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Little AS, Younker IT, Schechter MS, Bernardino PN, Méheust R, Stemczynski J, Scorza K, Mullowney MW, Sharan D, Waligurski E, Smith R, Ramanswamy R, Leiter W, Moran D, McMillin M, Odenwald MA, Iavarone AT, Sidebottom AM, Sundararajan A, Pamer EG, Eren AM, Light SH. Dietary- and host-derived metabolites are used by diverse gut bacteria for anaerobic respiration. Nat Microbiol 2024; 9:55-69. [PMID: 38177297 PMCID: PMC11055453 DOI: 10.1038/s41564-023-01560-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 11/14/2023] [Indexed: 01/06/2024]
Abstract
Respiratory reductases enable microorganisms to use molecules present in anaerobic ecosystems as energy-generating respiratory electron acceptors. Here we identify three taxonomically distinct families of human gut bacteria (Burkholderiaceae, Eggerthellaceae and Erysipelotrichaceae) that encode large arsenals of tens to hundreds of respiratory-like reductases per genome. Screening species from each family (Sutterella wadsworthensis, Eggerthella lenta and Holdemania filiformis), we discover 22 metabolites used as respiratory electron acceptors in a species-specific manner. Identified reactions transform multiple classes of dietary- and host-derived metabolites, including bioactive molecules resveratrol and itaconate. Products of identified respiratory metabolisms highlight poorly characterized compounds, such as the itaconate-derived 2-methylsuccinate. Reductase substrate profiling defines enzyme-substrate pairs and reveals a complex picture of reductase evolution, providing evidence that reductases with specificities for related cinnamate substrates independently emerged at least four times. These studies thus establish an exceptionally versatile form of anaerobic respiration that directly links microbial energy metabolism to the gut metabolome.
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Affiliation(s)
- Alexander S Little
- Duchossois Family Institute, University of Chicago, Chicago, IL, USA
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Isaac T Younker
- Duchossois Family Institute, University of Chicago, Chicago, IL, USA
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Matthew S Schechter
- Duchossois Family Institute, University of Chicago, Chicago, IL, USA
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Paola Nol Bernardino
- Duchossois Family Institute, University of Chicago, Chicago, IL, USA
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Raphaël Méheust
- Génomique Métabolique, CEA, Genoscope, Institut François Jacob, Université d'Évry, Université Paris-Saclay, CNRS, Evry, France
| | - Joshua Stemczynski
- Duchossois Family Institute, University of Chicago, Chicago, IL, USA
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Kaylie Scorza
- Duchossois Family Institute, University of Chicago, Chicago, IL, USA
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | | | - Deepti Sharan
- Duchossois Family Institute, University of Chicago, Chicago, IL, USA
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Emily Waligurski
- Duchossois Family Institute, University of Chicago, Chicago, IL, USA
| | - Rita Smith
- Duchossois Family Institute, University of Chicago, Chicago, IL, USA
| | | | - William Leiter
- Duchossois Family Institute, University of Chicago, Chicago, IL, USA
| | - David Moran
- Duchossois Family Institute, University of Chicago, Chicago, IL, USA
| | - Mary McMillin
- Duchossois Family Institute, University of Chicago, Chicago, IL, USA
| | - Matthew A Odenwald
- Duchossois Family Institute, University of Chicago, Chicago, IL, USA
- Section of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Anthony T Iavarone
- QB3/Chemistry Mass Spectrometry Facility, University of California, Berkeley, Berkeley, CA, USA
| | | | | | - Eric G Pamer
- Duchossois Family Institute, University of Chicago, Chicago, IL, USA
- Department of Microbiology, University of Chicago, Chicago, IL, USA
- Section of Infectious Diseases & Global Health, Department of Medicine, University of Chicago, Chicago, IL, USA
| | - A Murat Eren
- Helmholtz Institute for Functional Marine Biodiversity, Oldenburg, Germany
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenbug, Germany
| | - Samuel H Light
- Duchossois Family Institute, University of Chicago, Chicago, IL, USA.
- Department of Microbiology, University of Chicago, Chicago, IL, USA.
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Benoit SL, Maier RJ. The Campylobacter concisus BisA protein plays a dual role: oxide-dependent anaerobic respiration and periplasmic methionine sulfoxide repair. mBio 2023; 14:e0147523. [PMID: 37607056 PMCID: PMC10653797 DOI: 10.1128/mbio.01475-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 06/26/2023] [Indexed: 08/24/2023] Open
Abstract
IMPORTANCE Campylobacter concisus is an excellent model organism to study respiration diversity, including anaerobic respiration of physiologically relevant N-/S-oxides compounds, such as biotin sulfoxide, dimethyl sulfoxide, methionine sulfoxide (MetO), nicotinamide N-oxide, and trimethylamine N-oxide. All C. concisus strains harbor at least two, often three, and up to five genes encoding for putative periplasmic Mo/W-bisPGD-containing N-/S-oxide reductases. The respective role (substrate specificity) of each enzyme was studied using a mutagenesis approach. One of the N/SOR enzymes, annotated as "BisA", was found to be essential for anaerobic respiration of both N- and S-oxides. Additional phenotypes associated with disruption of the bisA gene included increased sensitivity toward oxidative stress and elongated cell morphology. Furthermore, a biochemical approach confirmed that BisA can repair protein-bound MetO residues. Hence, we propose that BisA plays a role as a periplasmic methionine sulfoxide reductase. This is the first report of a Mo/W-bisPGD-enzyme supporting both N- or S-oxide respiration and protein-bound MetO repair in a pathogen.
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Affiliation(s)
- Stéphane L. Benoit
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
- Center for Metalloenzyme Studies, University of Georgia, Athens, Georgia, USA
| | - Robert J. Maier
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
- Center for Metalloenzyme Studies, University of Georgia, Athens, Georgia, USA
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Wells M, Kim M, Akob DM, Basu P, Stolz JF. Impact of the Dimethyl Sulfoxide Reductase Superfamily on the Evolution of Biogeochemical Cycles. Microbiol Spectr 2023; 11:e0414522. [PMID: 36951557 PMCID: PMC10100899 DOI: 10.1128/spectrum.04145-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 03/01/2023] [Indexed: 03/24/2023] Open
Abstract
The dimethyl sulfoxide reductase (or MopB) family is a diverse assemblage of enzymes found throughout Bacteria and Archaea. Many of these enzymes are believed to have been present in the last universal common ancestor (LUCA) of all cellular lineages. However, gaps in knowledge remain about how MopB enzymes evolved and how this diversification of functions impacted global biogeochemical cycles through geologic time. In this study, we perform maximum likelihood phylogenetic analyses on manually curated comparative genomic and metagenomic data sets containing over 47,000 distinct MopB homologs. We demonstrate that these enzymes constitute a catalytically and mechanistically diverse superfamily defined not by the molybdopterin- or tungstopterin-containing [molybdopterin or tungstopterin bis(pyranopterin guanine dinucleotide) (Mo/W-bisPGD)] cofactor but rather by the structural fold that binds it in the protein. Our results suggest that major metabolic innovations were the result of the loss of the metal cofactor or the gain or loss of protein domains. Phylogenetic analyses also demonstrated that formate oxidation and CO2 reduction were the ancestral functions of the superfamily, traits that have been vertically inherited from the LUCA. Nearly all of the other families, which drive all other biogeochemical cycles mediated by this superfamily, originated in the bacterial domain. Thus, organisms from Bacteria have been the key drivers of catalytic and biogeochemical innovations within the superfamily. The relative ordination of MopB families and their associated catalytic activities emphasize fundamental mechanisms of evolution in this superfamily. Furthermore, it underscores the importance of prokaryotic adaptability in response to the transition from an anoxic to an oxidized atmosphere. IMPORTANCE The MopB superfamily constitutes a repertoire of metalloenzymes that are central to enduring mysteries in microbiology, from the origin of life and how microorganisms and biogeochemical cycles have coevolved over deep time to how anaerobic life adapted to increasing concentrations of O2 during the transition from an anoxic to an oxic world. Our work emphasizes that phylogenetic analyses can reveal how domain gain or loss events, the acquisition of novel partner subunits, and the loss of metal cofactors can stimulate novel radiations of enzymes that dramatically increase the catalytic versatility of superfamilies. We also contend that the superfamily concept in protein evolution can uncover surprising kinships between enzymes that have remarkably different catalytic and physiological functions.
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Affiliation(s)
- Michael Wells
- Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, Colorado, USA
| | - Minjae Kim
- Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, Colorado, USA
| | - Denise M. Akob
- United States Geological Survey, Geology, Energy, and Minerals Science Center, Reston, Virginia, USA
| | - Partha Basu
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis, Indiana, USA
| | - John F. Stolz
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
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Rosenbaum FP, Poehlein A, Daniel R, Müller V. Energy‐conserving dimethyl sulfoxide reduction in the acetogenic bacterium
Moorella thermoacetica. Environ Microbiol 2022; 24:2000-2012. [DOI: 10.1111/1462-2920.15971] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/02/2022] [Accepted: 03/07/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Florian P. Rosenbaum
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences Johann Wolfgang Goethe University Frankfurt Germany
| | - Anja Poehlein
- Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Institute of Microbiology and Genetics Georg‐August University Göttingen Göttingen 37077 Germany
| | - Rolf Daniel
- Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Institute of Microbiology and Genetics Georg‐August University Göttingen Göttingen 37077 Germany
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences Johann Wolfgang Goethe University Frankfurt Germany
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Nitrate-responsive suppression of DMSO respiration in a facultative anaerobic haloarchaeon Haloferax volcanii. J Bacteriol 2021; 203:e0065520. [PMID: 33820797 DOI: 10.1128/jb.00655-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Haloferax volcanii is a facultative anaerobic haloarchaeon that can grow using nitrate or dimethyl sulfoxide (DMSO) as respiratory substrates in an anaerobic condition. Comparative transcriptome analysis of denitrifying and aerobic cells of H. volcanii indicated extensive changes in the gene expression involving activation of denitrification, suppression of DMSO respiration, and conversion of the heme biosynthetic pathway under denitrifying condition. Anaerobic growth of H. volcanii by DMSO respiration was inhibited at nitrate concentrations lower than 1 mM, whereas the nitrate-responsive growth inhibition was not observed in the ΔnarO mutant. A reporter assay experiment demonstrated that transcription of the dms operon was suppressed by nitrate. In contrast, anaerobic growth of the ΔdmsR mutant by denitrification was little affected by addition of DMSO. NarO has been identified as an activator of the denitrification-related genes in response to anaerobic conditions, and here we found that NarO is also involved in nitrate-responsive suppression of the dms operon. Nitrate-responsive suppression of DMSO respiration is known in several bacteria, such as Escherichia coli and photosynthetic Rhodobacter sp. This is the first report to show that a regulatory mechanism that suppresses DMSO respiration in response to nitrate exists not only in bacteria but also in the haloarchaea.IMPORTANCE Haloferax volcanii can grow anaerobically by denitrification (nitrate respiration) or DMSO respiration. In the facultative anaerobic bacteria that can grow by both nitrate respiration and DMSO respiration, nitrate respiration is preferentially induced when both nitrate and DMSO are available as respiratory substrates. The results of transcriptome analysis, growth phenotyping, and reporter assay indicated that DMSO respiration is suppressed in response to nitrate in H. volcanii The haloarchaea-specific regulator NarO, which activates denitrification under anaerobic conditions, is suggested to be involved in the nitrate-responsive suppression of DMSO respiration.
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Yu X, Zhou J, Song W, Xu M, He Q, Peng Y, Tian Y, Wang C, Shu L, Wang S, Yan Q, Liu J, Tu Q, He Z. SCycDB: A curated functional gene database for metagenomic profiling of sulphur cycling pathways. Mol Ecol Resour 2020. [DOI: 10.1111/1755-0998.13306] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Xiaoli Yu
- Environmental Microbiomics Research Center School of Environmental Science and Engineering Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) Sun Yat‐sen University Guangzhou China
| | - Jiayin Zhou
- Institute of Marine Science and Technology Shandong University Qingdao China
| | - Wen Song
- Institute of Marine Science and Technology Shandong University Qingdao China
| | - Mengzhao Xu
- Institute of Marine Science and Technology Shandong University Qingdao China
| | - Qiang He
- Department of Civil and Environmental Engineering The University of Tennessee Knoxville TN USA
| | - Yisheng Peng
- Environmental Microbiomics Research Center School of Environmental Science and Engineering Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) Sun Yat‐sen University Guangzhou China
| | - Yun Tian
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems School of Life Sciences Xiamen University Xiamen China
| | - Cheng Wang
- Environmental Microbiomics Research Center School of Environmental Science and Engineering Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) Sun Yat‐sen University Guangzhou China
| | - Longfei Shu
- Environmental Microbiomics Research Center School of Environmental Science and Engineering Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) Sun Yat‐sen University Guangzhou China
| | - Shanquan Wang
- Environmental Microbiomics Research Center School of Environmental Science and Engineering Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) Sun Yat‐sen University Guangzhou China
| | - Qingyun Yan
- Environmental Microbiomics Research Center School of Environmental Science and Engineering Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) Sun Yat‐sen University Guangzhou China
| | - Jihua Liu
- Institute of Marine Science and Technology Shandong University Qingdao China
| | - Qichao Tu
- Institute of Marine Science and Technology Shandong University Qingdao China
| | - Zhili He
- Environmental Microbiomics Research Center School of Environmental Science and Engineering Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) Sun Yat‐sen University Guangzhou China
- College of Agronomy Hunan Agricultural University Changsha China
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7
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Methane, arsenic, selenium and the origins of the DMSO reductase family. Sci Rep 2020; 10:10946. [PMID: 32616801 PMCID: PMC7331816 DOI: 10.1038/s41598-020-67892-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 06/16/2020] [Indexed: 11/16/2022] Open
Abstract
Mononuclear molybdoenzymes of the dimethyl sulfoxide reductase (DMSOR) family catalyze a number of reactions essential to the carbon, nitrogen, sulfur, arsenic, and selenium biogeochemical cycles. These enzymes are also ancient, with many lineages likely predating the divergence of the last universal common ancestor into the Bacteria and Archaea domains. We have constructed rooted phylogenies for over 1,550 representatives of the DMSOR family using maximum likelihood methods to investigate the evolution of the arsenic biogeochemical cycle. The phylogenetic analysis provides compelling evidence that formylmethanofuran dehydrogenase B subunits, which catalyze the reduction of CO2 to formate during hydrogenotrophic methanogenesis, constitutes the most ancient lineage. Our analysis also provides robust support for selenocysteine as the ancestral ligand for the Mo/W atom. Finally, we demonstrate that anaerobic arsenite oxidase and respiratory arsenate reductase catalytic subunits represent a more ancient lineage of DMSORs compared to aerobic arsenite oxidase catalytic subunits, which evolved from the assimilatory nitrate reductase lineage. This provides substantial support for an active arsenic biogeochemical cycle on the anoxic Archean Earth. Our work emphasizes that the use of chalcophilic elements as substrates as well as the Mo/W ligand in DMSORs has indelibly shaped the diversification of these enzymes through deep time.
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8
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Huang M, Cheng J, Chen P, Zheng G, Wang D, Hu Y. Efficient production of succinic acid in engineered Escherichia coli strains controlled by anaerobically-induced nirB promoter using sweet potato waste hydrolysate. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 237:147-154. [PMID: 30784862 DOI: 10.1016/j.jenvman.2019.02.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 12/30/2018] [Accepted: 02/07/2019] [Indexed: 06/09/2023]
Abstract
Succinic acid has attracted interest worldwide as a precursor of many industrially crucial chemicals. Biosynthesis of succinic acid from biomass is developing as an environmentally friendly strategy now. Conversion of sweet potato waste (SPW) to succinic acid could implement high-value utilization of biomass, cut cost of the fermentation process and reduce the pollution of environment. Engineered Escherichia coli (E. coli) strain HD134 under the control of anaerobically-induced nirB promoter from Salmonella enterica (PSnirB) could produce about 16.30 g/L succinic acid with a yield of 0.83 g/g after 48 h on glucose. With SPW hydrolysate as the substrate, 18.65 g/L succinic acid with a yield of 0.94 g/g after 48 h fermentation achieved. Compared to SD134 under Trc control induced with Isopropyl β-D-Thiogalactoside (IPTG), this concentration and yield represented an 8.56% and 6.82% increase, respectively. The use of anaerobically-induced PSnirB not only could attain higher production of succinic acid than IPTG-induced Trc promoter, but omit cost of expensive exogenous inducers. The efficient production of succinic acid from SPW was firstly studied by anaerobically-induced PSnirB control, which achieved relative lower cost compared to glucose as substrate and IPTG as the inducer. This novel fermentation process conduces to the cosmically industrial succinic acid bioproduction.
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Affiliation(s)
- Meihua Huang
- Department of Chemical Engineering, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, PR China; State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China
| | - Jie Cheng
- Department of Chemical Engineering, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, PR China; State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China
| | - Peng Chen
- Department of Chemical Engineering, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, PR China
| | - Gaowei Zheng
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China
| | - Dan Wang
- Department of Chemical Engineering, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, PR China; State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China.
| | - Yuanliang Hu
- Hubei Key Laboratory of Edible Wild Plants Conservation & Utilization, College of Life Sciences, Hubei Normal University, Huangshi 435002, PR China.
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Iron-associated protein interaction networks reveal the key functional modules related to survival and virulence of Pasteurella multocida. Microb Pathog 2018; 127:257-266. [PMID: 30550841 DOI: 10.1016/j.micpath.2018.12.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 11/15/2018] [Accepted: 12/10/2018] [Indexed: 11/21/2022]
Abstract
Pasteurella multocida causes respiratory infectious diseases in a multitude of birds and mammals. A number of virulence-associated genes were reported across different strains of P. multocida, including those involved in the iron transport and metabolism. Comparative iron-associated genes of P. multocida among different animal hosts towards their interaction networks have not been fully revealed. Therefore, this study aimed to identify the iron-associated genes from core- and pan-genomes of fourteen P. multocida strains and to construct iron-associated protein interaction networks using genome-scale network analysis which might be associated with the virulence. Results showed that these fourteen strains had 1587 genes in the core-genome and 3400 genes constituting their pan-genome. Out of these, 2651 genes associated with iron transport and metabolism were selected to construct the protein interaction networks and 361 genes were incorporated into the iron-associated protein interaction network (iPIN) consisting of nine different iron-associated functional modules. After comparing with the virulence factor database (VFDB), 21 virulence-associated proteins were determined and 11 of these belonged to the heme biosynthesis module. From this study, the core heme biosynthesis module and the core outer membrane hemoglobin receptor HgbA were proposed as candidate targets to design novel antibiotics and vaccines for preventing pasteurellosis across the serotypes or animal hosts for enhanced precision agriculture to ensure sustainability in food security.
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Chan CS, Turner RJ. Biogenesis of Escherichia coli DMSO Reductase: A Network of Participants for Protein Folding and Complex Enzyme Maturation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 883:215-34. [PMID: 26621470 DOI: 10.1007/978-3-319-23603-2_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Protein folding and structure have been of interest since the dawn of protein chemistry. Following translation from the ribosome, a protein must go through various steps to become a functional member of the cellular society. Every protein has a unique function in the cell and is classified on this basis. Proteins that are involved in cellular respiration are the bioenergetic workhorses of the cell. Bacteria are resilient organisms that can survive in diverse environments by fine tuning these workhorses. One class of proteins that allow survival under anoxic conditions are anaerobic respiratory oxidoreductases, which utilize many different compounds other than oxygen as its final electron acceptor. Dimethyl sulfoxide (DMSO) is one such compound. Respiration using DMSO as a final electron acceptor is performed by DMSO reductase, converting it to dimethyl sulfide in the process. Microbial respiration using DMSO is reviewed in detail by McCrindle et al. (Adv Microb Physiol 50:147-198, 2005). In this chapter, we discuss the biogenesis of DMSO reductase as an example of the participant network for complex iron-sulfur molybdoenzyme maturation pathways.
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Affiliation(s)
- Catherine S Chan
- Department of Biological Sciences, University of Calgary, BI156 Biological Sciences Bldg, 2500 University Dr NW, Calgary, AB, T2N 1N4, Canada.
| | - Raymond J Turner
- Department of Biological Sciences, University of Calgary, BI156 Biological Sciences Bldg, 2500 University Dr NW, Calgary, AB, T2N 1N4, Canada.
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Abstract
The transition element molybdenum (Mo) is of primordial importance for biological systems as it is required by enzymes catalyzing key reactions in global carbon, sulfur, and nitrogen metabolism. In order to gain biological activity, Mo has to be complexed by a special cofactor. With the exception of bacterial nitrogenase, all Mo-dependent enzymes contain a unique pyranopterin-based cofactor coordinating a Mo atom at their catalytic site. Various types of reactions are catalyzed by Mo enzymes in prokaryotes, including oxygen atom transfer, sulfur or proton transfer, hydroxylation, or even nonredox ones. Mo enzymes are widespread in prokaryotes, and many of them were likely present in LUCA. To date, more than 50-mostly bacterial-Mo enzymes are described in nature. In a few eubacteria and in many archaea, Mo is replaced by tungsten bound to the same unique pyranopterin. How Moco is synthesized in bacteria is reviewed as well as the way until its insertion into apo-Mo-enzymes.
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12
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Yee N, Choi J, Porter AW, Carey S, Rauschenbach I, Harel A. Selenate reductase activity inEscherichia colirequires Isc iron-sulfur cluster biosynthesis genes. FEMS Microbiol Lett 2014; 361:138-43. [DOI: 10.1111/1574-6968.12623] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 09/29/2014] [Accepted: 10/07/2014] [Indexed: 11/29/2022] Open
Affiliation(s)
- Nathan Yee
- School of Environmental and Biological Sciences; Rutgers, The State University of New Jersey; New Brunswick NJ USA
| | - Jessica Choi
- School of Environmental and Biological Sciences; Rutgers, The State University of New Jersey; New Brunswick NJ USA
| | - Abigail W. Porter
- School of Environmental and Biological Sciences; Rutgers, The State University of New Jersey; New Brunswick NJ USA
| | - Sean Carey
- School of Environmental and Biological Sciences; Rutgers, The State University of New Jersey; New Brunswick NJ USA
| | - Ines Rauschenbach
- School of Environmental and Biological Sciences; Rutgers, The State University of New Jersey; New Brunswick NJ USA
| | - Arye Harel
- School of Environmental and Biological Sciences; Rutgers, The State University of New Jersey; New Brunswick NJ USA
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13
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Orfanoudaki G, Economou A. Proteome-wide subcellular topologies of E. coli polypeptides database (STEPdb). Mol Cell Proteomics 2014; 13:3674-87. [PMID: 25210196 DOI: 10.1074/mcp.o114.041137] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Cell compartmentalization serves both the isolation and the specialization of cell functions. After synthesis in the cytoplasm, over a third of all proteins are targeted to other subcellular compartments. Knowing how proteins are distributed within the cell and how they interact is a prerequisite for understanding it as a whole. Surface and secreted proteins are important pathogenicity determinants. Here we present the STEP database (STEPdb) that contains a comprehensive characterization of subcellular localization and topology of the complete proteome of Escherichia coli. Two widely used E. coli proteomes (K-12 and BL21) are presented organized into thirteen subcellular classes. STEPdb exploits the wealth of genetic, proteomic, biochemical, and functional information on protein localization, secretion, and targeting in E. coli, one of the best understood model organisms. Subcellular annotations were derived from a combination of bioinformatics prediction, proteomic, biochemical, functional, topological data and extensive literature re-examination that were refined through manual curation. Strong experimental support for the location of 1553 out of 4303 proteins was based on 426 articles and some experimental indications for another 526. Annotations were provided for another 320 proteins based on firm bioinformatic predictions. STEPdb is the first database that contains an extensive set of peripheral IM proteins (PIM proteins) and includes their graphical visualization into complexes, cellular functions, and interactions. It also summarizes all currently known protein export machineries of E. coli K-12 and pairs them, where available, with the secretory proteins that use them. It catalogs the Sec- and TAT-utilizing secretomes and summarizes their topological features such as signal peptides and transmembrane regions, transmembrane topologies and orientations. It also catalogs physicochemical and structural features that influence topology such as abundance, solubility, disorder, heat resistance, and structural domain families. Finally, STEPdb incorporates prediction tools for topology (TMHMM, SignalP, and Phobius) and disorder (IUPred) and implements the BLAST2STEP that performs protein homology searches against the STEPdb.
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Affiliation(s)
- Georgia Orfanoudaki
- From the ‡Institute of Molecular Biology and Biotechnology-FoRTH and §Department of Biology-University of Crete, P.O. Box 1385, Iraklio, Crete, Greece
| | - Anastassios Economou
- From the ‡Institute of Molecular Biology and Biotechnology-FoRTH and §Department of Biology-University of Crete, P.O. Box 1385, Iraklio, Crete, Greece; ¶Laboratory of Molecular Bacteriology; Rega Institute, Department of Microbiology and Immunology, KU Leuven, Herrestraat 49, B-3000 Leuven, Belgium
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14
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Mind the gap: diversity and reactivity relationships among multihaem cytochromes of the MtrA/DmsE family. Biochem Soc Trans 2013; 40:1268-73. [PMID: 23176466 DOI: 10.1042/bst20120106] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Shewanella oneidensis MR-1 has the ability to use many external terminal electron acceptors during anaerobic respiration, such as DMSO. The pathway that facilitates this electron transfer includes the decahaem cytochrome DmsE, a paralogue of the MtrA family of decahaem cytochromes. Although both DmsE and MtrA are decahaem cytochromes implicated in the long-range electron transfer across a ~300 Å (1 Å=0.1 nm) wide periplasmic 'gap', MtrA has been shown to be only 105 Å in maximal length. In the present paper, DmsE is further characterized via protein film voltammetry, revealing that the electrochemistry of the DmsE haem cofactors display macroscopic potentials lower than those of MtrA by 100 mV. It is possible this tuning of the redox potential of DmsE is required to shuttle electrons to the outer-membrane proteins specific to DMSO reduction. Other decahaem cytochromes found in S. oneidensis, such as the outer-membrane proteins MtrC, MtrF and OmcA, have been shown to have electrochemical properties similar to those of MtrA, yet possess a different evolutionary relationship.
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Kappler U, Nouwens AS. The molybdoproteome of Starkeya novella – insights into the diversity and functions of molybdenum containing proteins in response to changing growth conditions. Metallomics 2013; 5:325-34. [DOI: 10.1039/c2mt20230a] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Coursolle D, Gralnick JA. Reconstruction of Extracellular Respiratory Pathways for Iron(III) Reduction in Shewanella Oneidensis Strain MR-1. Front Microbiol 2012; 3:56. [PMID: 22363330 PMCID: PMC3282943 DOI: 10.3389/fmicb.2012.00056] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 02/02/2012] [Indexed: 11/13/2022] Open
Abstract
Shewanella oneidensis strain MR-1 is a facultative anaerobic bacterium capable of respiring a multitude of electron acceptors, many of which require the Mtr respiratory pathway. The core Mtr respiratory pathway includes a periplasmic c-type cytochrome (MtrA), an integral outer-membrane β-barrel protein (MtrB), and an outer-membrane-anchored c-type cytochrome (MtrC). Together, these components facilitate transfer of electrons from the c-type cytochrome CymA in the cytoplasmic membrane to electron acceptors at and beyond the outer-membrane. The genes encoding these core proteins have paralogs in the S. oneidensis genome (mtrB and mtrA each have four while mtrC has three) and some of the paralogs of mtrC and mtrA are able to form functional Mtr complexes. We demonstrate that of the additional three mtrB paralogs found in the S. oneidensis genome, only MtrE can replace MtrB to form a functional respiratory pathway to soluble iron(III) citrate. We also evaluate which mtrC/mtrA paralog pairs (a total of 12 combinations) are able to form functional complexes with endogenous levels of mtrB paralog expression. Finally, we reconstruct all possible functional Mtr complexes and test them in a S. oneidensis mutant strain where all paralogs have been eliminated from the genome. We find that each combination tested with the exception of MtrA/MtrE/OmcA is able to reduce iron(III) citrate at a level significantly above background. The results presented here have implications toward the evolution of anaerobic extracellular respiration in Shewanella and for future studies looking to increase the rates of substrate reduction for water treatment, bioremediation, or electricity production.
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Affiliation(s)
- Dan Coursolle
- Department of Microbiology, BioTechnology Institute, University of Minnesota Twin Cities St. Paul, MN, USA
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Hou B, Brüser T. The Tat-dependent protein translocation pathway. Biomol Concepts 2011; 2:507-23. [DOI: 10.1515/bmc.2011.040] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 08/05/2011] [Indexed: 11/15/2022] Open
Abstract
AbstractThe twin-arginine translocation (Tat) pathway is found in bacteria, archaea, and plant chloroplasts, where it is dedicated to the transmembrane transport of fully folded proteins. These proteins contain N-terminal signal peptides with a specific Tat-system binding motif that is recognized by the transport machinery. In contrast to other protein transport systems, the Tat system consists of multiple copies of only two or three usually small (∼8–30 kDa) membrane proteins that oligomerize to two large complexes that transiently interact during translocation. Only one of these complexes includes a polytopic membrane protein, TatC. The other complex consists of TatA. Tat systems of plants, proteobacteria, and several other phyla contain a third component, TatB. TatB is evolutionarily and structurally related to TatA and usually forms tight complexes with TatC. Minimal two-component Tat systems lacking TatB are found in many bacterial and archaeal phyla. They consist of a ‘bifunctional’ TatA that also covers TatB functionalities, and a TatC. Recent insights into the structure and interactions of the Tat proteins have various important implications.
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Affiliation(s)
- Bo Hou
- Institute of Microbiology, Leibniz University Hannover, Schneiderberg 50, D-30167 Hannover, Germany
| | - Thomas Brüser
- Institute of Microbiology, Leibniz University Hannover, Schneiderberg 50, D-30167 Hannover, Germany
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Italiano F, D’Amici GM, Rinalducci S, De Leo F, Zolla L, Gallerani R, Trotta M, Ceci LR. The photosynthetic membrane proteome of Rhodobacter sphaeroides R-26.1 exposed to cobalt. Res Microbiol 2011; 162:520-7. [DOI: 10.1016/j.resmic.2011.04.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 03/31/2011] [Indexed: 10/18/2022]
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Molecular cloning and characterization of the srdBCA operon, encoding the respiratory selenate reductase complex, from the selenate-reducing bacterium Bacillus selenatarsenatis SF-1. J Bacteriol 2011; 193:2141-8. [PMID: 21357486 DOI: 10.1128/jb.01197-10] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previously, we isolated a selenate- and arsenate-reducing bacterium, designated strain SF-1, from selenium-contaminated sediment and identified it as a novel species, Bacillus selenatarsenatis. B. selenatarsenatis strain SF-1 independently reduces selenate to selenite, arsenate to arsenite, and nitrate to nitrite by anaerobic respiration. To identify the genes involved in selenate reduction, 17 selenate reduction-defective mutant strains were isolated from a mutant library generated by random insertion of transposon Tn916. Tn916 was inserted into the same genome position in eight mutants, and the representative strain SF-1AM4 did not reduce selenate but did reduce nitrate and arsenate to the same extent as the wild-type strain. The disrupted gene was located in an operon composed of three genes designated srdBCA, which were predicted to encode a putative oxidoreductase complex by the BLASTX program. The plasmid vector pGEMsrdBCA, containing the srdBCA operon with its own promoter, conferred the phenotype of selenate reduction in Escherichia coli DH5α, although E. coli strains containing plasmids lacking any one or two of the open reading frames from srdBCA did not exhibit the selenate-reducing phenotype. Domain structure analysis of the deduced amino acid sequence revealed that SrdBCA had typical features of membrane-bound and molybdopterin-containing oxidoreductases. It was therefore proposed that the srdBCA operon encoded a respiratory selenate reductase complex. This is the first report of genes encoding selenate reductase in gram-positive bacteria.
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Palmer T, Berks BC, Sargent F. Analysis of Tat targeting function and twin-arginine signal peptide activity in Escherichia coli. Methods Mol Biol 2010; 619:191-216. [PMID: 20419412 DOI: 10.1007/978-1-60327-412-8_12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The Tat system is a protein export system dedicated to the transport of folded proteins across the prokaryotic cytoplasmic membrane and the thylakoid membrane of plant chloroplasts. Proteins are targeted for export by the Tat system via N-terminal signal peptides harbouring an S-R-R-x-F-L-K 'twin-arginine' motif. In this chapter qualitative and quantitative assays for native Tat substrates in the model organism Escherichia coli are described. Genetic screening methods designed to allow the rapid positive selection of Tat signal peptide activity and the first positive selection for mutations that inactivate the Tat pathway are also presented. Finally isothermal titration calorimetry (ITC) methods for measuring the affinity of twin-arginine signal peptide-chaperone interactions are discussed.
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Affiliation(s)
- Tracy Palmer
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, Scotland
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Price CE, Driessen AJM. Biogenesis of membrane bound respiratory complexes in Escherichia coli. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:748-66. [PMID: 20138092 DOI: 10.1016/j.bbamcr.2010.01.019] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 01/21/2010] [Accepted: 01/27/2010] [Indexed: 11/19/2022]
Abstract
Escherichia coli is one of the preferred bacteria for studies on the energetics and regulation of respiration. Respiratory chains consist of primary dehydrogenases and terminal reductases or oxidases linked by quinones. In order to assemble this complex arrangement of protein complexes, synthesis of the subunits occurs in the cytoplasm followed by assembly in the cytoplasm and/or membrane, the incorporation of metal or organic cofactors and the anchoring of the complex to the membrane. In the case of exported metalloproteins, synthesis, assembly and incorporation of metal cofactors must be completed before translocation across the cytoplasmic membrane. Coordination data on these processes is, however, scarce. In this review, we discuss the various processes that respiratory proteins must undergo for correct assembly and functional coupling to the electron transport chain in E. coli. Targeting to and translocation across the membrane together with cofactor synthesis and insertion are discussed in a general manner followed by a review of the coordinated biogenesis of individual respiratory enzyme complexes. Lastly, we address the supramolecular organization of respiratory enzymes into supercomplexes and their localization to specialized domains in the membrane.
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Affiliation(s)
- Claire E Price
- Department of Molecular Microbiology, University of Groningen, 9751 NN Haren, The Netherlands
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Schäfer H, Myronova N, Boden R. Microbial degradation of dimethylsulphide and related C1-sulphur compounds: organisms and pathways controlling fluxes of sulphur in the biosphere. JOURNAL OF EXPERIMENTAL BOTANY 2009; 61:315-334. [PMID: 20007683 DOI: 10.1093/jxb/erp355] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Dimethylsulphide (DMS) plays a major role in the global sulphur cycle. It has important implications for atmospheric chemistry, climate regulation, and sulphur transport from the marine to the atmospheric and terrestrial environments. In addition, DMS acts as an info-chemical for a wide range of organisms ranging from micro-organisms to mammals. Micro-organisms that cycle DMS are widely distributed in a range of environments, for instance, oxic and anoxic marine, freshwater and terrestrial habitats. Despite the importance of DMS that has been unearthed by many studies since the early 1970s, the understanding of the biochemistry, genetics, and ecology of DMS-degrading micro-organisms is still limited. This review examines current knowledge on the microbial cycling of DMS and points out areas for future research that should shed more light on the role of organisms degrading DMS and related compounds in the biosphere.
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Weiner JH, Li L. Proteome of the Escherichia coli envelope and technological challenges in membrane proteome analysis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:1698-713. [PMID: 17904518 DOI: 10.1016/j.bbamem.2007.07.020] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 07/19/2007] [Accepted: 07/23/2007] [Indexed: 11/28/2022]
Abstract
The envelope of Escherichia coli is a complex organelle composed of the outer membrane, periplasm-peptidoglycan layer and cytoplasmic membrane. Each compartment has a unique complement of proteins, the proteome. Determining the proteome of the envelope is essential for developing an in silico bacterial model, for determining cellular responses to environmental alterations, for determining the function of proteins encoded by genes of unknown function and for development and testing of new experimental technologies such as mass spectrometric methods for identifying and quantifying hydrophobic proteins. The availability of complete genomic information has led several groups to develop computer algorithms to predict the proteome of each part of the envelope by searching the genome for leader sequences, beta-sheet motifs and stretches of alpha-helical hydrophobic amino acids. In addition, published experimental data has been mined directly and by machine learning approaches. In this review we examine the somewhat confusing available literature and relate published experimental data to the most recent gene annotation of E. coli to describe the predicted and experimental proteome of each compartment. The problem of characterizing integral versus membrane-associated proteins is discussed. The E. coli envelope proteome provides an excellent test bed for developing mass spectrometric techniques for identifying hydrophobic proteins that have generally been refractory to analysis. We describe the gel based and solution based proteome analysis approaches along with protein cleavage and proteolysis methods that investigators are taking to tackle this difficult problem.
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Affiliation(s)
- Joel H Weiner
- Membrane Protein Research Group and The Institute for Biomolecular Design, University of Alberta, Canada.
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Jiang S, Sun X, Zhang S. The ycaC-related protein from the amphioxus Branchiostoma belcheri (BbycaCR) interacts with creatine kinase. FEBS J 2008; 275:4597-605. [DOI: 10.1111/j.1742-4658.2008.06602.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Duval S, Ducluzeau AL, Nitschke W, Schoepp-Cothenet B. Enzyme phylogenies as markers for the oxidation state of the environment: the case of respiratory arsenate reductase and related enzymes. BMC Evol Biol 2008; 8:206. [PMID: 18631373 PMCID: PMC2500031 DOI: 10.1186/1471-2148-8-206] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Accepted: 07/16/2008] [Indexed: 12/01/2022] Open
Abstract
Background Phylogenies of certain bioenergetic enzymes have proved to be useful tools for deducing evolutionary ancestry of bioenergetic pathways and their relationship to geochemical parameters of the environment. Our previous phylogenetic analysis of arsenite oxidase, the molybdopterin enzyme responsible for the biological oxidation of arsenite to arsenate, indicated its probable emergence prior to the Archaea/Bacteria split more than 3 billion years ago, in line with the geochemical fact that arsenite was present in biological habitats on the early Earth. Respiratory arsenate reductase (Arr), another molybdopterin enzyme involved in microbial arsenic metabolism, serves as terminal oxidase, and is thus situated at the opposite end of bioenergetic electron transfer chains as compared to arsenite oxidase. The evolutionary history of the Arr-enzyme has not been studied in detail so far. Results We performed a genomic search of genes related to arrA coding for the molybdopterin subunit. The multiple alignment of the retrieved sequences served to reconstruct a neighbor-joining phylogeny of Arr and closely related enzymes. Our analysis confirmed the previously proposed proximity of Arr to the cluster of polysulfide/thiosulfate reductases but also unravels a hitherto unrecognized clade even more closely related to Arr. The obtained phylogeny strongly suggests that Arr originated after the Bacteria/Archaea divergence in the domain Bacteria, and was subsequently laterally distributed within this domain. It further more indicates that, as a result of accumulation of arsenate in the environment, an enzyme related to polysulfide reductase and not to arsenite oxidase has evolved into Arr. Conclusion These findings are paleogeochemically rationalized by the fact that the accumulation of arsenate over arsenite required the increase in oxidation state of the environment brought about by oxygenic photosynthesis.
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Affiliation(s)
- Simon Duval
- Laboratoire de Bioénergétique et Ingénierie des Protéines UPR 9036, Institut de Biologie Structurale et Microbiologie, CNRS, F-13402 Marseille Cedex 20, France.
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Qiu Y, Zhang R, Binkowski TA, Tereshko V, Joachimiak A, Kossiakoff A. The 1.38 A crystal structure of DmsD protein from Salmonella typhimurium, a proofreading chaperone on the Tat pathway. Proteins 2008; 71:525-33. [PMID: 18175314 DOI: 10.1002/prot.21828] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The DmsD protein is necessary for the biogenesis of dimethyl sulphoxide (DMSO) reductase in many prokaryotes. It performs a critical chaperone function initiated through its binding to the twin-arginine signal peptide of DmsA, the catalytic subunit of DMSO reductase. Upon binding to DmsD, DmsA is translocated to the periplasm via the so-called twin-arginine translocation (Tat) pathway. Here we report the 1.38 A crystal structure of the protein DmsD from Salmonella typhimurium and compare it with a close functional homolog, TorD. DmsD has an all-alpha fold structure with a notable helical extension located at its N-terminus with two solvent exposed hydrophobic residues. A major difference between DmsD and TorD is that TorD structure is a domain-swapped dimer, while DmsD exists as a monomer. Nevertheless, these two proteins have a number of common features suggesting they function by using similar mechanisms. A possible signal peptide-binding site is proposed based on structural similarities. Computational analysis was used to identify a potential GTP binding pocket on similar surfaces of DmsD and TorD structures.
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Affiliation(s)
- Yang Qiu
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637, USA
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The twin-arginine transport system: moving folded proteins across membranes. Biochem Soc Trans 2008; 35:835-47. [PMID: 17956229 DOI: 10.1042/bst0350835] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The Tat (twin-arginine transport) pathway is a protein-targeting system dedicated to the transmembrane translocation of fully folded proteins. This system is highly prevalent in the cytoplasmic membranes of bacteria and archaea, and is also found in the thylakoid membranes of plant chloroplasts and possibly also in the inner membrane of plant mitochondria. Proteins are targeted to a membrane-embedded Tat translocase by specialized N-terminal twin-arginine signal peptides bearing an SRRXFLK amino acid motif. The genes encoding components of the Tat translocase were discovered approx. 10 years ago, and, since then, research in this area has expanded on a global scale. In this review, the key discoveries in this field are summarized, and recent studies of bacterial twin-arginine signal-peptide-binding proteins are discussed.
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Sargent F. Constructing the wonders of the bacterial world: biosynthesis of complex enzymes. Microbiology (Reading) 2007; 153:633-651. [PMID: 17322183 DOI: 10.1099/mic.0.2006/004762-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The prokaryotic cytoplasmic membrane not only maintains cell integrity and forms a barrier between the cell and its outside environment, but is also the location for essential biochemical processes. Microbial model systems provide excellent bases for the study of fundamental problems in membrane biology including signal transduction, chemotaxis, solute transport and, as will be the topic of this review, energy metabolism. Bacterial respiration requires a diverse array of complex, multi-subunit, cofactor-containing redox enzymes, many of which are embedded within, or located on the extracellular side of, the membrane. The biosynthesis of these enzymes therefore requires carefully controlled expression, assembly, targeting and transport processes. Here, focusing on the molybdenum-containing respiratory enzymes central to anaerobic respiration in Escherichia coli, recent descriptions of a chaperone-mediated 'proofreading' system involved in coordinating assembly and export of complex extracellular enzymes will be discussed. The paradigm proofreading chaperones are members of a large group of proteins known as the TorD family, and recent research in this area highlights common principles that underpin biosynthesis of both exported and non-exported respiratory enzymes.
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Affiliation(s)
- Frank Sargent
- Centre for Metalloprotein Spectroscopy and Biology, School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
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Nonaka H, Keresztes G, Shinoda Y, Ikenaga Y, Abe M, Naito K, Inatomi K, Furukawa K, Inui M, Yukawa H. Complete genome sequence of the dehalorespiring bacterium Desulfitobacterium hafniense Y51 and comparison with Dehalococcoides ethenogenes 195. J Bacteriol 2006; 188:2262-74. [PMID: 16513756 PMCID: PMC1428132 DOI: 10.1128/jb.188.6.2262-2274.2006] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Desulfitobacterium strains have the ability to dechlorinate halogenated compounds under anaerobic conditions by dehalorespiration. The complete genome of the tetrachloroethene (PCE)-dechlorinating strain Desulfitobacterium hafniense Y51 is a 5,727,534-bp circular chromosome harboring 5,060 predicted protein coding sequences. This genome contains only two reductive dehalogenase genes, a lower number than reported in most other dehalorespiring strains. More than 50 members of the dimethyl sulfoxide reductase superfamily and 30 paralogs of the flavoprotein subunit of the fumarate reductase are encoded as well. A remarkable feature of the genome is the large number of O-demethylase paralogs, which allow utilization of lignin-derived phenyl methyl ethers as electron donors. The large genome reveals a more versatile microorganism that can utilize a larger set of specialized electron donors and acceptors than previously thought. This is in sharp contrast to the PCE-dechlorinating strain Dehalococcoides ethenogenes 195, which has a relatively small genome with a narrow metabolic repertoire. A genomic comparison of these two very different strains allowed us to narrow down the potential candidates implicated in the dechlorination process. Our results provide further impetus to the use of desulfitobacteria as tools for bioremediation.
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Affiliation(s)
- Hiroshi Nonaka
- Microbiology Research Group, Research Institute of Innovative Technology for the Earth, 9-2, Kizugawadai, Kizu-Cho, Soraku-Gun, Kyoto 619-0292, Japan
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Poly F, Threadgill D, Stintzi A. Genomic diversity in Campylobacter jejuni: identification of C. jejuni 81-176-specific genes. J Clin Microbiol 2005; 43:2330-8. [PMID: 15872262 PMCID: PMC1153751 DOI: 10.1128/jcm.43.5.2330-2338.2005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Since the publication of the complete genomic sequence of Campylobacter jejuni NCTC 11168 in February 2000, evidence has been compiling that suggests C. jejuni strains exhibit high genomic diversity. In order to investigate this diversity, the unique genomic DNA sequences from a nonsequenced Campylobacter strain, C. jejuni 81-176, were identified by comparison with C. jejuni NCTC 11168 by using a shotgun DNA microarray approach. Up to 63 kb of new chromosomal DNA sequences unique to this pathogen were obtained. Eighty-six open reading frames were identified by the presence of uninterrupted coding regions encoding a minimum of 40 amino acids. In addition, this study shows that the whole-plasmid shotgun microarray approach is effective and provides a comprehensive coverage of DNA regions that differ between two closely related genomes. The two plasmids harbored by this Campylobacter strain, pTet and pVir, were also sequenced, with coverages of 2.5- and 2.9-fold, respectively, representing 72 and 92% of their complete nucleotide sequences. The unique chromosomal genes encode proteins involved in capsule and lipooligosaccharide biosynthesis, restriction and modification systems, and respiratory metabolism. Several of these unique genes are likely associated with C. jejuni 81-176 fitness and virulence. Interestingly, the comparison of C. jejuni 81-176 unique genes with those of C. jejuni ATCC 43431 revealed a single gene which encodes a probable TraG-like protein. The product of this gene might be associated with the mechanism of C. jejuni invasion into epithelial cells. In conclusion, this study extends the repertoire of C. jejuni genes and thus will permit the construction of a composite and more comprehensive microarray of C. jejuni.
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Affiliation(s)
- Frédéric Poly
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078, USA
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Kang Y, Weber KD, Qiu Y, Kiley PJ, Blattner FR. Genome-wide expression analysis indicates that FNR of Escherichia coli K-12 regulates a large number of genes of unknown function. J Bacteriol 2005; 187:1135-60. [PMID: 15659690 PMCID: PMC545700 DOI: 10.1128/jb.187.3.1135-1160.2005] [Citation(s) in RCA: 215] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The major regulator controlling the physiological switch between aerobic and anaerobic growth conditions in Escherichia coli is the DNA binding protein FNR. To identify genes controlled by FNR, we used Affymetrix Antisense GeneChips to compare global gene expression profiles from isogenic MG1655 wild-type and Deltafnr strains grown in glucose minimal media under aerobic or anaerobic conditions. We found that 297 genes contained within 184 operons were regulated by FNR and/or by O2 levels. The expression of many genes known to be involved in anaerobic respiration and fermentation was increased under anaerobic growth conditions, while that of genes involved in aerobic respiration and the tricarboxylic acid cycle were repressed as expected. The expression of nine operons associated with acid resistance was also increased under anaerobic growth conditions, which may reflect the production of acidic fermentation products. Ninety-one genes with no presently defined function were also altered in expression, including seven of the most highly anaerobically induced genes, six of which we found to be directly regulated by FNR. Classification of the 297 genes into eight groups by k-means clustering analysis indicated that genes with common gene expression patterns also had a strong functional relationship, providing clues for studying the function of unknown genes in each group. Six of the eight groups showed regulation by FNR; while some expression groups represent genes that are simply activated or repressed by FNR, others, such as those encoding functions for chemotaxis and motility, showed a more complex pattern of regulation. A computer search for FNR DNA binding sites within predicted promoter regions identified 63 new sites for 54 genes. We suggest that E. coli MG1655 has a larger metabolic potential under anaerobic conditions than has been previously recognized.
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Affiliation(s)
- Yisheng Kang
- Department of Genetics, 425 Henry Mall, University of Wisconsin, Madison, WI 53706, USA
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McCrindle SL, Kappler U, McEwan AG. Microbial Dimethylsulfoxide and Trimethylamine-N-Oxide Respiration. Adv Microb Physiol 2005; 50:147-98. [PMID: 16221580 DOI: 10.1016/s0065-2911(05)50004-3] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Over the last two decades, the biochemistry and genetics of dimethylsulfoxide (DMSO) and trimethylamine-N-oxide (TMAO) respiration has been characterised, particularly in Escherichia coli marine bacteria of the genus Shewanella and the purple phototrophic bacteria, Rhodobacter sphaeroides and R. capsulatus. All of the enzymes (or catalytic subunits) involved the final step in DMSO and TMAO respiration contain a pterin molybdenum cofactor and are members of the DMSO reductase family of molybdoenzymes. In E. coli, the dimethylsulfoxide reductase (DmsABC) can be purified from membranes as a complex, which exhibits quinol-DMSO oxidoreductase activity. The enzyme is anchored to the membrane via the DmsC subunit and its catalytic subunit DmsA is now considered to face the periplasm. Electron transfer to DmsA involves the DmsB subunit, which is a polyferredoxin related to subunits found in other molybdoenzymes such as nitrate reductase and formate dehydrogenase. A characteristic of the DmsAB-type DMSO reductase is its ability to reduce a variety of S- and N-oxides. E. coli contains a trimethylamine-N-oxide reductase (TorA) that is highly specific for N-oxides. This enzyme is located in the periplasm and is connected to the quinone pool via a membrane-bound penta-haem cytochrome (TorC). DorCA in purple phototrophic bacteria of the genus Rhodobacter is very similar to TorCA with the critical difference that DorA catalyses reduction of both DMSO and TMAO. It is known as a DMSO reductase because the S-oxide is the best substrate. Crystal structures of DorA and TorA have revealed critical differences at the Mo active site that may explain the differences between substrate specificity between the two enzymes. DmsA, TorA and DorA possess a "twin arginine" N-terminal signal sequence consistent with their secretion via the TAT secretory system and not the Sec system. The enzymes are secreted with their bound prosthetic groups: this take place in the cytoplasm and the biogenesis involves a chaperone protein, which is cognate for each enzyme. Expression of the DMSO and TMAO respiratory operons is induced in response to a fall in oxygen tension. dmsABC expression is positively controlled by the oxygen-responsive transcription factor, Fnr and ModE, a transcription factor that binds molybdate. In contrast, torCAD expression is not under Fnr- or ModE-control but is dependent upon a sensor histidine kinase-response regulator pair, TorSR, which activate gene expression under conditions of low oxygen tension in the presence of N- or S-oxide. Regulation of dorCDA expression is similar to that seen for torCAD but it appears that the expression of the sensor histidine kinase-response regulator pair, DorSR is regulated by Fnr and there is an additional tier of regulation involving the ModE-homologue MopB, molybdate and the transcription factor DorX. Analysis of microbial genomes has revealed the presence of dms and tor operons in a wide variety of bacteria and in some archaea and duplicate dms and tor operons have been identified in E. coli. Challenges ahead will include the determination of the significance of the presence of the dms operon in bacterial pathogens and the determination of the significance of DMSO respiration in the global turnover of marine organo-sulfur compounds.
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Affiliation(s)
- Sharon L McCrindle
- School of Molecular and Microbial Sciences, The University of Queensland, Brisbane 4072, Australia
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Bertsova YV, Bogachev AV. The origin of the sodium-dependent NADH oxidation by the respiratory chain ofKlebsiella pneumoniae. FEBS Lett 2004; 563:207-12. [PMID: 15063750 DOI: 10.1016/s0014-5793(04)00312-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2004] [Revised: 02/25/2004] [Accepted: 03/02/2004] [Indexed: 11/21/2022]
Abstract
Properties of Klebsiella pneumoniae respiratory chain enzymes catalyzing NADH oxidation have been studied. Using constructed K. pneumoniae mutant strains, it was shown that three enzymes belonging to different families of NADH:quinone oxidoreductases operate in this bacterium. The NDH-2-type enzyme is not coupled with energy conservation, the NDH-1-type enzyme is a primary proton pump, and the NQR-type enzyme is homologous to the sodium-motive NADH dehydrogenase of Vibrio and is shown to be a primary Na(+) pump. It is concluded that the NQR-type enzyme, not the NDH-1-type enzyme, catalyzes sodium-dependent NADH oxidation in K. pneumoniae.
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Affiliation(s)
- Yulia V Bertsova
- Department of Molecular Energetics of Microorganisms, A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
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Turner RJ, Papish AL, Sargent F. Sequence analysis of bacterial redox enzyme maturation proteins (REMPs). Can J Microbiol 2004; 50:225-38. [PMID: 15213747 DOI: 10.1139/w03-117] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The twin-arginine protein transport (Tat) system is a remarkable molecular machine dedicated to the translocation of fully folded proteins across energy-transducing membranes. Complex cofactor-containing Tat substrates acquire their cofactors prior to export, and substrate proteins actually require to be folded before transport can proceed. Thus, it is very likely that mechanisms exist to prevent wasteful export of immature Tat substrates or to curb competition between immature and mature substrates for the transporter. Here we assess the primary sequence relationships between the accessory proteins implicated in this process during assembly of key respiratory enzymes in the model prokaryote Escherichia coli. For each respiratory enzyme studied, a redox enzyme maturation protein (REMP) was assigned. The main finding from this review was the hitherto unexpected link between the Tat-linked REMP DmsD and the nitrate reductase biosynthetic protein NarJ. The evolutionary link between Tat transport and cofactor insertion processes is discussed.Key words: Tat translocase, twin-arginine leader, hydrogenase, nitrate reductase, TMAO reductase, DMSO reductase, formate dehydrogenase, Tor, Dms, Hya, Hyb, Fdh, Nap.
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Affiliation(s)
- Raymond J Turner
- Department of Biological Sciences, University of Calgary, Alberta, Canada.
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Geijer P, Weiner JH. Glutamate 87 is important for menaquinol binding in DmsC of the DMSO reductase (DmsABC) from Escherichia coli. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2004; 1660:66-74. [PMID: 14757221 DOI: 10.1016/j.bbamem.2003.10.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Escherichia coli dimethylsulfoxide (DMSO) reductase is a trimeric enzyme with a catalytic dimer (DmsAB) and an integral membrane anchor (DmsC). Using site-directed mutagenesis, we examined six residues in the periplasmic loop between helices two and three, potentially involved in menaquinol binding in DmsC. Mutants were characterised for growth, enzyme expression and activity, and 2-n-heptyl-4-hydroxoquinoline N-oxide (HOQNO) inhibitor binding. Mutations of leucine 66, glycine 67, arginine 71, phenylalanine 73 and serine 75 had no effect on menaquinol binding. Only a glutamate residue (E87) located in helix three was important for menaquinol binding. E87 was replaced with lysine, glutamine and aspartate. All three mutants were assembled into the membrane. Neither the lysine nor the glutamine mutant enzymes were able to support anaerobic growth on glycerol/DMSO minimal media or oxidise lapachol. The glutamine mutant bound the inhibitor with lower affinity compared to wild-type, whereas in the lysine mutant, binding was almost abolished. The aspartate mutant behaved as a wild-type enzyme. The data shows that E87 is important for menaquinol binding and oxidation and is likely to act as a proton acceptor in the menaquinol binding site.
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Affiliation(s)
- Paulina Geijer
- CIHR Membrane Protein Research Group, Department of Biochemistry, 474 Medical Sciences Building, University of Alberta, Edmonton, Alberta, Canada T6G 2H7.
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Lubitz SP, Weiner JH. The Escherichia coli ynfEFGHI operon encodes polypeptides which are paralogues of dimethyl sulfoxide reductase (DmsABC). Arch Biochem Biophys 2003; 418:205-16. [PMID: 14522592 DOI: 10.1016/j.abb.2003.08.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The ynfEFGHI operon is a paralogue of the Escherichia coli dmsABC operon. ynfE and ynfF are paralogues of dmsA. ynfG and ynfH are paralogues of dmsB and dmsC, respectively. YnfI (dmsD) has no dms paralogue. YnfE/F and YnfG could be detected by immunoblotting with anti-DmsAB antibodies when expressed under the control of a tac or dms promoter. Cells harbouring ynfFGH on a multicopy plasmid supported anaerobic growth with dimethyl sulfoxide (DMSO) as respiratory oxidant in a dmsABC deletion, suggesting that YnfFGH forms a heterotimeric enzyme complex similar to DmsABC. Exchange of DmsC by YnfH (DmsAB-YnfH) resulted in membrane localization, anaerobic growth on DMSO, and binding of 2-n-heptyl 4-hydroxyquinoline-N-oxide, indicating that YnfH was a competent anchor. YnfG can also replace DmsB as the electron transfer subunit and assembled [Fe-S] clusters as judged by electron paramagnetic resonance spectroscopy. YnfE and/or YnfF could not form a functional complex with DmsBC and expression of YnfE prevented the accumulation of YnfFGH.
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Affiliation(s)
- Shannon P Lubitz
- CIHR Membrane Protein Research Group, Department of Biochemistry, University of Alberta, Alta., T6G 2H7, Edmonton, Canada
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Baltes N, Hennig-Pauka I, Jacobsen I, Gruber AD, Gerlach GF. Identification of dimethyl sulfoxide reductase in Actinobacillus pleuropneumoniae and its role in infection. Infect Immun 2003; 71:6784-92. [PMID: 14638764 PMCID: PMC308893 DOI: 10.1128/iai.71.12.6784-6792.2003] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2003] [Revised: 06/24/2003] [Accepted: 09/03/2003] [Indexed: 11/20/2022] Open
Abstract
Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, is capable of persisting in oxygen-deprived surroundings, namely, tonsils and sequestered necrotic lung tissue. Utilization of alternative terminal electron acceptors in the absence of oxygen is a common strategy in bacteria under anaerobic growth conditions. In an experiment aimed at identification of genes expressed in vivo, the putative catalytic subunit DmsA of anaerobic dimethyl sulfoxide reductase was identified in an A. pleuropneumoniae serotype 7 strain. The 90-kDa protein exhibits 85% identity to the putative DmsA protein of Haemophilus influenzae, and its expression was found to be upregulated under anaerobic conditions. Analysis of the unfinished A. pleuropneumoniae genome sequence revealed putative open reading frames (ORFs) encoding DmsB and DmsC proteins situated downstream of the dmsA ORF. In order to investigate the role of the A. pleuropneumoniae DmsA protein in virulence, an isogenic deletion mutant, A. pleuropneumoniae DeltadmsA, was constructed and examined in an aerosol infection model. A. pleuropneumoniae DeltadmsA was attenuated in acute disease, which suggests that genes involved in oxidative metabolism under anaerobic conditions might contribute significantly to A. pleuropneumoniae virulence.
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Affiliation(s)
- Nina Baltes
- Department of Infectious Diseases, Institute for Microbiology, Veterinary School of Hannover, Germany.
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Parschat K, Hauer B, Kappl R, Kraft R, Huttermann J, Fetzner S. Gene cluster of Arthrobacter ilicis Ru61a involved in the degradation of quinaldine to anthranilate: characterization and functional expression of the quinaldine 4-oxidase qoxLMS genes. J Biol Chem 2003; 278:27483-94. [PMID: 12730200 DOI: 10.1074/jbc.m301330200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A genetic analysis of the anthranilate pathway of quinaldine degradation was performed. A 23-kb region of DNA from Arthrobacter ilicis Rü61a was cloned into the cosmid pVK100. Although Escherichia coli clones containing the recombinant cosmid did not transform quinaldine, cosmids harboring the 23-kb region, or a 10.8-kb stretch of this region, conferred to Pseudomonas putida KT2440 the ability to cometabolically convert quinaldine to anthranilate. The 10.8-kb fragment thus contains the genes coding for quinaldine 4-oxidase (Qox), 1H-4-oxoquinaldine 3-monooxygenase, 1H-3-hydroxy-4-oxoquinaldine 2,4-dioxygenase, and N-acetylanthranilate amidase. The qoxLMS genes coding for the molybdopterin cytosine dinucleotide-(MCD-), FeSI-, FeSII-, and FAD-containing Qox were inserted into the expression vector pJB653, generating pKP1. Qox is the first MCD-containing enzyme to be synthesized in a catalytically fully competent form by a heterologous host, P. putida KT2440 pKP1; the catalytic properties and the UV-visible and EPR spectra of Qox purified from P. putida KT2440 pKP1 were essentially like those of wild-type Qox. This provides a starting point for the construction of protein variants of Qox by site-directed mutagenesis. Downstream of the qoxLMS genes, a putative gene whose deduced amino acid sequence showed 37% similarity to the cofactor-inserting chaperone XdhC was located. Additional open reading frames identified on the 23-kb segment may encode further enzymes (a glutamyl tRNA synthetase, an esterase, two short-chain dehydrogenases/reductases, an ATPase belonging to the AAA family, a 2-hydroxyhepta-2,4-diene-1,7-dioate isomerase/5-oxopent-3-ene-1,2,5-tricarboxylate decarboxylase-like protein, and an enzyme of the mandelate racemase group) and hypothetical proteins involved in transcriptional regulation, and metabolite transport.
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Affiliation(s)
- Katja Parschat
- AG Mikrobiologie, Institut für Chemie und Biologie des Meeres, Carl von Ossietzky Universität Oldenburg, D-26111 Oldenburg, Germany
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Pollock VV, Conover RC, Johnson MK, Barber MJ. Biotin sulfoxide reductase: Tryptophan 90 is required for efficient substrate utilization. Arch Biochem Biophys 2003; 409:315-26. [PMID: 12504898 DOI: 10.1016/s0003-9861(02)00563-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Rhodobacter sphaeroides f. sp. denitrificans biotin sulfoxide reductase (BSOR) catalyzes the reduction of d-biotin d-sulfoxide to biotin and contains the molybdopterin guanine dinucleotide (MGD) cofactor as its sole prosthetic group. Comparison of the primary sequences of BSOR and the closely related enzyme dimethyl sulfoxide reductase (DMSOR) indicated a number of conserved residues, including an active-site tryptophan residue (W90), which has been suggested to be involved in hydrogen bonding to the oxo group on the Mo(VI) center in BSOR. Site-directed mutagenesis has been used to replace tryptophan 90 in BSOR with phenylalanine, tyrosine, and alanine residues to examine the role of this residue in catalysis. All three BSOR mutant proteins were purified to homogeneity and contained MGD. The mutant proteins retained very limited activity toward the oxidizing substrates tested, with W90F retaining the most activity (3.4% of wild type). All three W90 mutant proteins exhibited greatly reduced k(cat) values compared to that of the wild-type enzyme, which was accompanied by little change in K(mapp). In addition, the mutant proteins had perturbed visible absorption and circular dichroism spectra suggesting different oxidation states of the Mo center. Purified samples of wild-type BSOR did not exhibit electron paramagnetic resonance (EPR) signals indicating a Mo(VI) center. After redox-cycling, partially reduced samples of wild-type BSOR revealed a proton-split S=1/2 Mo(V) resonance (g(1,2,3)=1.999, 1.981, 1.967; A(1,2,3)=1.40, 1.00, 1.05 mT) analogous to that observed in DMSOR. In contrast, EPR studies of the purified W90 mutant proteins revealed distinct S=1/2 Mo(V) resonances that were resistant to both oxidation and reduction, indicating that the Mo was trapped in the intermediate Mo(V) oxidation state. These results strongly suggest that W90 in BSOR plays a critical role in catalysis by serving as a hydrogen bond donor to the oxo group on the Mo(VI) center.
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Affiliation(s)
- Veronica V Pollock
- Department of Biochemistry and Molecular Biology, College of Medicine, University of South Florida, Tampa, FL 33612, USA
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Bearson SMD, Albrecht JA, Gunsalus RP. Oxygen and nitrate-dependent regulation of dmsABC operon expression in Escherichia coli: sites for Fnr and NarL protein interactions. BMC Microbiol 2002; 2:13. [PMID: 12079504 PMCID: PMC116602 DOI: 10.1186/1471-2180-2-13] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2002] [Accepted: 06/12/2002] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Escherichia coli, can respire anaerobically using dimethyl sulfoxide (DMSO) or trimethylamine-N-oxide (TMAO) as the terminal electron acceptor for anaerobic energy generation. Expression of the dmsABC genes that encode the membrane-associated DMSO/TMAO reductase is positively regulated during anaerobic conditions by the Fnr protein and negatively regulated by the NarL protein when nitrate is present. RESULTS The regions of dmsA regulatory DNA required for Fnr and NarL interactions in response to anaerobiosis and nitrate, respectively, were examined. Mutations within the Fnr site that deviated from the wild type sequence, TTGATaccgAACAA, or that removed an entire half-site, either impaired or abolished the anaerobic activation of dmsA-lacZ expression. The region for phosphorylated NarL (NarL-phosphate) binding at the dmsA promoter was identified by DNase I and hydroxyl radical footprinting methods. A large 97 bp region that overlaps the Fnr and RNA polymerase recognition sites was protected by NarL-phosphate but not by the non-phosphorylated form of NarL. Hydroxyl radical footprinting analysis confirmed the NarL-phosphate DNase I protections of both dmsA strands and revealed 8-9 protected sites of 3-5 bp occurring at ten bp intervals that are offset by 3 bp in the 3' direction. CONCLUSION These findings suggest that multiple molecules of phosphorylated NarL bind along one face of the DNA and may interfere with Fnr and/or RNA polymerase interactions at the dmsA regulatory region. The interplay of these transcription factors insures a hierarchical expression of the dmsABC genes when respiration of the preferred electron acceptors, oxygen and nitrate, is not possible.
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Affiliation(s)
- Shawn MD Bearson
- Department of Microbiology, Immunology, and Molecular Genetics, and the Molecular Biology Institute, 1602 Molecular Sciences Building, University of California, Los Angeles, CA 90095, USA
- United States Department of Agriculture, National Animal Disease Center, Ames, IA 50010, USA
| | - Jeffrey A Albrecht
- Department of Microbiology, Immunology, and Molecular Genetics, and the Molecular Biology Institute, 1602 Molecular Sciences Building, University of California, Los Angeles, CA 90095, USA
- National Genetics Institute, Westwood, CA 90095, USA
| | - Robert P Gunsalus
- Department of Microbiology, Immunology, and Molecular Genetics, and the Molecular Biology Institute, 1602 Molecular Sciences Building, University of California, Los Angeles, CA 90095, USA
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Mander GJ, Duin EC, Linder D, Stetter KO, Hedderich R. Purification and characterization of a membrane-bound enzyme complex from the sulfate-reducing archaeon Archaeoglobus fulgidus related to heterodisulfide reductase from methanogenic archaea. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:1895-904. [PMID: 11952791 DOI: 10.1046/j.1432-1033.2002.02839.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Heterodisulfide reductase (Hdr) is a unique disulfide reductase that plays a key role in the energy metabolism of methanogenic archaea. The genome of the sulfate-reducing archaeon Archaeoglobus fulgidus encodes several proteins of unknown function with high sequence similarity to the catalytic subunit of Hdr. Here we report on the purification of a multisubunit membrane-bound enzyme complex from A. fulgidus that contains a subunit related to the catalytic subunit of Hdr. The purified enzyme is a heme/iron-sulfur protein, as deduced by UV/Vis spectroscopy, EPR spectroscopy, and the primary structure. It is composed of four different subunits encoded by a putative transcription unit (AF499, AF501-AF503). A fifth protein (AF500) encoded by this transcription unit could not be detected in the purified enzyme preparation. Subunit AF502 is closely related to the catalytic subunit HdrD of Hdr from Methanosarcina barkeri. AF501 encodes a membrane-integral cytochrome, and AF500 encodes a second integral membrane protein. AF499 encodes an extracytoplasmic iron-sulfur protein, and AF503 encodes an extracytoplasmic c-type cytochrome with three heme c-binding motifs. All of the subunits show high sequence similarity to proteins encoded by the dsr locus of Allochromatium vinosum and to subunits of the Hmc complex from Desulfovibrio vulgaris. The heme groups of the enzyme are rapidly reduced by reduced 2,3-dimethyl-1,4-naphthoquinone (DMNH2), which indicates that the enzyme functions as a menaquinol-acceptor oxidoreductase. The physiological electron acceptor has not yet been identified. Redox titrations monitored by EPR spectroscopy were carried out to characterize the iron-sulfur clusters of the enzyme. In addition to EPR signals due to [4Fe-4S]+ clusters, signals of an unusual paramagnetic species with g values of 2.031, 1.994, and 1.951 were obtained. The paramagnetic species could be reduced in a one-electron transfer reaction, but could not be further oxidized, and shows EPR properties similar to those of a paramagnetic species recently identified in Hdr. In Hdr this paramagnetic species is specifically induced by the substrates of the enzyme and is thought to be an intermediate of the catalytic cycle. Hence, Hdr and the A. fulgidus enzyme not only share sequence similarity, but may also have a similar active site and a similar catalytic function.
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Affiliation(s)
- Gerd J Mander
- Max-Planck-Institut für terrestrische Mikrobiologie, Marburg, Germany
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Johnson HA, Pelletier DA, Spormann AM. Isolation and characterization of anaerobic ethylbenzene dehydrogenase, a novel Mo-Fe-S enzyme. J Bacteriol 2001; 183:4536-42. [PMID: 11443088 PMCID: PMC95348 DOI: 10.1128/jb.183.15.4536-4542.2001] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2001] [Accepted: 04/27/2001] [Indexed: 11/20/2022] Open
Abstract
The first step in anaerobic ethylbenzene mineralization in denitrifying Azoarcus sp. strain EB1 is the oxidation of ethylbenzene to (S)-(-)-1-phenylethanol. Ethylbenzene dehydrogenase, which catalyzes this reaction, is a unique enzyme in that it mediates the stereoselective hydroxylation of an aromatic hydrocarbon in the absence of molecular oxygen. We purified ethylbenzene dehydrogenase to apparent homogeneity and showed that the enzyme is a heterotrimer (alphabetagamma) with subunit masses of 100 kDa (alpha), 35 kDa (beta), and 25 kDa (gamma). Purified ethylbenzene dehydrogenase contains approximately 0.5 mol of molybdenum, 16 mol of iron, and 15 mol of acid-labile sulfur per mol of holoenzyme, as well as a molydopterin cofactor. In addition to ethylbenzene, purified ethylbenzene dehydrogenase was found to oxidize 4-fluoro-ethylbenzene and the nonaromatic hydrocarbons 3-methyl-2-pentene and ethylidenecyclohexane. Sequencing of the encoding genes revealed that ebdA encodes the alpha subunit, a 974-amino-acid polypeptide containing a molybdopterin-binding domain. The ebdB gene encodes the beta subunit, a 352-amino-acid polypeptide with several 4Fe-4S binding domains. The ebdC gene encodes the gamma subunit, a 214-amino-acid polypeptide that is a potential membrane anchor subunit. Sequence analysis and biochemical data suggest that ethylbenzene dehydrogenase is a novel member of the dimethyl sulfoxide reductase family of molybdopterin-containing enzymes.
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Affiliation(s)
- H A Johnson
- Environmental Engineering and Science, Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305-4020, USA
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Saraiva LM, da Costa PN, Conte C, Xavier AV, LeGall J. In the facultative sulphate/nitrate reducer Desulfovibrio desulfuricans ATCC 27774, the nine-haem cytochrome c is part of a membrane-bound redox complex mainly expressed in sulphate-grown cells. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1520:63-70. [PMID: 11470160 DOI: 10.1016/s0167-4781(01)00250-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The bacterium Desulfovibrio desulfuricans ATCC 27774 belongs to the group of sulphate reducers also capable of utilising nitrate as its terminal electron acceptor for anaerobic growth. One of the complex multihaem proteins found in nitrate- or sulphate-grown cells of Desulfovibrio desulfuricans ATCC 27774 is the nine-haem cytochrome c. The present work shows that the gene encoding for Desulfovibrio desulfuricans ATCC 27774 nine-haem cytochrome c is part of an operon formed by the gene cluster 9hcA-D. Besides 9hcA, the gene encoding for the nine-haem cytochrome c, genes 9hcB to D encode for a protein containing four [4Fe-4S](2+/1+) centres, for a dihaem transmembrane cytochrome b and for an unknown hydrophobic protein, respectively. The four proteins have a predicted topology that is in accordance with the formation of a membrane-bound redox complex. Furthermore, the transcriptional studies show that not only the expression of the 9HcA-D complex is dependent on the growth phase, but also is markedly increased in sulphate-grown cells.
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Affiliation(s)
- L M Saraiva
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
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Sambasivarao D, Dawson HA, Zhang G, Shaw G, Hu J, Weiner JH. Investigation of Escherichia coli dimethyl sulfoxide reductase assembly and processing in strains defective for the sec-independent protein translocation system membrane targeting and translocation. J Biol Chem 2001; 276:20167-74. [PMID: 11389150 DOI: 10.1074/jbc.m010369200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dimethyl sulfoxide reductase is a heterotrimeric enzyme (DmsABC) localized to the cytoplasmic surface of the inner membrane. Targeting of the DmsA and DmsB catalytic subunits to the membrane requires the membrane targeting and translocation (Mtt) system. The DmsAB dimer is a member of a family of extrinsic, cytoplasmic facing membrane subunits that require Mtt in order to assemble on the membrane. We show that the MttA(2), MttB, and presumably MttA(1) but not the MttC proteins are required for targeting DmsAB to the membrane. Unlike other Mtt substrates such as trimethylamine N-oxide reductase, the soluble cytoplasmic DmsAB dimer that accumulates in the mtt deletions is very labile. Deletion of the mttA(2) or mttB genes also prevents anaerobic growth on fumarate even though fumarate reductase does not require Mtt for assembly. This was due to the lethality of membrane insertion of DmsC in the absence of the DmsAB subunits. In the absence of DmsC, DmsAB accumulates in the cytoplasm. A 45-amino acid leader on DmsA is removed during assembly. Processing does not require DmsC but does require Mtt. Translocation of DmsAB to the periplasm is not required for processing. The leader may be cleaved by a novel leader peptidase, or the long DmsA leader may traverse the membrane through the Mtt system resulting in cleavage by the periplasmic leader peptidase I followed by release of DmsA into the cytoplasm.
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Affiliation(s)
- D Sambasivarao
- CIHR Group in Molecular Biology of Membrane Proteins, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
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Orr N, Galen JE, Levine MM. Novel use of anaerobically induced promoter, dmsA, for controlled expression of fragment C of tetanus toxin in live attenuated Salmonella enterica serovar Typhi strain CVD 908-htrA. Vaccine 2001; 19:1694-700. [PMID: 11166893 DOI: 10.1016/s0264-410x(00)00400-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The anaerobically induced promoter dmsA (PdmsA) was adapted to optimize in vivo expression of foreign antigens in attenuated Salmonella enterica serovar Typhi live vector vaccines CVD 908-htrA. PdmsA from Escherichia coli and two derivatives, PdmsA2 and PdmsA3 were cloned into a plasmid driving the expression of a gene encoding tetanus toxin fragment C. Expression of fragment C varied from a low level induced by pTETdmsA, to moderate and high levels induced, respectively, by pTETdmsA2 and pTETdmsA3. Mice were immunized intranasally with CVD 908-htrA harboring pTETdmsA2 or pTETdmsA3, and the serum antitoxin response was compared to that elicited by CVD 908-htrA(pTETnir15) (Pnir15 is a benchmark anaerobically activated promoter). S. Typhi carrying pTETdmsA2 elicited modest tetanus antitoxin titers while S. Typhi harboring pTETdmsA3 generated elevated titers (GMT=55384) that were higher than elicited by pTETnir15 (GMT=4354) (P=0.007). Mice immunized with CVD 908-htrA carrying pTETdmsA3 and pTETnir15 survived tetanus toxin challenge. P(dmsA) derivatives are attractive promoters for in vivo expression of foreign genes in attenuated live vector vaccines.
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MESH Headings
- Anaerobiosis
- Animals
- Antibodies, Bacterial/blood
- Antibodies, Bacterial/immunology
- Antigens, Bacterial/genetics
- Antigens, Bacterial/immunology
- Antigens, Bacterial/toxicity
- Base Sequence
- Blotting, Western
- Cloning, Molecular
- Consensus Sequence/genetics
- Escherichia coli/genetics
- Gene Expression Regulation, Bacterial/drug effects
- Genes, Bacterial/genetics
- Immunoglobulin G/blood
- Immunoglobulin G/immunology
- Mice
- Mice, Inbred BALB C
- Molecular Sequence Data
- Nitrates/pharmacology
- Peptide Fragments/biosynthesis
- Peptide Fragments/genetics
- Peptide Fragments/immunology
- Peptide Fragments/toxicity
- Promoter Regions, Genetic/genetics
- Salmonella Vaccines/genetics
- Salmonella Vaccines/immunology
- Salmonella typhi/genetics
- Salmonella typhi/immunology
- Survival Rate
- Tetanus Toxin/biosynthesis
- Tetanus Toxin/genetics
- Tetanus Toxin/immunology
- Tetanus Toxin/toxicity
- Vaccines, Attenuated/genetics
- Vaccines, Attenuated/immunology
- Vaccines, Synthetic/genetics
- Vaccines, Synthetic/immunology
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Affiliation(s)
- N Orr
- Department of Pediatrics, University of Maryland School of Medicine, Center for Vaccine Development, 685 West Baltimore Street, Baltimore, MD 21201, USA.
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46
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Pollock VV, Barber MJ. Serine 121 is an essential amino acid for biotin sulfoxide reductase functionality. J Biol Chem 2000; 275:35086-90. [PMID: 10948204 DOI: 10.1074/jbc.m006872200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rhodobacter sphaeroides f. sp. denitrificans biotin sulfoxide reductase (BSOR) catalyzes the reduction of d-biotin d-sulfoxide (BSO) to biotin, an important step in oxidized vitamin salvaging. In addition to BSO, the enzyme also catalyzes the reduction of a variety of other substrates, including methionine sulfoxide, with decreased efficiencies, suggesting a potential role as a general cell protector against oxidative damage. Recombinant BSOR, expressed as a glutathione S-transferase fusion protein, contains the molybdopterin guanine dinucleotide cofactor (MGD) as its sole prosthetic group, which is required for the reduction of BSO by either NADPH or reduced methyl viologen. Comparison of the amino acid sequences of BSOR and the closely related MGD-containing enzyme, dimethyl sulfoxide reductase, has indicated a number of conserved residues, including an active site serine residue, serine 121, which has been potentially identified as the fifth coordinating ligand of Mo in BSOR. Site-directed mutagenesis has been used to replace serine 121 with cysteine, threonine, or alanine residues in the BSOR sequence to asses the role of this residue in catalysis and/or Mo coordination. All three BSOR mutant proteins were expressed, purified to homogeneity, and demonstrated to contain both MGD by fluorescence spectroscopy and Mo by inductively coupled plasma mass spectrometry, similar to wild-type enzyme. However, all three mutant proteins were devoid of BSOR activity using either NADPH or reduced methyl viologen as the electron donor. These results strongly suggest that serine 121 in BSOR is essential for catalysis but is not essential for either Mo coordination or MGD binding.
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Affiliation(s)
- V V Pollock
- Department of Biochemistry and Molecular Biology, College of Medicine and H. Lee Moffitt Cancer Center and Research Institute, University of South Florida, Tampa, Florida 33612, USA
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47
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Krafft T, Bowen A, Theis F, Macy JM. Cloning and sequencing of the genes encoding the periplasmic-cytochrome B-containing selenate reductase of Thauera selenatis. DNA SEQUENCE : THE JOURNAL OF DNA SEQUENCING AND MAPPING 2000; 10:365-77. [PMID: 10826693 DOI: 10.3109/10425170009015604] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The periplasmic selenate reductase (Ser) of Thauera selennatis is a component of the electron transport chain catalyzing selenate reduction with acetate as the electron donor (i.e., selenate respiration). The purified enzyme consists of three subunits (SerA, SerB and SerC). Using transposon (i.e., Tn5) mutagenesis selenate reductase mutants were isolated. Junction fragments of DNA adjacent to the integrated Tn5 were used, together with oligonucleotides derived from the N-termini of SerA and SerB, to clone from a gene bank a DNA fragment that contained the corresponding genes. After sequencing, serA, serB and serC were identified by sequence comparison with the N-termini of the three subunits. The genes are arranged in the order serA, serB, serC; a fourth open reading frame (serD) in between, but overlapping serB and serC, is also present. The serA gene product contains an apparent leader peptide with a twin-arginine motif. The remainder of the translated amino acid sequence is similar to that of a number of prokaryotic molybdenum-containing enzymes (e.g., nitrate reductases and formate dehydrogenases of Escherichia coli). The serB gene product contains four cysteine clusters and is similar to various iron-sulfur protein subunits. The serC gene product contains a putative Sec-dependent leader peptide, but there are no similarities between the remainder of the translated protein and other protein subunits. The SerC contains two histidine and four methionine residues, and these may noncovalently bind heme b--which is a component of the active selenate reductase. The serD gene product encodes a putative protein that shows no significant sequence similarities to other proteins. However, the location of the serD within the other ser genes is similar to that of narJ within the E. coli narGHJI operon (nitrate reductase A); thus suggesting that the role of SerD may be similar to that of NarJ, which is a system-specific chaperone protein.
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Affiliation(s)
- T Krafft
- Department of Microbiology, La Trobe University, Bundoora, Victoria, Australia
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48
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Iverson TM, Luna-Chavez C, Schröder I, Cecchini G, Rees DC. Analyzing your complexes: structure of the quinol-fumarate reductase respiratory complex. Curr Opin Struct Biol 2000; 10:448-55. [PMID: 10981634 DOI: 10.1016/s0959-440x(00)00113-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The integral membrane protein complex quinol-fumarate reductase catalyzes the terminal step of a major anaerobic respiratory pathway. The homologous enzyme succinate-quinone oxidoreductase participates in aerobic respiration both as complex II and as a member of the Krebs cycle. Last year, two structures of quinol-fumarate reductases were reported. These structures revealed the cofactor organization linking the fumarate and quinol sites, and showed a cofactor arrangement across the membrane that is suggestive of a possible energy coupling function.
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Affiliation(s)
- T M Iverson
- Graduate Option in Biochemistry, California Institute of Technology, Pasadena 91125, USA
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49
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Sambasivarao D, Turner RJ, Simala-Grant JL, Shaw G, Hu J, Weiner JH. Multiple roles for the twin arginine leader sequence of dimethyl sulfoxide reductase of Escherichia coli. J Biol Chem 2000; 275:22526-31. [PMID: 10801884 DOI: 10.1074/jbc.m909289199] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dimethyl sulfoxide (Me(2)SO) reductase of Escherichia coli is a terminal electron transport chain enzyme that is expressed under anaerobic growth conditions and is required for anaerobic growth with Me(2)SO as the terminal electron acceptor. The trimeric enzyme is composed of a membrane extrinsic catalytic dimer (DmsAB) and a membrane intrinsic anchor (DmsC). The amino terminus of DmsA has a leader sequence with a twin arginine motif that targets DmsAB to the membrane via a novel Sec-independent mechanism termed MTT for membrane targeting and translocation. We demonstrate that the Met-1 present upstream of the twin arginine motif serves as the correct translational start site. The leader is essential for the expression of DmsA, stability of the DmsAB dimer, and membrane targeting of the reductase holoenzyme. Mutation of arginine 17 to aspartate abolished membrane targeting. The reductase was labile in the leader sequence mutants. These mutants failed to support growth on glycerol-Me(2)SO minimal medium. Replacing the DmsA leader with the TorA leader of trimethylamine N-oxide reductase produced a membrane-bound DmsABC with greatly reduced enzyme activity and inefficient anaerobic respiration indicating that the twin arginine leaders may play specific roles in the assembly of redox enzymes.
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Affiliation(s)
- D Sambasivarao
- Medical Research Council Group in Molecular Biology of Membrane Proteins, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
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50
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Sargent F, Stanley NR, Berks BC, Palmer T. Sec-independent protein translocation in Escherichia coli. A distinct and pivotal role for the TatB protein. J Biol Chem 1999; 274:36073-82. [PMID: 10593889 DOI: 10.1074/jbc.274.51.36073] [Citation(s) in RCA: 252] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In Escherichia coli, transmembrane translocation of proteins can proceed by a number of routes. A subset of periplasmic proteins are exported via the Tat pathway to which proteins are directed by N-terminal "transfer peptides" bearing the consensus (S/T)RRXFLK "twin-arginine" motif. The Tat system involves the integral membrane proteins TatA, TatB, TatC, and TatE. Of these, TatA, TatB, and TatE are homologues of the Hcf106 component of the DeltapH-dependent protein import system of plant thylakoids. Deletion of the tatB gene alone is sufficient to block the export of seven endogenous Tat substrates, including hydrogenase-2. Complementation analysis indicates that while TatA and TatE are functionally interchangeable, the TatB protein is functionally distinct. This conclusion is supported by the observation that Helicobacter pylori tatA will complement an E. coli tatA mutant, but not a tatB mutant. Analysis of Tat component stability in various tat deletion backgrounds shows that TatC is rapidly degraded in the absence of TatB suggesting that TatC complexes, and is stabilized by, TatB.
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Affiliation(s)
- F Sargent
- Centre for Metalloprotein Spectroscopy and Biology, School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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