and
| | - Steven Johnson
- the Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom
| | - Susan M Lea
- the Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom
| | - Ben C Berks
- From the Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom and
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10
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Brito JA, Denkmann K, Pereira IAC, Archer M, Dahl C. Thiosulfate dehydrogenase (TsdA) from Allochromatium vinosum: structural and functional insights into thiosulfate oxidation. J Biol Chem 2015; 290:9222-38. [PMID: 25673691 DOI: 10.1074/jbc.m114.623397] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Indexed: 11/06/2022] Open
Abstract
Although the oxidative condensation of two thiosulfate anions to tetrathionate constitutes a well documented and significant part of the natural sulfur cycle, little is known about the enzymes catalyzing this reaction. In the purple sulfur bacterium Allochromatium vinosum, the reaction is catalyzed by the periplasmic diheme c-type cytochrome thiosulfate dehydrogenase (TsdA). Here, we report the crystal structure of the "as isolated" form of A. vinosum TsdA to 1.98 Å resolution and those of several redox states of the enzyme to different resolutions. The protein contains two typical class I c-type cytochrome domains wrapped around two hemes axially coordinated by His(53)/Cys(96) and His(164)/Lys(208). These domains are very similar, suggesting a gene duplication event during evolution. A ligand switch from Lys(208) to Met(209) is observed upon reduction of the enzyme. Cys(96) is an essential residue for catalysis, with the specific activity of the enzyme being completely abolished in several TsdA-Cys(96) variants. TsdA-K208N, K208G, and M209G variants were catalytically active in thiosulfate oxidation as well as in tetrathionate reduction, pointing to heme 2 as the electron exit point. In this study, we provide spectroscopic and structural evidence that the TsdA reaction cycle involves the transient presence of heme 1 in the high-spin state caused by movement of the Sγ atom of Cys(96) out of the iron coordination sphere. Based on the presented data, we draw important conclusions about the enzyme and propose a possible reaction mechanism for TsdA.
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Affiliation(s)
- José A Brito
- From the Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB-UNL), Avenida da República, 2780-157 Oeiras, Portugal and
| | - Kevin Denkmann
- the Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, D-53115 Bonn, Germany
| | - Inês A C Pereira
- From the Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB-UNL), Avenida da República, 2780-157 Oeiras, Portugal and
| | - Margarida Archer
- From the Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB-UNL), Avenida da República, 2780-157 Oeiras, Portugal and
| | - Christiane Dahl
- the Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, D-53115 Bonn, Germany
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11
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Dibrova DV, Cherepanov DA, Galperin MY, Skulachev VP, Mulkidjanian AY. Evolution of cytochrome bc complexes: from membrane-anchored dehydrogenases of ancient bacteria to triggers of apoptosis in vertebrates. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1827:1407-27. [PMID: 23871937 PMCID: PMC3839093 DOI: 10.1016/j.bbabio.2013.07.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Revised: 07/02/2013] [Accepted: 07/08/2013] [Indexed: 12/30/2022]
Abstract
This review traces the evolution of the cytochrome bc complexes from their early spread among prokaryotic lineages and up to the mitochondrial cytochrome bc1 complex (complex III) and its role in apoptosis. The results of phylogenomic analysis suggest that the bacterial cytochrome b6f-type complexes with short cytochromes b were the ancient form that preceded in evolution the cytochrome bc1-type complexes with long cytochromes b. The common ancestor of the b6f-type and the bc1-type complexes probably resembled the b6f-type complexes found in Heliobacteriaceae and in some Planctomycetes. Lateral transfers of cytochrome bc operons could account for the several instances of acquisition of different types of bacterial cytochrome bc complexes by archaea. The gradual oxygenation of the atmosphere could be the key evolutionary factor that has driven further divergence and spread of the cytochrome bc complexes. On the one hand, oxygen could be used as a very efficient terminal electron acceptor. On the other hand, auto-oxidation of the components of the bc complex results in the generation of reactive oxygen species (ROS), which necessitated diverse adaptations of the b6f-type and bc1-type complexes, as well as other, functionally coupled proteins. A detailed scenario of the gradual involvement of the cardiolipin-containing mitochondrial cytochrome bc1 complex into the intrinsic apoptotic pathway is proposed, where the functioning of the complex as an apoptotic trigger is viewed as a way to accelerate the elimination of the cells with irreparably damaged, ROS-producing mitochondria. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.
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Affiliation(s)
- Daria V Dibrova
- School of Physics, University of Osnabrueck, D-49069 Osnabrueck, Germany; School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119992, Russia; Institute of Mitoengineering, Lomonosov Moscow State University, Moscow 119992, Russia
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Suga M, Lai TL, Sugiura M, Shen JR, Boussac A. Crystal structure at 1.5Å resolution of the PsbV2 cytochrome from the cyanobacterium Thermosynechococcus elongatus. FEBS Lett 2013; 587:3267-72. [PMID: 23994160 DOI: 10.1016/j.febslet.2013.08.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 08/10/2013] [Accepted: 08/13/2013] [Indexed: 01/30/2023]
Abstract
PsbV2 is a c-type cytochrome present in a very low abundance in the thermophilic cyanobacterium Thermosynechococcus elongatus. We purified this cytochrome and solved its crystal structure at a resolution of 1.5Å. The protein existed as a dimer in the crystal, and has an overall structure similar to other c-type cytochromes like Cytc6 and Cytc550, for example. However, the 5th and 6th heme iron axial ligands were found to be His51 and Cys101, respectively, in contrast to the more common bis-His or His/Met ligands found in most cytochromes. Although a few other c-type cytochromes were suggested to have this axial coordination, this is the first crystal structure reported for a c-type heme with this unusual His/Cys axial coordination. Previous spectroscopic characterizations of PsbV2 are discussed in relation to its structural properties.
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Affiliation(s)
- Michihiro Suga
- Laboratory of Biomacromolecular Structure, Graduate School of Natural Science and Technology, Department of Biology, Faculty of Science, Okayama University, 1-1, Naka 3-chome, Tsushima, Kita-ku, Okayama 700-8530, Japan
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13
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Kappler U, Maher MJ. The bacterial SoxAX cytochromes. Cell Mol Life Sci 2013; 70:977-92. [PMID: 22907414 PMCID: PMC11113948 DOI: 10.1007/s00018-012-1098-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2012] [Revised: 07/09/2012] [Accepted: 07/17/2012] [Indexed: 10/28/2022]
Abstract
SoxAX cytochromes are heme-thiolate proteins that play a key role in bacterial thiosulfate oxidation, where they initiate the reaction cycle of a multi-enzyme complex by catalyzing the attachment of sulfur substrates such as thiosulfate to a conserved cysteine present in a carrier protein. SoxAX proteins have a wide phylogenetic distribution and form a family with at least three distinct types of SoxAX protein. The types of SoxAX cytochromes differ in terms of the number of heme groups present in the proteins (there are diheme and triheme versions) as well as in their subunit structure. While two of the SoxAX protein types are heterodimers, the third group contains an additional subunit, SoxK, that stabilizes the complex of the SoxA and SoxX proteins. Crystal structures are available for representatives of the two heterodimeric SoxAX protein types and both of these have shown that the cysteine ligand to the SoxA active site heme carries a modification to a cysteine persulfide that implicates this ligand in catalysis. EPR studies of SoxAX proteins have also revealed a high complexity of heme dependent signals associated with this active site heme; however, the exact mechanism of catalysis is still unclear at present, as is the exact number and types of redox centres involved in the reaction.
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Affiliation(s)
- Ulrike Kappler
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD, 4072, Australia.
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Denkmann K, Grein F, Zigann R, Siemen A, Bergmann J, van Helmont S, Nicolai A, Pereira IAC, Dahl C. Thiosulfate dehydrogenase: a widespread unusual acidophilicc-type cytochrome. Environ Microbiol 2012; 14:2673-88. [DOI: 10.1111/j.1462-2920.2012.02820.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ukita S, Fujii T, Hira D, Nishiyama T, Kawase T, Migita CT, Furukawa K. A heterodimeric cytochrome c complex with a very low redox potential from an anaerobic ammonium-oxidizing enrichment culture. FEMS Microbiol Lett 2010; 313:61-7. [PMID: 20883501 DOI: 10.1111/j.1574-6968.2010.02122.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
A dimeric cytochrome c with an apparent molecular mass of 25 kDa was isolated from an anammox bacterium, strain KSU-1, in a relatively large quantity. This protein was named the NaxLS complex. The spectrum of the oxidized form exhibited a peculiar Soret peak at 419 nm. The reduction of NaxLS was not complete even with the addition of excess dithionite, but was complete with titanium (III) citrate, indicating that the NaxLS complex has a very low redox potential. The genes encoding the two subunits, naxL and naxS, are adjacent on the genome. The deduced amino-acid sequences of the genes showed high identities with those of two genes encoding 'unknown proteins' in the genome of Candidatus Kuenenia stuttgartiensis, but had lower identities with other c-type heme proteins. The electron paramagnetic resonance spectra of NaxLS exhibited low-spin signals of two heme species in the range between g=2.6 and g=1.8, which strongly suggested an unusual His/Cys coordination. This unique coordination might account for the low redox potential of the hemes in NaxLS. NaxLS might participate in the transfer of low redox potential electrons in the intracellular anammoxosome compartment or the cytoplasm.
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Affiliation(s)
- Saki Ukita
- Department of Applied Life Science, Faculty of Biotechnology and Life Science, Sojo University, Ikeda, Kumamoto, Japan
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Grein F, Venceslau SS, Schneider L, Hildebrandt P, Todorovic S, Pereira IAC, Dahl C. DsrJ, an Essential Part of the DsrMKJOP Transmembrane Complex in the Purple Sulfur Bacterium Allochromatium vinosum, Is an Unusual Triheme Cytochrome c. Biochemistry 2010; 49:8290-9. [DOI: 10.1021/bi1007673] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Fabian Grein
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, D-53115 Bonn, Germany
| | - Sofia S. Venceslau
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da Republica, EAN, Apt 127, 2780-157 Oeiras, Portugal
| | - Lilian Schneider
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, D-53115 Bonn, Germany
| | - Peter Hildebrandt
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Smilja Todorovic
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da Republica, EAN, Apt 127, 2780-157 Oeiras, Portugal
| | - Inês A. C. Pereira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da Republica, EAN, Apt 127, 2780-157 Oeiras, Portugal
| | - Christiane Dahl
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, D-53115 Bonn, Germany
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Lavergne J, Verméglio A, Joliot P. Functional Coupling Between Reaction Centers and Cytochrome bc 1 Complexes. THE PURPLE PHOTOTROPHIC BACTERIA 2009. [DOI: 10.1007/978-1-4020-8815-5_26] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Kappler U, Bernhardt PV, Kilmartin J, Riley MJ, Teschner J, McKenzie KJ, Hanson GR. SoxAX cytochromes, a new type of heme copper protein involved in bacterial energy generation from sulfur compounds. J Biol Chem 2008; 283:22206-14. [PMID: 18552405 DOI: 10.1074/jbc.m800315200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
SoxAX cytochromes are essential for the function of the only confirmed pathway for bacterial thiosulfate oxidation, the so-called "Sox pathway," in which they catalyze the initial formation of a S-S bond between thiosulfate and the SoxYZ carrier protein. Our work using the Starkeya novella diheme SoxAX protein reveals for the first time that in addition to two active site heme groups, SoxAX contains a mononuclear Cu(II) center with a distorted tetragonal geometry and three to four nitrogen ligands, one of which is a histidine. The Cu(II) center enhanced SoxAX activity in a newly developed, glutathione-based assay system that mimics the natural reaction of SoxAX with SoxYZ. EPR spectroscopy confirmed that the SoxAX Cu(II) center is reduced by glutathione. At pH 7 a K(m) (app) of 0.19+/-0.028 mm and a k(cat) (app) of 5.7+/-0.25s(-1) were determined for glutathione. We propose that SoxAX cytochromes are a new type of heme-copper proteins, with SoxAX-mediated S-S bond formation involving both the copper and heme centers.
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Affiliation(s)
- Ulrike Kappler
- School of Molecular & Microbial Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia.
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Carballal S, Madzelan P, Zinola CF, Graña M, Radi R, Banerjee R, Alvarez B. Dioxygen Reactivity and Heme Redox Potential of Truncated Human Cystathionine β-Synthase. Biochemistry 2008; 47:3194-201. [DOI: 10.1021/bi700912k] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sebastián Carballal
- Laboratorio de Enzimología and Laboratorio de Electroquímica Fundamental, Facultad de Ciencias, Departamento de Bioquímica and Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay, Unité de Biochimie Structurale, Institut Pasteur, 75015 Paris, France, Redox Biology Center and the Biochemistry Department, University of Nebraska, Lincoln, Nebraska 68588-0664, and Department of Biological Chemistry, University of Michigan, Ann Arbor,
| | - Peter Madzelan
- Laboratorio de Enzimología and Laboratorio de Electroquímica Fundamental, Facultad de Ciencias, Departamento de Bioquímica and Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay, Unité de Biochimie Structurale, Institut Pasteur, 75015 Paris, France, Redox Biology Center and the Biochemistry Department, University of Nebraska, Lincoln, Nebraska 68588-0664, and Department of Biological Chemistry, University of Michigan, Ann Arbor,
| | - Carlos F. Zinola
- Laboratorio de Enzimología and Laboratorio de Electroquímica Fundamental, Facultad de Ciencias, Departamento de Bioquímica and Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay, Unité de Biochimie Structurale, Institut Pasteur, 75015 Paris, France, Redox Biology Center and the Biochemistry Department, University of Nebraska, Lincoln, Nebraska 68588-0664, and Department of Biological Chemistry, University of Michigan, Ann Arbor,
| | - Martín Graña
- Laboratorio de Enzimología and Laboratorio de Electroquímica Fundamental, Facultad de Ciencias, Departamento de Bioquímica and Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay, Unité de Biochimie Structurale, Institut Pasteur, 75015 Paris, France, Redox Biology Center and the Biochemistry Department, University of Nebraska, Lincoln, Nebraska 68588-0664, and Department of Biological Chemistry, University of Michigan, Ann Arbor,
| | - Rafael Radi
- Laboratorio de Enzimología and Laboratorio de Electroquímica Fundamental, Facultad de Ciencias, Departamento de Bioquímica and Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay, Unité de Biochimie Structurale, Institut Pasteur, 75015 Paris, France, Redox Biology Center and the Biochemistry Department, University of Nebraska, Lincoln, Nebraska 68588-0664, and Department of Biological Chemistry, University of Michigan, Ann Arbor,
| | - Ruma Banerjee
- Laboratorio de Enzimología and Laboratorio de Electroquímica Fundamental, Facultad de Ciencias, Departamento de Bioquímica and Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay, Unité de Biochimie Structurale, Institut Pasteur, 75015 Paris, France, Redox Biology Center and the Biochemistry Department, University of Nebraska, Lincoln, Nebraska 68588-0664, and Department of Biological Chemistry, University of Michigan, Ann Arbor,
| | - Beatriz Alvarez
- Laboratorio de Enzimología and Laboratorio de Electroquímica Fundamental, Facultad de Ciencias, Departamento de Bioquímica and Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay, Unité de Biochimie Structurale, Institut Pasteur, 75015 Paris, France, Redox Biology Center and the Biochemistry Department, University of Nebraska, Lincoln, Nebraska 68588-0664, and Department of Biological Chemistry, University of Michigan, Ann Arbor,
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Kimura Y, Alric J, Verméglio A, Masuda S, Hagiwara Y, Matsuura K, Shimada K, Nagashima KVP. A new membrane-bound cytochrome c works as an electron donor to the photosynthetic reaction center complex in the purple bacterium, Rhodovulum sulfidophilum. J Biol Chem 2006; 282:6463-72. [PMID: 17197696 DOI: 10.1074/jbc.m604452200] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A new type of membrane-bound cytochrome c was found in a marine purple photosynthetic bacterium, Rhodovulum sulfidophilum. This cytochrome c was significantly accumulated in cells growing under anaerobic photosynthetic conditions and showed an apparent molecular mass of approximately 100 kDa when purified and analyzed by SDS-PAGE. The midpoint potential of this cytochrome c was 369 mV. Flash-induced kinetic measurements showed that this new cytochrome c can work as an electron donor to the photosynthetic reaction center. The gene coding for this cytochrome c was cloned and analyzed. The deduced molecular mass was nearly equal to 50 kDa. Its C-terminal heme-containing region showed the highest sequence identity to the water-soluble cytochrome c(2), although its predicted secondary structure resembles that of cytochrome c(y). Phylogenetic analyses suggested that this new cytochrome c has evolved from cytochrome c(2). We, thus, propose its designation as cytochrome c(2m). Mutants lacking this cytochrome or cytochrome c(2) showed the same growth rate as the wild type. However, a double mutant lacking both cytochrome c(2) and c(2m) showed no growth under photosynthetic conditions. It was concluded that either the membrane-bound cytochrome c(2m) or the water-soluble cytochrome c(2) work as a physiological electron carrier in the photosynthetic electron transfer pathway of Rvu. sulfidophilum.
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Affiliation(s)
- Yasuaki Kimura
- Department of Biological Science, Tokyo Metropolitan University, Minamiohsawa 1-1, Hachioji, Tokyo 192-0397, Japan
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Comayras F, Jungas C, Lavergne J. Functional consequences of the organization of the photosynthetic apparatus in Rhodobacter sphaeroides. I. Quinone domains and excitation transfer in chromatophores and reaction center.antenna complexes. J Biol Chem 2005; 280:11203-13. [PMID: 15632164 DOI: 10.1074/jbc.m412088200] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The purpose of this study was to gain information on the functional consequences of the supramolecular organization of the photosynthetic apparatus in the bacterium Rhodobacter sphaeroides. Isolated complexes of the reaction center (RC) with its core antenna ring (light-harvesting complex 1 (LH1)) were studied in their dimeric (native) form or as monomers with respect to excitation transfer and distribution of the quinone pool. Similar issues were examined in chromatophore membranes. The relationship between the fluorescence yield and the amount of closed centers is indicative of a very efficient excitation transfer between the two monomers in isolated dimeric complexes. A similar dependence was observed in chromatophores, suggesting that excitation transfer in vivo from a closed RC.LH1 unit is also essentially directed to its partner in the dimer. The isolated complexes were found to retain 25-30% of the endogenous quinone acceptor pool, and the distribution of this pool among the complexes suggests a cooperative character for the association of quinones with the protein complexes. In chromatophores, the decrease in the amount of photoreducible quinones when inhibiting a fraction of the centers implies a confinement of the quinone pool over small domains, including one to six reaction centers. We suggest that the crowding of membrane proteins may not be the sole reason for quinone confinement and that a quinone-rich region is formed around the RC.LH1 complexes.
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Affiliation(s)
- Frédéric Comayras
- Unité Mixte de Recherche 6191 CNRS-Commissariat à l'Energie Atomique-Aix Marseille II, Département d'Ecophysiologie Végétale et de Microbiologie, Commissariat à l'Energie Atomique Cadarache, 13108 Saint Paul-lez-Durance Cedex, France
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