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Kishimoto H, Azai C, Yamamoto T, Mutoh R, Nakaniwa T, Tanaka H, Miyanoiri Y, Kurisu G, Oh-oka H. Soluble domains of cytochrome c-556 and Rieske iron-sulfur protein from Chlorobaculum tepidum: Crystal structures and interaction analysis. Curr Res Struct Biol 2023; 5:100101. [PMID: 37180033 PMCID: PMC10172866 DOI: 10.1016/j.crstbi.2023.100101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 04/04/2023] [Accepted: 04/11/2023] [Indexed: 05/15/2023] Open
Abstract
In photosynthetic green sulfur bacteria, the electron transfer reaction from menaquinol:cytochrome c oxidoreductase to the P840 reaction center (RC) complex occurs directly without any involvement of soluble electron carrier protein(s). X-ray crystallography has determined the three-dimensional structures of the soluble domains of the CT0073 gene product and Rieske iron-sulfur protein (ISP). The former is a mono-heme cytochrome c with an α-absorption peak at 556 nm. The overall fold of the soluble domain of cytochrome c-556 (designated as cyt c-556sol) consists of four α-helices and is very similar to that of water-soluble cyt c-554 that independently functions as an electron donor to the P840 RC complex. However, the latter's remarkably long and flexible loop between the α3 and α4 helices seems to make it impossible to be a substitute for the former. The structure of the soluble domain of the Rieske ISP (Rieskesol protein) shows a typical β-sheets-dominated fold with a small cluster-binding and a large subdomain. The architecture of the Rieskesol protein is bilobal and belongs to those of b6f-type Rieske ISPs. Nuclear magnetic resonance (NMR) measurements revealed weak non-polar but specific interaction sites on Rieskesol protein when mixed with cyt c-556sol. Therefore, menaquinol:cytochrome c oxidoreductase in green sulfur bacteria features a Rieske/cytb complex tightly associated with membrane-anchored cyt c-556.
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Affiliation(s)
- Hiraku Kishimoto
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Chihiro Azai
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Tomoya Yamamoto
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Risa Mutoh
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Tetsuko Nakaniwa
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Hideaki Tanaka
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Yohei Miyanoiri
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
- Corresponding author.
| | - Genji Kurisu
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
- Corresponding author.
| | - Hirozo Oh-oka
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
- Center for Education in Liberal Arts and Sciences, Osaka University, Toyonaka, Osaka, 560-0043, Japan
- Corresponding author. Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan.
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Kimura Y, Kasuga S, Unno M, Furusawa T, Osoegawa S, Sasaki Y, Ohno T, Wang-Otomo ZY. The roles of C-terminal residues on the thermal stability and local heme environment of cytochrome c' from the thermophilic purple sulfur bacterium Thermochromatium tepidum. PHOTOSYNTHESIS RESEARCH 2015; 124:19-29. [PMID: 25519852 DOI: 10.1007/s11120-014-0069-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 12/11/2014] [Indexed: 06/04/2023]
Abstract
A soluble cytochrome (Cyt) c' from thermophilic purple sulfur photosynthetic bacterium Thermochromatium (Tch.) tepidum exhibits marked thermal tolerance compared with that from the closely related mesophilic counterpart Allochromatium vinosum. Here, we focused on the difference in the C-terminal region of the two Cyts c' and examined the effects of D131 and R129 mutations on the thermal stability and local heme environment of Cyt c' by differential scanning calorimetry (DSC) and resonance Raman (RR) spectroscopy. In the oxidized forms, D131K and D131G mutants exhibited denaturing temperatures significantly lower than that of the recombinant control Cyt c'. In contrast, R129K and R129A mutants denatured at nearly identical temperatures with the control Cyt c', indicating that the C-terminal D131 is an important residue maintaining the enhanced thermal stability of Tch. tepidum Cyt c'. The control Cyt c' and all of the mutants increased their thermal stability upon the reduction. Interestingly, D131K exhibited narrow DSC curves and unusual thermodynamic parameters in both redox states. The RR spectra of the control Cyt c' exhibited characteristic bands at 1,635 and 1,625 cm(-1), ascribed to intermediate spin (IS) and high spin (HS) states, respectively. The IS/HS distribution was differently affected by the D131 and R129 mutations and pH changes. Furthermore, R129 mutants suggested the lowering of their redox potentials. These results strongly indicate that the D131 and R129 residues play significant roles in maintaining the thermal stability and modulating the local heme environment of Tch. tepidum Cyt c'.
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Affiliation(s)
- Yukihiro Kimura
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, Nada, Kobe, 657-8501, Japan,
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Yu LJ, Unno M, Kimura Y, Yanagimoto K, Oh-oka H, Wang-Otomo ZY. Structure analysis and characterization of the cytochrome c-554 from thermophilic green sulfur photosynthetic bacterium Chlorobaculum tepidum. PHOTOSYNTHESIS RESEARCH 2013; 118:249-258. [PMID: 24052268 DOI: 10.1007/s11120-013-9922-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 09/03/2013] [Indexed: 06/02/2023]
Abstract
The cytochrome (Cyt) c-554 in thermophilic green photosynthetic bacterium Chlorobaculum tepidum serves as an intermediate electron carrier, transferring electrons to the membrane-bound Cyt c z from various enzymes involved in the oxidations of sulfide, thiosulfate, and sulfite compounds. Spectroscopically, this protein exhibits an asymmetric α-absorption band for the reduced form and particularly large paramagnetic (1)H NMR shifts for the heme methyl groups with an unusual shift pattern in the oxidized form. The crystal structure of the Cyt c-554 has been determined at high resolution. The overall fold consists of four α-helices and is characterized by a remarkably long and flexible loop between the α3 and α4 helices. The axial ligand methionine has S-chirality at the sulfur atom with its C(ε)H3 group pointing toward the heme pyrrole ring I. This configuration corresponds to an orientation of the lone-pair orbital of the sulfur atom directed at the pyrrole ring II and explains the lowest-field (1)H NMR shift arising from the 18(1) heme methyl protons. Differing from most other class I Cyts c, no hydrogen bond was formed between the methionine sulfur atom and polypeptide chain. Lack of this hydrogen bond may account for the observed large paramagnetic (1)H NMR shifts of the heme methyl protons. The surface-exposed heme pyrrole ring II edge is in a relatively hydrophobic environment surrounded by several electronically neutral residues. This portion is considered as an electron transfer gateway. The structure of the Cyt c-554 is compared with those of other Cyts c, and possible interactions of this protein with its electron transport partners are discussed.
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Affiliation(s)
- Long-Jiang Yu
- Faculty of Science, Ibaraki University, Bunkyo 2-1-1, Mito, 310-8512, Japan
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Robin S, Arese M, Forte E, Sarti P, Kolaj-Robin O, Giuffrè A, Soulimane T. Functional dissection of the multi-domain di-heme cytochrome c(550) from Thermus thermophilus. PLoS One 2013; 8:e55129. [PMID: 23383080 PMCID: PMC3561395 DOI: 10.1371/journal.pone.0055129] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 12/18/2012] [Indexed: 11/18/2022] Open
Abstract
In bacteria, oxidation of sulfite to sulfate, the most common strategy for sulfite detoxification, is mainly accomplished by the molybdenum-containing sulfite:acceptor oxidoreductases (SORs). Bacterial SORs are very diverse proteins; they can exist as monomers or homodimers of their core subunit, as well as heterodimers with an additional cytochrome c subunit. We have previously described the homodimeric SOR from Thermus thermophilus HB8 (SOR(TTHB8)), identified its physiological electron acceptor, cytochrome c(550), and demonstrated the key role of the latter in coupling sulfite oxidation to aerobic respiration. Herein, the role of this di-heme cytochrome c was further investigated. The cytochrome was shown to be composed of two conformationally independent domains, each containing one heme moiety. Each domain was separately cloned, expressed in E. coli and purified to homogeneity. Stopped-flow experiments showed that: i) the N-terminal domain is the only one accepting electrons from SOR(TTHB8); ii) the N- and C-terminal domains are in rapid redox equilibrium and iii) both domains are able to transfer electrons further to cytochrome c(552), the physiological substrate of the ba(3) and caa(3) terminal oxidases. These findings show that cytochrome c(550) functions as a electron shuttle, without working as an electron wire with one heme acting as the electron entry and the other as the electron exit site. Although contribution of the cytochrome c(550) C-terminal domain to T. thermophilus sulfur respiration seems to be dispensable, we suggest that di-heme composition of the cytochrome physiologically enables storage of the two electrons generated from sulfite oxidation, thereof ensuring efficient contribution of sulfite detoxification to the respiratory chain-mediated energy generation.
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Affiliation(s)
- Sylvain Robin
- Chemical and Environmental Science Department, Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
| | - Marzia Arese
- Department of Biochemical Sciences and Istituto Pasteur – Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
| | - Elena Forte
- Department of Biochemical Sciences and Istituto Pasteur – Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
| | - Paolo Sarti
- Department of Biochemical Sciences and Istituto Pasteur – Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
- Consiglio Nazionale delle Ricerche Istituto di Biologia e Patologia Molecolari, Rome, Italy
| | - Olga Kolaj-Robin
- Chemical and Environmental Science Department, Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
| | - Alessandro Giuffrè
- Consiglio Nazionale delle Ricerche Istituto di Biologia e Patologia Molecolari, Rome, Italy
- * E-mail: (AG); (TS)
| | - Tewfik Soulimane
- Chemical and Environmental Science Department, Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
- * E-mail: (AG); (TS)
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Hirano Y, Kimura Y, Suzuki H, Miki K, Wang ZY. Structure Analysis and Comparative Characterization of the Cytochrome c′ and Flavocytochrome c from Thermophilic Purple Photosynthetic Bacterium Thermochromatium tepidum. Biochemistry 2012; 51:6556-67. [DOI: 10.1021/bi3005522] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yu Hirano
- Faculty of Science, Ibaraki University, Mito 310-8512, Japan
- Department of Chemistry, Graduate
School of Science, Kyoto University, Sakyo-ku,
Kyoto 606-8502, Japan
| | - Yukihiro Kimura
- Organization
of Advanced Science
and Technology, Kobe University, Nada,
Kobe 657-8501, Japan
| | - Hideaki Suzuki
- Faculty of Science, Ibaraki University, Mito 310-8512, Japan
| | - Kunio Miki
- Department of Chemistry, Graduate
School of Science, Kyoto University, Sakyo-ku,
Kyoto 606-8502, Japan
| | - Zheng-Yu Wang
- Faculty of Science, Ibaraki University, Mito 310-8512, Japan
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Comparative and Functional Genomics of Anoxygenic Green Bacteria from the Taxa Chlorobi, Chloroflexi, and Acidobacteria. FUNCTIONAL GENOMICS AND EVOLUTION OF PHOTOSYNTHETIC SYSTEMS 2012. [DOI: 10.1007/978-94-007-1533-2_3] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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A heterogeneous tag-attachment to the homodimeric type 1 photosynthetic reaction center core protein in the green sulfur bacterium Chlorobaculum tepidum. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:803-12. [DOI: 10.1016/j.bbabio.2011.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 03/10/2011] [Accepted: 03/15/2011] [Indexed: 01/26/2023]
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A sulfite respiration pathway from Thermus thermophilus and the key role of newly identified cytochrome c₅₅₀. J Bacteriol 2011; 193:3988-97. [PMID: 21665981 DOI: 10.1128/jb.05186-11] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sulfite, produced for instance during amino acid metabolism, is a very reactive and toxic compound. Various detoxification mechanisms exist, but sulfite oxidoreductases (SORs) are one of the major actors in sulfite remediation in bacteria and animals. Here we describe the existence of an operon in the extreme thermophilic bacterium Thermus thermophilus HB8 encoding both a SOR and a diheme c-type cytochrome. The in vitro analysis clearly showed that the newly identified cytochrome c₅₅₀ acts as an acceptor of the electrons generated by the SOR enzyme during the oxidation of sulfite. The electrons are then rapidly shuttled via cytochrome c₅₅₂ to the terminal ba₃- and caa₃-type oxidases, thereby unveiling a novel electron transfer pathway, linking sulfite oxidation to oxygen reduction in T. thermophilus: sulfite → SOR(HB8) → cytochrome c₅₅₀ → cytochrome c₅₅₂ → ba₃ oxidase/caa₃ oxidase → O₂. The description of the complete pathway reveals that electrons generated during sulfite oxidation by the SOR are funneled into the respiratory chain, participating in the energy production of T. thermophilus.
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Kimura Y, Inada Y, Yu LJ, Wang ZY, Ohno T. A Spectroscopic Variant of the Light-Harvesting 1 Core Complex from the Thermophilic Purple Sulfur Bacterium Thermochromatium tepidum. Biochemistry 2011; 50:3638-48. [DOI: 10.1021/bi200278u] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yukihiro Kimura
- Organization of Advanced Science and Technology, Kobe University, Nada, Kobe 657-8501, Japan
- Department of Agrobioscience, Graduate School of Agriculture, Kobe University, Nada, Kobe 657-8501, Japan
| | - Yuta Inada
- Department of Agrobioscience, Graduate School of Agriculture, Kobe University, Nada, Kobe 657-8501, Japan
| | - Long-Jiang Yu
- Faculty of Science, Ibaraki University, Bunkyo, Mito 310-8512, Japan
| | - Zheng-Yu Wang
- Faculty of Science, Ibaraki University, Bunkyo, Mito 310-8512, Japan
| | - Takashi Ohno
- Department of Agrobioscience, Graduate School of Agriculture, Kobe University, Nada, Kobe 657-8501, Japan
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Oostergetel GT, van Amerongen H, Boekema EJ. The chlorosome: a prototype for efficient light harvesting in photosynthesis. PHOTOSYNTHESIS RESEARCH 2010; 104:245-55. [PMID: 20130996 PMCID: PMC2882566 DOI: 10.1007/s11120-010-9533-0] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Accepted: 01/16/2010] [Indexed: 05/18/2023]
Abstract
Three phyla of bacteria include phototrophs that contain unique antenna systems, chlorosomes, as the principal light-harvesting apparatus. Chlorosomes are the largest known supramolecular antenna systems and contain hundreds of thousands of BChl c/d/e molecules enclosed by a single membrane leaflet and a baseplate. The BChl pigments are organized via self-assembly and do not require proteins to provide a scaffold for efficient light harvesting. Their excitation energy flows via a small protein, CsmA embedded in the baseplate to the photosynthetic reaction centres. Chlorosomes allow for photosynthesis at very low light intensities by ultra-rapid transfer of excitations to reaction centres and enable organisms with chlorosomes to live at extraordinarily low light intensities under which no other phototrophic organisms can grow. This article reviews several aspects of chlorosomes: the supramolecular and molecular organizations and the light-harvesting and spectroscopic properties. In addition, it provides some novel information about the organization of the baseplate.
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Affiliation(s)
- Gert T. Oostergetel
- Biophysical Chemistry, Groningen Biomolecular Sciences & Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Herbert van Amerongen
- Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, The Netherlands
| | - Egbert J. Boekema
- Biophysical Chemistry, Groningen Biomolecular Sciences & Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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Azai C, Tsukatani Y, Itoh S, Oh-oka H. C-type cytochromes in the photosynthetic electron transfer pathways in green sulfur bacteria and heliobacteria. PHOTOSYNTHESIS RESEARCH 2010; 104:189-199. [PMID: 20091230 DOI: 10.1007/s11120-009-9521-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Accepted: 12/17/2009] [Indexed: 05/28/2023]
Abstract
Green sulfur bacteria and heliobacteria are strictly anaerobic phototrophs that have homodimeric type 1 reaction center complexes. Within these complexes, highly reducing substances are produced through an initial charge separation followed by electron transfer reactions driven by light energy absorption. In order to attain efficient energy conversion, it is important for the photooxidized reaction center to be rapidly rereduced. Green sulfur bacteria utilize reduced inorganic sulfur compounds (sulfide, thiosulfate, and/or sulfur) as electron sources for their anoxygenic photosynthetic growth. Membrane-bound and soluble cytochromes c play essential roles in the supply of electrons from sulfur oxidation pathways to the P840 reaction center. In the case of gram-positive heliobacteria, the photooxidized P800 reaction center is rereduced by cytochrome c-553 (PetJ) whose N-terminal cysteine residue is modified with fatty acid chains anchored to the cytoplasmic membrane.
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Affiliation(s)
- Chihiro Azai
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
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Hirano Y, Higuchi M, Azai C, Oh-Oka H, Miki K, Wang ZY. Crystal structure of the electron carrier domain of the reaction center cytochrome c(z) subunit from green photosynthetic bacterium Chlorobium tepidum. J Mol Biol 2010; 397:1175-87. [PMID: 20156447 DOI: 10.1016/j.jmb.2010.02.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 02/02/2010] [Accepted: 02/09/2010] [Indexed: 11/18/2022]
Abstract
In green sulfur photosynthetic bacteria, the cytochrome c(z) (cyt c(z)) subunit in the reaction center complex mediates electron transfer mainly from menaquinol/cytochrome c oxidoreductase to the special pair (P840) of the reaction center. The cyt c(z) subunit consists of an N-terminal transmembrane domain and a C-terminal soluble domain that binds a single heme group. The periplasmic soluble domain has been proposed to be highly mobile and to fluctuate between oxidoreductase and P840 during photosynthetic electron transfer. We have determined the crystal structure of the oxidized form of the C-terminal functional domain of the cyt c(z) subunit (C-cyt c(z)) from thermophilic green sulfur bacterium Chlorobium tepidum at 1.3-A resolution. The overall fold of C-cyt c(z) consists of four alpha-helices and is similar to that of class I cytochrome c proteins despite the low similarity in their amino acid sequences. The N-terminal structure of C-cyt c(z) supports the swinging mechanism previously proposed in relation with electron transfer, and the surface properties provide useful information on possible interaction sites with its electron transfer partners. Several characteristic features are observed for the heme environment: These include orientation of the axial ligands with respect to the heme plane, surface-exposed area of the heme, positions of water molecules, and hydrogen-bond network involving heme propionate groups. These structural features are essential for elucidating the mechanism for regulating the redox state of cyt c(z).
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Affiliation(s)
- Yu Hirano
- Faculty of Science, Ibaraki University, 2-1-1 Bunkyo, Mito 310-8512, Japan
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