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Sudo M, Osvatic J, Taylor JD, Dufour SC, Prathep A, Wilkins LGE, Rattei T, Yuen B, Petersen JM. SoxY gene family expansion underpins adaptation to diverse hosts and environments in symbiotic sulfide oxidizers. mSystems 2024; 9:e0113523. [PMID: 38747602 PMCID: PMC11237559 DOI: 10.1128/msystems.01135-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 04/13/2024] [Indexed: 06/19/2024] Open
Abstract
Sulfur-oxidizing bacteria (SOB) have developed distinct ecological strategies to obtain reduced sulfur compounds for growth. These range from specialists that can only use a limited range of reduced sulfur compounds to generalists that can use many different forms as electron donors. Forming intimate symbioses with animal hosts is another highly successful ecological strategy for SOB, as animals, through their behavior and physiology, can enable access to sulfur compounds. Symbioses have evolved multiple times in a range of animal hosts and from several lineages of SOB. They have successfully colonized a wide range of habitats, from seagrass beds to hydrothermal vents, with varying availability of symbiont energy sources. Our extensive analyses of sulfur transformation pathways in 234 genomes of symbiotic and free-living SOB revealed widespread conservation in metabolic pathways for sulfur oxidation in symbionts from different host species and environments, raising the question of how they have adapted to such a wide range of distinct habitats. We discovered a gene family expansion of soxY in these genomes, with up to five distinct copies per genome. Symbionts harboring only the "canonical" soxY were typically ecological "specialists" that are associated with specific host subfamilies or environments (e.g., hydrothermal vents, mangroves). Conversely, symbionts with multiple divergent soxY genes formed versatile associations across diverse hosts in various marine environments. We hypothesize that expansion and diversification of the soxY gene family could be one genomic mechanism supporting the metabolic flexibility of symbiotic SOB enabling them and their hosts to thrive in a range of different and dynamic environments.IMPORTANCESulfur metabolism is thought to be one of the most ancient mechanisms for energy generation in microorganisms. A diverse range of microorganisms today rely on sulfur oxidation for their metabolism. They can be free-living, or they can live in symbiosis with animal hosts, where they power entire ecosystems in the absence of light, such as in the deep sea. In the millions of years since they evolved, sulfur-oxidizing bacteria have adopted several highly successful strategies; some are ecological "specialists," and some are "generalists," but which genetic features underpin these ecological strategies are not well understood. We discovered a gene family that has become expanded in those species that also seem to be "generalists," revealing that duplication, repurposing, and reshuffling existing genes can be a powerful mechanism driving ecological lifestyle shifts.
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Affiliation(s)
- Marta Sudo
- University of Vienna, Centre for Microbiology and Environmental Systems Science, Vienna, Austria
- Doctoral School in Microbiology and Environmental Science, University of Vienna, Vienna, Austria
| | - Jay Osvatic
- Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna, Vienna, Austria
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - John D. Taylor
- Life Sciences, The Natural History Museum, London, United Kingdom
| | - Suzanne C. Dufour
- Department of Biology, Memorial University of Newfoundland, St. John’s, Newfoundland, Canada
| | - Anchana Prathep
- Department of Biology, Faculty of Science, Prince of Songkla University, HatYai, Thailand
| | - Laetitia G. E. Wilkins
- Eco-Evolutionary Interactions Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Thomas Rattei
- University of Vienna, Centre for Microbiology and Environmental Systems Science, Vienna, Austria
| | - Benedict Yuen
- University of Vienna, Centre for Microbiology and Environmental Systems Science, Vienna, Austria
- Eco-Evolutionary Interactions Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Jillian M. Petersen
- University of Vienna, Centre for Microbiology and Environmental Systems Science, Vienna, Austria
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Kümpel C, Grosser M, Tanabe TS, Dahl C. Fe/S proteins in microbial sulfur oxidation. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119732. [PMID: 38631440 DOI: 10.1016/j.bbamcr.2024.119732] [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: 11/14/2023] [Revised: 02/26/2024] [Accepted: 04/04/2024] [Indexed: 04/19/2024]
Abstract
Iron-sulfur clusters serve as indispensable cofactors within proteins across all three domains of life. Fe/S clusters emerged early during the evolution of life on our planet and the biogeochemical cycle of sulfur is one of the most ancient and important element cycles. It is therefore no surprise that Fe/S proteins have crucial roles in the multiple steps of microbial sulfur metabolism. During dissimilatory sulfur oxidation in prokaryotes, Fe/S proteins not only serve as electron carriers in several steps, but also perform catalytic roles, including unprecedented reactions. Two cytoplasmic enzyme systems that oxidize sulfane sulfur to sulfite are of particular interest in this context: The rDsr pathway employs the reverse acting dissimilatory sulfite reductase rDsrAB as its key enzyme, while the sHdr pathway utilizes polypeptides resembling the HdrA, HdrB and HdrC subunits of heterodisulfide reductase from methanogenic archaea. Both pathways involve components predicted to bind unusual noncubane Fe/S clusters acting as catalysts for the formation of disulfide or sulfite. Mapping of Fe/S cluster machineries on the sulfur-oxidizing prokaryote tree reveals that ISC, SUF, MIS and SMS are all sufficient to meet the Fe/S cluster maturation requirements for operation of the sHdr or rDsr pathways. The sHdr pathway is dependent on lipoate-binding proteins that are assembled by a novel pathway, involving two Radical SAM proteins, namely LipS1 and LipS2. These proteins coordinate sulfur-donating auxiliary Fe/S clusters in atypical patterns by three cysteines and one histidine and act as lipoyl synthases by jointly inserting two sulfur atoms to an octanoyl residue. This article is part of a Special Issue entitled: Biogenesis and Function of Fe/S proteins.
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Affiliation(s)
- Carolin Kümpel
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Martina Grosser
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Tomohisa Sebastian Tanabe
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Christiane Dahl
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany.
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Ikei M, Miyazaki R, Monden K, Naito Y, Takeuchi A, Takahashi YS, Tanaka Y, Murata K, Mori T, Ichikawa M, Tsukazaki T. YeeD is an essential partner for YeeE-mediated thiosulfate uptake in bacteria and regulates thiosulfate ion decomposition. PLoS Biol 2024; 22:e3002601. [PMID: 38656967 PMCID: PMC11073785 DOI: 10.1371/journal.pbio.3002601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 05/06/2024] [Accepted: 03/26/2024] [Indexed: 04/26/2024] Open
Abstract
Uptake of thiosulfate ions as an inorganic sulfur source from the environment is important for bacterial sulfur assimilation. Recently, a selective thiosulfate uptake pathway involving a membrane protein YeeE (TsuA) in Escherichia coli was characterized. YeeE-like proteins are conserved in some bacteria, archaea, and eukaryotes. However, the precise function of YeeE, along with its potential partner protein in the thiosulfate ion uptake pathway, remained unclear. Here, we assessed selective thiosulfate transport via Spirochaeta thermophila YeeE in vitro and characterized E. coli YeeD (TsuB) as an adjacent and essential protein for YeeE-mediated thiosulfate uptake in vivo. We further showed that S. thermophila YeeD possesses thiosulfate decomposition activity and that a conserved cysteine in YeeD was modified to several forms in the presence of thiosulfate. Finally, the crystal structures of S. thermophila YeeE-YeeD fusion proteins at 3.34-Å and 2.60-Å resolutions revealed their interactions. The association was evaluated by a binding assay using purified S. thermophila YeeE and YeeD. Based on these results, a model of the sophisticated uptake of thiosulfate ions by YeeE and YeeD is proposed.
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Affiliation(s)
- Mai Ikei
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Ryoji Miyazaki
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Keigo Monden
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Yusuke Naito
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Azusa Takeuchi
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Yutaro S Takahashi
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Yoshiki Tanaka
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Keina Murata
- Department of Chemistry, Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Takaharu Mori
- Department of Chemistry, Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Muneyoshi Ichikawa
- State Key Laboratory of Genetic Engineering, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai, China
| | - Tomoya Tsukazaki
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
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Wang Y, Zhou Z, Zhang W, Guo J, Li N, Zhang Y, Gong D, Lyu Y. Metabolic mechanism of Cr(VI) pollution remediation by Alicycliphilus denitrificans Ylb10. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169135. [PMID: 38070572 DOI: 10.1016/j.scitotenv.2023.169135] [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: 10/04/2023] [Revised: 11/16/2023] [Accepted: 12/04/2023] [Indexed: 01/18/2024]
Abstract
Cr(VI) is a well-known toxic pollutant and its remediation has attracted great attention. It is important to continuously discover and explore new high-efficiency Cr(VI) reducing bacteria to further improve the efficiency of Cr(VI) pollution remediation. In this paper, metabolic mechanism of Cr(VI) reduction in a new highly efficient Cr(VI) reducing bacterium, Alicycliphilus denitrificans Ylb10, was investigated. The results showed that Ylb10 could tolerate and completely reduce 450 mg/L Cr(VI). Cr(VI) can be reduced in the intracellular compartment, membrane and the extracellular compartment, with the plasma membrane being the main active site for Cr(VI) reduction. With the addition of NADH, the reduction efficiency of cell membrane components for Cr(VI) increased 2.3-fold. The omics data analysis showed that sulfite reductase CysJ, thiosulfate dehydrogenase TsdA, nitrite reductase NrfA, nitric oxide reductase NorB, and quinone oxidoreductase ChrR play important roles in the reduction of Cr(VI), in the intracellular, and the extracellular compartment, and the membrane of Ylb10, and therefore Cr(VI) was reduced by the combined action of several reductases at these three locations.
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Affiliation(s)
- Yue Wang
- College of Biological & Pharmaceutical Sciences, China Three Gorges University, Yichang 443002, China
| | - Zhiyi Zhou
- College of Biological & Pharmaceutical Sciences, China Three Gorges University, Yichang 443002, China
| | - Wen Zhang
- College of Biological & Pharmaceutical Sciences, China Three Gorges University, Yichang 443002, China; Hubei Engineering Research Center for Biological Jiaosu, China Three Gorges University, Yichang 443002, China; Key Laboratory of Functional Yeast, China National Light Industry, China Three Gorges University, Yichang 443002, China
| | - Jinling Guo
- College of Biological & Pharmaceutical Sciences, China Three Gorges University, Yichang 443002, China; Hubei Engineering Research Center for Biological Jiaosu, China Three Gorges University, Yichang 443002, China; Key Laboratory of Functional Yeast, China National Light Industry, China Three Gorges University, Yichang 443002, China
| | - Ning Li
- College of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang 443002, China
| | - Yaoping Zhang
- DOE-Great Lakes Bioenergy Research Center (GLBRC), University of Wisconsin-Madison, Madison, WI, USA
| | - Dachun Gong
- College of Biological & Pharmaceutical Sciences, China Three Gorges University, Yichang 443002, China; Hubei Engineering Research Center for Biological Jiaosu, China Three Gorges University, Yichang 443002, China; Key Laboratory of Functional Yeast, China National Light Industry, China Three Gorges University, Yichang 443002, China
| | - Yucai Lyu
- College of Biological & Pharmaceutical Sciences, China Three Gorges University, Yichang 443002, China; Hubei Engineering Research Center for Biological Jiaosu, China Three Gorges University, Yichang 443002, China; Key Laboratory of Functional Yeast, China National Light Industry, China Three Gorges University, Yichang 443002, China.
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Deng T, He Z, Xu M, Dong M, Guo J, Sun G, Huang H. Species' functional traits and interactions drive nitrate-mediated sulfur-oxidizing community structure and functioning. mBio 2023; 14:e0156723. [PMID: 37702500 PMCID: PMC10653917 DOI: 10.1128/mbio.01567-23] [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] [Received: 06/22/2023] [Accepted: 07/18/2023] [Indexed: 09/14/2023] Open
Abstract
IMPORTANCE Understanding the processes and mechanisms governing microbial community assembly and their linkages to ecosystem functioning has long been a core issue in microbial ecology. An in-depth insight still requires combining with analyses of species' functional traits and microbial interactions. Our study showed how species' functional traits and interactions determined microbial community structure and functions by a well-controlled laboratory experiment with nitrate-mediated sulfur oxidation systems using high-throughput sequencing and culture-dependent technologies. The results provided solid evidences that species' functional traits and interactions were the intrinsic factors determining community structure and function. More importantly, our study established quantitative links between community structure and function based on species' functional traits and interactions, which would have important implications for the design and synthesis of microbiomes with expected functions.
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Affiliation(s)
- Tongchu Deng
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Institute of Microbiology, Guangdong Academy of Science, Guangzhou, China
- Guangdong Provincial Key Laboratory of Environmental Protection Microbiology and Regional Ecological Security, Guangzhou, Guangdong, China
| | - Zhili He
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
| | - Meiying Xu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Institute of Microbiology, Guangdong Academy of Science, Guangzhou, China
- Guangdong Provincial Key Laboratory of Environmental Protection Microbiology and Regional Ecological Security, Guangzhou, Guangdong, China
| | - Meijun Dong
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Institute of Microbiology, Guangdong Academy of Science, Guangzhou, China
- Guangdong Provincial Key Laboratory of Environmental Protection Microbiology and Regional Ecological Security, Guangzhou, Guangdong, China
| | - Jun Guo
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Institute of Microbiology, Guangdong Academy of Science, Guangzhou, China
- Guangdong Provincial Key Laboratory of Environmental Protection Microbiology and Regional Ecological Security, Guangzhou, Guangdong, China
| | - Guoping Sun
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Institute of Microbiology, Guangdong Academy of Science, Guangzhou, China
- Guangdong Provincial Key Laboratory of Environmental Protection Microbiology and Regional Ecological Security, Guangzhou, Guangdong, China
| | - Haobin Huang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Institute of Microbiology, Guangdong Academy of Science, Guangzhou, China
- Guangdong Provincial Key Laboratory of Environmental Protection Microbiology and Regional Ecological Security, Guangzhou, Guangdong, China
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Faulkner M, Hoeven R, Kelly PP, Sun Y, Park H, Liu LN, Toogood HS, Scrutton NS. Chemoautotrophic production of gaseous hydrocarbons, bioplastics and osmolytes by a novel Halomonas species. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:152. [PMID: 37821908 PMCID: PMC10568851 DOI: 10.1186/s13068-023-02404-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023]
Abstract
BACKGROUND Production of relatively low value, bulk commodity chemicals and fuels by microbial species requires a step-change in approach to decrease the capital and operational costs associated with scaled fermentation. The utilisation of the robust and halophilic industrial host organisms of the genus Halomonas could dramatically decrease biomanufacturing costs owing to their ability to grow in seawater, using waste biogenic feedstocks, under non-sterile conditions. RESULTS We describe the isolation of Halomonas rowanensis, a novel facultative chemoautotrophic species of Halomonas from a natural brine spring. We investigated the ability of this species to produce ectoine, a compound of considerable industrial interest, under heterotrophic conditions. Fixation of radiolabelled NaH14CO3 by H. rowanensis was confirmed in mineral medium supplied with thiosulfate as an energy source. Genome sequencing suggested carbon fixation proceeds via a reductive tricarboxylic acid cycle, and not the Calvin-Bensen-Bassham cycle. The mechanism of energy generation to support chemoautotrophy is unknown owing to the absence of an annotated SOX-based thiosulfate-mediated energy conversion system. We investigated further the biotechnological potential of the isolated H. rowanensis by demonstrating production of the gaseous hydrocarbon (bio-propane), bioplastics (poly-3-hydroxybutyrate) and osmolytes (ectoine) under heterotrophic and autotrophic CO2 fixation growth conditions. CONCLUSIONS This proof-of-concept study illustrates the value of recruiting environmental isolates as industrial hosts for chemicals biomanufacturing, where CO2 utilisation could replace, or augment, the use of biogenic feedstocks in non-sterile, industrialised bioreactors.
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Affiliation(s)
- Matthew Faulkner
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Robin Hoeven
- C3 Biotechnologies Ltd, 20 Mannin Way, Caton Road, Lancaster, LA1 35W, Lancashire, UK
- Engineering Building A, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Paul P Kelly
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Yaqi Sun
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7BE, UK
| | - Helen Park
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Lu-Ning Liu
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7BE, UK
| | - Helen S Toogood
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
- C3 Biotechnologies Ltd, 20 Mannin Way, Caton Road, Lancaster, LA1 35W, Lancashire, UK.
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
- C3 Biotechnologies Ltd, 20 Mannin Way, Caton Road, Lancaster, LA1 35W, Lancashire, UK.
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Zhang D, Li X, Wu Y, Xu X, Liu Y, Shi B, Peng Y, Dai D, Sha Z, Zheng J. Microbe-driven elemental cycling enables microbial adaptation to deep-sea ferromanganese nodule sediment fields. MICROBIOME 2023; 11:160. [PMID: 37491386 PMCID: PMC10367259 DOI: 10.1186/s40168-023-01601-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 06/17/2023] [Indexed: 07/27/2023]
Abstract
BACKGROUND Ferromanganese nodule-bearing deep-sea sediments cover vast areas of the ocean floor, representing a distinctive habitat in the abyss. These sediments harbor unique conditions characterized by high iron concentration and low degradable nutrient levels, which pose challenges to the survival and growth of most microorganisms. While the microbial diversity in ferromanganese nodule-associated sediments has been surveyed several times, little is known about the functional capacities of the communities adapted to these unique habitats. RESULTS Seven sediment samples collected adjacent to ferromanganese nodules from the Clarion-Clipperton Fracture Zone (CCFZ) in the eastern Pacific Ocean were subjected to metagenomic analysis. As a result, 179 high-quality metagenome-assembled genomes (MAGs) were reconstructed and assigned to 21 bacterial phyla and 1 archaeal phylum, with 88.8% of the MAGs remaining unclassified at the species level. The main mechanisms of resistance to heavy metals for microorganisms in sediments included oxidation (Mn), reduction (Cr and Hg), efflux (Pb), synergy of reduction and efflux (As), and synergy of oxidation and efflux (Cu). Iron, which had the highest content among all metallic elements, may occur mainly as Fe(III) that potentially functioned as an electron acceptor. We found that microorganisms with a diverse array of CAZymes did not exhibit higher community abundance. Instead, microorganisms mainly obtained energy from oxidation of metal (e.g., Mn(II)) and sulfur compounds using oxygen or nitrate as an electron acceptor. Chemolithoautotrophic organisms (Thaumarchaeota and Nitrospirota phyla) were found to be potential manganese oxidizers. The functional profile analysis of the dominant microorganisms further indicated that utilization of inorganic nutrients by redox reactions (rather than organic nutrient metabolism) is a major adaptive strategy used by microorganisms to support their survival in the ferromanganese nodule sediments. CONCLUSIONS This study provides a comprehensive metagenomic analysis of microbes inhabiting metal-rich ferromanganese nodule sediments. Our results reveal extensive redundancy across taxa for pathways of metal resistance and transformation, the highly diverse mechanisms used by microbes to obtain nutrition, and their participation in various element cycles in these unique environments. Video Abstract.
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Affiliation(s)
- Dechao Zhang
- Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Geology, Laoshan Laboratory, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xudong Li
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yuehong Wu
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, 310012, Hangzhou, China
| | - Xuewei Xu
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, 310012, Hangzhou, China
| | - Yanxia Liu
- Laboratory for Marine Geology, Laoshan Laboratory, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Benze Shi
- Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Geology, Laoshan Laboratory, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yujie Peng
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, China
| | - Dadong Dai
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhongli Sha
- Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
- Laboratory for Marine Geology, Laoshan Laboratory, Qingdao, 266237, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Jinshui Zheng
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China.
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, China.
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A metabolic puzzle: Consumption of C 1 compounds and thiosulfate in Hyphomicrobium denitrificans X T. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148932. [PMID: 36367491 DOI: 10.1016/j.bbabio.2022.148932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 10/17/2022] [Accepted: 10/24/2022] [Indexed: 11/09/2022]
Abstract
Many obligately heterotrophic methylotrophs oxidize thiosulfate as an additional electron source during growth on C1 compounds. Although two different pathways of thiosulfate oxidation are implemented in Hyphomicrobium denitrificans XT, a pronounced negative effect on growth rate is observed when it is cultured in the simultaneous presence of methanol and thiosulfate. In this model organism, periplasmic thiosulfate dehydrogenase TsdA catalyzes formation of the dead-end product tetrathionate. By reverse genetics we verified the second pathway that also starts in the periplasm where SoxXA catalyzes the oxidative fusion of thiosulfate to SoxYZ, from which sulfate is released by SoxB. Sulfane sulfur is then further oxidized in the cytoplasm by the sulfur-oxidizing heterodisulfide reductase-like system (sHdr) which is produced constitutively in a strain lacking the transcriptional repressor sHdrR. When exposed to thiosulfate, the ΔshdrR strain exhibited a strongly reduced growth rate even without thiosulfate in the pre-cultures. When grown on methanol, cells exhibit significantly increased NAD+/NADH ratios in the presence of thiosulfate. In contrast, thiosulfate did not exert any negative effect on growth rate or increase NAD+ levels during growth on formate. On both C1 substrates, excretion of up to 0.5 mM sulfite as an intermediate of thiosulfate (2 mM) oxidation was recorded. Sulfite is known to form adducts with pyrroloquinoline quinone, the cofactor of periplasmic methanol dehydrogenase. We rationalize that this causes specific inhibition of methanol degradation in the presence of thiosulfate while formate metabolism in the cytoplasm remains unaffected.
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Han S, Li Y, Gao H. Generation and Physiology of Hydrogen Sulfide and Reactive Sulfur Species in Bacteria. Antioxidants (Basel) 2022; 11:antiox11122487. [PMID: 36552695 PMCID: PMC9774590 DOI: 10.3390/antiox11122487] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
Sulfur is not only one of the most abundant elements on the Earth, but it is also essential to all living organisms. As life likely began and evolved in a hydrogen sulfide (H2S)-rich environment, sulfur metabolism represents an early form of energy generation via various reactions in prokaryotes and has driven the sulfur biogeochemical cycle since. It has long been known that H2S is toxic to cells at high concentrations, but now this gaseous molecule, at the physiological level, is recognized as a signaling molecule and a regulator of critical biological processes. Recently, many metabolites of H2S, collectively called reactive sulfur species (RSS), have been gradually appreciated as having similar or divergent regulatory roles compared with H2S in living organisms, especially mammals. In prokaryotes, even in bacteria, investigations into generation and physiology of RSS remain preliminary and an understanding of the relevant biological processes is still in its infancy. Despite this, recent and exciting advances in the fields are many. Here, we discuss abiotic and biotic generation of H2S/RSS, sulfur-transforming enzymes and their functioning mechanisms, and their physiological roles as well as the sensing and regulation of H2S/RSS.
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Jenner LP, Crack JC, Kurth JM, Soldánová Z, Brandt L, Sokol KP, Reisner E, Bradley JM, Dahl C, Cheesman MR, Butt JN. Reaction of Thiosulfate Dehydrogenase with a Substrate Mimic Induces Dissociation of the Cysteine Heme Ligand Giving Insights into the Mechanism of Oxidative Catalysis. J Am Chem Soc 2022; 144:18296-18304. [PMID: 36173876 PMCID: PMC9562282 DOI: 10.1021/jacs.2c06062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Thiosulfate dehydrogenases are bacterial cytochromes
that contribute
to the oxidation of inorganic sulfur. The active sites of these enzymes
contain low-spin c-type heme with Cys–/His axial ligation. However, the reduction potentials of these hemes
are several hundred mV more negative than that of the thiosulfate/tetrathionate
couple (Em, +198 mV), making it difficult
to rationalize the thiosulfate oxidizing capability. Here, we describe
the reaction of Campylobacter jejuni thiosulfate dehydrogenase (TsdA) with sulfite, an analogue of thiosulfate.
The reaction leads to stoichiometric conversion of the active site
Cys to cysteinyl sulfonate (Cα-CH2-S-SO3–) such that the protein exists in a form
closely resembling a proposed intermediate in the pathway for thiosulfate
oxidation that carries a cysteinyl thiosulfate (Cα-CH2-S-SSO3–). The active
site heme in the stable sulfonated protein displays an Em approximately 200 mV more positive than the Cys–/His-ligated state. This can explain the thiosulfate
oxidizing activity of the enzyme and allows us to propose a catalytic
mechanism for thiosulfate oxidation. Substrate-driven release of the
Cys heme ligand allows that side chain to provide the site of substrate
binding and redox transformation; the neighboring heme then simply
provides a site for electron relay to an appropriate partner. This
chemistry is distinct from that displayed by the Cys-ligated hemes
found in gas-sensing hemoproteins and in enzymes such as the cytochromes
P450. Thus, a further class of thiolate-ligated hemes is proposed,
as exemplified by the TsdA centers that have evolved to catalyze the
controlled redox transformations of inorganic oxo anions of sulfur.
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Affiliation(s)
- Leon P Jenner
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, NorwichNR4 7TJ, United Kingdom
| | - Jason C Crack
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, NorwichNR4 7TJ, United Kingdom
| | - Julia M Kurth
- Institut für Mikrobiologie & Biotechnologie, Friedrich Wilhelms Universität Bonn, D-53115Bonn, Germany
| | - Zuzana Soldánová
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, NorwichNR4 7TJ, United Kingdom
| | - Linda Brandt
- Institut für Mikrobiologie & Biotechnologie, Friedrich Wilhelms Universität Bonn, D-53115Bonn, Germany
| | - Katarzyna P Sokol
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, CambridgeCB2 1EW, United Kingdom
| | - Erwin Reisner
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, CambridgeCB2 1EW, United Kingdom
| | - Justin M Bradley
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, NorwichNR4 7TJ, United Kingdom
| | - Christiane Dahl
- Institut für Mikrobiologie & Biotechnologie, Friedrich Wilhelms Universität Bonn, D-53115Bonn, Germany
| | - Myles R Cheesman
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, NorwichNR4 7TJ, United Kingdom
| | - Julea N Butt
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, NorwichNR4 7TJ, United Kingdom
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11
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Abstract
Wetlands are the major natural source of methane, an important greenhouse gas. The sulfur and methane cycles in wetlands are linked—e.g., a strong sulfur cycle can inhibit methanogenesis. Although there has historically been a clear distinction drawn between methane and sulfur oxidizers, here, we isolated a methanotroph that also performed respiratory oxidization of sulfur compounds. We experimentally demonstrated that thiotrophy and methanotrophy are metabolically compatible, and both metabolisms could be expressed simultaneously in a single microorganism. These findings suggest that mixotrophic methane/sulfur-oxidizing bacteria are a previously overlooked component of environmental methane and sulfur cycles. This creates a framework for a better understanding of these redox cycles in natural and engineered wetlands. Natural and anthropogenic wetlands are major sources of the atmospheric greenhouse gas methane. Methane emissions from wetlands are mitigated by methanotrophic bacteria at the oxic–anoxic interface, a zone of intense redox cycling of carbon, sulfur, and nitrogen compounds. Here, we report on the isolation of an aerobic methanotrophic bacterium, ‘Methylovirgula thiovorans' strain HY1, which possesses metabolic capabilities never before found in any methanotroph. Most notably, strain HY1 is the first bacterium shown to aerobically oxidize both methane and reduced sulfur compounds for growth. Genomic and proteomic analyses showed that soluble methane monooxygenase and XoxF-type alcohol dehydrogenases are responsible for methane and methanol oxidation, respectively. Various pathways for respiratory sulfur oxidation were present, including the Sox–rDsr pathway and the S4I system. Strain HY1 employed the Calvin–Benson–Bassham cycle for CO2 fixation during chemolithoautotrophic growth on reduced sulfur compounds. Proteomic and microrespirometry analyses showed that the metabolic pathways for methane and thiosulfate oxidation were induced in the presence of the respective substrates. Methane and thiosulfate could therefore be independently or simultaneously oxidized. The discovery of this versatile bacterium demonstrates that methanotrophy and thiotrophy are compatible in a single microorganism and underpins the intimate interactions of methane and sulfur cycles in oxic–anoxic interface environments.
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12
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Du R, Gao D, Wang Y, Liu L, Cheng J, Liu J, Zhang XH, Yu M. Heterotrophic Sulfur Oxidation of Halomonas titanicae SOB56 and Its Habitat Adaptation to the Hydrothermal Environment. Front Microbiol 2022; 13:888833. [PMID: 35774465 PMCID: PMC9237845 DOI: 10.3389/fmicb.2022.888833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/24/2022] [Indexed: 11/23/2022] Open
Abstract
Halomonas bacteria are ubiquitous in global marine environments, however, their sulfur-oxidizing abilities and survival adaptations in hydrothermal environments are not well understood. In this study, we characterized the sulfur oxidation ability and metabolic mechanisms of Halomonas titanicae SOB56, which was isolated from the sediment of the Tangyin hydrothermal field in the Southern Okinawa Trough. Physiological characterizations showed that it is a heterotrophic sulfur-oxidizing bacterium that can oxidize thiosulfate to tetrathionate, with the Na2S2O3 degradation reaching 94.86%. Two potential thiosulfate dehydrogenase-related genes, tsdA and tsdB, were identified as encoding key catalytic enzymes, and their expression levels in strain SOB56 were significantly upregulated. Nine of fifteen examined Halomonas genomes possess TsdA- and TsdB-homologous proteins, whose amino acid sequences have two typical Cys-X2-Cys-His heme-binding regions. Moreover, the thiosulfate oxidation process in H. titanicae SOB56 might be regulated by quorum sensing, and autoinducer-2 synthesis protein LuxS was identified in its genome. Regarding the mechanisms underlying adaptation to hydrothermal environment, strain SOB56 was capable of forming biofilms and producing EPS. In addition, genes related to complete flagellum assembly system, various signal transduction histidine kinases, heavy metal transporters, anaerobic respiration, and variable osmotic stress regulation were also identified. Our results shed light on the potential functions of heterotrophic Halomonas bacteria in hydrothermal sulfur cycle and revealed possible adaptations for living at deep-sea hydrothermal fields by H. titanicae SOB56.
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Affiliation(s)
- Rui Du
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Di Gao
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Yiting Wang
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Lijun Liu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Jingguang Cheng
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Jiwen Liu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Xiao-Hua Zhang
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Min Yu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
- *Correspondence: Min Yu,
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13
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Zhou N, Keffer JL, Polson SW, Chan CS. Unraveling Fe(II)-Oxidizing Mechanisms in a Facultative Fe(II) Oxidizer, Sideroxydans lithotrophicus Strain ES-1, via Culturing, Transcriptomics, and Reverse Transcription-Quantitative PCR. Appl Environ Microbiol 2022; 88:e0159521. [PMID: 34788064 PMCID: PMC8788666 DOI: 10.1128/aem.01595-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 11/11/2021] [Indexed: 11/20/2022] Open
Abstract
Sideroxydans lithotrophicus ES-1 grows autotrophically either by Fe(II) oxidation or by thiosulfate oxidation, in contrast to most other isolates of neutrophilic Fe(II)-oxidizing bacteria (FeOB). This provides a unique opportunity to explore the physiology of a facultative FeOB and constrain the genes specific to Fe(II) oxidation. We compared the growth of S. lithotrophicus ES-1 on Fe(II), thiosulfate, and both substrates together. While initial growth rates were similar, thiosulfate-grown cultures had higher yield with or without Fe(II) present, which may give ES-1 an advantage over obligate FeOB. To investigate the Fe(II) and S oxidation pathways, we conducted transcriptomics experiments, validated with reverse transcription-quantitative PCR (RT-qPCR). We explored the long-term gene expression response at different growth phases (over days to a week) and expression changes during a short-term switch from thiosulfate to Fe(II) (90 min). The dsr and sox sulfur oxidation genes were upregulated in thiosulfate cultures. The Fe(II) oxidase gene cyc2 was among the top expressed genes during both Fe(II) and thiosulfate oxidation, and addition of Fe(II) to thiosulfate-grown cells caused an increase in cyc2 expression. These results support the role of Cyc2 as the Fe(II) oxidase and suggest that ES-1 maintains readiness to oxidize Fe(II), even in the absence of Fe(II). We used gene expression profiles to further constrain the ES-1 Fe(II) oxidation pathway. Notably, among the most highly upregulated genes during Fe(II) oxidation were genes for alternative complex III, reverse electron transport, and carbon fixation. This implies a direct connection between Fe(II) oxidation and carbon fixation, suggesting that CO2 is an important electron sink for Fe(II) oxidation. IMPORTANCE Neutrophilic FeOB are increasingly observed in various environments, but knowledge of their ecophysiology and Fe(II) oxidation mechanisms is still relatively limited. Sideroxydans isolates are widely observed in aquifers, wetlands, and sediments, and genome analysis suggests metabolic flexibility contributes to their success. The type strain ES-1 is unusual among neutrophilic FeOB isolates, as it can grow on either Fe(II) or a non-Fe(II) substrate, thiosulfate. Almost all our knowledge of neutrophilic Fe(II) oxidation pathways comes from genome analyses, with some work on metatranscriptomes. This study used culture-based experiments to test the genes specific to Fe(II) oxidation in a facultative FeOB and refine our model of the Fe(II) oxidation pathway. We gained insight into how facultative FeOB like ES-1 connect Fe, S, and C biogeochemical cycling in the environment and suggest a multigene indicator would improve understanding of Fe(II) oxidation activity in environments with facultative FeOB.
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Affiliation(s)
- Nanqing Zhou
- School of Marine Science and Policy, University of Delaware, Newark, Delaware, USA
| | - Jessica L. Keffer
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
| | - Shawn W. Polson
- Department of Computer and Information Sciences, University of Delaware, Newark, Delaware, USA
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware, USA
| | - Clara S. Chan
- School of Marine Science and Policy, University of Delaware, Newark, Delaware, USA
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
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14
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Sun W, Lin Z, Yu Q, Cheng S, Gao H. Promoting Extracellular Electron Transfer of Shewanella oneidensis MR-1 by Optimizing the Periplasmic Cytochrome c Network. Front Microbiol 2021; 12:727709. [PMID: 34675900 PMCID: PMC8524038 DOI: 10.3389/fmicb.2021.727709] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 09/13/2021] [Indexed: 11/13/2022] Open
Abstract
The low efficiency of extracellular electron transfer (EET) is a major bottleneck for Shewanella oneidensis MR-1 acting as an electroactive biocatalyst in bioelectrochemical systems. Although it is well established that a periplasmic c-type cytochrome (c-Cyt) network plays a critical role in regulating EET efficiency, the understanding of the network in terms of structure and electron transfer activity is obscure and partial. In this work, we attempted to systematically investigate the impacts of the network components on EET in their absence and overproduction individually in microbial fuel cell (MFC). We found that overexpression of c-Cyt CctA leads to accelerated electron transfer between CymA and the Mtr system, which function as the primary quinol oxidase and the outer-membrane (OM) electron hub in EET. In contrast, NapB, FccA, and TsdB in excess severely impaired EET, reducing EET capacity in MFC by more than 50%. Based on the results from both strategies, a series of engineered strains lacking FccA, NapB, and TsdB in combination while overproducing CctA were tested for a maximally optimized c-Cyt network. A strain depleted of all NapB, FccA, and TsdB with CctA overproduction achieved the highest maximum power density in MFCs (436.5 mW/m2), ∼3.62-fold higher than that of wild type (WT). By revealing that optimization of periplasmic c-Cyt composition is a practical strategy for improving EET efficiency, our work underscores the importance in understanding physiological and electrochemical characteristics of c-Cyts involved in EET.
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Affiliation(s)
- Weining Sun
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Zhufan Lin
- Department of Energy Engineering, State Key Laboratory of Clean Energy, Zhejiang University, Hangzhou, China
| | - Qingzi Yu
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Shaoan Cheng
- Department of Energy Engineering, State Key Laboratory of Clean Energy, Zhejiang University, Hangzhou, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, China
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15
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Yu Q, Sun W, Gao H. Thiosulfate oxidation in sulfur-reducing Shewanella oneidensis and its unexpected influences on the cytochrome c content. Environ Microbiol 2021; 23:7056-7072. [PMID: 34664382 DOI: 10.1111/1462-2920.15807] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/04/2021] [Accepted: 10/07/2021] [Indexed: 12/13/2022]
Abstract
Thiosulfate, an important form of sulfur compounds, can serve as both electron donor and acceptor in various microorganisms. In Shewanella oneidensis, a bacterium renowned for respiratory versatility, thiosulfate reduction has long been recognized but whether it can catalyse thiosulfate oxidation remains elusive. In this study, we discovered that S. oneidensis is capable of thiosulfate oxidation, a process specifically catalysed by two periplasmic cytochrome c (cyt c) proteins, TsdA and TsdB, which act as the catalytic subunit and the electron transfer subunit respectively. In the presence of oxygen, oxidation of thiosulfate has priority over reduction. Intriguingly, thiosulfate oxidation negatively regulates the cyt c content in S. oneidensis cells, largely by reducing intracellular levels of cAMP, which as the cofactor modulates activity of global regulator Crp required for transcription of many cyt c genes. This unexpected finding provides an additional dimension to interplays between the respiration regulator and the respiratory pathways in S. oneidensis. Moreover, the data presented here identified S. oneidensis as the first bacterium known to date owning both functional thiosulfate reductase and dehydrogenase, and importantly, genomics analyses suggested that the number of bacterial species possessing this feature is rather limited.
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Affiliation(s)
- Qingzi Yu
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, 310058, China
| | - Weining Sun
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, 310058, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, 310058, China
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16
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C-type cytochrome-initiated reduction of bacterial lytic polysaccharide monooxygenases. Biochem J 2021; 478:2927-2944. [PMID: 34240737 PMCID: PMC8981238 DOI: 10.1042/bcj20210376] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 07/06/2021] [Accepted: 07/09/2021] [Indexed: 11/29/2022]
Abstract
The release of glucose from lignocellulosic waste for subsequent fermentation into biofuels holds promise for securing humankind's future energy needs. The discovery of a set of copper-dependent enzymes known as lytic polysaccharide monooxygenases (LPMOs) has galvanised new research in this area. LPMOs act by oxidatively introducing chain breaks into cellulose and other polysaccharides, boosting the ability of cellulases to act on the substrate. Although several proteins have been implicated as electron sources in fungal LPMO biochemistry, no equivalent bacterial LPMO electron donors have been previously identified, although the proteins Cbp2D and E from Cellvibrio japonicus have been implicated as potential candidates. Here we analyse a small c-type cytochrome (CjX183) present in Cellvibrio japonicus Cbp2D, and show that it can initiate bacterial CuII/I LPMO reduction and also activate LPMO-catalyzed cellulose-degradation. In the absence of cellulose, CjX183-driven reduction of the LPMO results in less H2O2 production from O2, and correspondingly less oxidative damage to the enzyme than when ascorbate is used as the reducing agent. Significantly, using CjX183 as the activator maintained similar cellulase boosting levels relative to the use of an equivalent amount of ascorbate. Our results therefore add further evidence to the impact that the choice of electron source can have on LPMO action. Furthermore, the study of Cbp2D and other similar proteins may yet reveal new insight into the redox processes governing polysaccharide degradation in bacteria.
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17
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Insights into growth kinetics and roles of enzymes of Krebs' cycle and sulfur oxidation during exochemolithoheterotrophic growth of Achromobacter aegrifaciens NCCB 38021 on succinate with thiosulfate as the auxiliary electron donor. Arch Microbiol 2020; 203:561-578. [PMID: 32989476 DOI: 10.1007/s00203-020-02028-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/18/2020] [Accepted: 09/02/2020] [Indexed: 10/23/2022]
Abstract
Achromobacter aegrifaciens NCCB 38021 was grown heterotrophically on succinate versus exochemolithoheterotrophically on succinate with thiosulfate as auxiliary electron donor. In batch culture, no significant differences in specific molar growth yield or specific growth rate were found for the two growth conditions, but in continuous culture in the succinate-limited chemostat, the maximum specific growth yield coefficient increased by 23.3% with thiosulfate present, consistent with previous studies of endo- and exochemolithoheterotrophs and thermodynamic predictions. Thiosulfate oxidation was coupled to respiration at cytochrome c551, and thiosulfate-dependent ATP biosynthesis occurred. Specific activities of cytochrome c-linked thiosulfate dehydrogenase (E.C. 1.8.2.2) and two other enzymes of sulfur metabolism were significantly higher in exochemolithoheterotrophically grown cell extracts, while those of succinyl-transferring 2-oxoglutarate dehydrogenase (E.C. 1.2.4.2), fumarate hydratase (E.C. 4.2.1.2) and malate dehydrogenase (NAD+, E.C. 1.1.1.37) were significantly lower-presumably owing to less need to generate reducing equivalents during Krebs' cycle, since they could be produced from thiosulfate oxidation.
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18
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Pfanzagl V, Beale JH, Michlits H, Schmidt D, Gabler T, Obinger C, Djinović-Carugo K, Hofbauer S. X-ray-induced photoreduction of heme metal centers rapidly induces active-site perturbations in a protein-independent manner. J Biol Chem 2020; 295:13488-13501. [PMID: 32723869 DOI: 10.1074/jbc.ra120.014087] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/24/2020] [Indexed: 12/31/2022] Open
Abstract
Since the advent of protein crystallography, atomic-level macromolecular structures have provided a basis to understand biological function. Enzymologists use detailed structural insights on ligand coordination, interatomic distances, and positioning of catalytic amino acids to rationalize the underlying electronic reaction mechanisms. Often the proteins in question catalyze redox reactions using metal cofactors that are explicitly intertwined with their function. In these cases, the exact nature of the coordination sphere and the oxidation state of the metal is of utmost importance. Unfortunately, the redox-active nature of metal cofactors makes them especially susceptible to photoreduction, meaning that information obtained by photoreducing X-ray sources about the environment of the cofactor is the least trustworthy part of the structure. In this work we directly compare the kinetics of photoreduction of six different heme protein crystal species by X-ray radiation. We show that a dose of ∼40 kilograys already yields 50% ferrous iron in a heme protein crystal. We also demonstrate that the kinetics of photoreduction are completely independent from variables unique to the different samples tested. The photoreduction-induced structural rearrangements around the metal cofactors have to be considered when biochemical data of ferric proteins are rationalized by constraints derived from crystal structures of reduced enzymes.
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Affiliation(s)
- Vera Pfanzagl
- Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria.
| | | | - Hanna Michlits
- Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria
| | - Daniel Schmidt
- Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria
| | - Thomas Gabler
- Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria
| | - Christian Obinger
- Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria
| | - Kristina Djinović-Carugo
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria; Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Stefan Hofbauer
- Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria.
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19
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Zhang J, Liu R, Xi S, Cai R, Zhang X, Sun C. A novel bacterial thiosulfate oxidation pathway provides a new clue about the formation of zero-valent sulfur in deep sea. ISME JOURNAL 2020; 14:2261-2274. [PMID: 32457501 PMCID: PMC7608252 DOI: 10.1038/s41396-020-0684-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 05/06/2020] [Accepted: 05/12/2020] [Indexed: 11/09/2022]
Abstract
Zero-valent sulfur (ZVS) has been shown to be a major sulfur intermediate in the deep-sea cold seep of the South China Sea based on our previous work, however, the microbial contribution to the formation of ZVS in cold seep has remained unclear. Here, we describe a novel thiosulfate oxidation pathway discovered in the deep-sea cold seep bacterium Erythrobacter flavus 21–3, which provides a new clue about the formation of ZVS. Electronic microscopy, energy-dispersive, and Raman spectra were used to confirm that E. flavus 21–3 effectively converts thiosulfate to ZVS. We next used a combined proteomic and genetic method to identify thiosulfate dehydrogenase (TsdA) and thiosulfohydrolase (SoxB) playing key roles in the conversion of thiosulfate to ZVS. Stoichiometric results of different sulfur intermediates further clarify the function of TsdA in converting thiosulfate to tetrathionate (−O3S–S–S–SO3−), SoxB in liberating sulfone from tetrathionate to form ZVS and sulfur dioxygenases (SdoA/SdoB) in oxidizing ZVS to sulfite under some conditions. Notably, homologs of TsdA, SoxB, and SdoA/SdoB widely exist across the bacteria including in Erythrobacter species derived from different environments. This strongly indicates that this novel thiosulfate oxidation pathway might be frequently used by microbes and plays an important role in the biogeochemical sulfur cycle in nature.
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Affiliation(s)
- Jing Zhang
- CAS Key Laboratory of Experimental Marine Biology & Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,College of Earth Science, University of Chinese Academy of Sciences, Beijing, China.,Center of Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Rui Liu
- CAS Key Laboratory of Experimental Marine Biology & Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Center of Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Shichuan Xi
- College of Earth Science, University of Chinese Academy of Sciences, Beijing, China.,Center of Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China.,CAS Key Laboratory of Marine Geology and Environment & Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Ruining Cai
- CAS Key Laboratory of Experimental Marine Biology & Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,College of Earth Science, University of Chinese Academy of Sciences, Beijing, China.,Center of Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Xin Zhang
- Center of Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China.,CAS Key Laboratory of Marine Geology and Environment & Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Chaomin Sun
- CAS Key Laboratory of Experimental Marine Biology & Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China. .,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China. .,Center of Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China.
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20
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Mandal S, Rameez MJ, Chatterjee S, Sarkar J, Pyne P, Bhattacharya S, Shaw R, Ghosh W. Molecular mechanism of sulfur chemolithotrophy in the betaproteobacterium Pusillimonas ginsengisoli SBSA. MICROBIOLOGY-SGM 2020; 166:386-397. [PMID: 31999239 DOI: 10.1099/mic.0.000890] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Chemolithotrophic sulfur oxidation represents a significant part of the biogeochemical cycling of this element. Due to its long evolutionary history, this ancient metabolism is well known for its extensive mechanistic and phylogenetic diversification across a diverse taxonomic spectrum. Here we carried out whole-genome sequencing and analysis of a new betaproteobacterial isolate, Pusillimonas ginsengisoli SBSA, which is found to oxidize thiosulfate via the formation of tetrathionate as an intermediate. The 4.7 Mb SBSA genome was found to encompass a soxCDYZAXOB operon, plus single thiosulfate dehydrogenase (tsdA) and sulfite : acceptor oxidoreductase (sorAB) genes. Recombination-based knockout of tsdA revealed that the entire thiosulfate is first converted to tetrathionate by the activity of thiosulfate dehydrogenase (TsdA) and the Sox pathway is not functional in this bacterium despite the presence of all necessary sox genes. The ∆soxYZ and ∆soxXA knockout mutants exhibited a wild-type-like phenotype for thiosulfate/tetrathionate oxidation, whereas ∆soxB, ∆soxCD and soxO::KanR mutants only oxidized thiosulfate up to tetrathionate intermediate and had complete impairment in tetrathionate oxidation. The substrate-dependent O2 consumption rate of whole cells and the sulfur-oxidizing enzyme activities of cell-free extracts, measured in the presence/absence of thiol inhibitors/glutathione, indicated that glutathione plays a key role in SBSA tetrathionate oxidation. The present findings collectively indicate that the potential glutathione : tetrathionate coupling in P. ginsengisoli involves a novel enzymatic component, which is different from the dual-functional thiol dehydrotransferase (ThdT), while subsequent oxidation of the sulfur intermediates produced (e.g. glutathione : sulfodisulfane molecules) may proceed via the iterative action of soxBCD .
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Affiliation(s)
- Subhrangshu Mandal
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata-700054, India
| | - Moidu Jameela Rameez
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata-700054, India
| | - Sumit Chatterjee
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata-700054, India
| | - Jagannath Sarkar
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata-700054, India
| | - Prosenjit Pyne
- Present address: National Institute of Cholera and Enteric Diseases (NICED), P- C.I.T. Scheme XM, Beleghata, 33, CIT Rd, Beleghata, Kolkata - 700054, India.,Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata-700054, India
| | | | - Rahul Shaw
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata-700054, India
| | - Wriddhiman Ghosh
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata-700054, India
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21
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Edwards MJ, Richardson DJ, Paquete CM, Clarke TA. Role of multiheme cytochromes involved in extracellular anaerobic respiration in bacteria. Protein Sci 2019; 29:830-842. [PMID: 31721352 PMCID: PMC7096707 DOI: 10.1002/pro.3787] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 11/05/2019] [Accepted: 11/05/2019] [Indexed: 01/08/2023]
Abstract
Heme containing proteins are involved in a broad range of cellular functions, from oxygen sensing and transport to catalyzing oxidoreductive reactions. The two major types of cytochrome (b-type and c-type) only differ in their mechanism of heme attachment, but this has major implications for their cellular roles in both localization and mechanism. The b-type cytochromes are commonly cytoplasmic, or are within the cytoplasmic membrane, while c-type cytochromes are always found outside of the cytoplasm. The mechanism of heme attachment allows for complex c-type multiheme complexes, having the capacity to hold multiple electrons, to be assembled. These are increasingly being identified as secreted into the extracellular environment. For organisms that respire using extracellular substrates, these large multiheme cytochromes allow for electron transfer networks from the cytoplasmic membrane to the cell exterior for the reduction of extracellular electron acceptors. In this review the structures and functions of these networks and the mechanisms by which electrons are transferred to extracellular substrates is described.
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Affiliation(s)
- Marcus J Edwards
- Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia, Norwich, UK
| | - David J Richardson
- Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia, Norwich, UK
| | - Catarina M Paquete
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Oeiras, Portugal
| | - Thomas A Clarke
- Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia, Norwich, UK
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22
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Rameez MJ, Pyne P, Mandal S, Chatterjee S, Alam M, Bhattacharya S, Mondal N, Sarkar J, Ghosh W. Two pathways for thiosulfate oxidation in the alphaproteobacterial chemolithotroph Paracoccus thiocyanatus SST. Microbiol Res 2019; 230:126345. [PMID: 31585234 DOI: 10.1016/j.micres.2019.126345] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/08/2019] [Accepted: 09/21/2019] [Indexed: 02/02/2023]
Abstract
Chemolithotrophic bacteria oxidize various sulfur species for energy and electrons, thereby operationalizing biogeochemical sulfur cycles in nature. The best-studied pathway of bacterial sulfur-chemolithotrophy involves direct oxidation of thiosulfate (S2O32-) to sulfate (SO42-) without any free intermediate. This pathway mediated by SoxXAYZBCD is apparently the exclusive mechanism of thiosulfate oxidation in facultatively chemolithotrophic alphaproteobacteria. Here we explore the molecular mechanisms of sulfur oxidation in the thiosulfate- and tetrathionate(S4O62-)-oxidizing alphaproteobacterium Paracoccus thiocyanatus SST, and compare them with the prototypical Sox process of Paracoccus pantotrophus. Our results reveal a unique case where an alphaproteobacterium has Sox as its secondary pathway of thiosulfate oxidation converting ∼10% of the thiosulfate supplied, whilst ∼90% of the substrate is oxidized via a pathway that produces tetrathionate as an intermediate. Sulfur oxidation kinetics of a deletion mutant showed that thiosulfate-to-tetrathionate conversion, in SST, is catalyzed by a thiosulfate dehydrogenase (TsdA) homolog that has far-higher substrate-affinity than the Sox system of this bacterium, which in turn is also less efficient than the P. pantotrophus Sox. Deletion of soxB abolished sulfate-formation from thiosulfate/tetrathionate, while thiosulfate-to-tetrathionate conversion remained unperturbed. Physiological studies revealed the involvement of glutathione in SST tetrathionate oxidation. However, zero impact of the insertional mutation of a thiol dehydrotransferase (thdT) homolog, together with the absence of sulfite as an intermediate, indicated that SST tetrathionate oxidation is mechanistically novel, and distinct from its betaproteobacterial counterpart mediated by glutathione, ThdT, SoxBCD and sulfite:acceptor oxidoreductase. The present findings highlight extensive functional diversification of sulfur-oxidizing enzymes across phylogenetically close, as well as distant, bacteria.
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Affiliation(s)
- Moidu Jameela Rameez
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Prosenjit Pyne
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Subhrangshu Mandal
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Sumit Chatterjee
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Masrure Alam
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | | | - Nibendu Mondal
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Jagannath Sarkar
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Wriddhiman Ghosh
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India.
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Jenner LP, Kurth JM, van Helmont S, Sokol KP, Reisner E, Dahl C, Bradley JM, Butt JN, Cheesman MR. Heme ligation and redox chemistry in two bacterial thiosulfate dehydrogenase (TsdA) enzymes. J Biol Chem 2019; 294:18002-18014. [PMID: 31467084 PMCID: PMC6879331 DOI: 10.1074/jbc.ra119.010084] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/26/2019] [Indexed: 01/04/2023] Open
Abstract
Thiosulfate dehydrogenases (TsdAs) are bidirectional bacterial di-heme enzymes that catalyze the interconversion of tetrathionate and thiosulfate at measurable rates in both directions. In contrast to our knowledge of TsdA activities, information on the redox properties in the absence of substrates is rather scant. To address this deficit, we combined magnetic CD (MCD) spectroscopy and protein film electrochemistry (PFE) in a study to resolve heme ligation and redox chemistry in two representative TsdAs. We examined the TsdAs from Campylobacter jejuni, a microaerobic human pathogen, and from the purple sulfur bacterium Allochromatium vinosum. In these organisms, the enzyme functions as a tetrathionate reductase and a thiosulfate oxidase, respectively. The active site Heme 1 in both enzymes has His/Cys ligation in the ferric and ferrous states and the midpoint potentials (Em) of the corresponding redox transformations are similar, −185 mV versus standard hydrogen electrode (SHE). However, fundamental differences are observed in the properties of the second, electron transferring, Heme 2. In C. jejuni, TsdA Heme 2 has His/Met ligation and an Em of +172 mV. In A. vinosum TsdA, Heme 2 reduction triggers a switch from His/Lys ligation (Em, −129 mV) to His/Met (Em, +266 mV), but the rates of interconversion are such that His/Lys ligation would be retained during turnover. In summary, our findings have unambiguously assigned Em values to defined axial ligand sets in TsdAs, specified the rates of Heme 2 ligand exchange in the A. vinosum enzyme, and provided information relevant to describing their catalytic mechanism(s).
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Affiliation(s)
- Leon P Jenner
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Julia M Kurth
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich Wilhelms Universität Bonn, D-53115 Bonn, Germany
| | - Sebastian van Helmont
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich Wilhelms Universität Bonn, D-53115 Bonn, Germany
| | - Katarzyna P Sokol
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Erwin Reisner
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Christiane Dahl
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich Wilhelms Universität Bonn, D-53115 Bonn, Germany
| | - Justin M Bradley
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Julea N Butt
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Myles R Cheesman
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
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24
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Wang R, Lin JQ, Liu XM, Pang X, Zhang CJ, Yang CL, Gao XY, Lin CM, Li YQ, Li Y, Lin JQ, Chen LX. Sulfur Oxidation in the Acidophilic Autotrophic Acidithiobacillus spp. Front Microbiol 2019; 9:3290. [PMID: 30687275 PMCID: PMC6335251 DOI: 10.3389/fmicb.2018.03290] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 12/18/2018] [Indexed: 12/12/2022] Open
Abstract
Sulfur oxidation is an essential component of the earth's sulfur cycle. Acidithiobacillus spp. can oxidize various reduced inorganic sulfur compounds (RISCs) with high efficiency to obtain electrons for their autotrophic growth. Strains in this genus have been widely applied in bioleaching and biological desulfurization. Diverse sulfur-metabolic pathways and corresponding regulatory systems have been discovered in these acidophilic sulfur-oxidizing bacteria. The sulfur-metabolic enzymes in Acidithiobacillus spp. can be categorized as elemental sulfur oxidation enzymes (sulfur dioxygenase, sulfur oxygenase reductase, and Hdr-like complex), enzymes in thiosulfate oxidation pathways (tetrathionate intermediate thiosulfate oxidation (S4I) pathway, the sulfur oxidizing enzyme (Sox) system and thiosulfate dehydrogenase), sulfide oxidation enzymes (sulfide:quinone oxidoreductase) and sulfite oxidation pathways/enzymes. The two-component systems (TCSs) are the typical regulation elements for periplasmic thiosulfate metabolism in these autotrophic sulfur-oxidizing bacteria. Examples are RsrS/RsrR responsible for S4I pathway regulation and TspS/TspR for Sox system regulation. The proposal of sulfur metabolic and regulatory models provide new insights and overall understanding of the sulfur-metabolic processes in Acidithiobacillus spp. The future research directions and existing barriers in the bacterial sulfur metabolism are also emphasized here and the breakthroughs in these areas will accelerate the research on the sulfur oxidation in Acidithiobacillus spp. and other sulfur oxidizers.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Jian-Qun Lin
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Lin-Xu Chen
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
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25
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Shimizu T, Lengalova A, Martínek V, Martínková M. Heme: emergent roles of heme in signal transduction, functional regulation and as catalytic centres. Chem Soc Rev 2019; 48:5624-5657. [DOI: 10.1039/c9cs00268e] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Molecular mechanisms of unprecedented functions of exchangeable/labile heme and heme proteins including transcription, DNA binding, protein kinase activity, K+ channel functions, cis–trans isomerization, N–N bond formation, and other functions are described.
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Affiliation(s)
- Toru Shimizu
- Department of Biochemistry
- Faculty of Science
- Charles University
- Prague 2
- Czech Republic
| | - Alzbeta Lengalova
- Department of Biochemistry
- Faculty of Science
- Charles University
- Prague 2
- Czech Republic
| | - Václav Martínek
- Department of Biochemistry
- Faculty of Science
- Charles University
- Prague 2
- Czech Republic
| | - Markéta Martínková
- Department of Biochemistry
- Faculty of Science
- Charles University
- Prague 2
- Czech Republic
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26
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Divergent Nrf Family Proteins and MtrCAB Homologs Facilitate Extracellular Electron Transfer in Aeromonas hydrophila. Appl Environ Microbiol 2018; 84:AEM.02134-18. [PMID: 30266730 DOI: 10.1128/aem.02134-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 09/26/2018] [Indexed: 01/05/2023] Open
Abstract
Extracellular electron transfer (EET) is a strategy for respiration in which electrons generated from metabolism are moved outside the cell to a terminal electron acceptor, such as iron or manganese oxide. EET has primarily been studied in two model systems, Shewanella oneidensis and Geobacter sulfurreducens Metal reduction has also been reported in numerous microorganisms, including Aeromonas spp., which are ubiquitous Gammaproteobacteria found in aquatic ecosystems, with some species capable of pathogenesis in humans and fish. Genomic comparisons of Aeromonas spp. revealed a potential outer membrane conduit homologous to S. oneidensis MtrCAB. While the ability to respire metals and mineral oxides is not widespread in the genus Aeromonas, 90% of the sequenced Aeromonas hydrophila isolates contain MtrCAB homologs. A. hydrophila ATCC 7966 mutants lacking mtrA are unable to reduce metals. Expression of A. hydrophila mtrCAB in an S. oneidensis mutant lacking homologous components restored metal reduction. Although the outer membrane conduits for metal reduction were similar, homologs of the S. oneidensis inner membrane and periplasmic EET components CymA, FccA, and CctA were not found in A. hydrophila We characterized a cluster of genes predicted to encode components related to a formate-dependent nitrite reductase (NrfBCD), here named NetBCD (for Nrf-like electron transfer), and a predicted diheme periplasmic cytochrome, PdsA (periplasmic diheme shuttle). We present genetic evidence that proteins encoded by this cluster facilitate electron transfer from the cytoplasmic membrane across the periplasm to the MtrCAB conduit and function independently from an authentic NrfABCD system. A. hydrophila mutants lacking pdsA and netBCD were unable to reduce metals, while heterologous expression of these genes could restore metal reduction in an S. oneidensis mutant background. EET may therefore allow A. hydrophila and other species of Aeromonas to persist and thrive in iron- or manganese-rich oxygen-limited environments.IMPORTANCE Metal-reducing microorganisms are used for electricity production, bioremediation of toxic compounds, wastewater treatment, and production of valuable compounds. Despite numerous microorganisms being reported to reduce metals, the molecular mechanism has primarily been studied in two model systems, Shewanella oneidensis and Geobacter sulfurreducens We have characterized the mechanism of extracellular electron transfer in Aeromonas hydrophila, which uses the well-studied Shewanella system, MtrCAB, to move electrons across the outer membrane; however, most Aeromonas spp. appear to use a novel mechanism to transfer electrons from the inner membrane through the periplasm and to the outer membrane. The conserved use of MtrCAB in Shewanella spp. and Aeromonas spp. for metal reduction and conserved genomic architecture of metal reduction genes in Aeromonas spp. may serve as genomic markers for identifying metal-reducing microorganisms from genomic or transcriptomic sequencing. Understanding the variety of pathways used to reduce metals can allow for optimization and more efficient design of microorganisms used for practical applications.
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27
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Li J, Li H. Mechanical Unfolding Pathway of the High-Potential Iron-Sulfur Protein Revealed by Single-Molecule Atomic Force Microscopy: Toward a General Unfolding Mechanism for Iron-sulfur Proteins. J Phys Chem B 2018; 122:9340-9349. [PMID: 30212202 DOI: 10.1021/acs.jpcb.8b07614] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
High-potential iron-sulfur proteins (HiPIPs) are an important class of metalloproteins with a [4Fe-4S] cluster coordinated by four cysteine residues. Distinct from other iron-sulfur proteins, the cluster in HiPIP has a high reduction potential, making it an essential electron carrier in bacterial photosynthesis. Here, we combined single-molecule atomic force microscopy and protein engineering techniques to investigate the mechanical unfolding mechanism of HiPIP from Chromatium tepidum (cHiPIP). We found that cHiPIP unfolds in a two-step fashion with the protein sequence sequestered by the iron-sulfur center as a stable unfolding intermediate state. The rupture of the iron-sulfur center of cHiPIP proceeds in two distinct parallel pathways; one pathway involves the concurrent rupture of multiple iron-thiolate bonds, and the other one involves the sequential rupture of the iron-thiolate bonds. This mechanistic information was further confirmed by mutational studies. We found that the rupture of the iron-thiolate bonds in reduced and oxidized cHiPIP occurred in the range of 150-180 pN at a pulling speed of 400 nm/s, similar to that measured for iron-thiolate bonds in rubredoxin and ferredoxin. Our results may have important implications for understanding the general unfolding mechanism governing iron-sulfur proteins, as well as the mechanism governing the mechanical rupture of the iron-sulfur center.
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Affiliation(s)
- Jiayu Li
- Department of Chemistry , University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
| | - Hongbin Li
- Department of Chemistry , University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
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28
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Hou N, Xia Y, Wang X, Liu H, Liu H, Xun L. H 2S biotreatment with sulfide-oxidizing heterotrophic bacteria. Biodegradation 2018; 29:511-524. [PMID: 30141069 PMCID: PMC6245092 DOI: 10.1007/s10532-018-9849-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 08/10/2018] [Indexed: 12/17/2022]
Abstract
Many industrial activities produce H2S, which is toxic at high levels and odorous at even very low levels. Chemolithotrophic sulfur-oxidizing bacteria are often used in its remediation. Recently, we have reported that many heterotrophic bacteria can use sulfide:quinone oxidoreductase and persulfide dioxygenase to oxidize H2S to thiosulfate and sulfite. These bacteria may also potentially be used in H2S biotreatment. Here we report how various heterotrophic bacteria with these enzymes were cultured with organic compounds and the cells were able to rapidly oxidize H2S to zero-valence sulfur and thiosulfate, causing no apparent acidification. Some also converted the produced thiosulfate to tetrathionate. The rates of sulfide oxidation by some of the tested bacteria in suspension, ranging from 8 to 50 µmol min−1 g−1 of cell dry weight at pH 7.4, sufficient for H2S biotreatment. The immobilized bacteria removed H2S as efficiently as the bacteria in suspension, and the inclusion of Fe3O4 nanoparticles during immobilization resulted in increased efficiency for sulfide removal, in part due to chemical oxidation H2S by Fe3O4. Thus, heterotrophic bacteria may be used for H2S biotreatment under aerobic conditions.
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Affiliation(s)
- Ningke Hou
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, People's Republic of China
| | - Yongzhen Xia
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, People's Republic of China
| | - Xia Wang
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, People's Republic of China
| | - Huaiwei Liu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, People's Republic of China
| | - Honglei Liu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, People's Republic of China.
| | - Luying Xun
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, People's Republic of China.
- School of Molecular Biosciences, Washington State University, Pullman, WA, 99164-7520, USA.
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29
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Bollella P, Hibino Y, Kano K, Gorton L, Antiochia R. The influence of pH and divalent/monovalent cations on the internal electron transfer (IET), enzymatic activity, and structure of fructose dehydrogenase. Anal Bioanal Chem 2018; 410:3253-3264. [PMID: 29564502 PMCID: PMC5937911 DOI: 10.1007/s00216-018-0991-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 01/17/2018] [Accepted: 02/27/2018] [Indexed: 02/07/2023]
Abstract
We report on the influence of pH and monovalent/divalent cations on the catalytic current response, internal electron transfer (IET), and structure of fructose dehydrogenase (FDH) by using amperometry, spectrophotometry, and circular dichroism (CD). Amperometric measurements were performed on graphite electrodes, onto which FDH was adsorbed and the effect on the response current to fructose was investigated when varying the pH and the concentrations of divalent/monovalent cations in the contacting buffer. In the presence of 10 mM CaCl2, a current increase of up to ≈ 240% was observed, probably due to an intra-complexation reaction between Ca2+ and the aspartate/glutamate residues found at the interface between the dehydrogenase domain and the cytochrome domain of FDH. Contrary to CaCl2, addition of MgCl2 did not show any particular influence, whereas addition of monovalent cations (Na+ or K+) led to a slight linear increase in the maximum response current. To complement the amperometric investigations, spectrophotometric assays were carried out under homogeneous conditions in the presence of a 1-electron non-proton-acceptor, cytochrome c, or a 2-electron-proton acceptor, 2,6-dichloroindophenol (DCIP), respectively. In the case of cytochrome c, it was possible to observe a remarkable increase in the absorbance up to 200% when 10 mM CaCl2 was added. However, by further increasing the concentration of CaCl2 up to 50 mM and 100 mM, a decrease in the absorbance with a slight inhibition effect was observed for the highest CaCl2 concentration. Addition of MgCl2 or of the monovalent cations shows, surprisingly, no effect on the electron transfer to the electron acceptor. Contrary to the case of cytochrome c, with DCIP none of the cations tested seem to affect the rate of catalysis. In order to correlate the results obtained by amperometric and spectrophotometric measurements, CD experiments have been performed showing a great structural change of FDH when increasing the concentration CaCl2 up to 50 mM, at which the enzyme molecules start to agglomerate, hindering the substrate access to the active site probably due to a chelation reaction occurring at the enzyme surface with the glutamate/aspartate residues. Fructose dehydrogenase (FDH) consists of three subunits, but only two are involved in the electron transfer process: (I) 2e−/2H+ fructose oxidation, (II) internal electron transfer (IET), (III) direct electron transfer (DET) through 2 heme c; FDH activity either in solution or when immobilized onto an electrode surface is enhanced about 2.5-fold by adding 10 mM CaCl2 to the buffer solution, whereas MgCl2 had an “inhibition” effect. Moreover, the additions of KCl or NaCl led to a slight current increase ![]()
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Affiliation(s)
- Paolo Bollella
- Department of Chemistry and Drug Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.,Department of Analytical Chemistry/Biochemistry, Lund University, P.O. Box 124, 221 00, Lund, Sweden
| | - Yuya Hibino
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Kenji Kano
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Lo Gorton
- Department of Analytical Chemistry/Biochemistry, Lund University, P.O. Box 124, 221 00, Lund, Sweden.
| | - Riccarda Antiochia
- Department of Chemistry and Drug Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
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30
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Wasmund K, Mußmann M, Loy A. The life sulfuric: microbial ecology of sulfur cycling in marine sediments. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:323-344. [PMID: 28419734 PMCID: PMC5573963 DOI: 10.1111/1758-2229.12538] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Almost the entire seafloor is covered with sediments that can be more than 10 000 m thick and represent a vast microbial ecosystem that is a major component of Earth's element and energy cycles. Notably, a significant proportion of microbial life in marine sediments can exploit energy conserved during transformations of sulfur compounds among different redox states. Sulfur cycling, which is primarily driven by sulfate reduction, is tightly interwoven with other important element cycles (carbon, nitrogen, iron, manganese) and therefore has profound implications for both cellular- and ecosystem-level processes. Sulfur-transforming microorganisms have evolved diverse genetic, metabolic, and in some cases, peculiar phenotypic features to fill an array of ecological niches in marine sediments. Here, we review recent and selected findings on the microbial guilds that are involved in the transformation of different sulfur compounds in marine sediments and emphasise how these are interlinked and have a major influence on ecology and biogeochemistry in the seafloor. Extraordinary discoveries have increased our knowledge on microbial sulfur cycling, mainly in sulfate-rich surface sediments, yet many questions remain regarding how sulfur redox processes may sustain the deep-subsurface biosphere and the impact of organic sulfur compounds on the marine sulfur cycle.
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Affiliation(s)
- Kenneth Wasmund
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Research Network “Chemistry meets Microbiology”University of ViennaAlthanstrasse 14ViennaA‐1090Austria
- Austrian Polar Research InstituteViennaAustria
| | - Marc Mußmann
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Research Network “Chemistry meets Microbiology”University of ViennaAlthanstrasse 14ViennaA‐1090Austria
| | - Alexander Loy
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Research Network “Chemistry meets Microbiology”University of ViennaAlthanstrasse 14ViennaA‐1090Austria
- Austrian Polar Research InstituteViennaAustria
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31
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Grabarczyk DB, Berks BC. Intermediates in the Sox sulfur oxidation pathway are bound to a sulfane conjugate of the carrier protein SoxYZ. PLoS One 2017; 12:e0173395. [PMID: 28257465 PMCID: PMC5336275 DOI: 10.1371/journal.pone.0173395] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 02/20/2017] [Indexed: 01/04/2023] Open
Abstract
The Sox pathway found in many sulfur bacteria oxidizes thiosulfate to sulfate. Pathway intermediates are covalently bound to a cysteine residue in the carrier protein SoxYZ. We have used biochemical complementation by SoxYZ-conjugates to probe the identity of the intermediates in the Sox pathway. We find that unconjugated SoxYZ and SoxYZ-S-sulfonate are unlikely to be intermediates during normal turnover in disagreement with current models. By contrast, conjugates with multiple sulfane atoms are readily metabolised by the Sox pathway. The most parsimonious interpretation of these data is that the true carrier species in the Sox pathway is a SoxYZ-S-sulfane adduct.
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Affiliation(s)
| | - Ben C Berks
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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32
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Influence of haem environment on the catalytic properties of the tetrathionate reductase TsdA from Campylobacter jejuni. Biosci Rep 2016; 36:BSR20160457. [PMID: 27789780 PMCID: PMC5146829 DOI: 10.1042/bsr20160457] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 01/21/2023] Open
Abstract
In the present study, we provide a detailed analysis of the catalytic properties of the bifunctional thiosulfate dehydrogenases/tetrathionate reductases (TsdA) of the human food-borne pathogen Campylobacter jejuni. Structural differences in the immediate environment of Haem 2 were shown to influence the reaction directionality. Bifunctional dihaem cytochrome c thiosulfate dehydrogenases/tetrathionate reductases (TsdA) exhibit different catalytic properties depending on the source organism. In the human food-borne intestinal pathogen Campylobacter jejuni, TsdA functions as a tetrathionate reductase enabling respiration with tetrathionate as an alternative electron acceptor. In the present study, evidence is provided that Cys138 and Met255 serve as the sixth ligands of Haem 1 and Haem 2 respectively, in the oxidized CjTsdA wt protein. Replacement of Cys138 resulted in a virtually inactive enzyme, confirming Haem 1 as the active site haem. Significantly, TsdA variants carrying amino acid exchanges in the vicinity of the electron-transferring Haem 2 (Met255, Asn254 and Lys252) exhibited markedly altered catalytic properties of the enzyme, showing these residues play a key role in the physiological function of TsdA. The growth phenotypes and tetrathionate reductase activities of a series of ΔtsdA/*tsdA complementation strains constructed in the original host C. jejuni 81116, showed that in vivo, the TsdA variants exhibited the same catalytic properties as the pure, recombinantly produced enzymes. However, variants that catalysed tetrathionate reduction more effectively than the wild-type enzyme did not allow better growth.
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