Significance Metagenomic data have recently transformed our view of the role played by sulfur metabolism in anoxic environments showing that this trait is much more widespread than previously believed. A key enzyme dissimilatory sulfite reductase DsrAB ubiquitous organisms with a reductive, oxidative, or disproportionating activity. However, function some dsr genes, such as dsrD , has so far been unknown despite its use functional marker to genomically assign type energy metabolism,...

The thermodynamic properties of the Desulfovibrio vulgaris (Hildenborough) tetrahaem cytochrome c 3 (Dv ) are rationalised by a model which involves both homotropic (e − /e and heterotropic /H + cooperativity. paramagnetic shifts methyl group from each haem DV have been determined in stage oxidation at several pH values means two‐dimensional exchange NMR. parameters obtained fitting to NMR data redox titrations followed visible spectroscopy. They show significant positive cooperativity...

A prerequisite for any rational drug design strategy is understanding the mode of protein-ligand interaction. This motivated us to explore protein-substrate interaction in Type-II NADH:quinone oxidoreductase (NDH-2) from Staphylococcus aureus, a worldwide problem clinical medicine due its multiple resistant forms. NDHs-2 are involved respiratory chains and recognized as suitable targets novel antimicrobial therapies, these only enzymes with activity expressed many pathogenic organisms. We...

Abstract Shewanella are bacteria widespread in marine and brackish water environments emergent opportunistic pathogens. Their environmental versatility depends on the ability to produce numerous iron-rich proteins, mainly multiheme c -type cytochromes. Although iron plays a vital role of species, very few studies exist regarding strategies by which these scavenge from environment. Siderophore-mediated transport is commonly employed strategy for acquisition, it was identified among spp. over...

The bioenergetics of anaerobic metabolism frequently relies on redox loops performed by membrane complexes with substrate- and quinone-binding sites opposite sides the membrane. However, in sulfate respiration (a key process biogeochemical sulfur cycle), QrcABCD complex are periplasmic, their role energy conservation has not been elucidated. Here we show that Desulfovibrio vulgaris is electrogenic, as protons electrons required for quinone reduction extracted from membrane, a H+/e- ratio 1....

is an opportunistic pathogen that has emerged as a major public health threat due to the increased incidence of its drug resistance.

The effect of pH on the glucose metabolism non-growing cells L. lactis MG1363 was studied by in vivo NMR range 4.8 to 6.5. Immediate effects transporters and/or enzyme activities were distinguished from transcriptional/translational using grown at optimal 6.5 or pre-adjusted low growth 5.1. In 5.1, proceeds a rate 35% higher than non-adjusted same pH. Besides upregulation stress-related genes (such as dnaK and groEL), adjusted overexpressed H+-ATPase subunits well glycolytic genes. At...

To fully understand the structural bases for mechanisms of biological energy transduction, it is essential to determine microscopic thermodynamic parameters which describe properties each centre involved in reactions, as well its interactions with others. These between centres can then be interpreted light features proteins. Redox titrations cytochrome c3 from Desulfovibrio desulfuricans ATCC 27774 followed by NMR and visible spectroscopy were analysed using an equilibrium model. The network...

Nuclear magnetic resonance and visible spectroscopies were used to determine the thermodynamic parameters of four hemes in cytochrome c3 from Desulfovibrio gigas at 298 277 K investigate mechanism electron/proton energy transduction. Data obtained pH range 5 9 analyzed according a model which interact with each other (redox cooperativities) an ionizable center (redox−Bohr cooperativities). The results two temperatures allow deconvolution entropic contribution free hemes, acid−base...

A thermodynamic model is presented to describe the redox behaviour of tetraheme cytochrome c 3 from Desulfovibrio gigas. This molecule displays different intrinsic potentials for four hemes and during titration Process, interactions among occur, thus altering values according which are oxidized [Santos, H., Moura, J. G., I., LeGall, & Xavier, A. V. (1984) Eur. Biochem. 141 , 283–296]. complex cooperative [Xavier, (1986) Inorg. 28 239–243] has been analyzed here using an I 2 H 4...

Trihaem cytochrome c 3 (also known as 551.5 and 7 ) is isolated from the periplasmic space of Desulfuromonas acetoxidans , a sulfur‐reducing bacterium. Thermodynamic kinetic data for trihaem are presented discussed in context possible physiological implications its functional properties with respect to natural habitat D. namely symbiont green sulfur bacteria working mini‐sulfuretum. The thermodynamic were determined through fit redox titration data, followed by NMR visible spectroscopy,...

BsDyP from<italic>Bacillus subtilis</italic>belongs to the new dye-decolourising peroxidase (DyP) family. Here, we use transient kinetics provide details on catalytic cycle of BsDyP.

Type-II NADH:quinone oxidoreductases (NDH-2s) are membrane proteins involved in respiratory chains and the only enzymes with oxidoreductase activity expressed Staphylococcus aureus (S. aureus), one of most common causes clinical infections. NDH-2s members two-Dinucleotide Binding Domains Flavoprotein (tDBDF) superfamily, having a flavin adenine dinucleotide, FAD, as prosthetic group NAD(P)H substrate. The establishment Charge-Transfer Complex (CTC) between isoalloxazine ring reduced...

Cell metabolism relies on energy transduction usually performed by complex membrane-spanning proteins that couple different chemical processes, <i>e.g.</i> electron and proton transfer in proton-pumps. There is great interest determining at the molecular level structural details control these events, particularly those involving multiple electrons protons, because tight required to avoid production of dangerous reactive intermediates. Tetraheme cytochrome <i>c</i>₃ a small soluble...

Data collected for interactions among redox centres, and between centres acid–base residues in a family of small multihaem cytochromes are analysed. The distance dependent attenuation the non‐surface charges, separations that range from 8 to 23 Å, can be described by simple function derived Debye–Hückel formalism, fit 9.5 7.6 as values relative dielectric constant Debye length, respectively. However, there is considerable scatter data despite structural similarities proteins, which discussed...

The tetraheme cytochrome c3 isolated from Desulfomicrobium baculatum (DSM 1743)(Dsmb) was cloned, and the sequence analysis showed that this differs in just three amino acid residues norvegicum (Dsmn): (DsmnXXDsmb) Thr-37 --> Ser, Val-45 Ala, Phe-88 Tyr. X-ray crystallography used to determine structure of Dsmb, showing it is very similar published Dsmn. A detailed thermodynamic kinetic characterization these two cytochromes performed by using NMR visible spectroscopy. results obtained show...

In the analysis of kinetic data from multicentre redox proteins, it is essential to distinguish between observable macroscopic rate constants and structurally relevant microscopic properties. This distinction complicated by existence interactions centres. The problem illustrated case two interacting centres generalised for stopped-flow reduction cytochrome c(3), in which four at least one proteolytic centre are mutually interacting. It shown that fast intramolecular electron transfer,...