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Hon-Nami K, Hijikata A, Yura K, Bessho Y. Whole genome analyses for c-type cytochromes associated with respiratory chains in the extreme thermophile, Thermus thermophilus. J GEN APPL MICROBIOL 2023; 69:68-78. [PMID: 37394433 DOI: 10.2323/jgam.2023.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
In thermophilic microorganisms, c-type cytochrome (cyt) proteins mainly function in the respiratory chain as electron carriers. Genome analyses at the beginning of this century revealed a variety of genes harboring the heme c motif. Here, we describe the results of surveying genes with the heme c motif, CxxCH, in a genome database comprising four strains of Thermus thermophilus, including strain HB8, and the confirmation of 19 c-type cytochromes among 27 selected genes. We analyzed the 19 genes, including the expression of four, by a bioinformatics approach to elucidate their individual attributes. One of the approaches included an analysis based on the secondary structure alignment pattern between the heme c motif and the 6th ligand. The predicted structures revealed many cyt c domains with fewer β-strands, such as mitochondrial cyt c, in addition to the β-strand unique to Thermus inserted in cyt c domains, as in T. thermophilus cyt c552 and caa3 cyt c oxidase subunit IIc. The surveyed thermophiles harbor potential proteins with a variety of cyt c folds. The gene analyses led to the development of an index for the classification of cyt c domains. Based on these results, we propose names for T. thermophilus genes harboring the cyt c fold.
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Affiliation(s)
| | - Atsushi Hijikata
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences
| | - Kei Yura
- Graduate School of Humanities and Sciences, Ochanomizu University
- Center for Interdisciplinary AI and Data Science, Ochanomizu University
- Graduate School of Advanced Science and Engineering, Waseda University
| | - Yoshitaka Bessho
- Center for Interdisciplinary AI and Data Science, Ochanomizu University
- RIKEN SPring-8 Center, Harima Institute
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Barrows JK, Van Dyke MW. A CsoR family transcriptional regulator, TTHA1953, controls the sulfur oxidation pathway in Thermus thermophilus HB8. J Biol Chem 2023; 299:104759. [PMID: 37116710 DOI: 10.1016/j.jbc.2023.104759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 04/09/2023] [Accepted: 04/21/2023] [Indexed: 04/30/2023] Open
Abstract
Transcription regulation is a critical means by which microorganisms sense and adapt to their environments. Bacteria contain a wide range of highly conserved families of transcription factors that have evolved to regulate diverse sets of genes. It is increasingly apparent that structural similarities between transcription factors do not always equate to analogous transcription regulatory networks. For example, transcription factors within the CsoR/RcnR family have been found to repress a wide range of gene targets, including various metal efflux genes, as well as genes involved in sulfide and formaldehyde detoxification machinery. In this study, we identify the preferred DNA binding sequence for the CsoR-like protein, TTHA1953, from the model extremophile Thermus thermophilus HB8 using the iterative selection approach, restriction endonuclease, protection, selection and amplification (REPSA). By mapping significant DNA motifs to the T. thermophilus HB8 genome, we identify potentially regulated genes that we validate with in vitro and in vivo methodologies. We establish TTHA1953 as a master regulator of the sulfur oxidation (Sox) pathway, providing the first link between CsoR-like proteins and Sox regulation.
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Affiliation(s)
- John K Barrows
- Department of Chemistry and Biochemistry, Kennesaw State University, Kennesaw, Georgia, USA
| | - Michael W Van Dyke
- Department of Chemistry and Biochemistry, Kennesaw State University, Kennesaw, Georgia, USA.
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Shortall K, Magner E, Soulimane T. Expression, Purification, and in vitro Enzyme Activity Assay of a Recombinant Aldehyde Dehydrogenase from Thermus thermophilus, Using an Escherichia coli Host. Bio Protoc 2022; 12:e4401. [PMID: 35800460 PMCID: PMC9090581 DOI: 10.21769/bioprotoc.4401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/10/2022] [Indexed: 12/29/2022] Open
Abstract
Based on previous in-depth characterisation, aldehyde dehydrogenases (ALDH) are a diverse superfamily of enzymes, in terms of both structure and function, present in all kingdoms of life. They catalyse the oxidation of an aldehyde to carboxylic acid using the cofactor nicotinamide adenine dinucleotide (phosphate) (NAD(P)+), and are often not substrate-specific, but rather have a broad range of associated biological functions, including detoxification and biosynthesis. We studied the structure of ALDHTt from Thermus thermophilus, as well as performed its biochemical characterisation. This allowed for insight into its potential substrates and biological roles. In this protocol, we describe ALDHTt heterologous expression in E. coli, purification, and activity assay (based on Shortall et al., 2021 ). ALDHTt was first copurified as a contaminant during caa3-type cytochrome oxidase isolation from T. thermophilus. This recombinant production system was employed for structural and biochemical analysis of wild-type and mutants, and proved efficient, yielding approximately 15-20 mg/L ALDHTt. For purification of the thermophilic his-tagged ALDHTt, heat treatment, immobilized metal affinity chromatography (IMAC), and gel filtration chromatography were used. The enzyme activity assay was performed via UV-Vis spectrophotometry, monitoring the production of reduced nicotinamide adenine dinucleotide (NADH). Graphical abstract: Flow chart outlining the steps in ALDHTt expression and purification, highlighting the approximate time required for each step.
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Affiliation(s)
- Kim Shortall
- Department of Chemical Sciences, Bernal Institute, University of Limerick, V94 T9PX, Limerick, Ireland
| | - Edmond Magner
- Department of Chemical Sciences, Bernal Institute, University of Limerick, V94 T9PX, Limerick, Ireland
| | - Tewfik Soulimane
- Department of Chemical Sciences, Bernal Institute, University of Limerick, V94 T9PX, Limerick, Ireland,
*For correspondence:
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Sulfite oxidation by the quinone-reducing molybdenum sulfite dehydrogenase SoeABC from the bacterium Aquifex aeolicus. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148279. [DOI: 10.1016/j.bbabio.2020.148279] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/03/2020] [Accepted: 07/10/2020] [Indexed: 01/26/2023]
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The Heterotrophic Bacterium Cupriavidus pinatubonensis JMP134 Oxidizes Sulfide to Sulfate with Thiosulfate as a Key Intermediate. Appl Environ Microbiol 2020; 86:AEM.01835-20. [PMID: 32917752 DOI: 10.1128/aem.01835-20] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 09/02/2020] [Indexed: 12/26/2022] Open
Abstract
Heterotrophic bacteria actively participate in the biogeochemical cycle of sulfur on Earth. The heterotrophic bacterium Cupriavidus pinatubonensis JMP134 contains several enzymes involved in sulfur oxidation, but how these enzymes work together to oxidize sulfide in the bacterium has not been studied. Using gene-deletion and whole-cell assays, we determined that the bacterium uses sulfide:quinone oxidoreductase to oxidize sulfide to polysulfide, which is further oxidized to sulfite by persulfide dioxygenase. Sulfite spontaneously reacts with polysulfide to produce thiosulfate. The sulfur-oxidizing (Sox) system oxidizes thiosulfate to sulfate. Flavocytochrome c sulfide dehydrogenase enhances thiosulfate oxidation by the Sox system but couples with the Sox system for sulfide oxidation to sulfate in the absence of sulfide:quinone oxidoreductase. Thus, C. pinatubonensis JMP134 contains a main pathway and a contingent pathway for sulfide oxidation.IMPORTANCE We establish a new pathway of sulfide oxidation with thiosulfate as a key intermediate in Cupriavidus pinatubonensis JMP134. The bacterium mainly oxidizes sulfide by using sulfide:quinone oxidoreductase, persulfide dioxygenase, and the Sox system with thiosulfate as a key intermediate. Although the purified and reconstituted Sox system oxidizes sulfide, its rate of sulfide oxidation in C. pinatubonensis JMP134 is too low to be physiologically relevant. The findings reveal how these sulfur-oxidizing enzymes participate in sulfide oxidation in a single bacterium.
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Functional mononuclear molybdenum enzymes: challenges and triumphs in molecular cloning, expression, and isolation. J Biol Inorg Chem 2020; 25:547-569. [PMID: 32279136 DOI: 10.1007/s00775-020-01787-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/30/2020] [Indexed: 10/24/2022]
Abstract
Mononuclear molybdenum enzymes catalyze a variety of reactions that are essential in the cycling of nitrogen, carbon, arsenic, and sulfur. For decades, the structure and function of these crucial enzymes have been investigated to develop a fundamental knowledge for this vast family of enzymes and the chemistries they carry out. Therefore, obtaining abundant quantities of active enzyme is necessary for exploring this family's biochemical capability. This mini-review summarizes the methods for overexpressing mononuclear molybdenum enzymes in the context of the challenges encountered in the process. Effective methods for molybdenum cofactor synthesis and incorporation, optimization of expression conditions, improving isolation of active vs. inactive enzyme, incorporation of additional prosthetic groups, and inclusion of redox enzyme maturation protein chaperones are discussed in relation to the current molybdenum enzyme literature. This article summarizes the heterologous and homologous expression studies providing underlying patterns and potential future directions.
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Djeghader A, Rossotti M, Abdulkarim S, Biaso F, Gerbaud G, Nitschke W, Schoepp-Cothenet B, Soulimane T, Grimaldi S. Structural evidence for a reaction intermediate mimic in the active site of a sulfite dehydrogenase. Chem Commun (Camb) 2020; 56:9850-9853. [DOI: 10.1039/d0cc03634j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We provide structural and spectroscopic evidence for a molybdenum–phosphate adduct mimicking a proposed reaction intermediate in the active site of a prokaryotic sulfite oxidizing enzyme.
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Affiliation(s)
- Ahmed Djeghader
- Department of Chemical Sciences and Bernal Institute
- University of Limerick
- Ireland
| | | | - Saleh Abdulkarim
- Department of Chemical Sciences and Bernal Institute
- University of Limerick
- Ireland
| | | | | | | | | | - Tewfik Soulimane
- Department of Chemical Sciences and Bernal Institute
- University of Limerick
- Ireland
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Hanauer K, Förster C, Heinze K. Redox-Controlled Stabilization of an Open-Shell Intermediate in a Bioinspired Enzyme Model. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201800570] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Kristina Hanauer
- Institute of Inorganic Chemistry and Analytical Chemistry; Johannes Gutenberg University of Mainz; Duesbergweg 10-14 55128 Mainz Germany
| | - Christoph Förster
- Institute of Inorganic Chemistry and Analytical Chemistry; Johannes Gutenberg University of Mainz; Duesbergweg 10-14 55128 Mainz Germany
| | - Katja Heinze
- Institute of Inorganic Chemistry and Analytical Chemistry; Johannes Gutenberg University of Mainz; Duesbergweg 10-14 55128 Mainz Germany
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VLDL Induced Modulation of Nitric Oxide Signalling and Cell Redox Homeostasis in HUVEC. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:2697364. [PMID: 29085553 PMCID: PMC5632467 DOI: 10.1155/2017/2697364] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 07/31/2017] [Accepted: 08/15/2017] [Indexed: 12/25/2022]
Abstract
High levels of circulating lipoprotein constitute a risk factor for cardiovascular diseases, and in this context, the specific role of the very-low-density lipoproteins (VLDL) is poorly understood. The response of human umbilical vein endothelial cells (HUVEC) to VLDL exposure was studied, especially focusing on the pathways involved in alteration of redox homeostasis and nitric oxide (NO) bioavailability. The results obtained by the analysis of the expression level of genes implicated in the NO metabolism and oxidative stress response indicated a strong activation of inducible NO synthase (iNOS) upon 24 h exposure to VLDL, particularly if these have been preventively oxidised. Simultaneously, both mRNA and protein expression of endothelial NO synthase (eNOS) were decreased and its phosphorylation pattern, at the key residues Tyr495 and Ser1177, strongly suggested the occurrence of the eNOS uncoupling. The results are consistent with the observed increased production of nitrites and nitrates (NOx), reactive oxygen species (ROS), 3-nitrotyrosine (3-NT), and, at mitochondrial level, a deficit in mitochondrial O2 consumption. Altogether, these data suggest that the VLDL, particularly if oxidised, when allowed to persist in contact with endothelial cells, strongly alter NO bioavailability, affecting redox homeostasis and mitochondrial function.
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Melin F, Schoepp-Cothenet B, Abdulkarim S, Noor MR, Soulimane T, Hellwig P. Electrochemical study of an electron shuttle diheme protein: The cytochrome c from T. thermophilus. Inorganica Chim Acta 2017. [DOI: 10.1016/j.ica.2017.05.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Heinze K. Bioinspired functional analogs of the active site of molybdenum enzymes: Intermediates and mechanisms. Coord Chem Rev 2015. [DOI: 10.1016/j.ccr.2015.04.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Hüttinger K, Förster C, Heinze K. Intramolecular electron transfer between molybdenum and iron mimicking bacterial sulphite dehydrogenase. Chem Commun (Camb) 2014; 50:4285-8. [PMID: 24452096 DOI: 10.1039/c3cc46919k] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Diferrocenyl/diferrocenium substituted dioxido molybdenum(VI) complexes [Fe2MoO2] 2(Fc)/[2(FC)]²⁺ mimic the catalytic active site including the redox subunits as well as the catalytic function of bacterial sulphite oxidases.
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Affiliation(s)
- Kristina Hüttinger
- Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg-University of Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
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Pastorino L, Dellacasa E, Noor MR, Soulimane T, Bianchini P, D'Autilia F, Antipov A, Diaspro A, Tofail SAM, Ruggiero C. Multilayered polyelectrolyte microcapsules: interaction with the enzyme cytochrome C oxidase. PLoS One 2014; 9:e112192. [PMID: 25372607 PMCID: PMC4221607 DOI: 10.1371/journal.pone.0112192] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 10/13/2014] [Indexed: 02/01/2023] Open
Abstract
Cell-sized polyelectrolyte capsules functionalized with a redox-driven proton pump protein were assembled for the first time. The interaction of polyelectrolyte microcapsules, fabricated by electrostatic layer-by-layer assembly, with cytochrome c oxidase molecules was investigated. We found that the cytochrome c oxidase retained its functionality, that the functionalized microcapsules interacting with cytochrome c oxidase were permeable and that the permeability characteristics of the microcapsule shell depend on the shell components. This work provides a significant input towards the fabrication of an integrated device made of biological components and based on specific biomolecular functions and properties.
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Affiliation(s)
- Laura Pastorino
- Department of Informatics, Bioengineering, Robotics and Systems Engineering, University of Genova, Genova, Italy
| | - Elena Dellacasa
- Department of Informatics, Bioengineering, Robotics and Systems Engineering, University of Genova, Genova, Italy
| | - Mohamed R. Noor
- Department of Chemical and Environmental Sciences, University of Limerick, Limerick, Ireland
- Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
| | - Tewfik Soulimane
- Department of Chemical and Environmental Sciences, University of Limerick, Limerick, Ireland
- Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
| | | | | | | | | | - Syed A. M. Tofail
- Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
| | - Carmelina Ruggiero
- Department of Informatics, Bioengineering, Robotics and Systems Engineering, University of Genova, Genova, Italy
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Kappler U, Enemark JH. Sulfite-oxidizing enzymes. J Biol Inorg Chem 2014; 20:253-64. [DOI: 10.1007/s00775-014-1197-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 09/15/2014] [Indexed: 11/24/2022]
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Abstract
Despite its reactivity and hence toxicity to living cells, sulfite is readily converted by various microorganisms using distinct assimilatory and dissimilatory metabolic routes. In respiratory pathways, sulfite either serves as a primary electron donor or terminal electron acceptor (yielding sulfate or sulfide, respectively), and its conversion drives electron transport chains that are coupled to chemiosmotic ATP synthesis. Notably, such processes are also seen to play a general role in sulfite detoxification, which is assumed to have an evolutionary ancient origin. The diversity of sulfite conversion is reflected by the fact that the range of microbial sulfite-converting enzymes displays different cofactors such as siroheme, heme c, or molybdopterin. This chapter aims to summarize the current knowledge of microbial sulfite metabolism and focuses on sulfite catabolism. The structure and function of sulfite-converting enzymes and the emerging picture of the modular architecture of the corresponding respiratory/detoxifying electron transport chains is emphasized.
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Affiliation(s)
- Jörg Simon
- Department of Biology, Microbial Energy Conversion and Biotechnology, Technische Universität Darmstadt, Schnittspahnstrasse 10, 64287 Darmstadt, Germany.
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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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Carbonero F, Benefiel AC, Alizadeh-Ghamsari AH, Gaskins HR. Microbial pathways in colonic sulfur metabolism and links with health and disease. Front Physiol 2012; 3:448. [PMID: 23226130 PMCID: PMC3508456 DOI: 10.3389/fphys.2012.00448] [Citation(s) in RCA: 345] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 11/08/2012] [Indexed: 12/20/2022] Open
Abstract
Sulfur is both crucial to life and a potential threat to health. While colonic sulfur metabolism mediated by eukaryotic cells is relatively well studied, much less is known about sulfur metabolism within gastrointestinal microbes. Sulfated compounds in the colon are either of inorganic (e.g., sulfates, sulfites) or organic (e.g., dietary amino acids and host mucins) origin. The most extensively studied of the microbes involved in colonic sulfur metabolism are the sulfate-reducing bacteria (SRB), which are common colonic inhabitants. Many other microbial pathways are likely to shape colonic sulfur metabolism as well as the composition and availability of sulfated compounds, and these interactions need to be examined in more detail. Hydrogen sulfide is the sulfur derivative that has attracted the most attention in the context of colonic health, and the extent to which it is detrimental or beneficial remains in debate. Several lines of evidence point to SRB or exogenous hydrogen sulfide as potential players in the etiology of intestinal disorders, inflammatory bowel diseases (IBDs) and colorectal cancer in particular. Generation of hydrogen sulfide via pathways other than dissimilatory sulfate reduction may be as, or more, important than those involving the SRB. We suggest here that a novel axis of research is to assess the effects of hydrogen sulfide in shaping colonic microbiome structure. Clearly, in-depth characterization of the microbial pathways involved in colonic sulfur metabolism is necessary for a better understanding of its contribution to colonic disorders and development of therapeutic strategies.
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Affiliation(s)
- Franck Carbonero
- Department of Animal Sciences, University of Illinois Urbana, IL, USA
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