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Chen JH, Yu LJ, Boussac A, Wang-Otomo ZY, Kuang T, Shen JR. Properties and structure of a low-potential, penta-heme cytochrome c 552 from a thermophilic purple sulfur photosynthetic bacterium Thermochromatium tepidum. PHOTOSYNTHESIS RESEARCH 2019; 139:281-293. [PMID: 29691716 DOI: 10.1007/s11120-018-0507-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 03/30/2018] [Indexed: 06/08/2023]
Abstract
The thermophilic purple sulfur bacterium Thermochromatium tepidum possesses four main water-soluble redox proteins involved in the electron transfer behavior. Crystal structures have been reported for three of them: a high potential iron-sulfur protein, cytochrome c', and one of two low-potential cytochrome c552 (which is a flavocytochrome c) have been determined. In this study, we purified another low-potential cytochrome c552 (LPC), determined its N-terminal amino acid sequence and the whole gene sequence, characterized it with absorption and electron paramagnetic spectroscopy, and solved its high-resolution crystal structure. This novel cytochrome was found to contain five c-type hemes. The overall fold of LPC consists of two distinct domains, one is the five heme-containing domain and the other one is an Ig-like domain. This provides a representative example for the structures of multiheme cytochromes containing an odd number of hemes, although the structures of multiheme cytochromes with an even number of hemes are frequently seen in the PDB database. Comparison of the sequence and structure of LPC with other proteins in the databases revealed several characteristic features which may be important for its functioning. Based on the results obtained, we discuss the possible intracellular function of this LPC in Tch. tepidum.
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Affiliation(s)
- Jing-Hua Chen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20, Nanxincun, Xiangshan, Beijing, 100093, China
- Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
- University of Chinese Academy of Sciences, Yuquan Rd, Shijingshan District, Beijing, 100049, China
| | - Long-Jiang Yu
- Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
| | - Alain Boussac
- I2BC, SB2SM, CNRS UMR 9198, CEA Saclay, 91191, Gif-sur-Yvette, France
| | | | - Tingyun Kuang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20, Nanxincun, Xiangshan, Beijing, 100093, China
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20, Nanxincun, Xiangshan, Beijing, 100093, China.
- Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan.
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2
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Florentino AP, Pereira IAC, Boeren S, van den Born M, Stams AJM, Sánchez-Andrea I. Insight into the sulfur metabolism of Desulfurella amilsii by differential proteomics. Environ Microbiol 2018; 21:209-225. [PMID: 30307104 PMCID: PMC6378623 DOI: 10.1111/1462-2920.14442] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 08/28/2018] [Accepted: 10/05/2018] [Indexed: 11/30/2022]
Abstract
Many questions regarding proteins involved in microbial sulfur metabolism remain unsolved. For sulfur respiration at low pH, the terminal electron acceptor is still unclear. Desulfurella amilsii is a sulfur-reducing bacterium that respires elemental sulfur (S0 ) or thiosulfate, and grows by S0 disproportionation. Due to its versatility, comparative studies on D. amilsii may shed light on microbial sulfur metabolism. Requirement of physical contact between cells and S0 was analyzed. Sulfide production decreased by around 50% when S0 was trapped in dialysis membranes, suggesting that contact between cells and S0 is beneficial, but not strictly needed. Proteome analysis was performed under the aforementioned conditions. A Mo-oxidoreductase suggested from genome analysis to act as sulfur reductase was not detected in any growth condition. Thiosulfate and sulfite reductases showed increased abundance in thiosulfate-reducing cultures, while rhodanese-like sulfurtransferases were highly abundant in all conditions. DsrE and DsrL were abundantly detected during thiosulfate reduction, suggesting a modified mechanism of sulfite reduction. Proteogenomics suggest a different disproportionation pathway from what has been reported. This work points to an important role of rhodaneses in sulfur processes and these proteins should be considered in searches for sulfur metabolism in broader fields like meta-omics.
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Affiliation(s)
- Anna P Florentino
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Inês A C Pereira
- Instituto de Tecnologia Quimica e Biologica António Xavier, Universidade Nova de Lisboa, Av. da Republica-EAN, 2780-157, Oeiras, Portugal
| | - Sjef Boeren
- Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Michael van den Born
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Alfons J M Stams
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.,CEB-Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Irene Sánchez-Andrea
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
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Monteiro de Castro MC, Cunha IT, Gomes de Mendonça F, Augusti R, de Mesquita JP, Araujo MH, Martínez Escandell M, Molina Sabio M, Lago RM, Rodríguez Reinoso F. Micromesoporous Activated Carbons as Catalysts for the Efficient Oxidation of Aqueous Sulfide. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:11857-11861. [PMID: 28957632 DOI: 10.1021/acs.langmuir.7b01499] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
KOH activation of a mesophase pitch produces very efficient carbons for the removal of sulfide in aqueous solution, increasing the sulfur oxidation rate with the degree of activation of the carbon. These carbons are characterized by their graphitic structures, with domains of sizes of around 20 nm, and a moderate concentration of surface oxygen groups (0.2-0.5 mmol·g-1) dominating the basic groups. Because the activation leads first to a strong development of the micropores and later to a development of the mesopores, the surface area values are always high, reaching values of as high as 3250 m2·g-1 in the most activated carbon, with a volume of mesopores of as high as 44% of the total pore volume. In the presence of this carbon, the sulfide oxidation rate is 100 times higher than that found for a commercial activated carbon, the results indicating that the porosity of the carbon, especially mesoporosity, plays a role more important than the structure or the chemical nature of the carbon in the kinetics of sulfide oxidation to different polysulfides.
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Affiliation(s)
| | - Igor Tadeu Cunha
- Departamento de Química, Universidade Federal de Minas Gerais , Belo Horizonte, Brazil
| | | | - Rodinei Augusti
- Departamento de Química, Universidade Federal de Minas Gerais , Belo Horizonte, Brazil
| | - Joao Paulo de Mesquita
- Departamento de Química, Universidade Federal de Vale do Jequitinhonha e Mucuri , Diamantina, Brazil
| | - Maria Helena Araujo
- Departamento de Química, Universidade Federal de Minas Gerais , Belo Horizonte, Brazil
| | - Manuel Martínez Escandell
- Laboratorio de Materiales Avanzados, Departamento de Química Inorgánica, Universidad de Alicante , Alicante, Spain
| | - Miguel Molina Sabio
- Laboratorio de Materiales Avanzados, Departamento de Química Inorgánica, Universidad de Alicante , Alicante, Spain
| | - Rochel Montero Lago
- Departamento de Química, Universidade Federal de Minas Gerais , Belo Horizonte, Brazil
| | - Francisco Rodríguez Reinoso
- Laboratorio de Materiales Avanzados, Departamento de Química Inorgánica, Universidad de Alicante , Alicante, Spain
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4
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Findlay AJ. Microbial impact on polysulfide dynamics in the environment. FEMS Microbiol Lett 2016; 363:fnw103. [DOI: 10.1093/femsle/fnw103] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2016] [Indexed: 11/12/2022] Open
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5
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Molecular cloning of rhodanese gene from soil metagenome of cold desert of North-West Himalayas: sequence and structural features of the rhodanese enzyme. 3 Biotech 2015; 5:513-521. [PMID: 28324556 PMCID: PMC4522728 DOI: 10.1007/s13205-014-0249-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 08/26/2014] [Indexed: 11/25/2022] Open
Abstract
Rhodanese is a multifunctional, sulfur transferase that catalyzes the detoxification of cyanide by sulphuration in a double displacement (ping pong) mechanistic reaction. In the present study, small-insert metagenomic library from soil sample collected from Ladakh (3,000–3,600 m.a.s.l) in northwestern Himalayas, India was constructed. Function-driven screening of ~8,500 colonies led to the isolation of one esterase-positive clone (clone-est) harboring 2.43 kb insert. Sequence analysis of the insert identified two ORF’s, phosM encoding phosphoesterase and rodM encoding rhodanese. The 800 bp rodM gene encoded a polypeptide of 227 amino acids (RodM). The RodM showed maximum homology with the rhodanese-like protein from Cyanobacterium synechococcus species with a score identity of only 51 %. Putative 3D structure of RodM developed by homology modeling resembles to homodimeric protein of SUD sulfur transferase of Wolinellasuccinogenes with properly structured active-site cysteine (Cys) residue. Rhodanese has been reported from few culturable microorganisms.
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Prat L, Maillard J, Rohrbach-Brandt E, Holliger C. An unusual tandem-domain rhodanese harbouring two active sites identified in Desulfitobacterium hafniense. FEBS J 2012; 279:2754-67. [PMID: 22686689 DOI: 10.1111/j.1742-4658.2012.08660.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The rhodanese protein domain is common throughout all kingdoms of life and is characterized by an active site cysteine residue that is able to bind sulfane sulfur and catalyse sulfur transfer. No unique function has been attributed to rhodanese-domain-containing proteins, most probably because of their diversity at both the level of sequence and protein domain architecture. In this study, we investigated the biochemical properties of an unusual rhodanese protein, PhsE, from Desulfitobacterium hafniense strain TCE1 which we have previously shown to be massively expressed under anaerobic respiration with tetrachloroethene. The peculiarity of the PhsE protein is its domain architecture which is constituted of two rhodanese domains each with an active site cysteine. The N-terminal rhodanese domain is preceded by a lipoprotein signal peptide anchoring PhsE on the outside of the cytoplasmic membrane. In vitro sulfur-transferase activity of recombinant PhsE variants was measured for both domains contrasting with other tandem-domain rhodaneses in which usually only the C-terminal domain has been found to be active. The genetic context of phsE shows that it is part of a six-gene operon displaying homology with gene clusters encoding respiratory molybdoenzymes of the PhsA/PsrA family, possibly involved in the reduction of sulfur compounds. Our data suggest, however, that the presence of sulfide in the medium is responsible for the high expression of PhsE in Desulfitobacterium, where it could play a role in the sulfur homeostasis of the cell.
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Affiliation(s)
- Laure Prat
- Laboratory for Environmental Biotechnology, Institute of Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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Aussignargues C, Giuliani MC, Infossi P, Lojou E, Guiral M, Giudici-Orticoni MT, Ilbert M. Rhodanese functions as sulfur supplier for key enzymes in sulfur energy metabolism. J Biol Chem 2012; 287:19936-48. [PMID: 22496367 DOI: 10.1074/jbc.m111.324863] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
How microorganisms obtain energy is a challenging topic, and there have been numerous studies on the mechanisms involved. Here, we focus on the energy substrate traffic in the hyperthermophilic bacterium Aquifex aeolicus. This bacterium can use insoluble sulfur as an energy substrate and has an intricate sulfur energy metabolism involving several sulfur-reducing and -oxidizing supercomplexes and enzymes. We demonstrate that the cytoplasmic rhodanese SbdP participates in this sulfur energy metabolism. Rhodaneses are a widespread family of proteins known to transfer sulfur atoms. We show that SbdP has also some unusual characteristics compared with other rhodaneses; it can load a long sulfur chain, and it can interact with more than one partner. Its partners (sulfur reductase and sulfur oxygenase reductase) are key enzymes of the sulfur energy metabolism of A. aeolicus and share the capacity to use long sulfur chains as substrate. We demonstrate a positive effect of SbdP, once loaded with sulfur chains, on sulfur reductase activity, most likely by optimizing substrate uptake. Taken together, these results lead us to propose a physiological role for SbdP as a carrier and sulfur chain donor to these key enzymes, therefore enabling channeling of sulfur substrate in the cell as well as greater efficiency of the sulfur energy metabolism of A. aeolicus.
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Affiliation(s)
- Clément Aussignargues
- Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée-CNRS, Aix-Marseille University, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
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8
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Majumdar A, Sarkar S. Bioinorganic chemistry of molybdenum and tungsten enzymes: A structural–functional modeling approach. Coord Chem Rev 2011. [DOI: 10.1016/j.ccr.2010.11.027] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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9
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Warner MD, Lukose V, Lee KH, Lopez K, H Sazinsky M, Crane EJ. Characterization of an NADH-dependent persulfide reductase from Shewanella loihica PV-4: implications for the mechanism of sulfur respiration via FAD-dependent enzymes. Biochemistry 2010; 50:194-206. [PMID: 21090815 DOI: 10.1021/bi101232y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The NADH-dependent persulfide reductase (Npsr), a recently discovered member of the PNDOR family of flavoproteins that contains both the canonical flavoprotein reductase domain and a rhodanese domain, is proposed to be involved in the dissimilatory reduction of S(0) for Shewanella loihica PV-4. We have previously shown that polysulfide is a substrate for this enzyme, and a recently determined structure of a closely related enzyme (CoADR-Rhod from Bacillus anthracis) suggested the importance of a bound coenzyme A in the mechanism. The work described here shows that the in vivo oxidizing substrates of Npsr are the persulfides of small thiols such as CoA and glutathione. C43S, C531S, and C43,531S mutants were created to determine the role of the flavoprotein domain cysteine (C43) and the rhodanese domain cysteine (C531) in the mechanism. The absolute requirement for C43 in persulfide or DTNB reductase activity shows that this residue is involved in S-S bond breakage. C531 contributes to, but is not required for, catalysis of DTNB reduction, while it is absolutely required for reduction of any persulfide substrates. Titrations of the enzyme with NADH, dithionite, titanium(III), or TCEP demonstrate the presence of a mixed-disulfide between C43 and a tightly bound CoA, and structures of the C43 and C43,531S mutants confirm that this coenzyme A remains tightly bound to the enzyme in the absence of a C43-CoA S-S bond. The structure of Npsr suggests a likely site for binding and reaction with the persulfide substrate on the rhodanese domain. On the basis of kinetic, titration, and structural data, a mechanism for the reduction of persulfides by Npsr is proposed.
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Affiliation(s)
- Megan D Warner
- Pomona College Department of Chemistry, Claremont, California 91711, United States
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10
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Papenbrock J, Guretzki S, Henne M. Latest news about the sulfurtransferase protein family of higher plants. Amino Acids 2010; 41:43-57. [PMID: 20135153 DOI: 10.1007/s00726-010-0478-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2009] [Accepted: 01/06/2010] [Indexed: 01/30/2023]
Abstract
Sulfurtransferases/rhodaneses (Str) comprise a group of enzymes widely distributed in all phyla which catalyze in vitro the transfer of a sulfur atom from suitable sulfur donors to nucleophilic sulfur acceptors. The best characterized Str is bovine rhodanese (EC 2.8.1.1) which catalyses in vitro the transfer of a sulfane sulfur atom from thiosulfate to cyanide, leading to the formation of sulfite and thiocyanate. Plants as well as other organisms contain many proteins carrying a typical rhodanese pattern or domain forming multi-protein families (MPF). Despite the presence of Str activities in many living organisms, the physiological role of the members of this MPF has not been established unambiguously. While in mammals these proteins are involved in the elimination of toxic cyanogenic compounds, their ubiquity suggests additional physiological functions. In plants, Str are localized in the cytoplasm, mitochondria, plastids, and nucleus. Str probably also transfer reduced sulfur onto substrates as large as peptides or proteins. Several studies in different organisms demonstrate a protein-protein interaction with members of the thioredoxin MPF indicating a role of Str in maintenance of the cellular redox homeostasis. The increased expression of several members of the Str MPF in various stress conditions could be a response to oxidative stress. In summary, data indicate that Str are involved in various essential metabolic reactions.
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Quatrini R, Appia-Ayme C, Denis Y, Jedlicki E, Holmes DS, Bonnefoy V. Extending the models for iron and sulfur oxidation in the extreme acidophile Acidithiobacillus ferrooxidans. BMC Genomics 2009; 10:394. [PMID: 19703284 PMCID: PMC2754497 DOI: 10.1186/1471-2164-10-394] [Citation(s) in RCA: 220] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2009] [Accepted: 08/24/2009] [Indexed: 11/10/2022] Open
Abstract
Background Acidithiobacillus ferrooxidans gains energy from the oxidation of ferrous iron and various reduced inorganic sulfur compounds at very acidic pH. Although an initial model for the electron pathways involved in iron oxidation has been developed, much less is known about the sulfur oxidation in this microorganism. In addition, what has been reported for both iron and sulfur oxidation has been derived from different A. ferrooxidans strains, some of which have not been phylogenetically characterized and some have been shown to be mixed cultures. It is necessary to provide models of iron and sulfur oxidation pathways within one strain of A. ferrooxidans in order to comprehend the full metabolic potential of the pangenome of the genus. Results Bioinformatic-based metabolic reconstruction supported by microarray transcript profiling and quantitative RT-PCR analysis predicts the involvement of a number of novel genes involved in iron and sulfur oxidation in A. ferrooxidans ATCC23270. These include for iron oxidation: cup (copper oxidase-like), ctaABT (heme biogenesis and insertion), nuoI and nuoK (NADH complex subunits), sdrA1 (a NADH complex accessory protein) and atpB and atpE (ATP synthetase F0 subunits). The following new genes are predicted to be involved in reduced inorganic sulfur compounds oxidation: a gene cluster (rhd, tusA, dsrE, hdrC, hdrB, hdrA, orf2, hdrC, hdrB) encoding three sulfurtransferases and a heterodisulfide reductase complex, sat potentially encoding an ATP sulfurylase and sdrA2 (an accessory NADH complex subunit). Two different regulatory components are predicted to be involved in the regulation of alternate electron transfer pathways: 1) a gene cluster (ctaRUS) that contains a predicted iron responsive regulator of the Rrf2 family that is hypothesized to regulate cytochrome aa3 oxidase biogenesis and 2) a two component sensor-regulator of the RegB-RegA family that may respond to the redox state of the quinone pool. Conclusion Bioinformatic analysis coupled with gene transcript profiling extends our understanding of the iron and reduced inorganic sulfur compounds oxidation pathways in A. ferrooxidans and suggests mechanisms for their regulation. The models provide unified and coherent descriptions of these processes within the type strain, eliminating previous ambiguity caused by models built from analyses of multiple and divergent strains of this microorganism.
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Affiliation(s)
- Raquel Quatrini
- Center for Bioinformatics and Genome Biology, MIFAB, Fundación Ciencia para la Vida and Depto. de Ciencias Biologicas, Universidad Andres Bello, Santiago, Chile.
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12
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Lin YJ, Dancea F, Löhr F, Klimmek O, Pfeiffer-Marek S, Nilges M, Wienk H, Kröger A, Rüterjans H. Solution structure of the 30 kDa polysulfide-sulfur transferase homodimer from Wolinella succinogenes. Biochemistry 2004; 43:1418-24. [PMID: 14769017 DOI: 10.1021/bi0356597] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The periplasmic polysulfide-sulfur transferase (Sud) protein encoded by Wolinella succinogenes is involved in oxidative phosphorylation with polysulfide-sulfur as a terminal electron acceptor. The polysulfide-sulfur is covalently bound to the catalytic Cys residue of the Sud protein and transferred to the active site of the membranous polysulfide reductase. The solution structure of the homodimeric Sud protein has been determined using heteronuclear multidimensional NMR techniques. The structure is based on NOE-derived distance restraints, backbone hydrogen bonds, and torsion angle restraints as well as residual dipolar coupling restraints for a refinement of the relative orientation of the monomer units. The monomer structure consists of a five-stranded parallel beta-sheet enclosing a hydrophobic core, a two-stranded antiparallel beta-sheet, and six alpha-helices. The dimer fold is stabilized by hydrophobic residues and ion pairs found in the contact area between the two monomers. Similar to rhodanese enzymes, Sud catalyzes the transfer of the polysulfide-sulfur to the artificial acceptor cyanide. Despite their similar functions and active sites, the amino acid sequences and structures of these proteins are quite different.
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Affiliation(s)
- Yi-Jan Lin
- Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance, J. W. Goethe-University, Marie-Curie-Strasse 9, D-60439 Frankfurt am Main, Germany
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13
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Prisner T, Lyubenova S, Atabay Y, MacMillan F, Kröger A, Klimmek O. Multifrequency cw-EPR investigation of the catalytic molybdenum cofactor of polysulfide reductase from Wolinella succinogenes. J Biol Inorg Chem 2003; 8:419-26. [PMID: 12761663 DOI: 10.1007/s00775-002-0432-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2002] [Accepted: 11/11/2002] [Indexed: 11/30/2022]
Abstract
Electron paramagnetic resonance (EPR) spectra of the molybdenum centre in polysulfide reductase (Psr) from Wolinella succinogenes with unusually high G-tensor values have been observed for the first time. Three different Mo(V) states have been generated (by the addition of the substrate polysulfide and different redox agents) and analysed by their G- and hyperfine tensors using multifrequency (S-, X- and Q-band) cw-EPR spectroscopy. The unusually high G-tensor values are attributed to a large number of sulfur ligands. Four sulfur ligands are assumed to arise from two pterin cofactors; one additional sulfur ligand was identified from mutagenesis studies to be a cysteine residue of the protein backbone. One further sulfur ligand is proposed for two of the Mo(V) states, based on the experimentally observed shift of the g(av) value. This sixth sulfur ligand is postulated to belong to the polysulfide substrate consumed within the catalytic reaction cycle of the enzyme. The influence of the co-protein sulfur transferase on the Mo(V) G-tensor supports this assignment.
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Affiliation(s)
- Thomas Prisner
- Institute of Physical and Theoretical Chemistry, Johann Wolfgang Goethe-University Frankfurt, Marie-Curie-Strasse 11, 60439, Frankfurt am Main, Germany.
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14
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Cheesman MR, Little PJ, Berks BC. Novel heme ligation in a c-type cytochrome involved in thiosulfate oxidation: EPR and MCD of SoxAX from Rhodovulum sulfidophilum. Biochemistry 2001; 40:10562-9. [PMID: 11523998 DOI: 10.1021/bi0100081] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The SoxAX complex of the bacterium Rhodovulum sulfidophilum is a heterodimeric c-type cytochrome that plays an essential role in photosynthetic thiosulfate and sulfide oxidation. The three heme sites of SoxAX have been analyzed using electronic absorption, electron paramagnetic resonance, and magnetic circular dichroism spectroscopies. Heme-3 in the ferric state is characterized by a Large g(max) EPR signal and has histidine and methionine axial heme iron ligands which are retained on reduction to the ferrous state. Hemes-1 and -2 both have thiolate plus nitrogenous ligand sets in the ferric state and give rise to rhombic EPR spectra. Heme-1, whose ligands derive from cysteinate and histidine residues, remains ferric in the presence of dithionite ion. Ferric heme-2 exists with a preparation-dependent mixture of two different ligand sets, one being cysteinate/histidine, the other an unidentified pair with a weaker crystal-field strength. Upon reduction of the SoxAX complex with dithionite, a change occurs in the ligands of heme-2 in which the thiolate is either protonated or replaced by an unidentified ligand. Sequence analysis places the histidine/methionine-coordinated heme in SoxX and the thiolate-liganded hemes in SoxA. SoxAX is the first naturally occurring c-type cytochrome in which a thiolate-coordinated heme has been identified.
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Affiliation(s)
- M R Cheesman
- School of Chemical Sciences, Centre for Metalloprotein Spectroscopy and Biology, University of East Anglia, Norwich NR4 7TJ, UK.
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15
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Ray WK, Zeng G, Potters MB, Mansuri AM, Larson TJ. Characterization of a 12-kilodalton rhodanese encoded by glpE of Escherichia coli and its interaction with thioredoxin. J Bacteriol 2000; 182:2277-84. [PMID: 10735872 PMCID: PMC111278 DOI: 10.1128/jb.182.8.2277-2284.2000] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Rhodaneses catalyze the transfer of the sulfane sulfur from thiosulfate or thiosulfonates to thiophilic acceptors such as cyanide and dithiols. In this work, we define for the first time the gene, and hence the amino acid sequence, of a 12-kDa rhodanese from Escherichia coli. Well-characterized rhodaneses are comprised of two structurally similar ca. 15-kDa domains. Hence, it is thought that duplication of an ancestral rhodanese gene gave rise to the genes that encode the two-domain rhodaneses. The glpE gene, a member of the sn-glycerol 3-phosphate (glp) regulon of E. coli, encodes the 12-kDa rhodanese. As for other characterized rhodaneses, kinetic analysis revealed that catalysis by purified GlpE occurs by way of an enzyme-sulfur intermediate utilizing a double-displacement mechanism requiring an active-site cysteine. The K(m)s for SSO(3)(2-) and CN(-) were 78 and 17 mM, respectively. The apparent molecular mass of GlpE under nondenaturing conditions was 22.5 kDa, indicating that GlpE functions as a dimer. GlpE exhibited a k(cat) of 230 s(-1). Thioredoxin 1 from E. coli, a small multifunctional dithiol protein, served as a sulfur acceptor substrate for GlpE with an apparent K(m) of 34 microM when thiosulfate was near its K(m), suggesting that thioredoxin 1 or related dithiol proteins could be physiological substrates for sulfurtransferases. The overall degree of amino acid sequence identity between GlpE and the active-site domain of mammalian rhodaneses is limited ( approximately 17%). This work is significant because it begins to reveal the variation in amino acid sequences present in the sulfurtransferases. GlpE is the first among the 41 proteins in COG0607 (rhodanese-related sulfurtransferases) of the database Clusters of Orthologous Groups of proteins (http://www.ncbi.nlm.nih.gov/COG/) for which sulfurtransferase activity has been confirmed.
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Affiliation(s)
- W K Ray
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
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