Tungsten and molybdenum regulation of formate dehydrogenase expression in Desulfovibrio vulgaris Hildenborough.

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 FdhABC₃ protein being the main enzyme in cells grown in the presence of molybdenum.

Hydrogen as an energy source for the human pathogen Bilophila wadsworthia.

The gram-negative anaerobic gut bacterium Bilophila wadsworthia is the third most common isolate in perforated and gangrenous appendicitis, being also found in a variety of other infections. This organism performs a unique kind of anaerobic respiration in which taurine, a major organic solute in mammals, is used as a source of sulphite that serves as terminal acceptor for the electron transport chain. We show here that molecular hydrogen, one of the major products of fermentative bacteria in the colon, is an excellent growth substrate for B.

Energy metabolism in Desulfovibrio vulgaris Hildenborough: insights from transcriptome analysis.

Sulphate-reducing bacteria are important players in the global sulphur and carbon cycles, with considerable economical and ecological impact. However, the process of sulphate respiration is still incompletely understood. Several mechanisms of energy conservation have been proposed, but it is unclear how the different strategies contribute to the overall process.

The [NiFeSe] hydrogenase from Desulfovibrio vulgaris Hildenborough is a bacterial lipoprotein lacking a typical lipoprotein signal peptide.

Desulfovibrio vulgaris Hildenborough has a membrane-bound [NiFeSe] hydrogenase whose mode of membrane association was unknown since it is constituted by two hydrophilic subunits. This work shows that this hydrogenase is a bacterial lipoprotein bound to the membrane by lipidic groups found at the N-terminus of the large subunit, which is unusual since it is missing the typical lipoprotein signal peptide. Nevertheless, the large subunit has a conserved four residue lipobox and its synthesis is sensitive to the signal peptidase II inhibitor globomycin.

Selenium is involved in regulation of periplasmic hydrogenase gene expression in Desulfovibrio vulgaris Hildenborough.

Desulfovibrio vulgaris Hildenborough is a good model organism to study hydrogen metabolism in sulfate-reducing bacteria. Hydrogen is a key compound for these organisms, since it is one of their major energy sources in natural habitats and also an intermediate in the energy metabolism. The D.

Resonance Raman fingerprinting of multiheme cytochromes from the cytochrome c3 family.

Resonance Raman (RR) spectroscopy was used to investigate conformational characteristics of the hemes of several ferricytochromes of the cytochrome c3 family, electron transfer proteins isolated from the periplasm and membranes of sulfate-reducing bacteria. Our analysis concentrated on the low-frequency region of the RR spectra, a fingerprint region that includes vibrations for heme-protein C-S bonds [nu(C(a)S)]. It has been proposed that these bonds are directly involved in the electron transfer process.

Hydrogenases in Desulfovibrio vulgaris Hildenborough: structural and physiologic characterisation of the membrane-bound [NiFeSe] hydrogenase.

The genome of Desulfovibrio vulgaris Hildenborough (DvH) encodes for six hydrogenases (Hases), making it an interesting organism to study the role of these proteins in sulphate respiration. In this work we address the role of the [NiFeSe] Hase, found to be the major Hase associated with the cytoplasmic membrane. The purified enzyme displays interesting catalytic properties, such as a very high H(2) production activity, which is dependent on the presence of phospholipids or detergent, and resistance to oxygen inactivation since it is isolated aerobically in a Ni(II) oxidation state.

A novel membrane-bound Ech [NiFe] hydrogenase in Desulfovibrio gigas.

In the present study, we report the identification of an operon with six coding regions for a multisubunit membrane-bound [NiFe] hydrogenase in the genome of Desulfovibrio gigas. Sequence analysis of the deduced polypeptides reveals a high similarity to subunits of proteins belonging to the family of Ech hydrogenases. The operon is organised similarly to the operon coding for the Ech hydrogenase from Methanosarcina barkeri, suggesting that both encode very similar hydrogenases.

Sulfate respiration in Desulfovibrio vulgaris Hildenborough. Structure of the 16-heme cytochrome c HmcA AT 2.5-A resolution and a view of its role in transmembrane electron transfer.

The crystal structure of the high molecular mass cytochrome c HmcA from Desulfovibrio vulgaris Hildenborough is described. HmcA contains the unprecedented number of sixteen hemes c attached to a single polypeptide chain, is associated with a membrane-bound redox complex, and is involved in electron transfer from the periplasmic oxidation of hydrogen to the cytoplasmic reduction of sulfate. The structure of HmcA is organized into four tetraheme cytochrome c(3)-like domains, of which the first is incomplete and contains only three hemes, and the final two show great similarity to the nine-heme cytochrome c from Desulfovibrio desulfuricans.

Reclassification of the only species of the genus Desulfomonas, Desulfomonas pigra, as Desulfovibrio piger comb. nov.

The growth characteristics, DNA G+C content and sequences of 16S rDNA and the transcribed 16S-23S rDNA internal spacer were determined for Desulfomonas pigra ATCC 29098T, Desulfovibrio desulfuricans subsp. desulfuricans strains Essex 6T (= ATCC 29577T) and MB (= ATCC 27774) and 'Desulfovibrio fairfieldensis' ATCC 700045. Despite phenotypic differences (shape and motility) between Desulfomonas pigra and Desulfovibrio strains, the molecular analysis suggests that Desulfomonas pigra should be reclassified within the genus Desulfovibrio.