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Calisto F, Sousa FM, Sena FV, Refojo PN, Pereira MM. Mechanisms of Energy Transduction by Charge Translocating Membrane Proteins. Chem Rev 2021; 121:1804-1844. [PMID: 33398986 DOI: 10.1021/acs.chemrev.0c00830] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Life relies on the constant exchange of different forms of energy, i.e., on energy transduction. Therefore, organisms have evolved in a way to be able to harvest the energy made available by external sources (such as light or chemical compounds) and convert these into biological useable energy forms, such as the transmembrane difference of electrochemical potential (Δμ̃). Membrane proteins contribute to the establishment of Δμ̃ by coupling exergonic catalytic reactions to the translocation of charges (electrons/ions) across the membrane. Irrespectively of the energy source and consequent type of reaction, all charge-translocating proteins follow two molecular coupling mechanisms: direct- or indirect-coupling, depending on whether the translocated charge is involved in the driving reaction. In this review, we explore these two coupling mechanisms by thoroughly examining the different types of charge-translocating membrane proteins. For each protein, we analyze the respective reaction thermodynamics, electron transfer/catalytic processes, charge-translocating pathways, and ion/substrate stoichiometries.
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Affiliation(s)
- Filipa Calisto
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Filipe M Sousa
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Filipa V Sena
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Patricia N Refojo
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal
| | - Manuela M Pereira
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
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2
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Zanello P. The competition between chemistry and biology in assembling iron–sulfur derivatives. Molecular structures and electrochemistry. Part V. {[Fe4S4](SCysγ)4} proteins. Coord Chem Rev 2017. [DOI: 10.1016/j.ccr.2016.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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3
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Liu J, Chakraborty S, Hosseinzadeh P, Yu Y, Tian S, Petrik I, Bhagi A, Lu Y. Metalloproteins containing cytochrome, iron-sulfur, or copper redox centers. Chem Rev 2014; 114:4366-469. [PMID: 24758379 PMCID: PMC4002152 DOI: 10.1021/cr400479b] [Citation(s) in RCA: 574] [Impact Index Per Article: 57.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Indexed: 02/07/2023]
Affiliation(s)
- Jing Liu
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Saumen Chakraborty
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Parisa Hosseinzadeh
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yang Yu
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Shiliang Tian
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Igor Petrik
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Ambika Bhagi
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yi Lu
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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4
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Bird LJ, Saraiva IH, Park S, Calçada EO, Salgueiro CA, Nitschke W, Louro RO, Newman DK. Nonredundant roles for cytochrome c2 and two high-potential iron-sulfur proteins in the photoferrotroph Rhodopseudomonas palustris TIE-1. J Bacteriol 2014; 196:850-8. [PMID: 24317397 PMCID: PMC3911180 DOI: 10.1128/jb.00843-13] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 11/28/2013] [Indexed: 11/20/2022] Open
Abstract
The purple bacterium Rhodopseudomonas palustris TIE-1 expresses multiple small high-potential redox proteins during photoautotrophic growth, including two high-potential iron-sulfur proteins (HiPIPs) (PioC and Rpal_4085) and a cytochrome c2. We evaluated the role of these proteins in TIE-1 through genetic, physiological, and biochemical analyses. Deleting the gene encoding cytochrome c2 resulted in a loss of photosynthetic ability by TIE-1, indicating that this protein cannot be replaced by either HiPIP in cyclic electron flow. PioC was previously implicated in photoferrotrophy, an unusual form of photosynthesis in which reducing power is provided through ferrous iron oxidation. Using cyclic voltammetry (CV), electron paramagnetic resonance (EPR) spectroscopy, and flash-induced spectrometry, we show that PioC has a midpoint potential of 450 mV, contains all the typical features of a HiPIP, and can reduce the reaction centers of membrane suspensions in a light-dependent manner at a much lower rate than cytochrome c2. These data support the hypothesis that PioC linearly transfers electrons from iron, while cytochrome c2 is required for cyclic electron flow. Rpal_4085, despite having spectroscopic characteristics and a reduction potential similar to those of PioC, is unable to reduce the reaction center. Rpal_4085 is upregulated by the divalent metals Fe(II), Ni(II), and Co(II), suggesting that it might play a role in sensing or oxidizing metals in the periplasm. Taken together, our results suggest that these three small electron transfer proteins perform different functions in the cell.
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Affiliation(s)
- Lina J. Bird
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Divisions of Biology and Geological and Planetary Sciences, Howard Hughes Medical Institute at the California Institute of Technology, Pasadena, California, USA
| | - Ivo H. Saraiva
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Shannon Park
- Divisions of Biology and Geological and Planetary Sciences, Howard Hughes Medical Institute at the California Institute of Technology, Pasadena, California, USA
| | - Eduardo O. Calçada
- Requimte, CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Monte da Caparica, Portugal
| | - Carlos A. Salgueiro
- Requimte, CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Monte da Caparica, Portugal
| | - Wolfgang Nitschke
- Laboratoire de Bioénergétique et Ingénierie des Protéines (UMR7281), CNRS/AMU, FR3479, Marseille, France
| | - Ricardo O. Louro
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Dianne K. Newman
- Divisions of Biology and Geological and Planetary Sciences, Howard Hughes Medical Institute at the California Institute of Technology, Pasadena, California, USA
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5
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Majumder ELW, King JD, Blankenship RE. Alternative Complex III from phototrophic bacteria and its electron acceptor auracyanin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:1383-91. [PMID: 23357331 DOI: 10.1016/j.bbabio.2013.01.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 01/12/2013] [Accepted: 01/15/2013] [Indexed: 12/30/2022]
Abstract
Alternative Complex III (ACIII) is a multisubunit integral membrane protein electron transfer complex that is proposed to be an energy-conserving functional replacement for the bacterial cytochrome bc1 or b6f complexes. Clues to the structure and function of this novel complex come from its relation to other bacterial enzyme families. The ACIII complex has menaquinone: electron acceptor oxidoreductase activity and contains protein subunits with multiple Fe-S centers and c-type hemes. ACIII is found in a diverse group of bacteria, including both phototrophic and nonphototrophic taxa. In the phototrophic filamentous anoxygenic phototrophs, the electron acceptor is the small blue copper protein auracyanin instead of a soluble cytochrome. Recent work on ACIII and the copper protein auracyanin is reviewed with focus on the photosynthetic systems and potential electron transfer pathways and mechanisms. Taken together, the ACIII complexes constitute a unique system for photosynthetic electron transfer and energy conservation. This article is part of a Special Issue entitled: Respiratory Complex III and related bc complexes.
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Affiliation(s)
- Erica L W Majumder
- Washington University in St. Louis, Departments of Biology and Chemistry, Campus Box 1137, One Brookings Dr, St. Louis, MO 63130, USA
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6
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Refojo PN, Teixeira M, Pereira MM. The Alternative complex III: properties and possible mechanisms for electron transfer and energy conservation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1852-9. [PMID: 22609325 DOI: 10.1016/j.bbabio.2012.05.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 05/09/2012] [Accepted: 05/10/2012] [Indexed: 11/17/2022]
Abstract
Alternative complexes III (ACIII) are recently identified membrane-bound enzymes that replace functionally the cytochrome bc(1/)b(6)f complexes. In general, ACIII are composed of four transmembrane proteins and three peripheral subunits that contain iron-sulfur centers and C-type hemes. ACIII are built by a combination of modules present in different enzyme families, namely the complex iron-sulfur molybdenum containing enzymes. In this article a historical perspective on the investigation of ACIII is presented, followed by an overview of the present knowledge on these enzymes. Electron transfer pathways within the protein are discussed taking into account possible different locations (cytoplasmatic or periplasmatic) of the iron-sulfur containing protein and their contribution to energy conservation. In this way several hypotheses for energy conservation modes are raised including linear and bifurcating electron transfer pathways. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012).
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7
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Energy conservation by Rhodothermus marinus respiratory complex I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:509-15. [PMID: 20100453 DOI: 10.1016/j.bbabio.2010.01.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Revised: 01/11/2010] [Accepted: 01/15/2010] [Indexed: 11/21/2022]
Abstract
A sodium ion efflux, together with a proton influx and an inside-positive DeltaPsi, was observed during NADH-respiration by Rhodothermus marinus membrane vesicles. Proton translocation was monitored by fluorescence spectroscopy and sodium ion transport by (23)Na-NMR spectroscopy. Specific inhibitors of complex I (rotenone) and of the dioxygen reductase (KCN) inhibited the proton and the sodium ion transport, but the KCN effect was totally reverted by the addition of menaquinone analogues, indicating that both transports were catalyzed by complex I. We concluded that the coupling ion of the system is the proton and that neither the catalytic reaction nor the establishment of the delta-pH are dependent on sodium, but the presence of sodium increases proton transport. Moreover, studies of NADH oxidation at different sodium concentrations and of proton and sodium transport activities allowed us to propose a model for the mechanism of complex I in which the presence of two different energy coupling sites is suggested.
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8
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Structure at 1.0 Å resolution of a high-potential iron–sulfur protein involved in the aerobic respiratory chain of Rhodothermus marinus. J Biol Inorg Chem 2009; 15:303-13. [DOI: 10.1007/s00775-009-0603-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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9
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Melo AMP, Lobo SAL, Sousa FL, Fernandes AS, Pereira MM, Hreggvidsson GO, Kristjansson JK, Saraiva LM, Teixeira M. A nhaD Na+/H+ antiporter and a pcd homologues are among the Rhodothermus marinus complex I genes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1709:95-103. [PMID: 16023073 DOI: 10.1016/j.bbabio.2005.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Revised: 06/07/2005] [Accepted: 06/10/2005] [Indexed: 11/18/2022]
Abstract
The NADH:menaquinone oxidoreductase (Nqo) is one of the enzymes present in the respiratory chain of the thermohalophilic bacterium Rhodothermus marinus. The genes coding for the R. marinus Nqo subunits were isolated and sequenced, clustering in two operons [nqo1 to nqo7 (nqoA) and nqo10 to nqo14 (nqoB)] and two independent genes (nqo8 and nqo9). Unexpectedly, two genes encoding homologues of a NhaD Na+/H+ antiporter (NhaD) and of a pterin-4alpha-carbinolamine dehydratase (PCD) were identified within nqoB, flanked by nqo13 and nqo14. Eight conserved motives to harbour iron-sulphur centres are identified in the deduced primary structures, as well as two consensus sequences to bind nucleotides, in this case NADH and FMN. Moreover, the open-reading-frames of the putative NhaD and PCD were shown to be co-transcribed with the other complex I genes encoded by nqoB. The possible role of these two genes in R. marinus complex I is discussed.
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Affiliation(s)
- Ana M P Melo
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, Apartado 127, 2781-901 Oeiras, Portugal
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10
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Bjornsdottir SH, Blondal T, Hreggvidsson GO, Eggertsson G, Petursdottir S, Hjorleifsdottir S, Thorbjarnardottir SH, Kristjansson JK. Rhodothermus marinus: physiology and molecular biology. Extremophiles 2005; 10:1-16. [PMID: 16075163 DOI: 10.1007/s00792-005-0466-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2004] [Accepted: 06/17/2005] [Indexed: 11/24/2022]
Abstract
Rhodothermus marinus has been the subject of many studies in recent years. It is a thermohalophilic bacterium and is the only validly described species in the genus Rhodothermus. It is not closely related to other well-known thermophiles and is the only thermophile within the family Crenotrichaceae. R. marinus has been isolated from several similar but distantly located geothermal habitats, many of which are subject to large fluctuations in environmental conditions. This presumably affects the physiology of R. marinus. Many of its enzymes show optimum activity at temperatures considerably higher than 65 degrees C, the optimum for growth, and some are active over a broad temperature range. Studies have found distinguishing components in the R. marinus electron transport chain as well as in its pool of intracellular solutes, which accumulate during osmotic stress. The species hosts both bacteriophages and plasmids and a functional intein has been isolated from its chromosome. Despite these interesting features and its unknown genetics, interest in R. marinus has been mostly stimulated by its thermostable enzymes, particularly polysaccharide hydrolysing enzymes and enzymes of DNA synthesis which may be useful in industry and in the laboratory. R. marinus has not been amenable to genetic analysis until recently when a system for gene transfer was established. Here, we review the current literature on R. marinus.
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11
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Fernandes AS, Konstantinov AA, Teixeira M, Pereira MM. Quinone reduction by Rhodothermus marinus succinate:menaquinone oxidoreductase is not stimulated by the membrane potential. Biochem Biophys Res Commun 2005; 330:565-70. [PMID: 15796920 DOI: 10.1016/j.bbrc.2005.03.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2005] [Indexed: 11/23/2022]
Abstract
Succinate:quinone oxidoreductase (SQR), a di-haem enzyme purified from Rhodothermus marinus, reveals an HQNO-sensitive succinate:quinone oxidoreductase activity with several menaquinone analogues as electron acceptors that decreases with lowering the redox midpoint potential of the quinones. A turnover with the low-potential 2,3-dimethyl-1,4-naphthoquinone that is the closest analogue of menaquinone, although low, can be detected in liposome-reconstituted SQR. Reduction of the quinone is not stimulated by an imposed K+-diffusion membrane potential of a physiological sign (positive inside the vesicles). Nor does the imposed membrane potential increase the reduction level of the haems in R. marinus SQR poised with the succinate/fumarate redox couple. The data do not support a widely discussed hypothesis on the electrogenic transmembrane electron transfer from succinate to menaquinone catalysed by di-haem SQRs. The role of the membrane potential in regulation of the SQR activity is discussed.
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Affiliation(s)
- Andreia S Fernandes
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, Apartado 127, 2784-505 Oeiras, Portugal
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12
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Lieutaud C, Alric J, Bauzan M, Nitschke W, Schoepp-Cothenet B. Study of the high-potential iron sulfur protein in Halorhodospira halophila confirms that it is distinct from cytochrome c as electron carrier. Proc Natl Acad Sci U S A 2005; 102:3260-5. [PMID: 15728382 PMCID: PMC552902 DOI: 10.1073/pnas.0407768102] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2004] [Accepted: 01/14/2005] [Indexed: 11/18/2022] Open
Abstract
The role of high-potential iron sulfur protein (HiPIP) in donating electrons to the photosynthetic reaction center in the halophilic gamma-proteobacterium Halorhodospira halophila was studied by EPR and time-resolved optical spectroscopy. A tight complex between HiPIP and the reaction center was observed. The EPR spectrum of HiPIP in this complex was drastically different from that of the purified protein and provides an analytical tool for the detection and characterization of the complexed form in samples ranging from whole cells to partially purified protein. The bound HiPIP was identified as iso-HiPIP II. Its Em value at pH 7 in the form bound to the reaction center was approximately 100 mV higher (+140 +/- 20 mV) than that of the purified protein. EPR on oriented samples showed HiPIP II to be bound in a well defined geometry, indicating the presence of specific protein-protein interactions at the docking site. At moderately reducing conditions, the bound HiPIP II donates electrons to the cytochrome subunit bound to the reaction center with a half-time of < or =11 micros. This donation reaction was analyzed by using Marcus's outer-sphere electron-transfer theory and compared with those observed in other HiPIP-containing purple bacteria. The results indicate substantial differences between the HiPIP- and the cytochrome c2-mediated re-reduction of the reaction center.
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Affiliation(s)
- Clément Lieutaud
- Laboratoire de Bioénergétique et Ingénierie des Protéines, Unité Propre de Recherche 9036, Institut de Biologie Structurale et Microbiologie, Centre National de la Recherche Scientifique, 13402 Marseille Cedex 20, France
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Nogi T, Hirano Y, Miki K. Structural and functional studies on the tetraheme cytochrome subunit and its electron donor proteins: the possible docking mechanisms during the electron transfer reaction. PHOTOSYNTHESIS RESEARCH 2005; 85:87-99. [PMID: 15977061 DOI: 10.1007/s11120-004-2416-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2004] [Accepted: 08/30/2004] [Indexed: 05/03/2023]
Abstract
The photosynthetic reaction centers (RCs) classified as the group II possess a peripheral cytochrome (Cyt) subunit, which serves as the electron mediator to the special-pair. In the cycle of the photosynthetic electron transfer reactions, the Cyt subunit accepts electrons from soluble electron carrier proteins, and re-reduces the photo-oxidized special-pair of the bacteriochlorophyll. Physiologically, high-potential cytochromes such as the cytochrome c2 and the high-potential iron-sulfur protein (HiPIP) function as the electron donors to the Cyt subunit. Most of the Cyt subunits possess four heme c groups, and it was unclear which heme group first accepts the electron from the electron donor. The most distal heme to the special-pair, the heme-1, has a lower redox potential than the electron donors, which makes it difficult to understand the electron transfer mechanism mediated by the Cyt subunit. Extensive mutagenesis combined with kinetic studies has made a great contribution to our understanding of the molecular interaction mechanisms, and has demonstrated the importance of the region close to the heme-1 in the electron transfer. Moreover, crystallographic studies have elucidated two high-resolution three-dimensional structures for the RCs containing the Cyt subunit, the Blastochloris viridis and Thermochromatium tepidum RCs, as well as the structures of their electron donors. An examination of the structural data also suggested that the binding sites for both the cytochrome c2 and the HiPIP are located adjacent to the solvent-accessible edge of the heme-1. In addition, it is also indicated by the structural and biochemical data that the cytochrome c2 and the HiPIP dock with the Cyt subunit by c2 is recognized through electrostatic interactions while hydrophobic interactions are important in the HiPIP docking.
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Affiliation(s)
- Terukazu Nogi
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, 565-0871, Japan
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14
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Lieutaud C, Nitschke W, Verméglio A, Parot P, Schoepp-Cothenet B. HiPIP in Rubrivivax gelatinosus is firmly associated to the membrane in a conformation efficient for electron transfer towards the photosynthetic reaction centre. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1557:83-90. [PMID: 12615351 DOI: 10.1016/s0005-2728(02)00397-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
High potential iron-sulfur protein (HiPIP), a small soluble redox protein, has been shown to serve in vivo as electron donor to the photosynthetic reaction centre (RC) in Rubrivivax gelatinosus [Biochemistry 34 (1995) 11736]. The results of time-resolved optical spectroscopy on membrane-fragments from this organism indicates that the photooxidized RC is re-reduced by HiPIP even in the absence of the soluble fraction. This implies that a significant fraction of HiPIP can firmly bind to the membrane in a conformation able to interact with the RCs. Salt treatment of the membrane-fragments abolishes these re-reduction kinetics, demonstrating the presence of HiPIP on the membrane due to association with the RC rather than due to simple trapping in hypothetical chromatophores. The existence of such a functional complex in membranes is confirmed and its structure further examined by electron paramagnetic resonance (EPR) performed on membrane-fragments. Orientation-dependent EPR spectra of HiPIP were recorded on partially ordered membranes, oxidized either chemically or photochemically. Whereas hardly any preferential orientation of the HiPIP was seen in the chemically oxidised sample, a subpopulation of HiPIP showing specific orientations could be photooxidised. This fraction arises from the electron transfer complex between HiPIP and the RC.
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Affiliation(s)
- Clément Lieutaud
- Laboratoire de Biophysique des Transporteurs d'Electrons, Faculté des Sciences de Luminy, 136 Avenue de Luminy, 13288 Marseille Cedex 9, France
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15
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Fernandes AS, Pereira MM, Teixeira M. Purification and characterization of the complex I from the respiratory chain of Rhodothermus marinus. J Bioenerg Biomembr 2002; 34:413-21. [PMID: 12678433 DOI: 10.1023/a:1022509907553] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The rotenone sensitive NADH:menaquinone oxidoreductase (NDH-I or complex I) from the thermohalophilic bacterium Rhodothermus marinus has been purified and characterized. Three of its subunits react with antibodies against 78, 51, and 21.3c kDa subunits of Neurospora crassa complex I. The optimum conditions for NADH dehydrogenase activity are 50 degrees C and pH 8.1, and the enzyme presents a KM of 9 microM for NADH. The enzyme also displays NADH:quinone oxidoreductase activity with two menaquinone analogs, 1,4-naphtoquinone (NQ) and 2,3-dimethyl-1,4-naphtoquinone (DMN), being the last one rotenone sensitive, indicating the complex integrity as purified. When incorporated in liposomes, a stimulation of the NADH:DMN oxidoreductase activity is observed by dissipation of the membrane potential, upon addition of CCCP. The purified enzyme contains 13.5 +/- 3.5 iron atoms and approximately 3.7 menaquinone per FMN. At least five iron-sulfur centers are observed by EPR spectroscopy: two [2Fe-2S](2+/1+) and three [4Fe-4S](2+/1+) centers. By fluorescence spectroscopy a still unidentified chromophore was detected in R. marinus complex I.
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Affiliation(s)
- Andreia S Fernandes
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal
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16
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Sigurdson H, Namslauer A, Pereira MM, Teixeira M, Brzezinski P. Ligand binding and the catalytic reaction of cytochrome caa(3) from the thermophilic bacterium Rhodothermus marinus. Biochemistry 2001; 40:10578-85. [PMID: 11524000 DOI: 10.1021/bi010344h] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ligand-binding dynamics and the reaction with O(2) of the fully (five-electron) reduced cytochrome caa(3) from the thermohalophilic bacterium Rhodothermus (R.) marinus were investigated. The enzyme is a proton pump which has all the residues of the proton-transfer pathways found in the mitochondrial-like enzymes conserved, except for one of the key elements of the D-pathway, the helix-VI glutamate [Glu(I-286), R. sphaeroides numbering]. In contrast to what has been suggested previously as general characteristics of thermophilic enzymes, during formation of the R. marinus caa(3)-CO complex, CO binds weakly to Cu(B), and is rapidly (k(Ba) = 450 s(-1)) trapped by irreversible (K(Ba) = 4.5 x 10(3)) binding to heme a(3). Upon reaction of the fully reduced enzyme with O(2), four kinetic phases were resolved during the first 10 ms after initiation of the reaction. On the basis of a comparison to reactions observed with the bovine enzyme, these phases were attributed to the following transitions between intermediates (pH 7.8, 1 mM O(2)): R --> A (tau congruent with 8 micros), A --> P(r) (tau congruent with 35 micros), P(r) --> F (tau congruent with 240 micros), F --> O (tau congruent with 2.5 ms), where the last two phases were associated with proton uptake from the bulk solution. Oxidation of heme c was observed only during the last two reaction steps. The slower transition times as compared to those observed with the bovine enzyme most likely reflect the replacement of Glu(I-286) of the helix-VI motif -XGHPEV- by a tyrosine in the R. marinus enzyme in the motif -YSHPXV-. The presence of an additional, fifth electron in the enzyme was reflected by two additional kinetic phases with time constants of approximately 20 and approximately 720 ms during which the fifth electron reequilibrated within the enzyme.
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Affiliation(s)
- H Sigurdson
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
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Fernandes AS, Pereira MM, Teixeira M. The succinate dehydrogenase from the thermohalophilic bacterium Rhodothermus marinus: redox-Bohr effect on heme bL. J Bioenerg Biomembr 2001; 33:343-52. [PMID: 11710809 DOI: 10.1023/a:1010663424846] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The succinate dehydrogenase from the thermohalophilic bacterium Rhodothermus marinus is a member of the succinate:menaquinone oxidoreductases family. It is constituted by three subunits with apparent molecular masses of 70, 32, and 18 kDa. The optimum temperature for succinate dehydrogenase activity is 80 degrees C, higher than the optimum growth temperature of R. marinus, 65 degrees C. The enzyme shows a high affinity for both succinate (Km = 0.165 mM) and fumarate (Km = 0.10 mM). It contains the canonical iron-sulfur centers S1, S2, and S3, as well as two B-type hemes. In contrast to other succinate dehydrogenases, the S3 center has an unusually high reduction potential of +130 mV and is present in two different conformations, one of which presents an unusual EPR signal with g values at 2.035, 2.009, and 2.001. The apparent midpoint reduction potentials of the hemes, +75 and -65 mV at pH 7.5, are also higher than those reported for other enzymes. The heme with the lower potential (heme bL) presents a considerable dependence of the reduction potential with pH (redox-Bohr effect), having a pKa(OX) = 6.5 and a pKa(red) = 8.7. This behavior is consistent with the proposal that in these enzymes menaquinone reduction occurs close to heme bL, near to the periplasmic side of the membrane, and involving dissipation of the proton transmembrane gradient.
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Affiliation(s)
- A S Fernandes
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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Santana M, Pereira MM, Elias NP, Soares CM, Teixeira M. Gene cluster of Rhodothermus marinus high-potential iron-sulfur Protein: oxygen oxidoreductase, a caa(3)-type oxidase belonging to the superfamily of heme-copper oxidases. J Bacteriol 2001; 183:687-99. [PMID: 11133964 PMCID: PMC94926 DOI: 10.1128/jb.183.2.687-699.2001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2000] [Accepted: 10/15/2000] [Indexed: 11/20/2022] Open
Abstract
The respiratory chain of the thermohalophilic bacterium Rhodothermus marinus contains an oxygen reductase, which uses HiPIP (high potential iron-sulfur protein) as an electron donor. The structural genes encoding the four subunits of this HiPIP:oxygen oxidoreductase were cloned and sequenced. The genes for subunits II, I, III, and IV (named rcoxA to rcoxD) are found in this order and seemed to be organized in an operon of at least five genes with a terminator structure a few nucleotides downstream of rcoxD. Examination of the amino acid sequence of the Rcox subunits shows that the subunits of the R. marinus enzyme have homology to the corresponding subunits of oxidases belonging to the superfamily of heme-copper oxidases. RcoxB has the conserved histidines involved in binding the binuclear center and the low-spin heme. All of the residues proposed to be involved in proton transfer channels are conserved, with the exception of the key glutamate residue of the D-channel (E(278), Paracoccus denitrificans numbering). Analysis of the homology-derived structural model of subunit I shows that the phenol group of a tyrosine (Y) residue and the hydroxyl group of the following serine (S) may functionally substitute the glutamate carboxyl in proton transfer. RcoxA has an additional sequence for heme C binding, after the Cu(A) domain, that is characteristic of caa(3) oxidases belonging to the superfamily. Homology modeling of the structure of this cytochrome domain of subunit II shows no marked electrostatic character, especially around the heme edge region, suggesting that the interaction with a redox partner is not of an electrostatic nature. This observation is analyzed in relation to the electron donor for this caa(3) oxidase, the HiPIP. In conclusion, it is shown that an oxidase, which uses an iron-sulfur protein as an electron donor, is structurally related to the caa(3) class of heme-copper cytochrome c oxidases. The data are discussed in the framework of the evolution of oxidases within the superfamily of heme-copper oxidases.
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Affiliation(s)
- M Santana
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2780-156 Oeiras, Portugal
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Pereira MM, Verkhovskaya ML, Teixeira M, Verkhovsky MI. The caa(3) terminal oxidase of Rhodothermus marinus lacking the key glutamate of the D-channel is a proton pump. Biochemistry 2000; 39:6336-40. [PMID: 10828946 DOI: 10.1021/bi992848+] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The thermohalophilic bacterium Rhodothermus marinus expresses a caa(3)-type dioxygen reductase as one of its terminal oxidases. The subunit I amino acid sequence shows the presence of all the essential residues of the D- and K-proton channels, defined in most heme-copper oxidases, with the exception of the key glutamate residue located in the middle of the membrane dielectric (E278 in Paracoccus denitrificans). On the basis of homology modeling studies, a tyrosine residue (Y256, R. marinus numbering) has been proposed to act as a functional substitute [Pereira, M. M., Santana, M., Soares, C. M., Mendes, J., Carita, J. N., Fernandes, A. S., Saraste, M., Carrondo, M. A., and Teixeira, M. (1999) Biochim. Biophys. Acta 1413, 1-13]. Here, R. marinus caa(3) oxidase was reconstituted in liposomes and shown to operate as a proton pump, translocating protons from the cytoplasmic side of the bacterial inner membrane to the periplasmatic space with a stoichiometry of 1H(+)/e(-), as in the case in heme-copper oxidases that contain the glutamate residue. Possible mechanisms of proton transfer in the D-channel with the participation of the tyrosine residue are discussed. The observation that the tyrosine residue is conserved in several other members of the heme-copper oxidase superfamily suggests a common alternative mode of action for the D-channel.
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Affiliation(s)
- M M Pereira
- Helsinki Bioenergetics Group, Department of Medical Chemistry, Institute of Biomedical Sciences and Biocentrum Helsinki, University of Helsinki, Finland
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Pereira MM, Carita JN, Anglin R, Saraste M, Teixeira M. Heme centers of Rhodothermus marinus respiratory chain. Characterization of its cbb3 oxidase. J Bioenerg Biomembr 2000; 32:143-52. [PMID: 11768747 DOI: 10.1023/a:1005555829301] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Rhodothermus (R.) marinus, a thermohalophilic gram-negative, and strict aerobic bacterium, has a rather distinct respiratory chain, containing a caa3 terminal oxidase, a novel cytochrome bc complex and a HiPIP, which is an electron carrier between this complex and a terminal oxidase (Pereira et al (1999a, c). To further elucidate this unusual respiratory system, its membrane-bound heme centers were characterized by visible and EPR spectroscopies as well as by redox potentiometry. Rhodothermus marinus contains mostly B- and C-type hemes; a small amount of A-type heme is also detected. The heme centers have relatively low reduction potentials, ranging from ca. +250 to -60 mV, at pH 7. A Rieske-type center was not detected, suggesting the absence of a canonical complex III. The major terminal oxidase expressed by R. marinus is a cbb3-type oxidase. Its presence is in agreement with molecular biology studies, which reveal the existence of a gene encoding for a FixN-type oxidase. The oxidase was partially purified and appears to have five subunits, with apparent molecular masses of 64, 57, 36, 26 (C-type heme subunit), and 13 kDa. It contains two low-spin heme C centers, one high-, and one low-spin heme B centers. A full description of the equilibrium redox behavior of the heme centers was obtained for a cbb3 oxidase for the first time. The optical spectrum for each heme center and the corresponding reduction potentials were determined at pH 7: + 195 (heme C), +120 (heme B), -50 (heme C), and -50 mV (heme B3).
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Affiliation(s)
- M M Pereira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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Pereira MM, Santana M, Soares CM, Mendes J, Carita JN, Fernandes AS, Saraste M, Carrondo MA, Teixeira M. The caa3 terminal oxidase of the thermohalophilic bacterium Rhodothermus marinus: a HiPIP:oxygen oxidoreductase lacking the key glutamate of the D-channel. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1413:1-13. [PMID: 10524259 DOI: 10.1016/s0005-2728(99)00073-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The respiratory chain of the thermohalophilic bacterium Rhodothermus marinus contains a novel complex III and a high potential iron-sulfur protein (HiPIP) as the main electron shuttle (Pereira et al., Biochemistry 38 (1999) 1268-1275 and 1276-1283). In this paper, one of the terminal oxidases expressed in this bacterium is extensively characterised. It is a caa3-type oxidase, isolated with four subunits (apparent molecular masses of 42, 19 and 15 kDa and a C-haem containing subunit of 35 kDa), which has haems of the A(s) type. This oxidase is capable of using TMPD and horse heart cytochrome c as substrates, but has a higher turnover with HiPIP, being the first example of a HiPIP:oxygen oxidoreductase. The oxidase has unusually low reduction potentials of 260 (haem C), 255 (haem A) and 180 mV (haem A3). Subunit I of R. marinus caa3 oxidase has an overall significant homology with the subunits I of the COX type oxidases, namely the metal binding sites and most residues considered to be functionally important for proton uptake and pumping (K- and D-channels). However, a major difference is present: the putative essential glutamate (E278 in Paraccocus denitrificans) of the D-channel is missing in the R. marinus oxidase. Homology modelling of the R. marinus oxidase shows that the phenol group of a tyrosine residue may occupy a similar spatial position as the glutamate carboxyl, in relation to the binuclear centre. Moreover, sequence comparisons reveal that several enzymes lacking that glutamate have a conserved substitution pattern in helix VI: -YSHPXV- instead of -XGHPEV-. These observations are discussed in terms of the mechanisms for proton uptake and it is suggested that, in these enzymes, tyrosine may play the role of the glutamate in the proton channel.
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Affiliation(s)
- M M Pereira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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On the role of high-potential iron-sulfur proteins and cytochromes in the respiratory chain of two facultative phototrophs. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1410:51-60. [PMID: 10076014 DOI: 10.1016/s0005-2728(98)00173-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The capability of high potential iron-sulfur proteins (HiPIPs) and soluble cytochromes to shuttle electrons between the bc1 complex and the terminal oxidase in aerobically grown cells of Rhodoferax fermentans and Rhodospirillum salinarum, two facultative phototrophs, was evaluated. In Rs. salinarum, HiPIP and a c-type cytochrome (alpha-band at 550 nm, Em,7=+290 mV) are both involved in the electron transfer step from the bc1 complex to the terminal oxidase. Kinetic studies indicate that cytochrome c550 is more efficient than HiPIP in oxidizing the bc1 complex, and that HiPIP is a more efficient reductant of the terminal oxidase as compared to cytochrome c550. Rs. salinarum cells contain an additional c-type cytochrome (asymmetric alpha-band at 556 nm, Em,7=+180 mV) which is able to reduce the terminal oxidase, but unable to oxidize the bc1 complex. c-type cytochromes could not be isolated from Rf. fermentans, in which HiPIP, the most abundant soluble electron carrier, is reduced by the bc1 complex (zero-order kinetics) and oxidized by the terminal oxidase (first-order kinetics), respectively. These data, taken together, indicate for the first time that HiPIPs play a significant role in bacterial respiratory electron transfer.
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Pereira MM, Carita JN, Teixeira M. Membrane-bound electron transfer chain of the thermohalophilic bacterium Rhodothermus marinus: a novel multihemic cytochrome bc, a new complex III. Biochemistry 1999; 38:1268-75. [PMID: 9930987 DOI: 10.1021/bi9818063] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel multihemic cytochrome bc complex was isolated from the membranes of Rhodothermus marinus. It is a complex with a minimum of three subunits (43, 27, and 18 kDa), containing five low-spin heme centers of the B and C types, in a 1:4 ratio. All the C-type hemes are in the same subunit (27 kDa). Three distinct redox transitions, at 235, 80, and -45 mV, were observed by visible redox titrations. The first involves one B- and one C-type hemes, and in the other two transitions one and two C-type hemes are involved, respectively. Spectroscopic data strongly suggest that the two hemes intervening in the last transition are in van der Waals contact, yielding a split Soret band. Electron paramagnetic resonance spectra of the oxidized complex show resonances of five low-spin ferric heme centers. Upon reduction with ascorbate, all these resonances vanish and a new one attributed to the last pair of hemes appears. A [3Fe-4S]1+/0 center copurifies with this complex, having a high reduction potential of +140 mV. No Rieske-type centers are detected in R. marinus and no effect is observed in the respiratory rates when the typical bc1 complex inhibitors are present, suggesting that such a complex is absent in R. marinus [Pereira et al. (1994) FEBS Lett. 352, 327-330]. The newly isolated cytochrome bc complex has quinol:cytochrome c or high-potential iron-sulfur protein (HiPIP) oxidoreductase activity, being a functional analogue of the canonical bc1 complexes; i.e., it is the complex III in R. marinus. This complex plays a central role in this bacterium's electron-transfer chain, coupling the electron transfer between the quinols reduced by the dehydrogenases and the HiPIP, the final electron donor to the terminal oxidases [Pereira, M. M., Carita, J. N., and Teixeira, M. (1999) Biochemistry 38, 1276-1283].
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Affiliation(s)
- M M Pereira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, APT 127, 2780 Oeiras, Portugal
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Pereira MM, Carita JN, Teixeira M. Membrane-bound electron transfer chain of the thermohalophilic bacterium Rhodothermus marinus: characterization of the iron-sulfur centers from the dehydrogenases and investigation of the high-potential iron-sulfur protein function by in vitro reconstitution of the respiratory chain. Biochemistry 1999; 38:1276-83. [PMID: 9930988 DOI: 10.1021/bi981807v] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rhodothermus marinus, a thermohalophilic bacterium, has a unique electron-transfer chain, containing, besides a cbb3 and a caa3 terminal oxidases, a novel cytochrome bc complex [Pereira, M. M., Carita, J. N., and Teixeira, M. (1999) Biochemistry 38, 1268-1275]. The membrane-bound iron-sulfur centers of this bacterium were studied by electron paramagnetic resonance (EPR) spectroscopy, leading to the identification of its main electron-transfer complexes. The resonances typical for the Rieske-type centers are not detected. Clusters S1 and S3 from succinate dehydrogenase were identified; interestingly, center S3 is shown to be present in two different conformations, with g values at 2.035, 2.009, and 2.001 and at 2.025, 2.002, and 2.000. Upon addition of NADH and dithionite, EPR signals assigned to resonances characteristic of binuclear and tetranuclear clusters develop and are attributed to the iron-sulfur centers of complexes I and II. A high-potential iron-sulfur protein- (HiPIP-) type center previously detected in the membranes of this bacterium [Pereira et al. (1994) FEBS Lett. 352, 327-330] is shown to belong indeed to a canonical HiPIP. This protein was purified and extensively characterized. It is a small water-soluble protein of approximately 10 kDa, containing a single [4Fe-4S]3+/2+ cluster. The reduction potential, determined by EPR redox titrations in intact and detergent-solubilized membranes as well as by cyclic voltammetry in solution, has a pH-independent value of 260 +/- 20 mV, in the range 6-9. In vitro reconstitution of the R. marinus electron-transfer chain shows that the HiPIP plays a fundamental role in the chain, as the electron shuttle between R. marinus cytochrome bc complex and the caa3 terminal oxidase, being thus simultaneously identified a HiPIP reductase and a HiPIP oxidase.
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Affiliation(s)
- M M Pereira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, APT 127, 2780 Oeiras, Portugal
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Schoepp B, Brugna M, Lebrun E, Nitschke W. Iron-Sulfur Centers Involved in Photosynthetic Light Reactions. ADVANCES IN INORGANIC CHEMISTRY 1999. [DOI: 10.1016/s0898-8838(08)60082-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gomes CM, Huber H, Stetter KO, Teixeira M. Evidence for a novel type of iron cluster in the respiratory chain of the archaeon Sulfolobus metallicus. FEBS Lett 1998; 432:99-102. [PMID: 9720904 DOI: 10.1016/s0014-5793(98)00836-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A new type of metal centre was detected in the membranes of the thermoacidophilic archaeon Sulfolobus metallicus. This centre has an S = 1/2 ground state in the oxidised form, yielding an axial EPR signal with g values at 2.035 (g(parallel)) and 1.97 (g(perpendicular)), optimally detected at 4.6-10 K; in the reduced form it is EPR silent (even spin). These magnetic properties point to a spin-coupled iron cluster, with a minimum of two iron ions. The centre has a high reduction potential of +350 mV, at pH 6.5. The physiological role of this novel centre was probed through a general characterisation of S. metallicus respiratory chain: this archaeon contains NADH and succinate dehydrogenase activities, and cytochromes b562, a586 and a600 on the oxygen reductase system. Since it is reduced in the presence of succinate, and taking into account its high reduction potential, this centre is proposed to be a functional analogue of the Rieske centres.
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Affiliation(s)
- C M Gomes
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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Van Driessche G, Ciurli S, Hochkoeppler A, Van Beeumen JJ. The primary structure of Rhodoferax fermentans high-potential iron-sulfur protein, an electron donor to the photosynthetic reaction center. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 244:371-7. [PMID: 9119002 DOI: 10.1111/j.1432-1033.1997.00371.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The complete amino acid sequence of Rhodoferax fermentans high-potential iron-sulfur protein (Hipip), which is known to be an efficient electron donor to the photosynthetic reaction center, has been determined using both N-terminal and C-terminal analyses. The sequence contains 75 residues, with 11 positive charges, 10 negative charges, and one histidine residue. The molecular mass of apo-Hipip, determined by electrospray ionization mass spectrometry, is 7849.64 Da. Multiple sequence alignment, based both on primary and tertiary structure information, reveals conservation of Tyr19 and Gly75 (Chromatium vinosum numbering) in addition to the four [Fe4S4]-bound cysteines. The Hipip from Rf. fermentans is most similar (57% similarity) to the Hipip from Rubrivivax gelatinosus, a photosynthetic bacterium belonging to the beta-1 subgroup of the proteobacteria.
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Affiliation(s)
- G Van Driessche
- Department of Biochemistry, Physiology and Microbiology, University of Gent, Belgium
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Hochkoeppler A, Kofod P, Zannoni D. HiPiP oxido-reductase activity in membranes from aerobically grown cells of the facultative phototroph Rhodoferax fermentans. FEBS Lett 1995; 375:197-200. [PMID: 7498498 DOI: 10.1016/0014-5793(95)01188-k] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The role of the periplasmically located, water-soluble, HiPIP (high-potential iron-sulfur protein) in the respiratory chain of the facultative phototroph Rhodoferax fermentans has been examined. The oxidized HiPIP is reduced by succinate-dependent respiration via the bc1 complex, this reaction being inhibited by myxothiazol and/or stigmatellin. The reduced HiPIP can be oxidized by the membrane-bound cytochrome oxidase, this reaction being inhibited by 0.1 mM cyanide. We conclude that aerobically grown Rf. fermentans contains a redox chain in which HiPIP mediates electron transfer between the bc1 complex and the cb-type cytochrome oxidase.
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Hochkoeppler A, Ciurli S, Venturoli G, Zannoni D. The high potential iron-sulfur protein (HiPIP) from Rhodoferax fermentans is competent in photosynthetic electron transfer. FEBS Lett 1995; 357:70-4. [PMID: 8001683 DOI: 10.1016/0014-5793(94)01334-w] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The functional role of the High Potential Iron-sulfur Protein (HiPIP) from the photosynthetic bacterium Rhodoferax fermentans was investigated. We demonstrated that the HiPIP increased the rate of light-induced oxygen reduction mediated by the photosynthetic reaction center (RC); this stimulation reached half-saturation at [HiPIP]/[RC] ca. 15. The capability of the HiPIP in delivering electrons to the reaction center of Rhodoferax fermentans was demonstrated through kinetic spectrophotometry of cytochrome c-556 oxidation in the presence or in the absence of HiPIP. It is concluded that the HiPIP is competent in the photosynthetic electron transfer chain of Rhodoferax fermentans.
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