1
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Fan M, Tan S, Wang W, Zhang X. Improvement in Salt Tolerance Ability of Pseudomonas putida KT2440. BIOLOGY 2024; 13:404. [PMID: 38927284 PMCID: PMC11200750 DOI: 10.3390/biology13060404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 05/25/2024] [Accepted: 05/29/2024] [Indexed: 06/28/2024]
Abstract
Pseudomonas putida KT2440 is a popular platform for bioremediation due to its robust tolerance to environmental stress and strong biodegradation capacity. Limited research on the salt tolerance of P. putida KT2440 has hindered its application. In this study, the strain KT2440 was tested to tolerate a maximum of 4% w/v NaCl cultured with minimal salts medium. Transcriptomic data in a high-salinity environment showed significant expression changes in genes in membrane components, redox processes, chemotaxis, and cellular catabolic processes. betB-encoding betaine-aldehyde dehydrogenase was identified from the transcriptome data to overexpress and enhance growth profile of the strain KT2440 in minimal salts medium containing 4% w/v NaCl. Meanwhile, screening for exogenous salt-tolerant genes revealed that the Na+/H+ antiporter EcnhaA from Escherichia coli significantly increased the growth of the strain KT2440 in 4% w/v NaCl. Then, co-expression of EcnhaA and betB (KT2440-EcnhaA-betB) increased the maximum salt tolerance of strain KT2440 to 5% w/v NaCl. Further addition of betaine and proline improved the salt tolerance of the engineered strain to 6% w/v NaCl. Finally, the engineered strain KT2440-EcnhaA-betB was able to degrade 56.70% of benzoic acid and 95.64% of protocatechuic acid in minimal salt medium containing 4% w/v NaCl in 48 h, while no biodegradation was observed in the normal strain KT2440 in the same conditions. However, the strain KT2440-EcnhaA-betB failed to degrade catechol in minimal salt medium containing 3% w/v NaCl. This study illustrated the improvement in the salt tolerance performance of Pseudomonas putida KT2440 and the feasibility of engineered strain KT2440 as a potential salt-tolerant bioremediation platform.
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Affiliation(s)
| | | | | | - Xuehong Zhang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; (M.F.); (S.T.); (W.W.)
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2
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Zhang L, Yuan Y, Li C, Zhang Y, Sun H, Xu R, Liu Y. Biomineralization of phosphorus during anaerobic treatment of distillery wastewaters. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 925:171431. [PMID: 38442755 DOI: 10.1016/j.scitotenv.2024.171431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 02/29/2024] [Accepted: 02/29/2024] [Indexed: 03/07/2024]
Abstract
This study addresses the pressing environmental concerns associated with the rapidly growing distillery industry, which is a significant contributor to wastewater generation. By focusing on the treatment of distillery wastewater using anaerobic digestion, this research explores the potential to convert organic materials into biofuels (methane). Moreover, the study aims to recover both methane and phosphorus from distillery wastewater in a single anaerobic reactor, which represents a novel and unexplored approach. Laboratory-scale experiments were conducted using mesophilic and thermophilic upflow anaerobic sludge blanket reactors. A key aspect of the study involved the implementation of a unique strategy: the mixing of centrate and spent caustic wastewater streams. This approach was intended to enhance treatment performance, manipulate the microbial community structure, and thereby optimizing the overall treatment performance. The integration of the centrate and spent caustic streams yielded remarkable co-benefits, resulting in significant biomethane production and efficient phosphorus precipitation. The study demonstrated a phosphorus removal efficiency of ∼60 % throughout the 130-140 days operation period. The recovery of phosphorus via the reactor sludge offers exciting opportunities for its utilization as a fertilizer or as a raw material within the phosphorus refinery industry. The biomethane produced during the treatment exhibits significant energy potential, estimated at 0.5 GJ/(m3 distillery wastewater).
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Affiliation(s)
- Lei Zhang
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada; School of Civil & Environmental Engineering, Queensland University of Technology, Brisbane, QLD, Australia
| | - Yiyang Yuan
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada
| | - Chengyuan Li
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada
| | - Yingdi Zhang
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada
| | - Huijuan Sun
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada
| | - Rui Xu
- School of Metallurgy and Environment, Central South University, Changsha, China
| | - Yang Liu
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada; School of Civil & Environmental Engineering, Queensland University of Technology, Brisbane, QLD, Australia.
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3
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Giacomini JJ, Torres-Morales J, Tang J, Dewhirst FE, Borisy GG, Mark Welch JL. Spatial ecology of Haemophilus and Aggregatibacter in the human oral cavity. Microbiol Spectr 2024; 12:e0401723. [PMID: 38488280 PMCID: PMC10986600 DOI: 10.1128/spectrum.04017-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 01/26/2024] [Indexed: 04/06/2024] Open
Abstract
Haemophilus and Aggregatibacter are two of the most common bacterial genera in the human oral cavity, encompassing both commensals and pathogens of substantial ecological and medical significance. In this study, we conducted a metapangenomic analysis of oral Haemophilus and Aggregatibacter species to uncover genomic diversity, phylogenetic relationships, and habitat specialization within the human oral cavity. Using three metrics-pangenomic gene content, phylogenomics, and average nucleotide identity (ANI)-we first identified distinct species and sub-species groups among these genera. Mapping of metagenomic reads then revealed clear patterns of habitat specialization, such as Aggregatibacter species predominantly in dental plaque, a distinctive Haemophilus parainfluenzae sub-species group on the tongue dorsum, and H. sp. HMT-036 predominantly in keratinized gingiva and buccal mucosa. In addition, we found that supragingival plaque samples contained predominantly only one out of the three taxa, H. parainfluenzae, Aggregatibacter aphrophilus, and A. sp. HMT-458, suggesting independent niches or a competitive relationship. Functional analyses revealed the presence of key metabolic genes, such as oxaloacetate decarboxylase, correlated with habitat specialization, suggesting metabolic versatility as a driving force. Additionally, heme synthesis distinguishes H. sp. HMT-036 from closely related Haemophilus haemolyticus, suggesting that the availability of micronutrients, particularly iron, was important in the evolutionary ecology of these species. Overall, our study exemplifies the power of metapangenomics to identify factors that may affect ecological interactions within microbial communities, including genomic diversity, habitat specialization, and metabolic versatility. IMPORTANCE Understanding the microbial ecology of the mouth is essential for comprehending human physiology. This study employs metapangenomics to reveal that various Haemophilus and Aggregatibacter species exhibit distinct ecological preferences within the oral cavity of healthy individuals, thereby supporting the site-specialist hypothesis. Additionally, it was observed that the gene pool of different Haemophilus species correlates with their ecological niches. These findings shed light on the significance of key metabolic functions in shaping microbial distribution patterns and interspecies interactions in the oral ecosystem.
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Affiliation(s)
| | | | - Jonathan Tang
- The Forsyth Institute, Cambridge, Massachusetts, USA
| | - Floyd E. Dewhirst
- The Forsyth Institute, Cambridge, Massachusetts, USA
- Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | | | - Jessica L. Mark Welch
- The Forsyth Institute, Cambridge, Massachusetts, USA
- Marine Biological Laboratory, Woods Hole, Massachusetts, USA
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4
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Kostiuk B, Becker ME, Churaman CN, Black JJ, Payne SM, Pukatzki S, Koestler BJ. Vibrio cholerae Alkalizes Its Environment via Citrate Metabolism to Inhibit Enteric Growth In Vitro. Microbiol Spectr 2023; 11:e0491722. [PMID: 36916917 PMCID: PMC10100763 DOI: 10.1128/spectrum.04917-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/22/2023] [Indexed: 03/16/2023] Open
Abstract
Vibrio cholerae is a Gram-negative pathogen, living in constant competition with other bacteria in marine environments and during human infection. One competitive advantage of V. cholerae is the ability to metabolize diverse carbon sources, such as chitin and citrate. We observed that when some V. cholerae strains were grown on a medium with citrate, the medium's chemical composition turned into a hostile alkaline environment for Gram-negative bacteria, such as Escherichia coli and Shigella flexneri. We found that although the ability to exclude competing bacteria was not contingent on exogenous citrate, V. cholerae C6706 citrate metabolism mutants ΔoadA-1, ΔcitE, and ΔcitF were not able to inhibit S. flexneri or E. coli growth. Lastly, we demonstrated that while the V. cholerae C6706-mediated increased medium pH was necessary for the enteric exclusion phenotype, secondary metabolites, such as bicarbonate (protonated to carbonate in the raised pH) from the metabolism of citrate, enhanced the ability to inhibit the growth of E. coli. These data provide a novel example of how V. cholerae outcompetes other Gram-negative bacteria. IMPORTANCE Vibrio cholerae must compete with other bacteria in order to cause disease. Here, we show that V. cholerae creates an alkaline environment, which is able to inhibit the growth of other enteric bacteria. We demonstrate that V. cholerae environmental alkalization is linked to the capacity of the bacteria to metabolize citrate. This behavior could potentially contribute to V. cholerae's ability to colonize the human intestine.
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Affiliation(s)
- Benjamin Kostiuk
- Department of Medical Microbiology and Immunology, 6-020 Katz Group Centre, University of Alberta, Edmonton, Alberta, Canada
| | - Mark E. Becker
- Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Candice N. Churaman
- Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan, USA
| | - Joshua J. Black
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Shelley M. Payne
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Stefan Pukatzki
- Department of Biology, The City College of New York, New York, New York, USA
| | - Benjamin J. Koestler
- Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan, USA
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5
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Candidatus Eremiobacterota, a metabolically and phylogenetically diverse terrestrial phylum with acid-tolerant adaptations. THE ISME JOURNAL 2021; 15:2692-2707. [PMID: 33753881 PMCID: PMC8397712 DOI: 10.1038/s41396-021-00944-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 02/11/2021] [Accepted: 02/18/2021] [Indexed: 02/01/2023]
Abstract
Candidatus phylum Eremiobacterota (formerly WPS-2) is an as-yet-uncultured bacterial clade that takes its name from Ca. Eremiobacter, an Antarctic soil aerobe proposed to be capable of a novel form of chemolithoautotrophy termed atmospheric chemosynthesis, that uses the energy derived from atmospheric H2-oxidation to fix CO2 through the Calvin-Benson-Bassham (CBB) cycle via type 1E RuBisCO. To elucidate the phylogenetic affiliation and metabolic capacities of Ca. Eremiobacterota, we analysed 63 public metagenome-assembled genomes (MAGs) and nine new MAGs generated from Antarctic soil metagenomes. These MAGs represent both recognized classes within Ca. Eremiobacterota, namely Ca. Eremiobacteria and UBP9. Ca. Eremiobacteria are inferred to be facultatively acidophilic with a preference for peptides and amino acids as nutrient sources. Epifluorescence microscopy revealed Ca. Eremiobacteria cells from Antarctica desert soil to be coccoid in shape. Two orders are recognized within class Ca. Eremiobacteria: Ca. Eremiobacterales and Ca. Baltobacterales. The latter are metabolically versatile, with individual members having genes required for trace gas driven autotrophy, anoxygenic photosynthesis, CO oxidation, and anaerobic respiration. UBP9, here renamed Ca. Xenobia class. nov., are inferred to be obligate heterotrophs with acidophilic adaptations, but individual members having highly divergent metabolic capacities compared to Ca. Eremiobacteria, especially with regard to respiration and central carbon metabolism. We conclude Ca. Eremiobacterota to be an ecologically versatile phylum with the potential to thrive under an array of "extreme" environmental conditions.
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6
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The Classical, Yet Controversial, First Enzyme of Lipid Synthesis: Escherichia coli Acetyl-CoA Carboxylase. Microbiol Mol Biol Rev 2021; 85:e0003221. [PMID: 34132100 DOI: 10.1128/mmbr.00032-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Escherichia coli acetyl-CoA carboxylase (ACC), the enzyme responsible for synthesis of malonyl-CoA, the building block of fatty acid synthesis, is the paradigm bacterial ACC. Many reports on the structures and stoichiometry of the four subunits comprising the active enzyme as well as on regulation of ACC activity and expression have appeared in the almost 20 years since this subject was last reviewed. This review seeks to update and expand on these reports.
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7
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Koendjbiharie JG, van Kranenburg R, Kengen SWM. The PEP-pyruvate-oxaloacetate node: variation at the heart of metabolism. FEMS Microbiol Rev 2021; 45:fuaa061. [PMID: 33289792 PMCID: PMC8100219 DOI: 10.1093/femsre/fuaa061] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 11/18/2020] [Indexed: 12/15/2022] Open
Abstract
At the junction between the glycolysis and the tricarboxylic acid cycle-as well as various other metabolic pathways-lies the phosphoenolpyruvate (PEP)-pyruvate-oxaloacetate node (PPO-node). These three metabolites form the core of a network involving at least eleven different types of enzymes, each with numerous subtypes. Obviously, no single organism maintains each of these eleven enzymes; instead, different organisms possess different subsets in their PPO-node, which results in a remarkable degree of variation, despite connecting such deeply conserved metabolic pathways as the glycolysis and the tricarboxylic acid cycle. The PPO-node enzymes play a crucial role in cellular energetics, with most of them involved in (de)phosphorylation of nucleotide phosphates, while those responsible for malate conversion are important redox enzymes. Variations in PPO-node therefore reflect the different energetic niches that organisms can occupy. In this review, we give an overview of the biochemistry of these eleven PPO-node enzymes. We attempt to highlight the variation that exists, both in PPO-node compositions, as well as in the roles that the enzymes can have within those different settings, through various recent discoveries in both bacteria and archaea that reveal deviations from canonical functions.
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Affiliation(s)
- Jeroen G Koendjbiharie
- Laboratory of Microbiology, Wageningen University, Stippeneng4, 6708 WE Wageningen, The Netherlands
| | - Richard van Kranenburg
- Laboratory of Microbiology, Wageningen University, Stippeneng4, 6708 WE Wageningen, The Netherlands
- Corbion, Arkelsedijk 46, 4206 AC Gorinchem, The Netherlands
| | - Servé W M Kengen
- Laboratory of Microbiology, Wageningen University, Stippeneng4, 6708 WE Wageningen, The Netherlands
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8
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Folch PL, Bisschops MM, Weusthuis RA. Metabolic energy conservation for fermentative product formation. Microb Biotechnol 2021; 14:829-858. [PMID: 33438829 PMCID: PMC8085960 DOI: 10.1111/1751-7915.13746] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 12/16/2020] [Accepted: 12/21/2020] [Indexed: 12/02/2022] Open
Abstract
Microbial production of bulk chemicals and biofuels from carbohydrates competes with low-cost fossil-based production. To limit production costs, high titres, productivities and especially high yields are required. This necessitates metabolic networks involved in product formation to be redox-neutral and conserve metabolic energy to sustain growth and maintenance. Here, we review the mechanisms available to conserve energy and to prevent unnecessary energy expenditure. First, an overview of ATP production in existing sugar-based fermentation processes is presented. Substrate-level phosphorylation (SLP) and the involved kinase reactions are described. Based on the thermodynamics of these reactions, we explore whether other kinase-catalysed reactions can be applied for SLP. Generation of ion-motive force is another means to conserve metabolic energy. We provide examples how its generation is supported by carbon-carbon double bond reduction, decarboxylation and electron transfer between redox cofactors. In a wider perspective, the relationship between redox potential and energy conservation is discussed. We describe how the energy input required for coenzyme A (CoA) and CO2 binding can be reduced by applying CoA-transferases and transcarboxylases. The transport of sugars and fermentation products may require metabolic energy input, but alternative transport systems can be used to minimize this. Finally, we show that energy contained in glycosidic bonds and the phosphate-phosphate bond of pyrophosphate can be conserved. This review can be used as a reference to design energetically efficient microbial cell factories and enhance product yield.
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Affiliation(s)
- Pauline L. Folch
- Bioprocess EngineeringWageningen University & ResearchPost office box 16Wageningen6700 AAThe Netherlands
| | - Markus M.M. Bisschops
- Bioprocess EngineeringWageningen University & ResearchPost office box 16Wageningen6700 AAThe Netherlands
| | - Ruud A. Weusthuis
- Bioprocess EngineeringWageningen University & ResearchPost office box 16Wageningen6700 AAThe Netherlands
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9
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Abstract
Bacteria power their energy metabolism using membrane-bound respiratory enzymes that capture chemical energy and transduce it by pumping protons or Na+ ions across their cell membranes. Recent breakthroughs in molecular bioenergetics have elucidated the architecture and function of many bacterial respiratory enzymes, although key mechanistic principles remain debated. In this Review, we present an overview of the structure, function and bioenergetic principles of modular bacterial respiratory chains and discuss their differences from the eukaryotic counterparts. We also discuss bacterial supercomplexes, which provide central energy transduction systems in several bacteria, including important pathogens, and which could open up possible avenues for treatment of disease.
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10
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Calisto F, Sousa FM, Sena FV, Refojo PN, Pereira MM. Mechanisms of Energy Transduction by Charge Translocating Membrane Proteins. Chem Rev 2021; 121:1804-1844. [PMID: 33398986 DOI: 10.1021/acs.chemrev.0c00830] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Life relies on the constant exchange of different forms of energy, i.e., on energy transduction. Therefore, organisms have evolved in a way to be able to harvest the energy made available by external sources (such as light or chemical compounds) and convert these into biological useable energy forms, such as the transmembrane difference of electrochemical potential (Δμ̃). Membrane proteins contribute to the establishment of Δμ̃ by coupling exergonic catalytic reactions to the translocation of charges (electrons/ions) across the membrane. Irrespectively of the energy source and consequent type of reaction, all charge-translocating proteins follow two molecular coupling mechanisms: direct- or indirect-coupling, depending on whether the translocated charge is involved in the driving reaction. In this review, we explore these two coupling mechanisms by thoroughly examining the different types of charge-translocating membrane proteins. For each protein, we analyze the respective reaction thermodynamics, electron transfer/catalytic processes, charge-translocating pathways, and ion/substrate stoichiometries.
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Affiliation(s)
- Filipa Calisto
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Filipe M Sousa
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Filipa V Sena
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Patricia N Refojo
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal
| | - Manuela M Pereira
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
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11
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Utter DR, Borisy GG, Eren AM, Cavanaugh CM, Mark Welch JL. Metapangenomics of the oral microbiome provides insights into habitat adaptation and cultivar diversity. Genome Biol 2020; 21:293. [PMID: 33323129 PMCID: PMC7739467 DOI: 10.1186/s13059-020-02200-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 11/09/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The increasing availability of microbial genomes and environmental shotgun metagenomes provides unprecedented access to the genomic differences within related bacteria. The human oral microbiome with its diverse habitats and abundant, relatively well-characterized microbial inhabitants presents an opportunity to investigate bacterial population structures at an ecosystem scale. RESULTS Here, we employ a metapangenomic approach that combines public genomes with Human Microbiome Project (HMP) metagenomes to study the diversity of microbial residents of three oral habitats: tongue dorsum, buccal mucosa, and supragingival plaque. For two exemplar taxa, Haemophilus parainfluenzae and the genus Rothia, metapangenomes reveal distinct genomic groups based on shared genome content. H. parainfluenzae genomes separate into three distinct subgroups with differential abundance between oral habitats. Functional enrichment analyses identify an operon encoding oxaloacetate decarboxylase as diagnostic for the tongue-abundant subgroup. For the genus Rothia, grouping by shared genome content recapitulates species-level taxonomy and habitat preferences. However, while most R. mucilaginosa are restricted to the tongue as expected, two genomes represent a cryptic population of R. mucilaginosa in many buccal mucosa samples. For both H. parainfluenzae and the genus Rothia, we identify not only limitations in the ability of cultivated organisms to represent populations in their native environment, but also specifically which cultivar gene sequences are absent or ubiquitous. CONCLUSIONS Our findings provide insights into population structure and biogeography in the mouth and form specific hypotheses about habitat adaptation. These results illustrate the power of combining metagenomes and pangenomes to investigate the ecology and evolution of bacteria across analytical scales.
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Affiliation(s)
- Daniel R Utter
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA.
| | | | - A Murat Eren
- The Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA, 02543, USA
- Department of Medicine, University of Chicago, Chicago, IL, 60637, USA
| | - Colleen M Cavanaugh
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA.
| | - Jessica L Mark Welch
- The Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA, 02543, USA.
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12
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Hobmeier K, Goëss MC, Sehr C, Schwaminger S, Berensmeier S, Kremling A, Kunte HJ, Pflüger-Grau K, Marin-Sanguino A. Anaplerotic Pathways in Halomonas elongata: The Role of the Sodium Gradient. Front Microbiol 2020; 11:561800. [PMID: 33101236 PMCID: PMC7545133 DOI: 10.3389/fmicb.2020.561800] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 08/12/2020] [Indexed: 11/13/2022] Open
Abstract
Salt tolerance in the γ-proteobacterium Halomonas elongata is linked to its ability to produce the compatible solute ectoine. The metabolism of ectoine production is of great interest since it can shed light on the biochemical basis of halotolerance as well as pave the way for the improvement of the biotechnological production of such compatible solute. Ectoine belongs to the biosynthetic family of aspartate-derived amino-acids. Aspartate is formed from oxaloacetate, thereby connecting ectoine production to the anaplerotic reactions that refill carbon into the tricarboxylic acid cycle (TCA cycle). This places a high demand on these reactions and creates the need to regulate them not only in response to growth but also in response to extracellular salt concentration. In this work, we combine modeling and experiments to analyze how these different needs shape the anaplerotic reactions in H. elongata. First, the stoichiometric and thermodynamic factors that condition the flux distributions are analyzed, then the optimal patterns of operation for oxaloacetate production are calculated. Finally, the phenotype of two deletion mutants lacking potentially relevant anaplerotic enzymes: phosphoenolpyruvate carboxylase (Ppc) and oxaloacetate decarboxylase (Oad) are experimentally characterized. The results show that the anaplerotic reactions in H. elongata are indeed subject to evolutionary pressures that differ from those faced by other gram-negative bacteria. Ectoine producing halophiles must meet a higher metabolic demand for oxaloacetate and the reliance of many marine bacteria on the Entner-Doudoroff pathway compromises the anaplerotic efficiency of Ppc, which is usually one of the main enzymes fulfilling this role. The anaplerotic flux in H. elongata is contributed not only by Ppc but also by Oad, an enzyme that has not yet been shown to play this role in vivo. Ppc is necessary for H. elongata to grow normally at low salt concentrations but it is not required to achieve near maximal growth rates as long as there is a steep sodium gradient. On the other hand, the lack of Oad presents serious difficulties to grow at high salt concentrations. This points to a shared role of these two enzymes in guaranteeing the supply of oxaloacetate for biosynthetic reactions.
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Affiliation(s)
- Karina Hobmeier
- Professorship for Systems Biotechnology, Technical University of Munich, Munich, Germany
| | - Marie C. Goëss
- Professorship for Systems Biotechnology, Technical University of Munich, Munich, Germany
| | - Christiana Sehr
- Professorship for Systems Biotechnology, Technical University of Munich, Munich, Germany
| | - Sebastian Schwaminger
- Bioseparation Engineering Group, Department of Mechanical Engineering, Technical University of Munich, Munich, Germany
| | - Sonja Berensmeier
- Bioseparation Engineering Group, Department of Mechanical Engineering, Technical University of Munich, Munich, Germany
| | - Andreas Kremling
- Professorship for Systems Biotechnology, Technical University of Munich, Munich, Germany
| | - Hans Jörg Kunte
- Division of Biodeterioration and Reference Organisms, Bundesanstalt Für Materialforschung und -Prüfung (BAM), Berlin, Germany
| | - Katharina Pflüger-Grau
- Professorship for Systems Biotechnology, Technical University of Munich, Munich, Germany
| | - Alberto Marin-Sanguino
- Professorship for Systems Biotechnology, Technical University of Munich, Munich, Germany
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13
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Xu X, Shi H, Gong X, Chen P, Gao Y, Zhang X, Xiang S. Structural insights into sodium transport by the oxaloacetate decarboxylase sodium pump. eLife 2020; 9:53853. [PMID: 32459174 PMCID: PMC7274780 DOI: 10.7554/elife.53853] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 05/22/2020] [Indexed: 12/16/2022] Open
Abstract
The oxaloacetate decarboxylase sodium pump (OAD) is a unique primary-active transporter that utilizes the free energy derived from oxaloacetate decarboxylation for sodium transport across the cell membrane. It is composed of 3 subunits: the α subunit catalyzes carboxyl-transfer from oxaloacetate to biotin, the membrane integrated β subunit catalyzes the subsequent carboxyl-biotin decarboxylation and the coupled sodium transport, the γ subunit interacts with the α and β subunits and stabilizes the OAD complex. We present here structure of the Salmonella typhimurium OAD βγ sub-complex. The structure revealed that the β and γ subunits form a β3γ3 hetero-hexamer with extensive interactions between the subunits and shed light on the OAD holo-enzyme assembly. Structure-guided functional studies provided insights into the sodium binding sites in the β subunit and the coupling between carboxyl-biotin decarboxylation and sodium transport by the OAD β subunit.
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Affiliation(s)
- Xin Xu
- Department of Biochemistry and Molecular Biology, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University, Tianjin, China
| | - Huigang Shi
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xiaowen Gong
- CAS Key Laboratory of Nutrition, Metabolism and Food safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Pu Chen
- Department of Biochemistry and Molecular Biology, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University, Tianjin, China
| | - Ying Gao
- CAS Key Laboratory of Nutrition, Metabolism and Food safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xinzheng Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Song Xiang
- Department of Biochemistry and Molecular Biology, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University, Tianjin, China
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14
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Bertsova YV, Baykov AA, Bogachev AV. A simple strategy to differentiate between H +- and Na +-transporting NADH:quinone oxidoreductases. Arch Biochem Biophys 2020; 681:108266. [PMID: 31953132 DOI: 10.1016/j.abb.2020.108266] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 12/30/2019] [Accepted: 01/12/2020] [Indexed: 10/25/2022]
Abstract
We describe here a simple strategy to characterize transport specificity of NADH:quinone oxidoreductases, using Na+-translocating (NQR) and H+-translocating (NDH-1) enzymes of the soil bacterium Azotobactervinelandii as the models. Submillimolar concentrations of Na+ and Li+ increased the rate of deaminoNADH oxidation by the inverted membrane vesicles prepared from the NDH-1-deficient strain. The vesicles generated carbonyl cyanide m-chlorophenyl hydrazone (CCCP)-resistant electric potential difference and CCCP-stimulated pH difference (alkalinization inside) in the presence of Na+. These findings testified a primary Na+-pump function of A. vinelandii NQR. Furthermore, ΔpH measurements with fluorescent probes (acridine orange and pyranine) demonstrated that A. vinelandii NQR cannot transport H+ under various conditions. The opposite results obtained in similar measurements with the vesicles prepared from the NQR-deficient strain indicated a primary H+-pump function of NDH-1. Based on our findings, we propose a package of simple experiments that are necessary and sufficient to unequivocally identify the pumping specificity of a bacterial Na+ or H+ transporter. The NQR-deficient strain, but not the NDH-1-deficient one, exhibited impaired growth characteristics under diazotrophic condition, suggesting a role for the Na+ transport in nitrogen fixation by A. vinelandii.
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Affiliation(s)
- Yulia V Bertsova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Alexander A Baykov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Alexander V Bogachev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
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15
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Bertsova YV, Mamedov MD, Bogachev AV. Na+-Translocating Ferredoxin:NAD+ Oxidoreductase Is a Component of Photosynthetic Electron Transport Chain in Green Sulfur Bacteria. BIOCHEMISTRY (MOSCOW) 2019; 84:1403-1410. [PMID: 31760926 DOI: 10.1134/s0006297919110142] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Genomes of photoautotrophic organisms containing type I photosynthetic reaction center were searched for the rnf genes encoding Na+-translocating ferredoxin:NAD+ oxidoreductase (RNF). These genes were absent in heliobacteria, cyanobacteria, algae, and plants; however, genomes of many green sulfur bacteria (especially marine ones) were found to contain the full rnf operon. Analysis of RNA isolated from the marine green sulfur bacterium Chlorobium phaeovibrioides revealed a high level of rnf expression. It was found that the activity of Na+-dependent flavodoxin:NAD+ oxidoreductase detected in the membrane fraction of Chl. phaeovibrioides was absent in the membrane fraction of the freshwater green sulfur bacterium Chlorobaculum limnaeum, which is closely related to Chl. phaeovibrioides but whose genome lacks the rnf genes. Illumination of the membrane fraction of Chl. phaeovibrioides but not of Cba. limnaeum resulted in the light-induced NAD+ reduction. Based on the obtained data, we concluded that in some green sulfur bacteria, RNF may be involved in the NADH formation that should increase the efficiency of light energy conservation in these microorganisms and can serve as the first example of the use of Na+ energetics in photosynthetic electron transport chains.
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Affiliation(s)
- Y V Bertsova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - M D Mamedov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - A V Bogachev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
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16
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Rozova ON, Mustakhimov II, But SY, Reshetnikov AS, Khmelenina VN. Role of the malic enzyme in metabolism of the halotolerant methanotroph Methylotuvimicrobium alcaliphilum 20Z. PLoS One 2019; 14:e0225054. [PMID: 31738793 PMCID: PMC6860931 DOI: 10.1371/journal.pone.0225054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 10/28/2019] [Indexed: 01/10/2023] Open
Abstract
The bacteria utilizing methane as a growth substrate (methanotrophs) are important constituents of the biosphere. Methanotrophs mitigate the emission of anthropogenic and natural greenhouse gas methane to the environment and are the promising agents for future biotechnologies. Many aspects of CH4 bioconversion by methanotrophs require further clarification. This study was aimed at characterizing the biochemical properties of the malic enzyme (Mae) from the halotolerant obligate methanotroph Methylotuvimicrobium alcaliphilum 20Z. The His6-tagged Mae was obtained by heterologous expression in Escherichia coli BL21 (DE3) and purified by affinity metal chelating chromatography. As determined by gel filtration and non-denaturating gradient gel electrophoresis, the molecular mass of the native enzyme is 260 kDa. The homotetrameric Mae (65x4 kDa) catalyzed an irreversible NAD+-dependent reaction of L-malate decarboxylation into pyruvate with a specific activity of 32 ± 2 units mg-1 and Km value of 5.5 ± 0.8 mM for malate and 57 ± 5 μM for NAD+. The disruption of the mae gene by insertion mutagenesis resulted in a 20-fold increase in intracellular malate level in the mutant compared to the wild type strain. Based on both enzyme and mutant properties, we conclude that the malic enzyme is involved in the control of intracellular L-malate level in Mtm. alcaliphilum 20Z. Genomic analysis has revealed that Maes present in methanotrophs fall into two different clades in the amino acid-based phylogenetic tree, but no correlation of the division with taxonomic affiliations of the host bacteria was observed.
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Affiliation(s)
- Olga N. Rozova
- Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Ildar I. Mustakhimov
- Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Sergei Y. But
- Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Aleksandr S. Reshetnikov
- Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Valentina N. Khmelenina
- Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
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17
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Gallo G, Presta L, Perrin E, Gallo M, Marchetto D, Puglia AM, Fani R, Baldi F. Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages. BMC Microbiol 2018; 18:198. [PMID: 30482178 PMCID: PMC6258164 DOI: 10.1186/s12866-018-1330-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 10/29/2018] [Indexed: 12/24/2022] Open
Abstract
Background Klebsiella oxytoca DSM 29614 - isolated from acid mine drainages - grows anaerobically using Fe(III)-citrate as sole carbon and energy source, unlike other enterobacteria and K. oxytoca clinical isolates. The DSM 29614 strain is multi metal resistant and produces metal nanoparticles that are embedded in its very peculiar capsular exopolysaccharide. These metal nanoparticles were effective as antimicrobial and anticancer compounds, chemical catalysts and nano-fertilizers. Results The DSM 29614 strain genome was sequenced and analysed by a combination of in silico procedures. Comparative genomics, performed between 85 K. oxytoca representatives and K. oxytoca DSM 29614, revealed that this bacterial group has an open pangenome, characterized by a very small core genome (1009 genes, about 2%), a high fraction of unique (43,808 genes, about 87%) and accessory genes (5559 genes, about 11%). Proteins belonging to COG categories “Carbohydrate transport and metabolism” (G), “Amino acid transport and metabolism” (E), “Coenzyme transport and metabolism” (H), “Inorganic ion transport and metabolism” (P), and “membrane biogenesis-related proteins” (M) are particularly abundant in the predicted proteome of DSM 29614 strain. The results of a protein functional enrichment analysis - based on a previous proteomic analysis – revealed metabolic optimization during Fe(III)-citrate anaerobic utilization. In this growth condition, the observed high levels of Fe(II) may be due to different flavin metal reductases and siderophores as inferred form genome analysis. The presence of genes responsible for the synthesis of exopolysaccharide and for the tolerance to heavy metals was highlighted too. The inferred genomic insights were confirmed by a set of phenotypic tests showing specific metabolic capability in terms of i) Fe2+ and exopolysaccharide production and ii) phosphatase activity involved in precipitation of metal ion-phosphate salts. Conclusion The K. oxytoca DSM 29614 unique capabilities of using Fe(III)-citrate as sole carbon and energy source in anaerobiosis and tolerating diverse metals coincides with the presence at the genomic level of specific genes that can support i) energy metabolism optimization, ii) cell protection by the biosynthesis of a peculiar exopolysaccharide armour entrapping metal ions and iii) general and metal-specific detoxifying activities by different proteins and metabolites. Electronic supplementary material The online version of this article (10.1186/s12866-018-1330-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Giuseppe Gallo
- Laboratory of Molecular Microbiology and Biotechnology, Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, Viale delle Scienze, ed. 16, 90128, Palermo, Italy.
| | - Luana Presta
- Laboratory of Microbial and Molecular Evolution, Department of Biology, University of Florence, Via Madonna del Piano 6, I-50019 Sesto F.no, Florence, Italy
| | - Elena Perrin
- Laboratory of Microbial and Molecular Evolution, Department of Biology, University of Florence, Via Madonna del Piano 6, I-50019 Sesto F.no, Florence, Italy
| | - Michele Gallo
- Dipartimento di Scienze Molecolari e Nanosistemi, University Cà Foscari Venezia, Via Torino 155, 30172, Mestre, Venezia, Italy
| | - Davide Marchetto
- Dipartimento di Scienze Molecolari e Nanosistemi, University Cà Foscari Venezia, Via Torino 155, 30172, Mestre, Venezia, Italy
| | - Anna Maria Puglia
- Laboratory of Molecular Microbiology and Biotechnology, Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, Viale delle Scienze, ed. 16, 90128, Palermo, Italy
| | - Renato Fani
- Laboratory of Microbial and Molecular Evolution, Department of Biology, University of Florence, Via Madonna del Piano 6, I-50019 Sesto F.no, Florence, Italy
| | - Franco Baldi
- Dipartimento di Scienze Molecolari e Nanosistemi, University Cà Foscari Venezia, Via Torino 155, 30172, Mestre, Venezia, Italy
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18
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Investigating the Central Metabolism of Clostridium thermosuccinogenes. Appl Environ Microbiol 2018; 84:AEM.00363-18. [PMID: 29678919 DOI: 10.1128/aem.00363-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 04/15/2018] [Indexed: 01/28/2023] Open
Abstract
Clostridium thermosuccinogenes is a thermophilic anaerobic bacterium able to convert various carbohydrates to succinate and acetate as main fermentation products. Genomes of the four publicly available strains have been sequenced, and the genome of the type strain has been closed. The annotated genomes were used to reconstruct the central metabolism, and enzyme assays were used to validate annotations and to determine cofactor specificity. The genes were identified for the pathways to all fermentation products, as well as for the Embden-Meyerhof-Parnas pathway and the pentose phosphate pathway. Notably, a candidate transaldolase was lacking, and transcriptomics during growth on glucose versus that on xylose did not provide any leads to potential transaldolase genes or alternative pathways connecting the C5 with the C3/C6 metabolism. Enzyme assays showed xylulokinase to prefer GTP over ATP, which could be of importance for engineering xylose utilization in related thermophilic species of industrial relevance. Furthermore, the gene responsible for malate dehydrogenase was identified via heterologous expression in Escherichia coli and subsequent assays with the cell extract, which has proven to be a simple and powerful method for the basal characterization of thermophilic enzymes.IMPORTANCE Running industrial fermentation processes at elevated temperatures has several advantages, including reduced cooling requirements, increased reaction rates and solubilities, and a possibility to perform simultaneous saccharification and fermentation of a pretreated biomass. Most studies with thermophiles so far have focused on bioethanol production. Clostridium thermosuccinogenes seems an attractive production organism for organic acids, succinic acid in particular, from lignocellulosic biomass-derived sugars. This study provides valuable insights into its central metabolism and GTP and PPi cofactor utilization.
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19
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The fumarylacetoacetate hydrolase (FAH) superfamily of enzymes: multifunctional enzymes from microbes to mitochondria. Biochem Soc Trans 2018; 46:295-309. [PMID: 29487229 DOI: 10.1042/bst20170518] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/23/2017] [Accepted: 01/02/2018] [Indexed: 11/17/2022]
Abstract
Prokaryotic and eukaryotic fumarylacetoacetate hydrolase (FAH) superfamily members, sharing conserved regions that form the so-called FAH-domain, catalyze a remarkable variety of reactions. These enzymes are essential in the metabolic pathways to degrade aromatic compounds in prokaryotes and eukaryotes. It appears that prokaryotic FAH superfamily members evolved mainly to allow microbes to generate energy and useful metabolites from complex carbon sources. We review recent findings, indicating that both prokaryotic and eukaryotic members of the FAH superfamily also display oxaloacetate decarboxylase (ODx) activity. The identification of human FAH domain-containing protein 1 as mitochondrial ODx regulating mitochondrial function supports the new concept that, during evolution, eukaryotic FAH superfamily members have acquired important regulatory functions beyond catabolism of complex carbon sources. Molecular studies on the evolution and function of FAH superfamily members are expected to provide new mechanistic insights in their physiological roles.
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20
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21
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Marreiros BC, Calisto F, Castro PJ, Duarte AM, Sena FV, Silva AF, Sousa FM, Teixeira M, Refojo PN, Pereira MM. Exploring membrane respiratory chains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1039-1067. [PMID: 27044012 DOI: 10.1016/j.bbabio.2016.03.028] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/16/2016] [Accepted: 03/18/2016] [Indexed: 01/20/2023]
Abstract
Acquisition of energy is central to life. In addition to the synthesis of ATP, organisms need energy for the establishment and maintenance of a transmembrane difference in electrochemical potential, in order to import and export metabolites or to their motility. The membrane potential is established by a variety of membrane bound respiratory complexes. In this work we explored the diversity of membrane respiratory chains and the presence of the different enzyme complexes in the several phyla of life. We performed taxonomic profiles of the several membrane bound respiratory proteins and complexes evaluating the presence of their respective coding genes in all species deposited in KEGG database. We evaluated 26 quinone reductases, 5 quinol:electron carriers oxidoreductases and 18 terminal electron acceptor reductases. We further included in the analyses enzymes performing redox or decarboxylation driven ion translocation, ATP synthase and transhydrogenase and we also investigated the electron carriers that perform functional connection between the membrane complexes, quinones or soluble proteins. Our results bring a novel, broad and integrated perspective of membrane bound respiratory complexes and thus of the several energetic metabolisms of living systems. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.
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Affiliation(s)
- Bruno C Marreiros
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157 Oeiras, Portugal
| | - Filipa Calisto
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157 Oeiras, Portugal
| | - Paulo J Castro
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157 Oeiras, Portugal
| | - Afonso M Duarte
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157 Oeiras, Portugal
| | - Filipa V Sena
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157 Oeiras, Portugal
| | - Andreia F Silva
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157 Oeiras, Portugal
| | - Filipe M Sousa
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157 Oeiras, Portugal
| | - Miguel Teixeira
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157 Oeiras, Portugal
| | - Patrícia N Refojo
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157 Oeiras, Portugal
| | - Manuela M Pereira
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157 Oeiras, Portugal.
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22
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Carlson RP, Oshota O, Shipman M, Caserta JA, Hu P, Saunders CW, Xu J, Jay ZJ, Reeder N, Richards A, Pettigrew C, Peyton BM. Integrated molecular, physiological and in silico characterization of two Halomonas isolates from industrial brine. Extremophiles 2016; 20:261-74. [PMID: 26888357 DOI: 10.1007/s00792-015-0806-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 12/06/2015] [Indexed: 01/15/2023]
Abstract
Two haloalkaliphilic bacteria isolated from industrial brine solutions were characterized via molecular, physiological, and in silico metabolic pathway analyses. Genomes from the organisms, designated Halomonas BC1 and BC2, were sequenced; 16S ribosomal subunit-based phylogenetic analysis revealed a high level of similarity to each other and to Halomonas meridiana. Both strains were moderate halophiles with near optimal specific growth rates (≥60 % μ max) observed over <0.1-5 % (w/v) NaCl and pH ranging from 7.4 to 10.2. Isolate BC1 was further characterized by measuring uptake or synthesis of compatible solutes under different growth conditions; in complex medium, uptake and accumulation of external glycine betaine was observed while ectoine was synthesized de novo in salts medium. Transcriptome analysis of isolate BC1 grown on glucose or citrate medium measured differences in glycolysis- and gluconeogenesis-based metabolisms, respectively. The annotated BC1 genome was used to build an in silico, genome-scale stoichiometric metabolic model to study catabolic energy strategies and compatible solute synthesis under gradients of oxygen and nutrient availability. The theoretical analysis identified energy metabolism challenges associated with acclimation to high salinity and high pH. The study documents central metabolism data for the industrially and scientifically important haloalkaliphile genus Halomonas.
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Affiliation(s)
- Ross P Carlson
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, 59717, USA. .,Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA.
| | - Olusegun Oshota
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, 59717, USA.,Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Matt Shipman
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, 59717, USA.,U.S. Navy, Washington, DC, USA
| | | | - Ping Hu
- Procter and Gamble Co., Cincinnati, OH, 45202, USA
| | | | - Jun Xu
- Procter and Gamble Co., Cincinnati, OH, 45202, USA
| | - Zackary J Jay
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, 59717, USA.,Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA
| | - Nancy Reeder
- Procter and Gamble Co., Cincinnati, OH, 45202, USA
| | - Abigail Richards
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, 59717, USA.,Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA
| | | | - Brent M Peyton
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, 59717, USA. .,Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA.
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23
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The well-coordinated linkage between acidogenicity and aciduricity via insoluble glucans on the surface of Streptococcus mutans. Sci Rep 2015; 5:18015. [PMID: 26657939 PMCID: PMC4675080 DOI: 10.1038/srep18015] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 11/10/2015] [Indexed: 11/25/2022] Open
Abstract
Streptococcus mutans is considered the principal cariogenic bacterium for dental caries. Despite the recognition of their importance for cariogenesis, the possible coordination among S. mutans’ main virulence factors, including glucan production, acidogenicity and aciduricity, has been less well studied. In the present study, using S. mutans strains with surface-displayed pH-sensitive pHluorin, we revealed sucrose availability- and Gtf functionality-dependent proton accumulation on S. mutans surface. Consistent with this, using a pH-sensitive dye, we demonstrated that both in vivo cell-produced and in vitro enzymatically synthesized insoluble glucans displayed proton-concentrating ability. Global transcriptomics revealed proton accumulation triggers the up-regulation of genes encoding functions involved in acid tolerance response in a glucan-dependent manner. Our data suggested that this proton enrichment around S. mutans could pre-condition the bacterium for acid-stress. Consistent with this hypothesis, we found S. mutans strains defective in glucan production were more acid sensitive. Our study revealed for the first time that insoluble glucans is likely an essential factor linking acidogenicity with aciduricity. The coordination of these key virulence factors could provide new insights on how S. mutans may have become a major cariogenic pathogen.
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24
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Abstract
Environmental citrate or malonate is degraded by a variety of aerobic or anaerobic bacteria. For selected examples, the genes encoding the specific enzymes of the degradation pathway are described together with the encoded proteins and their catalytic mechanisms. Aerobic bacteria degrade citrate readily by the basic enzyme equipment of the cell if a specific transporter for citrate is available. Anaerobic degradation of citrate in Klebsiella pneumoniae requires the so-called substrate activation module to convert citrate into its thioester with the phosphoribosyl dephospho-CoA prosthetic group of citrate lyase. The citryl thioester is subsequently cleaved into oxaloacetate and the acetyl thioester, from which a new citryl thioester is formed as the turnover continues. The degradation of malonate likewise includes a substrate activation module with a phosphoribosyl dephospho-CoA prosthetic group. The machinery gets ready for turnover after forming the acetyl thioester with the prosthetic group. The acetyl residue is then exchanged by a malonyl residue, which is easily decarboxylated with the regeneration of the acetyl thioester. This equipment suffices for aerobic growth on malonate, since ATP is produced via the oxidation of acetate. Anaerobic growth on citrate or malonate, however, depends on additional enzymes of a so-called energy conservation module. This allows the conversion of decarboxylation energy into an electrochemical gradient of Na+ ions. In citrate-fermenting K. pneumoniae, the Na+ gradient is formed by the oxaloacetate decarboxylase and mainly used to drive the active transport of citrate into the cell. To use this energy source for this purpose is possible, since ATP is generated by substrate phosphorylation in the well-known sequence from pyruvate to acetate. In the malonate-fermenting bacterium Malonomonas rubra, however, no reactions for substrate level phosphorylation are available and the Na+ gradient formed in the malonate decarboxylation reaction must therefore be used as the driving force for ATP synthesis.
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25
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Inoue M, Li X. Highly active and stable oxaloacetate decarboxylase Na⁺ pump complex for structural analysis. Protein Expr Purif 2015; 115:34-8. [PMID: 25986323 DOI: 10.1016/j.pep.2015.05.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 05/09/2015] [Accepted: 05/09/2015] [Indexed: 11/18/2022]
Abstract
The oxaloacetate decarboxylase primary Na(+) pump (Oad) produces energy for the surviving of some pathogenic bacteria under anaerobic conditions. Oad composes of three subunits: Oad-α, a biotinylated soluble subunit and catalyzes the decarboxylation of oxaloacetate; Oad-β, a transmembrane subunit and functions as a Na(+) pump; and Oad-γ, a single transmembrane α-helical anchor subunit and assembles Oad-α/β/γ complex. The molecular mechanism of Oad complex coupling the exothermic decarboxylation to generate the Na(+) electrochemical gradient remains unsolved. Our biophysical and biochemical studies suggested that the stoichiometry of Oad complex from Vibrio cholerae composed of α, β, γ in 4:2:2 stoichiometry not that of 4:4:4. The high-resolution structure determination of the Oad complex would reveal the energetic transformation mechanism from the catalytical soluble α subunit to membrane β subunit. Sufficient amount stable, conformational homogenous and active Oad complex with the right stoichiometry is the prerequisite for structural analysis. Here we report an easy and reproducible protocol to obtain high quantity and quality Oad complex protein for structural analysis.
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Affiliation(s)
- Michio Inoue
- The Laboratory of Biomolecular Research, Paul Scherrer Institut, 5232 Villigen, Switzerland.
| | - Xiaodan Li
- The Laboratory of Biomolecular Research, Paul Scherrer Institut, 5232 Villigen, Switzerland.
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26
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Bertsova YV, Bogachev AV, Skulachev VP. Proteorhodopsin from Dokdonia sp. PRO95 is a light-driven Na+-pump. BIOCHEMISTRY (MOSCOW) 2015; 80:449-54. [DOI: 10.1134/s0006297915040082] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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27
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Sheng X, Liu Y. QM/MM Study of the Reaction Mechanism of the Carboxyl Transferase Domain of Pyruvate Carboxylase from Staphylococcus aureus. Biochemistry 2014; 53:4455-66. [DOI: 10.1021/bi500020r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xiang Sheng
- School
of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
| | - Yongjun Liu
- School
of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
- Northwest
Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810001, China
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Rhie MN, Yoon HE, Oh HY, Zedler S, Unden G, Kim OB. A Na+-coupled C4-dicarboxylate transporter (Asuc_0304) and aerobic growth of Actinobacillus succinogenes on C4-dicarboxylates. MICROBIOLOGY-SGM 2014; 160:1533-1544. [PMID: 24742960 DOI: 10.1099/mic.0.076786-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Actinobacillus succinogenes, which is known to produce large amounts of succinate during fermentation of hexoses, was able to grow on C4-dicarboxylates such as fumarate under aerobic and anaerobic conditions. Anaerobic growth on fumarate was stimulated by glycerol and the major product was succinate, indicating the involvement of fumarate respiration similar to succinate production from glucose. The aerobic growth on C4-dicarboxylates and the transport proteins involved were studied. Fumarate was oxidized to acetate. The genome of A. succinogenes encodes six proteins with similarity to secondary C4-dicarboxylate transporters, including transporters of the Dcu (C4-dicarboxylate uptake), DcuC (C4-dicarboxylate uptake C), DASS (divalent anion : sodium symporter) and TDT (tellurite resistance dicarboxylate transporter) family. From the cloned genes, Asuc_0304 of the DASS family protein was able to restore aerobic growth on C4-dicarboxylates in a C4-dicarboxylate-transport-negative Escherichia coli strain. The strain regained succinate or fumarate uptake, which was dependent on the electrochemical proton potential and the presence of Na(+). The transport had an optimum pH ~7, indicating transport of the dianionic C4-dicarboxylates. Transport competition experiments suggested substrate specificity for fumarate and succinate. The transport characteristics for C4-dicarboxylate uptake by cells of aerobically grown A. succinogenes were similar to those of Asuc_0304 expressed in E. coli, suggesting that Asuc_0304 has an important role in aerobic fumarate uptake in A. succinogenes. Asuc_0304 has sequence similarity to bacterial Na(+)-dicarboxylate cotransporters and contains the carboxylate-binding signature. Asuc_0304 was named SdcA (sodium-coupled C4-dicarboxylate transporter from A. succinogenes).
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Affiliation(s)
- Mi Na Rhie
- Department of Life Sciences, Division of EcoCreative, Ewha Womans University, 120-750 Seoul, Korea
| | - Hyo Eun Yoon
- Department of Life Sciences, Division of EcoCreative, Ewha Womans University, 120-750 Seoul, Korea
| | - Hye Yun Oh
- Department of Life Sciences, Division of EcoCreative, Ewha Womans University, 120-750 Seoul, Korea
| | - Sandra Zedler
- Institute for Microbiology and Wine Research, Johannes Gutenberg University Mainz, Becherweg 15, 55099 Mainz, Germany
| | - Gottfried Unden
- Institute for Microbiology and Wine Research, Johannes Gutenberg University Mainz, Becherweg 15, 55099 Mainz, Germany
| | - Ok Bin Kim
- Department of Life Sciences, Division of EcoCreative, Ewha Womans University, 120-750 Seoul, Korea
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29
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Lietzan AD, St. Maurice M. Functionally diverse biotin-dependent enzymes with oxaloacetate decarboxylase activity. Arch Biochem Biophys 2014; 544:75-86. [DOI: 10.1016/j.abb.2013.10.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Revised: 10/15/2013] [Accepted: 10/18/2013] [Indexed: 12/31/2022]
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30
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Eberhardt RY, Chang Y, Bateman A, Murzin AG, Axelrod HL, Hwang WC, Aravind L. Filling out the structural map of the NTF2-like superfamily. BMC Bioinformatics 2013; 14:327. [PMID: 24246060 PMCID: PMC3924330 DOI: 10.1186/1471-2105-14-327] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 11/15/2013] [Indexed: 12/03/2022] Open
Abstract
Background The NTF2-like superfamily is a versatile group of protein domains sharing a common fold. The sequences of these domains are very diverse and they share no common sequence motif. These domains serve a range of different functions within the proteins in which they are found, including both catalytic and non-catalytic versions. Clues to the function of protein domains belonging to such a diverse superfamily can be gleaned from analysis of the proteins and organisms in which they are found. Results Here we describe three protein domains of unknown function found mainly in bacteria: DUF3828, DUF3887 and DUF4878. Structures of representatives of each of these domains: BT_3511 from Bacteroides thetaiotaomicron (strain VPI-5482) [PDB:3KZT], Cj0202c from Campylobacter jejuni subsp. jejuni serotype O:2 (strain NCTC 11168) [PDB:3K7C], rumgna_01855) and RUMGNA_01855 from Ruminococcus gnavus (strain ATCC 29149) [PDB:4HYZ] have been solved by X-ray crystallography. All three domains are similar in structure and all belong to the NTF2-like superfamily. Although the function of these domains remains unknown at present, our analysis enables us to present a hypothesis concerning their role. Conclusions Our analysis of these three protein domains suggests a potential non-catalytic ligand-binding role. This may regulate the activities of domains with which they are combined in the same polypeptide or via operonic linkages, such as signaling domains (e.g. serine/threonine protein kinase), peptidoglycan-processing hydrolases (e.g. NlpC/P60 peptidases) or nucleic acid binding domains (e.g. Zn-ribbons).
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Affiliation(s)
- Ruth Y Eberhardt
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, CB10 1SA, UK.
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31
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Song M, Zhang Z, Fan C, Li D, Xu Q, Zhang S. A theoretical study on ethylenediamine catalyzed decarboxylation of oxaloacetic acid. COMPUT THEOR CHEM 2013. [DOI: 10.1016/j.comptc.2013.08.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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32
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Ca2+-citrate uptake and metabolism in Lactobacillus casei ATCC 334. Appl Environ Microbiol 2013; 79:4603-12. [PMID: 23709502 DOI: 10.1128/aem.00925-13] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The putative citrate metabolic pathway in Lactobacillus casei ATCC 334 consists of the transporter CitH, a proton symporter of the citrate-divalent metal ion family of transporters CitMHS, citrate lyase, and the membrane-bound oxaloacetate decarboxylase complex OAD-ABDH. Resting cells of Lactobacillus casei ATCC 334 metabolized citrate in complex with Ca(2+) and not as free citrate or the Mg(2+)-citrate complex, thereby identifying Ca(2+)-citrate as the substrate of the transporter CitH. The pathway was induced in the presence of Ca(2+) and citrate during growth and repressed by the presence of glucose and of galactose, most likely by a carbon catabolite repression mechanism. The end products of Ca(2+)-citrate metabolism by resting cells of Lb. casei were pyruvate, acetate, and acetoin, demonstrating the activity of the membrane-bound oxaloacetate decarboxylase complex OAD-ABDH. Following pyruvate, the pathway splits into two branches. One branch is the classical citrate fermentation pathway producing acetoin by α-acetolactate synthase and α-acetolactate decarboxylase. The other branch yields acetate, for which the route is still obscure. Ca(2+)-citrate metabolism in a modified MRS medium lacking a carbohydrate did not significantly affect the growth characteristics, and generation of metabolic energy in the form of proton motive force (PMF) was not observed in resting cells. In contrast, carbohydrate/Ca(2+)-citrate cometabolism resulted in a higher biomass yield in batch culture. However, also with these cells, no generation of PMF was associated with Ca(2+)-citrate metabolism. It is concluded that citrate metabolism in Lb. casei is beneficial when it counteracts acidification by carbohydrate metabolism in later growth stages.
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Biochemical and genetic characterization of the Enterococcus faecalis oxaloacetate decarboxylase complex. Appl Environ Microbiol 2013; 79:2882-90. [PMID: 23435880 DOI: 10.1128/aem.03980-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enterococcus faecalis encodes a biotin-dependent oxaloacetate decarboxylase (OAD), which is constituted by four subunits: E. faecalis carboxyltransferase subunit OadA (termed Ef-A), membrane pump Ef-B, biotin acceptor protein Ef-D, and the novel subunit Ef-H. Our results show that in E. faecalis, subunits Ef-A, Ef-D, and Ef-H form a cytoplasmic soluble complex (termed Ef-AHD) which is also associated with the membrane. In order to characterize the role of the novel Ef-H subunit, coexpression of oad genes was performed in Escherichia coli, showing that this subunit is vital for Ef-A and Ef-D interaction. Diminished growth of the oadA and oadD single deletion mutants in citrate-supplemented medium indicated that the activity of the complex is essential for citrate utilization. Remarkably, the oadB-deficient strain was still capable of growing to wild-type levels but with a delay during the citrate-consuming phase, suggesting that the soluble Ef-AHD complex is functional in E. faecalis. These results suggest that the Ef-AHD complex is active in its soluble form, and that it is capable of interacting in a dynamic way with the membrane-bound Ef-B subunit to achieve its maximal alkalinization capacity during citrate fermentation.
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34
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Structure and function of biotin-dependent carboxylases. Cell Mol Life Sci 2012; 70:863-91. [PMID: 22869039 DOI: 10.1007/s00018-012-1096-0] [Citation(s) in RCA: 258] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 07/07/2012] [Accepted: 07/09/2012] [Indexed: 12/14/2022]
Abstract
Biotin-dependent carboxylases include acetyl-CoA carboxylase (ACC), propionyl-CoA carboxylase (PCC), 3-methylcrotonyl-CoA carboxylase (MCC), geranyl-CoA carboxylase, pyruvate carboxylase (PC), and urea carboxylase (UC). They contain biotin carboxylase (BC), carboxyltransferase (CT), and biotin-carboxyl carrier protein components. These enzymes are widely distributed in nature and have important functions in fatty acid metabolism, amino acid metabolism, carbohydrate metabolism, polyketide biosynthesis, urea utilization, and other cellular processes. ACCs are also attractive targets for drug discovery against type 2 diabetes, obesity, cancer, microbial infections, and other diseases, and the plastid ACC of grasses is the target of action of three classes of commercial herbicides. Deficiencies in the activities of PCC, MCC, or PC are linked to serious diseases in humans. Our understanding of these enzymes has been greatly enhanced over the past few years by the crystal structures of the holoenzymes of PCC, MCC, PC, and UC. The structures reveal unanticipated features in the architectures of the holoenzymes, including the presence of previously unrecognized domains, and provide a molecular basis for understanding their catalytic mechanism as well as the large collection of disease-causing mutations in PCC, MCC, and PC. This review will summarize the recent advances in our knowledge on the structure and function of these important metabolic enzymes.
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35
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Li T, Huo L, Pulley C, Liu A. Decarboxylation mechanisms in biological system. Bioorg Chem 2012; 43:2-14. [PMID: 22534166 DOI: 10.1016/j.bioorg.2012.03.001] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 03/04/2012] [Accepted: 03/19/2012] [Indexed: 11/30/2022]
Abstract
This review examines the mechanisms propelling cofactor-independent, organic cofactor-dependent and metal-dependent decarboxylase chemistry. Decarboxylation, the removal of carbon dioxide from organic acids, is a fundamentally important reaction in biology. Numerous decarboxylase enzymes serve as key components of aerobic and anaerobic carbohydrate metabolism and amino acid conversion. In the past decade, our knowledge of the mechanisms enabling these crucial decarboxylase reactions has continued to expand and inspire. This review focuses on the organic cofactors biotin, flavin, NAD, pyridoxal 5'-phosphate, pyruvoyl, and thiamin pyrophosphate as catalytic centers. Significant attention is also placed on the metal-dependent decarboxylase mechanisms.
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Affiliation(s)
- Tingfeng Li
- Department of Biochemistry, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA
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36
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Chen JS, Reddy V, Chen JH, Shlykov MA, Zheng WH, Cho J, Yen MR, Saier MH. Phylogenetic characterization of transport protein superfamilies: superiority of SuperfamilyTree programs over those based on multiple alignments. J Mol Microbiol Biotechnol 2012; 21:83-96. [PMID: 22286036 DOI: 10.1159/000334611] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Transport proteins function in the translocation of ions, solutes and macromolecules across cellular and organellar membranes. These integral membrane proteins fall into >600 families as tabulated in the Transporter Classification Database (www.tcdb.org). Recent studies, some of which are reported here, define distant phylogenetic relationships between families with the creation of superfamilies. Several of these are analyzed using a novel set of programs designed to allow reliable prediction of phylogenetic trees when sequence divergence is too great to allow the use of multiple alignments. These new programs, called SuperfamilyTree1 and 2 (SFT1 and 2), allow display of protein and family relationships, respectively, based on thousands of comparative BLAST scores rather than multiple alignments. Superfamilies analyzed include: (1) Aerolysins, (2) RTX Toxins, (3) Defensins, (4) Ion Transporters, (5) Bile/Arsenite/Riboflavin Transporters, (6) Cation:Proton Antiporters, and (7) the Glucose/Fructose/Lactose superfamily within the prokaryotic phosphoenol pyruvate-dependent Phosphotransferase System. In addition to defining the phylogenetic relationships of the proteins and families within these seven superfamilies, evidence is provided showing that the SFT programs outperform programs that are based on multiple alignments whenever sequence divergence of superfamily members is extensive. The SFT programs should be applicable to virtually any superfamily of proteins or nucleic acids.
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Affiliation(s)
- Jonathan S Chen
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
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37
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Balsera M, Buey RM, Li XD. Quaternary structure of the oxaloacetate decarboxylase membrane complex and mechanistic relationships to pyruvate carboxylases. J Biol Chem 2011; 286:9457-67. [PMID: 21209096 PMCID: PMC3058996 DOI: 10.1074/jbc.m110.197442] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 12/16/2010] [Indexed: 01/15/2023] Open
Abstract
The oxaloacetate decarboxylase primary Na(+) pump (OAD) is an essential membrane protein complex that functions in the citrate fermentation pathway of some pathogenic bacteria under anaerobic conditions. OAD contains three different subunits: Oad-α, a biotinylated extrinsic protein that catalyzes the α-ketodecarboxylation of oxaloacetate; Oad-γ, a structural bitopic membrane protein whose cytosolic tail (named as Oad-γ') binds tightly to Oad-α; and Oad-β, a multispan transmembrane α-helical protein that constitutes the Na(+) channel. How OAD is organized structurally at the membrane and what the molecular determinants are that lead to an efficient energy coupling mechanism remain elusive. In the present work, we elucidate the stoichiometry of the native complex as well as the low resolution structure of the peripheral components of OAD (Oad-α and Oad-γ') by small angle x-ray scattering. Our results point to a quaternary assembly similar to the pyruvate carboxylase complex organization. Herein, we propose a model in which the association in pairs of Oad-α dimers, mediated by Oad-γ, results in the acquisition of a functional oligomeric state at the bacterial membrane. New structural insights for the conformational rearrangements associated with the carboxylbiotin transfer reaction within OAD are provided.
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Affiliation(s)
- Monica Balsera
- From Biomolecular Research, Paul Scherrer Institut, 5232 Villigen, Switzerland
- the Departamento de Estrés Abiótico, Instituto de Recursos Naturales y Agrobiología de Salamanca, Consejo Superior de Investigaciones Científicas, 37008 Salamanca, Spain, and
| | - Ruben M. Buey
- From Biomolecular Research, Paul Scherrer Institut, 5232 Villigen, Switzerland
- the Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas-Universidad de Salamanca, Campus Unamuno, 37008 Salamanca, Spain
| | - Xiao-Dan Li
- From Biomolecular Research, Paul Scherrer Institut, 5232 Villigen, Switzerland
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38
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von Rozycki T, Nies DH, Saier MH. Genomic analyses of transport proteins in Ralstonia metallidurans. Comp Funct Genomics 2010; 6:17-56. [PMID: 18629293 PMCID: PMC2448597 DOI: 10.1002/cfg.454] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2004] [Revised: 12/14/2004] [Accepted: 12/15/2004] [Indexed: 11/06/2022] Open
Abstract
Ralstonia (Wautersia, Cupriavidus) metallidurans (Rme) is better able to withstand
high concentrations of heavy metals than any other well-studied organism. This fact
renders it a potential agent of bioremediation as well as an ideal model organism for
understanding metal resistance phenotypes. We have analysed the genome of Rme
for genes encoding homologues of established and putative transport proteins; 13%
of all genes in Rme encode such homologues. Nearly one-third of the transporters
identified (32%) appear to function in inorganic ion transport with three-quarters
of these acting on cations. Transporters specific for amino acids outnumber sugar
transporters nearly 3 : 1, and this fact plus the large number of uptake systems for
organic acids indicates the heterotrophic preferences of these bacteria. Putative drug
efflux pumps comprise 10% of the encoded transporters, but numerous efflux pumps
for heavy metals, metabolites and macromolecules were also identified. The results
presented should facilitate genetic manipulation and mechanistic studies of transport
in this remarkable bacterium.
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Affiliation(s)
- Torsten von Rozycki
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
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39
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Klaffl S, Eikmanns BJ. Genetic and functional analysis of the soluble oxaloacetate decarboxylase from Corynebacterium glutamicum. J Bacteriol 2010; 192:2604-12. [PMID: 20233922 PMCID: PMC2863558 DOI: 10.1128/jb.01678-09] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Accepted: 03/07/2010] [Indexed: 11/20/2022] Open
Abstract
Soluble, divalent cation-dependent oxaloacetate decarboxylases (ODx) catalyze the irreversible decarboxylation of oxaloacetate to pyruvate and CO(2). Although these enzymes have been characterized in different microorganisms, the genes that encode them have not been identified, and their functions have been only poorly analyzed so far. In this study, we purified a soluble ODx from wild-type C. glutamicum about 65-fold and used matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) analysis and peptide mass fingerprinting for identification of the corresponding odx gene. Inactivation and overexpression of odx led to an absence of ODx activity and to a 30-fold increase in ODx specific activity, respectively; these findings unequivocally confirmed that this gene encodes a soluble ODx. Transcriptional analysis of odx indicated that there is a leaderless transcript that is organized in an operon together with a putative S-adenosylmethionine-dependent methyltransferase gene. Biochemical analysis of ODx revealed that the molecular mass of the native enzyme is about 62 +/- 1 kDa and that the enzyme is composed of two approximately 29-kDa homodimeric subunits and has a K(m) for oxaloacetate of 1.4 mM and a V(max) of 201 micromol of oxaloacetate converted per min per mg of protein, resulting in a k(cat) of 104 s(-1). Introduction of plasmid-borne odx into a pyruvate kinase-deficient C. glutamicum strain restored growth of this mutant on acetate, indicating that a high level of ODx activity redirects the carbon flux from oxaloacetate to pyruvate in vivo. Consistently, overexpression of the odx gene in an L-lysine-producing strain of C. glutamicum led to accumulation of less L-lysine. However, inactivation of the odx gene did not improve L-lysine production under the conditions tested.
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Affiliation(s)
- Simon Klaffl
- Institute of Microbiology and Biotechnology, University of Ulm, D-89069 Ulm, Germany
| | - Bernhard J. Eikmanns
- Institute of Microbiology and Biotechnology, University of Ulm, D-89069 Ulm, Germany
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40
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Abstract
Since its discovery in 1924 by J Clarke, Streptococcus mutans has been the focus of rigorous research efforts due to its involvement in caries initiation and progression. Its ability to ferment a range of dietary carbohydrates can rapidly drop the external environmental pH, thereby making dental plaque inhabitable to many competing species and can ultimately lead to tooth decay. Acid production by this oral pathogen would prove suicidal if not for its remarkable ability to withstand the acid onslaught by utilizing a wide variety of highly evolved acid-tolerance mechanisms. The elucidation of these mechanisms will be discussed, serving as the focus of this review.
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Affiliation(s)
- Robert Matsui
- Room 449A Faculty of Dentistry, University of Toronto, 124 Edward St., Toronto, ON, M5G 1G6, Canada, Tel.: +1 416 979 4917 ext. 4592, Fax: +1 416 978 4936
| | - Dennis Cvitkovitch
- Room 449A Faculty of Dentistry, University of Toronto, 124 Edward St., Toronto, ON, M5G 1G6, Canada, Tel.: +1 416 979 4917 ext. 4592, Fax: +1 416 978 4936
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Transcriptional regulation of the citrate gene cluster of Enterococcus faecalis Involves the GntR family transcriptional activator CitO. J Bacteriol 2008; 190:7419-30. [PMID: 18805984 DOI: 10.1128/jb.01704-07] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genome of the gram-positive bacterium Enterococcus faecalis contains the genes that encode the citrate lyase complex. This complex splits citrate into oxaloacetate and acetate and is involved in all the known anaerobic bacterial citrate fermentation pathways. Although citrate fermentation in E. faecalis has been investigated before, the regulation and transcriptional pattern of the cit locus has still not been fully explored. To fill this gap, in this paper we demonstrate that the GntR transcriptional regulator CitO is a novel positive regulator involved in the expression of the cit operons. The transcriptional analysis of the cit clusters revealed two divergent operons: citHO, which codes for the transporter (citH) and the regulatory protein (citO), and upstream from it and in the opposite direction the oadHDB-citCDEFX-oadA-citMG operon, which includes the citrate lyase subunits (citD, citE, and citF), the soluble oxaloacetate decarboxylase (citM), and also the genes encoding a putative oxaloacetate decarboxylase complex (oadB, oadA, oadD and oadH). This analysis also showed that both operons are specifically activated by the addition of citrate to the medium. In order to study the functional role of CitO, a mutant strain with an interrupted citO gene was constructed, causing a total loss of the ability to degrade citrate. Reintroduction of a functional copy of citO to the citO-deficient strain restored the response to citrate and the Cit(+) phenotype. Furthermore, we present evidence that CitO binds to the cis-acting sequences O(1) and O(2), located in the cit intergenic region, increasing its affinity for these binding sites when citrate is present and allowing the induction of both cit promoters.
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Sevvana M, Vijayan V, Zweckstetter M, Reinelt S, Madden DR, Herbst-Irmer R, Sheldrick GM, Bott M, Griesinger C, Becker S. A ligand-induced switch in the periplasmic domain of sensor histidine kinase CitA. J Mol Biol 2008; 377:512-23. [PMID: 18258261 DOI: 10.1016/j.jmb.2008.01.024] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2007] [Revised: 01/08/2008] [Accepted: 01/10/2008] [Indexed: 11/26/2022]
Abstract
Sensor histidine kinases of two-component signal-transduction systems are essential for bacteria to adapt to variable environmental conditions. However, despite their prevalence, it is not well understood how extracellular signals such as ligand binding regulate the activity of these sensor kinases. CitA is the sensor histidine kinase in Klebsiella pneumoniae that regulates the transport and anaerobic metabolism of citrate in response to its extracellular concentration. We report here the X-ray structures of the periplasmic sensor domain of CitA in the citrate-free and citrate-bound states. A comparison of the two structures shows that ligand binding causes a considerable contraction of the sensor domain. This contraction may represent the molecular switch that activates transmembrane signaling in the receptor.
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Affiliation(s)
- Madhumati Sevvana
- Department of Structural Chemistry, University of Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
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Barabote RD, Rendulic S, Schuster SC, Saier MH. Comprehensive analysis of transport proteins encoded within the genome of Bdellovibrio bacteriovorus. Genomics 2007; 90:424-46. [PMID: 17706914 PMCID: PMC3415317 DOI: 10.1016/j.ygeno.2007.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Revised: 06/07/2007] [Accepted: 06/08/2007] [Indexed: 10/22/2022]
Abstract
Bdellovibrio bacteriovorus is a bacterial parasite with an unusual lifestyle. It grows and reproduces in the periplasm of a host prey bacterium. The complete genome sequence of B. bacteriovorus has recently been reported. We have reanalyzed the transport proteins encoded within the B. bacteriovorus genome according to the current content of the Transporter Classification Database. A comprehensive analysis is given on the types and numbers of transport systems that B. bacteriovorus has. In this regard, the potential protein secretory capabilities of at least four types of inner-membrane secretion systems and five types of outer-membrane secretion systems are described. Surprisingly, B. bacteriovorus has a disproportionate percentage of cytoplasmic membrane channels and outer-membrane porins. It has far more TonB/ExbBD-type systems and MotAB-type systems for energizing outer-membrane transport and motility than does Escherichia coli. Analysis of probable substrate specificities of its transporters provides clues to its metabolic preferences. Interesting examples of gene fusions and of potentially overlapping genes are also noted. Our analyses provide a comprehensive, detailed appreciation of the transport capabilities of B. bacteriovorus. They should serve as a guide for functional experimental analyses.
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Affiliation(s)
- Ravi D. Barabote
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116
| | - Snjezana Rendulic
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116
| | - Stephan C. Schuster
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116
| | - Milton H. Saier
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116
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Boiangiu CD, Jayamani E, Brügel D, Herrmann G, Kim J, Forzi L, Hedderich R, Vgenopoulou I, Pierik AJ, Steuber J, Buckel W. Sodium ion pumps and hydrogen production in glutamate fermenting anaerobic bacteria. J Mol Microbiol Biotechnol 2006; 10:105-19. [PMID: 16645308 DOI: 10.1159/000091558] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Anaerobic bacteria ferment glutamate via two different pathways to ammonia, carbon dioxide, acetate, butyrate and molecular hydrogen. The coenzyme B12-dependent pathway in Clostridium tetanomorphum via 3-methylaspartate involves pyruvate:ferredoxin oxidoreductase and a novel enzyme, a membrane-bound NADH:ferredoxin oxidoreductase. The flavin- and iron-sulfur-containing enzyme probably uses the energy difference between reduced ferredoxin and NADH to generate an electrochemical Na+ gradient, which drives transport processes. The other pathway via 2-hydroxyglutarate in Acidaminococcus fermentans and Fusobacterium nucleatum involves glutaconyl-CoA decarboxylase, which uses the free energy of decarboxylation to generate also an electrochemical Na+ gradient. In the latter two organisms, similar membrane-bound NADH:ferredoxin oxidoreductases have been characterized. We propose that in the hydroxyglutarate pathway these oxidoreductases work in the reverse direction, whereby the reduction of ferredoxin by NADH is driven by the Na+ gradient. The reduced ferredoxin is required for hydrogen production and the activation of radical enzymes. Further examples show that reduced ferredoxin is an agent, whose reducing energy is about 1 ATP 'richer' than that of NADH.
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Affiliation(s)
- Clara D Boiangiu
- Laboratorium für Mikrobiologie, Fachbereich Biologie, Philipps-Universität, Marburg, Germany
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Yang L, Jiang J, Zhang B, Zhao B, Wang L, Yang SS. A primary sodium pump gene of the moderate halophile Halobacillus dabanensis exhibits secondary antiporter properties. Biochem Biophys Res Commun 2006; 346:612-7. [PMID: 16774742 DOI: 10.1016/j.bbrc.2006.05.181] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2006] [Accepted: 05/27/2006] [Indexed: 11/23/2022]
Abstract
The primary sodium pump has been proved to be involved in Na(+) extrusion of bacteria. In our present study, a novel gene encoding a putative primary sodium pump was cloned from chromosomal DNA of moderate halophile Halobacillus dabanensis D-8 by functional complementation, which expression resulted in the growth of antiporter-deficient Escherichia coli strain KNabc in the presence of 0.2 M NaCl. The gene was sequenced and designated nap. The deduced amino acid sequence of Nap has 56% identity to NADH dehydrogenase of Bacillus cereus and 55% to NADH oxidase of Bacillus halodurans C-125. E. coli KNabc carrying nap exhibited resistance to uncoupler CCCP (carbonyl-cyanide m-chlorophenylhydrazone). Everted membrane vesicles prepared from E. coli KNabc carrying nap exhibited secondary Na(+)/H(+) antiporter activity, and nap also supported the growth of respiratory-deficient E. coli ANN0222 lacking NADH dehydrogenase. Based on these results, we proposed that Nap possessed both characteristics of secondary Na(+)/H(+) antiporter and primary sodium pump.
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Affiliation(s)
- Lifu Yang
- Department of Microbiology and Immunology, College of Biological Sciences, China Agricultural University, Key Laboratory of Agro-Microbial Resource and Application of Ministry of Agriculture, Beijing
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Dahinden P, Pos KM, Dimroth P. Identification of a domain in the α-subunit of the oxaloacetate decarboxylase Na+ pump that accomplishes complex formation with the γ-subunit. FEBS J 2005; 272:846-55. [PMID: 15670164 DOI: 10.1111/j.1742-4658.2004.04524.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The oxaloacetate decarboxylase Na+ pumps OAD-1 and OAD-2 of Vibrio cholerae are composed of a peripheral alpha-subunit associated with two integral membrane-bound subunits (beta and gamma). The alpha-subunit contains the carboxyltransferase domain in its N-terminal portion and the biotin-binding domain in its C-terminal portion. The gamma-subunit plays a profound role in the assembly of the complex. It interacts with the beta-subunit through its N-terminal membrane-spanning region and with the alpha-subunit through its hydrophilic C-terminal domain. The biochemical and structural requirements for the latter interaction were analysed with OAD-2 expression clones for subunit alpha-2 and the C-terminal domain of gamma-2, termed gamma'-2. If the two proteins were synthesized together in Escherichia coli they formed a complex that was stable at neutral pH and dissociated at pH<5.0. An internal stretch of 40 amino acids of alpha-2 was identified by deletion mutagenesis to be essential for the binding with gamma'-2. This portion of the alpha-subunit is connected via flexible linker peptides to the carboxyltransferase domain at its N terminus and to the biotin-binding domain at its C terminus. Results of site-directed mutagenesis indicated that a conserved tyrosine (491) and threonine 494 of this peptide contributed significantly to the stability of the complex with gamma'-2. This peptide therefore represents a newly identified, separate domain of the alpha-subunit and has been called the 'association domain'.
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Affiliation(s)
- Pius Dahinden
- Institute of Microbiology ETH Zürich, ETH Hönggerberg, Zürich, Switzerland
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Dahinden P, Auchli Y, Granjon T, Taralczak M, Wild M, Dimroth P. Oxaloacetate decarboxylase of Vibrio cholerae: purification, characterization, and expression of the genes in Escherichia coli. Arch Microbiol 2005; 183:121-9. [PMID: 15647905 DOI: 10.1007/s00203-004-0754-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2004] [Revised: 12/02/2004] [Accepted: 12/06/2004] [Indexed: 11/27/2022]
Abstract
The oxaloacetate decarboxylase (OAD) Na(+) pump consists of subunits alpha, beta, and gamma, which are expressed from an oadGAB gene cluster present in various anaerobic bacteria. Vibrio cholerae has two copies of oad genes, which are termed oad-1 and oad-2. The oad-2 genes are part of the citrate fermentation operon, while the oad-1 genes are flanked by genes encoding products not involved in a catabolic pathway. The gene sequences of oad-1 and oad-2 of V. cholerae strain O395-N1 were determined. The apparent frameshift in the published sequence of the oadA-2 gene from V. cholerae El Tor N16961 was not present in strain O395-N1. Upon anaerobic growth of V. cholerae on citrate, exclusively the oad-2 genes are expressed. OAD was isolated from these cells by monomeric avidin-Sepharose affinity chromatography. The enzyme was of higher specific activity than that from Klebsiella pneumoniae and was significantly more stable. Decarboxylase activity was Na(+) dependent, and the activation profile showed strong cooperativity with a Hill coefficient n(H)=1.8. Oxalate and oxomalonate inhibited the enzyme with half-maximal concentrations of 10 microM and 200 microM, respectively. After reconstitution into proteoliposomes, the enzyme acted as a Na(+) pump. With size-exclusion chromatography, the enzyme eluted in a symmetrical peak at a retention volume corresponding to an apparent molecular mass of approximately 570 kDa, suggesting a tetrameric structure for OAD-2. The two oad gene clusters were heterologously expressed in Escherichia coli, and the decarboxylases were isolated from the host cells.
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Affiliation(s)
- Pius Dahinden
- Institut für Mikrobiologie der ETH Zürich, ETH Hönggerberg, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland
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Chang AB, Lin R, Keith Studley W, Tran CV, Saier MH. Phylogeny as a guide to structure and function of membrane transport proteins. Mol Membr Biol 2004; 21:171-81. [PMID: 15204625 DOI: 10.1080/09687680410001720830] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Protein phylogeny, based on primary amino acid sequence relatedness, reflects the evolutionary process and therefore provides a guide to structure, mechanism and function. Any two proteins that are related by common descent are expected to exhibit similar structures and functions to a degree proportional to the degree of their sequence similarity; but two independently evolving proteins should not. This principle provides the impetus to define protein phylogenetic relationships and interrelate families when possible. In this mini-review, we summarize the computational approaches and criteria we use to establish common evolutionary origin. We apply these tools to define distant superfamily relationships between several previously recognized transport protein families. In some cases, available structural and functional data are evaluated in order to substantiate our claim that molecular phylogeny provides a reliable guide to protein structure and function.
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Affiliation(s)
- Abraham B Chang
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
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Sauer U, Eikmanns BJ. The PEP-pyruvate-oxaloacetate node as the switch point for carbon flux distribution in bacteria. FEMS Microbiol Rev 2004; 29:765-94. [PMID: 16102602 DOI: 10.1016/j.femsre.2004.11.002] [Citation(s) in RCA: 361] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2004] [Revised: 10/27/2004] [Accepted: 11/01/2004] [Indexed: 11/16/2022] Open
Abstract
In many organisms, metabolite interconversion at the phosphoenolpyruvate (PEP)-pyruvate-oxaloacetate node involves a structurally entangled set of reactions that interconnects the major pathways of carbon metabolism and thus, is responsible for the distribution of the carbon flux among catabolism, anabolism and energy supply of the cell. While sugar catabolism proceeds mainly via oxidative or non-oxidative decarboxylation of pyruvate to acetyl-CoA, anaplerosis and the initial steps of gluconeogenesis are accomplished by C3- (PEP- and/or pyruvate-) carboxylation and C4- (oxaloacetate- and/or malate-) decarboxylation, respectively. In contrast to the relatively uniform central metabolic pathways in bacteria, the set of enzymes at the PEP-pyruvate-oxaloacetate node represents a surprising diversity of reactions. Variable combinations are used in different bacteria and the question of the significance of all these reactions for growth and for biotechnological fermentation processes arises. This review summarizes what is known about the enzymes and the metabolic fluxes at the PEP-pyruvate-oxaloacetate node in bacteria, with a particular focus on the C3-carboxylation and C4-decarboxylation reactions in Escherichia coli, Bacillus subtilis and Corynebacterium glutamicum. We discuss the activities of the enzymes, their regulation and their specific contribution to growth under a given condition or to biotechnological metabolite production. The present knowledge unequivocally reveals the PEP-pyruvate-oxaloacetate nodes of bacteria to be a fascinating target of metabolic engineering in order to achieve optimized metabolite production.
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Affiliation(s)
- Uwe Sauer
- Institute of Biotechnology, ETH Zürich, Switzerland
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Morales G, Linares JF, Beloso A, Albar JP, Martínez JL, Rojo F. The Pseudomonas putida Crc global regulator controls the expression of genes from several chromosomal catabolic pathways for aromatic compounds. J Bacteriol 2004; 186:1337-44. [PMID: 14973036 PMCID: PMC344427 DOI: 10.1128/jb.186.5.1337-1344.2004] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Crc protein is involved in the repression of several catabolic pathways for the assimilation of some sugars, nitrogenated compounds, and hydrocarbons in Pseudomonas putida and Pseudomonas aeruginosa when other preferred carbon sources are present in the culture medium (catabolic repression). Crc appears to be a component of a signal transduction pathway modulating carbon metabolism in pseudomonads, although its mode of action is unknown. To better understand the role of Crc, the proteome profile of two otherwise isogenic P. putida strains containing either a wild-type or an inactivated crc allele was compared. The results showed that Crc is involved in the catabolic repression of the hpd and hmgA genes from the homogentisate pathway, one of the central catabolic pathways for aromatic compounds that is used to assimilate intermediates derived from the oxidation of phenylalanine, tyrosine, and several aromatic hydrocarbons. This led us to analyze whether Crc also regulates the expression of the other central catabolic pathways for aromatic compounds present in P. putida. It was found that genes required to assimilate benzoate through the catechol pathway (benA and catBCA) and 4-OH-benzoate through the protocatechuate pathway (pobA and pcaHG) are also negatively modulated by Crc. However, the pathway for phenylacetate appeared to be unaffected by Crc. These results expand the influence of Crc to pathways used to assimilate several aromatic compounds, which highlights its importance as a master regulator of carbon metabolism in P. putida.
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Affiliation(s)
- Gracia Morales
- Departamento de Biotecnología Microbiana. Servicio de Proteómica, Centro Nacional de Biotecnología, CSIC, Campus de la Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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