Selenium Is Involved in Regulation of Periplasmic Hydrogenase Gene Expression in
            <i>Desulfovibrio vulgaris</i>
            Hildenborough

Valente, Filipa M. A.; Almeida, Cláudia C.; Pacheco, Isabel; Carita, João N.; Saraiva, Lı́gia M.; Pereira, Inês A. C.

doi:10.1128/jb.188.9.3228-3235.2006

Cited by 59 publications

(59 citation statements)

References 39 publications

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“…The higher solubility of tungsten sulfides than molybdenum sulfides may change the relative abundance and bioavailability of these metals, and thus the capacity to use both of them increases the metabolic versatility and is likely to confer a selective advantage to the organism. A similar versatility is observed in D. vulgaris regarding the periplasmic uptake hydrogenases, where three different enzymes are expressed in response to Ni and Se availability (49). Thus, adaptation to trace element availability seems to be a fitness factor in D. vulgaris.…”

Section: Discussionmentioning

confidence: 57%

Tungsten and Molybdenum Regulation of Formate Dehydrogenase Expression in Desulfovibrio vulgaris Hildenborough

et al. 2011

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Formate is an important energy substrate for sulfate-reducing bacteria in natural environments, and both molybdenum-and tungsten-containing formate dehydrogenases have been reported in these organisms. In this work, we studied the effect of both metals on the levels of the three formate dehydrogenases encoded in the genome of Desulfovibrio vulgaris Hildenborough, with lactate, formate, or hydrogen as electron donors. Using Western blot analysis, quantitative real-time PCR, activity-stained gels, and protein purification, we show that a metal-dependent regulatory mechanism is present, resulting in the dimeric FdhAB protein being the main enzyme present in cells grown in the presence of tungsten and the trimeric FdhABC 3 protein being the main enzyme in cells grown in the presence of molybdenum. The putatively membrane-associated formate dehydrogenase is detected only at low levels after growth with tungsten. Purification of the three enzymes and metal analysis shows that FdhABC 3 specifically incorporates Mo, whereas FdhAB can incorporate both metals. The FdhAB enzyme has a much higher catalytic efficiency than the other two. Since sulfate reducers are likely to experience high sulfide concentrations that may result in low Mo bioavailability, the ability to use W is likely to constitute a selective advantage.Formate is a key metabolite in anaerobic habitats, arising as a metabolic product of bacterial fermentations and functioning as a growth substrate for many microorganisms (for example, methanogens and sulfate-reducing bacteria [SRB]). Formate is also an intermediate in the energy metabolism of several prokaryotes and a crucial compound in many syntrophic associations, whereby organisms live close to the thermodynamic limit (30,45). Recent reports indicate that formate plays an even more important role in anaerobic microbial metabolism than previously considered (14,24,27). The key enzyme in formate metabolism is formate dehydrogenase (FDH) (50), a member of the dimethyl sulfoxide (DMSO) reductase family. It catalyzes the reversible two-electron oxidation of formate or reduction of CO 2 and plays a role in energy metabolism and carbon fixation. In anaerobic microorganisms, FDH includes a molybdenum or tungsten bis-(pyranopterin guanidine dinucleotide) cofactor and iron-sulfur clusters (20, 41) and shows great variability in quaternary structure, physiological redox partner, and cellular location (7,23,38,50).FDH was the first enzyme shown to naturally incorporate tungsten, at a time when this element was considered to be mostly an antagonist to molybdenum (2, 52). Since then, several tungstoenzymes have been isolated and characterized, mainly but not exclusively from archaeal organisms, including FDHs, formylmethanofuran dehydrogenases (FMDH), aldehyde oxidoreductases (AOR) (not belonging to the xanthine oxidase family), and acetylene hydratase (3,4,20,25,31,41). FDHs and FMDHs can naturally incorporate either tungsten or molybdenum. Since these two elements have very similar chemical and catalytic properties,...

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Section: Discussionmentioning

confidence: 57%

Tungsten and Molybdenum Regulation of Formate Dehydrogenase Expression in Desulfovibrio vulgaris Hildenborough

et al. 2011

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“…The impaired growth of the hys mutants might indicate the importance of the [NiFeSe] hydrogenase for lactate fermentation during the early stages of coculture growth with M. maripaludis, while the [NiFe] hydrogenase is more important under steady-state conditions in the chemostat. The hydrogenases possess unique kinetic properties as a result of dissimilar metal compositions in their active sites and are differently regulated in D. vulgaris strain Hildenborough during sulfate respiration as a function of medium composition and growth conditions (64)(65)(66). Both, hyn and hys were suggested to function bidirectionally (67); however, the recently discovered supercomplex between the [NiFe] hydrogenase, TpIc 3 , and Qrc (68) might ensure an optimized electron transfer that is necessary for syntrophic H 2 production under constantly elevated H 2 levels.…”

Section: Discussionmentioning

confidence: 99%

Variation among Desulfovibrio Species in Electron Transfer Systems Used for Syntrophic Growth

Meyer

Kuehl

Deutschbauer

et al. 2012

Journal of Bacteriology

102

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bMineralization of organic matter in anoxic environments relies on the cooperative activities of hydrogen producers and consumers linked by interspecies electron transfer in syntrophic consortia that may include sulfate-reducing species (e.g., Desulfovibrio). Physiological differences and various gene repertoires implicated in syntrophic metabolism among Desulfovibrio species suggest considerable variation in the biochemical basis of syntrophy. In this study, comparative transcriptional and mutant analyses of Desulfovibrio alaskensis strain G20 and Desulfovibrio vulgaris strain Hildenborough growing syntrophically with Methanococcus maripaludis on lactate were used to develop new and revised models for their alternative electron transfer and energy conservation systems. Lactate oxidation by strain G20 generates a reduced thiol-disulfide redox pair(s) and ferredoxin that are energetically coupled to H ؉ /CO 2 reduction by periplasmic formate dehydrogenase and hydrogenase via a flavin-based reverse electron bifurcation process (electron confurcation) and a menaquinone (MQ) redox loop-mediated reverse electron flow involving the membrane-bound Qmo and Qrc complexes. In contrast, strain Hildenborough uses a larger number of cytoplasmic and periplasmic proteins linked in three intertwining pathways to couple H ؉ reduction to lactate oxidation. The faster growth of strain G20 in coculture is associated with a kinetic advantage conferred by the Qmo-MQ-Qrc loop as an electron transfer system that permits higher lactate oxidation rates under elevated hydrogen levels (thereby enhancing methanogenic growth) and use of formate as the main electron-exchange mediator (>70% electron flux), as opposed to the primarily hydrogen-based exchange by strain Hildenborough. This study further demonstrates the absence of a conserved gene core in Desulfovibrio that would determine the ability for a syntrophic lifestyle. In anoxic environments depleted in inorganic electron acceptors (e.g., freshwater and marine sediments, flooded soils, landfills, and sewage digesters), the complete mineralization of complex organic matter to CO 2 and methane relies on the cooperative activities of phylogenetically and metabolically distinct microbial groups assembled in syntrophic consortia. In these assemblages, sulfate-reducing bacteria (SRB) function as secondary fermenters obligately linked via interspecies electron transfer to the metabolic activity of methanogenic archaea since the oxidation of common substrates (organic acids and alcohols) yields sufficient energy only for cell maintenance and growth when the methanogens maintain low concentrations of the products of SRB metabolism (acetate, hydrogen, and formate) (1-3). As a result, the metabolism of one community member is directly influenced by and dependent upon the activity of the other. Hydrogen and formate are considered the primary shuttle compounds for interspecies electron transfer (1-3). Additionally, single reports suggest the involvement of cysteine or exogenous carriers such as humi...

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“…In the present work the genes for the periplasmic hydrogenases (Valente et al 2006). Since the [NiFeSe] hydrogenase is much less sensitive to oxygen than the other periplasmic hydrogenases (Valente et al 2005), it makes sense that it should be up-regulated in these conditions.…”

Section: Genes Involved In Energy Metabolismmentioning

confidence: 99%

Transcriptional response of Desulfovibrio vulgaris Hildenborough to oxidative stress mimicking environmental conditions

Pereira

Xavier

et al. 2007

Arch Microbiol

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Sulphate-reducing bacteria are anaerobes readily found in oxic-anoxic interfaces. Multiple defence pathways against oxidative conditions were identified in these organisms and proposed to be differentially expressed under different concentrations of oxygen, contributing to their ability to survive oxic conditions. In this study, Desulfovibrio vulgaris Hildenborough cells were exposed to the highest concentration of oxygen that sulphate-reducing bacteria are likely to encounter in natural habitats, and the global transcriptomic response was determined. 307 genes were responsive, with cellular roles in energy metabolism, protein fate, cell envelope and regulatory functions, including multiple genes encoding heat shock proteins, peptidases and proteins with heat shock promoters. Of the oxygen reducing mechanisms of D. vulgaris only the periplasmic hydrogen-dependent mechanism is up-regulated, involving the [NiFeSe] hydrogenase, formate dehydrogenase(s) and the Hmc membrane complex. The oxidative defence response concentrates on damage repair by metal-free enzymes. . These data, together with the down regulation of the Fur operon, which restricts the availability of iron, and the lack of response of the PerR operon, suggest that a major effect of this oxygen stress is the inactivation and/or degradation of multiple metalloproteins present in D. vulgaris as a consequence of oxidative damage to their metal clusters.

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Selenium Is Involved in Regulation of Periplasmic Hydrogenase Gene Expression in Desulfovibrio vulgaris Hildenborough

Cited by 59 publications

References 39 publications

Tungsten and Molybdenum Regulation of Formate Dehydrogenase Expression in Desulfovibrio vulgaris Hildenborough

Tungsten and Molybdenum Regulation of Formate Dehydrogenase Expression in Desulfovibrio vulgaris Hildenborough

Variation among Desulfovibrio Species in Electron Transfer Systems Used for Syntrophic Growth

Transcriptional response of Desulfovibrio vulgaris Hildenborough to oxidative stress mimicking environmental conditions

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