| simple formal kinetics for the reversible uptake of molecular hydrogen by [ni-fe] hydrogenase from desulfovibrio gigas. | enzymatic electrocatalysis, triggered and monitored by means of cyclic voltammetry, enabled us to achieve quantitative analysis of the kinetics of the hydrogenase catalyzed process, in the 7.8-10.0 ph range, in the presence of an electrochemically generated redox mediator. the quantitative analysis can be carried out by use of a quite simple src model. the simplicity of the src model is compatible with the existence of multiple redox microstates, which can be combined in a potential adjustable t ... | 2000 | 11054107 |
| transition from anaerobic to aerobic growth conditions for the sulfate-reducing bacterium desulfovibrio oxyclinae results in flocculation. | a chemostat culture of the sulfate-reducing bacterium desulfovibrio oxyclinae isolated from the oxic layer of a hypersaline cyanobacterial mat was grown anaerobically and then subjected to gassing with 1% oxygen, both at a dilution rate of 0.05 h(-1). the sulfate reduction rate under anaerobic conditions was 370 nmol of so(4)(2-) mg of protein(-1) min(-1). at the onset of aerobic gassing, sulfate reduction decreased by 40%, although viable cell numbers did not decrease. after 42 h, the sulfate r ... | 2000 | 11055956 |
| sulfate reduction and possible aerobic metabolism of the sulfate-reducing bacterium desulfovibrio oxyclinae in a chemostat coculture with marinobacter sp. strain mb under exposure to increasing oxygen concentrations. | a chemostat coculture of the sulfate-reducing bacterium desulfovibrio oxyclinae together with a facultative aerobe heterotroph tentatively identified as marinobacter sp. strain mb was grown under anaerobic conditions and then exposed to a stepwise-increasing oxygen influx (0 to 20% o(2) in the incoming gas phase). the coculture consumed oxygen efficiently, and no residual oxygen was detected with an oxygen supply of up to 5%. sulfate reduction persisted at all levels of oxygen input, even at the ... | 2000 | 11055957 |
| oxygen-dependent growth of the sulfate-reducing bacterium desulfovibrio oxyclinae in coculture with marinobacter sp. strain mb in an aerated sulfate-depleted chemostat. | a chemostat coculture of the sulfate-reducing bacterium desulfovibrio oxyclinae and the facultatively aerobic heterotroph marinobacter sp. strain mb was grown for 1 week under anaerobic conditions at a dilution rate of 0.05 h(-1). it was then exposed to an oxygen flux of 223 micromol min(-1) by gassing the growth vessel with 5% o(2). sulfate reduction persisted under these conditions, though the amount of sulfate reduced decreased by 45% compared to the amount reduced during the initial anaerobi ... | 2000 | 11055958 |
| heteronuclear relayed e.cosy revisited: determination of 3j(h(alpha),c(gamma)) couplings in asx and aromatic residues in proteins. | constant-time 3d heteronuclear relayed e.cosy [schmidt et al. (1996) j. biomol. nmr, 7, 142-152], as based on generic 2d small-flip-angle hmqc-cosy [schmidt et al. (1995) j. biomol. nmr, 6, 95-105], has been modified to allow for quantitative determination of heteronuclear three-bond 3j(h(alpha),c(gamma)) couplings. the method is applicable to amino acid spin topologies with carbons in the gamma position which lack attached protons, i.e. to asparagine, aspartate, and aromatic residues in uniform ... | 2000 | 11061224 |
| structure of a dioxygen reduction enzyme from desulfovibrio gigas. | desulfovibrio gigas is a strict anaerobe that contains a well-characterized metabolic pathway that enables it to survive transient contacts with oxygen. the terminal enzyme in this pathway, rubredoxin:oxygen oxidoreductase (roo) reduces oxygen to water in a direct and safe way. the 2.5 a resolution crystal structure of roo shows that each monomer of this homodimeric enzyme consists of a novel combination of two domains, a flavodoxin-like domain and a zn-beta-lactamase-like domain that contains a ... | 2000 | 11062560 |
| oxygen detoxification in the strict anaerobic archaeon archaeoglobus fulgidus: superoxide scavenging by neelaredoxin. | archaeoglobus fulgidus is a hyperthermophilic sulphate-reducing archaeon. it has an optimum growth temperature of 83 degrees c and is described as a strict anaerobe. its genome lacks any homologue of canonical superoxide (o2.-) dismutases. in this work, we show that neelaredoxin (nlr) is the main o2.- scavenger in a. fulgidus, by studying both the wild-type and recombinant proteins. nlr is a 125-amino-acid blue-coloured protein containing a single iron atom/molecule, which in the oxidized state ... | 2000 | 11069658 |
| iron hydrogenases and the evolution of anaerobic eukaryotes. | hydrogenases, oxygen-sensitive enzymes that can make hydrogen gas, are key to the function of hydrogen-producing organelles (hydrogenosomes), which occur in anaerobic protozoa scattered throughout the eukaryotic tree. hydrogenases also play a central role in the hydrogen and syntrophic hypotheses for eukaryogenesis. here, we show that sequences related to iron-only hydrogenases ([fe] hydrogenases) are more widely distributed among eukaryotes than reports of hydrogen production have suggested. ge ... | 2000 | 11070057 |
| hybrid-cluster protein (hcp) from desulfovibrio vulgaris (hildenborough) at 1.6 a resolution. | the three-dimensional structure of the hybrid cluster protein from desulfovibrio vulgaris (hildenborough) has been determined at 1.6 a resolution using synchrotron x-ray radiation. the protein can be divided into three domains: an n-terminal mainly alpha-helical domain and two similar domains comprising a central beta-sheet flanked by alpha-helices. the protein contains two 4fe clusters with an edge-to-edge distance of 10.9 a. four cysteine residues at the n-terminus of the protein are ligands t ... | 2000 | 11106482 |
| rubrerythrin and rubredoxin oxidoreductase in desulfovibrio vulgaris: a novel oxidative stress protection system. | evidence is presented for an alternative to the superoxide dismutase (sod)-catalase oxidative stress defense system in desulfovibrio vulgaris (strain hildenborough). this alternative system consists of the nonheme iron proteins, rubrerythrin (rbr) and rubredoxin oxidoreductase (rbo), the product of the rbo gene (also called desulfoferrodoxin). a deltarbo strain of d. vulgaris was found to be more sensitive to internal superoxide exposure than was the wild type. unlike rbo, expression of plasmid- ... | 2001 | 11114906 |
| spectroscopic studies and characterization of a novel electron-transfer chain from escherichia coli involving a flavorubredoxin and its flavoprotein reductase partner. | a novel two-component enzyme system from escherichia coli involving a flavorubredoxin (flrd) and its reductase was studied in terms of spectroscopic, redox, and biochemical properties of its constituents. flrd contains one fmn and one rubredoxin (rd) center per monomer. to assess the role of the rd domain, flrd and a truncated form lacking the rd domain (flrddeltard), were characterized. flrd contains 2.9+/-0.5 iron atoms/subunit, whereas flrddeltard contains 2.1+/-0.6 iron atoms/subunit. while ... | 2000 | 11123953 |
| is there a rate-limiting step in the catalytic cycle of ni-fe hydrogenases? | the question of the existence of a rate-limiting step in the catalytic cycle of ni-fe hydrogenases was taken up by using the sets of data available in the case of two specific enzymes: the hydrogenase from thiocapsa roseopercisina, in which isotope effects have been systematically investigated over a wide ph range, and the enzyme from desulfovibrio fructosovorans, for which the activities and the redox properties have been studied in two different forms, the wild type and the p238c mutant. when ... | 2000 | 11128995 |
| desulfoferrodoxin: a modular protein. | the gene encoding the non-heme iron-containing desulfoferrodoxin from desulfovibrio vulgaris was cloned in two fragments in order to obtain polypeptides corresponding to the n- and c-terminal domains observed in the tertiary structure. these fragments were expressed in escherichia coli, purified to homogeneity and biochemically and spectroscopically characterized. both recombinant fragments behaved as independent metal-binding domains. the n-terminal fragment exhibited properties similar to desu ... | 2000 | 11128999 |
| ionic strength dependence of the non-physiological electron transfer between flavodoxin and cytochrome c553 from d vulgaris. | a hypothetical model for the non-physiological electron transfer complex between cytochrome c553 (c553) and the flavodoxin (fld) from the sulphate-reducing bacteria desulfovibrio vulgaris has been recently published [1] based on rigid-body docking and refined by molecular dynamics. in this study, the functional validity of this model is tested by looking at the role of electrostatics in the non-physiological interprotein electron transfer between the two proteins at different ionic strengths. th ... | 2000 | 11129000 |
| redox thermodynamics of low-potential iron-sulfur proteins. | the enthalpy and entropy changes associated with protein reduction (deltahdegrees,(rc), deltasdegrees,(rc)) were determined for a number of low-potential iron-sulfur proteins through variable temperature direct electrochemical experiments. these data add to previous estimates making available, overall, the reduction thermodynamics for twenty species from various sources containing all the different types of metal centers. these parameters are discussed with reference to structural data and calcu ... | 2000 | 11129002 |
| a member of the delta subgroup of proteobacteria from a pyogenic liver abscess is a typical sulfate reducer of the genus desulfovibrio. | strain fh26001/95 (atcc 700045) was previously isolated from a pyogenic liver abscess from a human. comparative 16s rrna gene sequence analysis showed that this strain is related to members of the delta subgroup of the proteobacteria, within a cluster of sulfate-reducing bacteria (desulfovibrio spp.) and non-sulfate-reducing bacteria (bilophila wadsworthia and lawsonia spp.). the phenotype of strain fh26001/95 was found to be typical of members of the genus desulfovibrio. growth and substrate tr ... | 2001 | 11158153 |
| five-gene cluster in clostridium thermoaceticum consisting of two divergent operons encoding rubredoxin oxidoreductase- rubredoxin and rubrerythrin-type a flavoprotein- high-molecular-weight rubredoxin. | a five-gene cluster encoding four nonheme iron proteins and a flavoprotein from the thermophilic anaerobic bacterium clostridium thermoaceticum (moorella thermoacetica) was cloned and sequenced. based on analysis of deduced amino acid sequences, the genes were identified as rub (rubredoxin), rbo (rubredoxin oxidoreductase), rbr (rubrerythrin), fpra (type a flavoprotein), and a gene referred to as hrb (high-molecular-weight rubredoxin). northern blot analysis demonstrated that the five-gene clust ... | 2001 | 11160086 |
| dissimilatory sulfite reductase (desulfoviridin) of the taurine-degrading, non-sulfate-reducing bacterium bilophila wadsworthia rzatau contains a fused dsrb-dsrd subunit. | a dissimilatory sulfite reductase (dsr) was purified from the anaerobic, taurine-degrading bacterium bilophila wadsworthia rzatau to apparent homogeneity. the enzyme is involved in energy conservation by reducing sulfite, which is formed during the degradation of taurine as an electron acceptor, to sulfide. according to its uv-visible absorption spectrum with maxima at 392, 410, 583, and 630 nm, the enzyme belongs to the desulfoviridin type of dsrs. the sulfite reductase was isolated as an alpha ... | 2001 | 11160104 |
| analysis of the desulfovibrio gigas transcriptional unit containing rubredoxin (rd) and rubredoxin-oxygen oxidoreductase (roo) genes and upstream orfs. | rubredoxin-oxygen oxidoreductase, an 86-kda homodimeric flavoprotein, is the final component of a soluble electron transfer chain that couples nadh oxidation with oxygen reduction to water from the sulfate-reducing bacterium desulfovibrio gigas. a 4.2-kb fragment of d. gigas chromosomal dna containing the roo gene and the rubredoxin gene was sequenced. additional open reading frames designated as orf-1, orf-2, and orf-3 were also identified in this dna fragment. orf-1 encodes a protein exhibitin ... | 2001 | 11162545 |
| three-dimensional structure of the nonaheme cytochrome c from desulfovibrio desulfuricans essex in the fe(iii) state at 1.89 a resolution. | a nine heme group containing cytochrome c isolated from the soluble and membrane fractions of desulfovibrio desulfuricans essex, termed nonaheme cytochrome c, was crystallized, and the structure was solved using the multiple wavelength anomalous dispersion (mad) phasing method. refinement was carried out to a resolution of 1.89 a, and anisotropic temperature factors were addressed to the iron and sulfur atoms in the model. the structure revealed two cytochrome c(3) like domains with the typical ... | 2001 | 11170457 |
| nonaheme cytochrome c, a new physiological electron acceptor for [ni,fe] hydrogenase in the sulfate-reducing bacterium desulfovibrio desulfuricans essex: primary sequence, molecular parameters, and redox properties. | a nonaheme cytochrome c was purified to homogeneity from the soluble and the membrane fractions of the sulfate-reducing bacterium desulfovibrio desulfuricans essex. the gene encoding for the protein was cloned and sequenced. the primary structure of the multiheme protein was highly homologous to that of the nonaheme cytochrome c from d. desulfuricans atcc 27774 and to that of the 16-heme hmca protein from desulfovibrio vulgaris hildenborough. the analysis of the sequence downstream of the gene e ... | 2001 | 11170458 |
| two-iron rubredoxin of pseudomonas oleovorans: production, stability and characterization of the individual iron-binding domains by optical, cd and nmr spectroscopies. | a minigene encoding the c-terminal domain of the 2fe rubredoxin of pseudomonas oleovorans was created from the parental alk g gene contained in the expression plasmid pkk223-3. the vector directed the high-level production of the c-terminal domain of this rubredoxin; a simple procedure was used to purify the recombinant domain in the 1fe form. the 1fe form of the c-terminal domain was readily converted into the apoprotein and cadmium forms after precipitation with trichloroacetic acid and resolu ... | 2001 | 11171083 |
| structure determination of bacterioferritin from desulfovibrio desulfuricans by the mad method at the fe k-edge. | bacterioferritins constitute a subfamily of heme ferritins, proteins involved in iron storage and homeostasis. the protein isolated from desulfovibrio desulfuricans atcc 27774 is a homodimer of mass 52 kda. the monomers are linked by an iron-coproporphyrin group and each monomer contains a diferric center. the 24-monomer clusters found in the crystal are probably the functional particles. mad data from cubic bacterioferritin crystals were collected at the k-shell iron edge. preliminary phasing w ... | 2001 | 11173495 |
| volatile sulfur production by pig cecal bacteria in batch culture and screening inhibitors of sulfate reducing bacteria. | we studied the effects of specific inhibitors of methanogenesis (2-bromoethane sulfonate, bes) and sulfate reduction (sodium molybdate) on volatile sulfur production in batch cultures of pig cecal bacteria. the volatile sulfur concentration in headspace gas was determined by flame-photometric detector gas chromatography. bes stimulated production of hydrogen sulfide (h2s) and methanethiol, and sodium molybdate completely inhibited the production of these volatile sulfur compounds. the results in ... | 2000 | 11185657 |
| [nife] hydrogenase from desulfovibrio desulfuricans atcc 27774: gene sequencing, three-dimensional structure determination and refinement at 1.8 a and modelling studies of its interaction with the tetrahaem cytochrome c3. | the primary and three-dimensional structures of a [nife] hydrogenase isolated from d. desulfitricans atcc 27774 were determined, by nucleotide analysis and single-crystal x-ray crystallography. the three-dimensional structural model was refined to r=0.167 and rfree=0.223 using data to 1.8 a resolution. two unique structural features are observed: the [4fe-4s] cluster nearest the [nife] centre has been modified [4fe-3s-3o] by loss of one sulfur atom and inclusion of three oxygen atoms; a three-fo ... | 2001 | 11191224 |
| modeling the active sites of metalloenzymes. 4. predictions of the unready states of [nife] desulfovibrio gigas hydrogenase from density functional theory. | density functional theory has been used to predict the structures of a variety of active site models for the unready states, ni-a and ni-su, of the [nife] hydrogenase from desulfovibrio gigas. by comparing available experimental results on ni-a, ni-su, and ni-si with the computational results on these model complexes, we have been able to identify the most likely formulas and structures for the active sites of ni-a and ni-su. ni-a is predicted to be a ni(iii)-fe(ii) species with the bridging hyd ... | 2001 | 11195380 |
| eseem and mims endor spectroscopies of cis,trans-(l-n2s2)movo(sch2ph): detection of the two benzylthiolate alpha protons. | | 2000 | 11196982 |
| engineering artificial redox chains by molecular 'lego'. | this work reports on a novel approach for building artificial redox chains: the molecular 'lego' approach. this exploits the scaffold of natural redox proteins by fusing together functional protein modules with the desired properties. the molecular 'lego' mimics the natural molecular evolution that proceeded by modular assembly of genes/dna segments. non-physiological electron transfer partners, flavodoxin (fld) and cytochrome c553 (c553) from desulfovibrio vulgaris and the haem domain of p450 b ... | 2000 | 11197475 |
| aerotaxis in desulfovibrio. | aerotaxis of two sulphate-reducing bacteria, the freshwater strain desulfovibrio desulfuricans csn (dsm 9104) and the marine strain desulfovibrio oxyclinae n13 (dsm 11498), was studied using capillary microslides, microscopy and oxygen microsensors. the bacteria formed ring-shaped bands in oxygen diffusion gradients surrounding o2 bubbles, which were placed into anoxic sulphate-free cell suspensions in capillary microslides. the radial expansion of the oxic volume by diffusion was stopped by aer ... | 1999 | 11207770 |
| cloning and expression of the catalase gene from the anaerobic bacterium desulfovibrio vulgaris (miyazaki f). | we identified a gene encoding a catalase from the anaerobic bacteria desulfovibrio vulgaris (miyazaki f), and the expression of its gene in escherichia coli. the 3.3-kbp dna fragment isolated from d. vulgaris (miyazaki f) by double digestion with ecori and sali was found to produce a protein that binds protoheme ix as a prosthetic group in e. coli. this dna fragment contained a putative open reading frame (kat) and one part of another open reading frame (orf-1). the amino acid sequence of the am ... | 2001 | 11226874 |
| purification and characterization of homo- and hetero-dimeric acetate kinases from the sulfate-reducing bacterium desulfovibrio vulgaris. | two distinct forms of acetate kinase were purified to homogeneity from a sulfate-reducing bacterium desulfovibrio vulgaris miyazaki f. the enzymes were separated from the soluble fraction of the cells on anion exchange columns. one acetate kinase (ak-i) was a homodimer (alpha(s)(2)) and the other (ak-ii) was a heterodimer (alpha(s)alpha(l)). on sds-page, alpha(l) and alpha(s) subunits migrated as bands of 49.3 and 47.8 kda, respectively, but they had an identical n-terminal amino acid sequence. ... | 2001 | 11226881 |
| enzymatic reduction of chromate: comparative studies using sulfate-reducing bacteria. key role of polyheme cytochromes c and hydrogenases. | various sulfate-reducing bacteria of the genera desulfovibrio and desulfomicrobium were tested and compared for enzymatic reduction of chromate. our study demonstrated that the ability to reduce chromate is widespread among sulfate-reducing bacteria. among them, desulfomicrobium norvegicum reduced cr(vi) with the highest reaction rate. this strain grew in the presence of up to 500 microm chromate, but cr(vi) reduction in the absence of sulfate was not associated with growth. the presence of chro ... | 2001 | 11234966 |
| evaluation of the hydrogen bonding interactions and their effects on the oxidation-reduction potentials for the riboflavin complex of the desulfovibrio vulgaris flavodoxin. | the oxidation-reduction potentials for the riboflavin complex of the desulfovibrio vulgaris flavodoxin are substantially different from those of the flavin mononucleotide (fmn) containing native protein, with the midpoint potential for the semiquinone-hydroquinone couple for the riboflavin complex being 180 mv less negative. this increase has been attributed to the absence in the riboflavin complex of unfavorable electrostatic effects of the dianionic 5'-phosphate of the fmn on the stability of ... | 2001 | 11245795 |
| crystal structure of the 100 kda arsenite oxidase from alcaligenes faecalis in two crystal forms at 1.64 a and 2.03 a. | arsenite oxidase from alcaligenes faecalis ncib 8687 is a molybdenum/iron protein involved in the detoxification of arsenic. it is induced by the presence of aso(2-) (arsenite) and functions to oxidize as(iii)o(2-), which binds to essential sulfhydryl groups of proteins and dithiols, to the relatively less toxic as(v)o(4)(3-) (arsenate) prior to methylation. | 2001 | 11250197 |
| structures and comparison of the y98h (2.0 a) and y98w (1.5 a) mutants of flavodoxin (desulfovibrio vulgaris). | the structures for two mutants at the tyr98 site of desulfovibrio vulgaris flavodoxin have been determined. the first, a tyrosine-to-histidine (y98h) variant, was determined at the moderately high resolution of 2.0 a, while the tyrosine-to-tryptophan variant (y98w) yielded very high resolution data (beyond 1.5 a) allowing a detailed look at the water structure, alternate side-chain conformations and the planarity of the fmn. both structures were solved by molecular replacement beginning with the ... | 2001 | 11264581 |
| a simple, rapid, and highly efficient gene expression system for multiheme cytochromes c. | the genes of tetraheme cytochrome c3 and hexadecaheme high-molecular-weight cytochrome c from desulfovibrio vulgaris could be overexpressed as holoproteins in shewanella oneidensis tsp-c using puc-type vectors of e. coli. surprisingly, s. oneidensis was transformed directly by puc-type vectors through electroporation. the yields of the recombinant proteins in this expression system were much higher than the previously reported ones. | 2001 | 11272827 |
| metabolism of benzoate, cyclohex-1-ene carboxylate, and cyclohexane carboxylate by "syntrophus aciditrophicus" strain sb in syntrophic association with h(2)-using microorganisms. | the metabolism of benzoate, cyclohex-1-ene carboxylate, and cyclohexane carboxylate by "syntrophus aciditrophicus" in cocultures with hydrogen-using microorganisms was studied. cyclohexane carboxylate, cyclohex-1-ene carboxylate, pimelate, and glutarate (or their coenzyme a [coa] derivatives) transiently accumulated during growth with benzoate. identification was based on comparison of retention times and mass spectra of trimethylsilyl derivatives to the retention times and mass spectra of authe ... | 2001 | 11282627 |
| colonic infection by bilophila wadsworthia in pigs. | bilophila wadsworthia is a common inhabitant of the human colon and has been associated with appendicitis and other local sites of inflammation in humans. challenge-exposure or prevalence studies in laboratory and other animals have not been reported. b. wadsworthia is closely related phylogenetically to desulfovibrio sp. and lawsonia intracellularis, which are considered colon pathogens. we developed a pcr specific for b. wadsworthia dna. samples of bacterial dna extracted from the feces of pig ... | 2001 | 11283090 |
| differences between desulfovibrio desulfuricans intestinal strains with respect to their ability of sulphasalazine biotransformation. | in presented study, differences among six intestinal desulfovibrio desulfuricans strains were investigated regarding their ability of sulphasalazine (sas) biotransformation. bacterial strains were incubated (24 or 48 h) in liquid medium supplemented with sas (12.2-150 microm). it has been demonstrated that investigated d. desulfuricans strains converted sas with various rates, depending on the strain used and on time of drug contact with bacterial cells. significantly different (50% coefficient ... | 2000 | 11293241 |
| equilibrium unfolding of dimeric desulfoferrodoxin involves a monomeric intermediate: iron cofactors dissociate after polypeptide unfolding. | here we report the conformational stability of homodimeric desulfoferrodoxin (dfx) from desulfovibrio desulfuricans (atcc 27774). the dimer is formed by two dfx monomers linked through beta-strand interactions in two domains; in addition, each monomer contains two different iron centers: one fe-(s-cys)(4) center and one fe-[s-cys+(n-his)(4)] center. the dissociation constant for dfx was determined to be 1 microm (deltag = 34 kj/mol of dimer) from the concentration dependence of aromatic residue ... | 2001 | 11305909 |
| superoxide reductase from desulfoarculus baarsii: reaction mechanism and role of glutamate 47 and lysine 48 in catalysis. | superoxide reductase (sor) is a small metalloenzyme that catalyzes reduction of o(2)(*)(-) to h(2)o(2) and thus provides an antioxidant mechanism against superoxide radicals. its active site contains an unusual mononuclear ferrous center, which is very efficient during electron transfer to o(2)(*)(-) [lombard, m., fontecave, m., touati, d., and nivière, v. (2000) j. biol. chem. 275, 115-121]. the reaction of the enzyme from desulfoarculus baarsii with superoxide was studied by pulse radiolysis m ... | 2001 | 11305919 |
| coexistence of a sulphate-reducing desulfovibrio species and the dehalorespiring desulfitobacterium frappieri tce1 in defined chemostat cultures grown with various combinations of sulfate and tetrachloroethene. | a two-member co-culture consisting of the dehalorespiring desulfitobacterium frappieri tce1 and the sulphate-reducing desulfovibrio sp. strain sulf1 was obtained via anaerobic enrichment from soil contaminated with tetrachloroethene (pce). in this co-culture, pce dechlorination to cis-dichloroethene was due to the activity of the dehalorespiring bacterium only. chemostat experiments with lactate as the primary electron donor for both strains along with varying sulphate and pce concentrations sho ... | 2001 | 11321548 |
| coiiiedta- reduction by desulfovibrio vulgaris and propagation of reactions involving dissolved sulfide and polysulfides. | the migration of 60co, dominantly via transport of co-edta complexes, into surface water and groundwater is a recognized concern at many nuclear production and storage sites. reduction of coiiiedta- to coiiedta2- should decrease the mobility of 60co in natural environments by stimulating ligand displacement with fe(iii) or al(iii) or by precipitation of cosx in sulfidic environments. in this study, we examine direct (enzymatic) and indirect (metabolite) reduction processes of coiiiedta- by the s ... | 2001 | 11329708 |
| the 'strict' anaerobe desulfovibrio gigas contains a membrane-bound oxygen-reducing respiratory chain. | sulfate-reducing bacteria are considered as strict anaerobic microorganisms, in spite of the fact that some strains have been shown to tolerate the transient presence of dioxygen. this report shows that membranes from desulfovibrio gigas grown in fumarate/sulfate contain a respiratory chain fully competent to reduce dioxygen to water. in particular, a membrane-bound terminal oxygen reductase, of the cytochrome bd family, was isolated, characterized, and shown to completely reduce oxygen to water ... | 2001 | 11343703 |
| two crystal structures of the cytoplasmic molybdate-binding protein modg suggest a novel cooperative binding mechanism and provide insights into ligand-binding specificity. | the x-ray structures of the cytoplasmic molybdate-binding protein modg from azotobacter vinelandii in two different crystal forms have been determined. for such a small protein it is remarkably complex. each 14.3 kda subunit contains two small beta-barrel domains, which display an ob-fold motif, also seen in the related structure of mode, a molybdenum-dependent transcriptional regulator, and very recently in the mop protein that, like modg, has been implicated in molybdenum homeostasis within th ... | 2001 | 11352591 |
| spectroscopic investigation and determination of reactivity and structure of the tetraheme cytochrome c3 from desulfovibrio desulfuricans essex 6. | cytochrome c3, a small (14-kda) soluble tetraheme protein was isolated from the periplasmic fraction of desulfovibrio desulfuricans strain essex 6. its major physiological function appears to be that of an electron carrier for the periplasmic hydrogenase. it has been also shown to interact with the high-molecular-mass cytochrome complex in the cytoplasmic membrane, which eventually feeds electrons into the membraneous quinone pool, as well as with the membrane-associated dissimilatory sulfite re ... | 2001 | 11358521 |
| the rate of formation of cytochrome c553 is not dependent on the nature of the unfolded state. | | 2001 | 11370667 |
| tungsten-containing formate dehydrogenase from desulfovibrio gigas: metal identification and preliminary structural data by multi-wavelength crystallography. | the tungsten-containing formate dehydrogenase (w-fdh) isolated from desulfovibrio gigas has been crystallized in space group p2(1), with cell parameters a = 73.8 a, b = 111.3 a, c = 156.6 a and beta = 93.7 degrees. these crystals diffract to beyond 2.0 a on a synchrotron radiation source. w-fdh is a heterodimer (92 kda and 29 kda subunits) and two w-fdh molecules are present in the asymmetric unit. although a molecular replacement solution was found using the periplasmic nitrate reductase as a s ... | 2001 | 11372198 |
| recent theoretical predictions of the active site for the observed forms in the catalytic cycle of ni-fe hydrogenase. | various states or forms of the active site in ni-fe hydrogenase, both catalytically active and inactive forms, have been identified and investigated experimentally. until recently, the geometric structure of each form remained an open question. several recent theoretical studies with density functional theory have attempted to redress this deficiency. in this commentary, the similarities and differences among the structures proposed by these studies will be addressed. | 2001 | 11372206 |
| the influence of fluid shear and aici3 on the material properties of pseudomonas aeruginosa pao1 and desulfovibrio sp. ex265 biofilms. | an understanding of the material properties of biofilms is important when describing how biofilms physically interact with their environment. in this study, aerobic biofilms of pseudomonas aeruginosa pao1 and anaerobic sulfate-reducing bacteria (srb) biofilms of desulfovibrio sp. ex265 were grown under different fluid shear stresses (tau g) in a chemostat recycle loop. individual biofilm microcolonies were deformed by varying the fluid wall shear stress (tau w). the deformation was quantified in ... | 2001 | 11381956 |
| the effect of culture media on antigenic expression in sulfate-reducing bacteria. | the importance of sulfate-reducing bacteria (srb) in nature has been widely recognized for many years. however, little is known about the ecology of srb. the problem has been detecting, classifying, and quantifying these organisms. there are many shortcomings in the use of culture media for this purpose. as an alternative, fluorescent antibody (fa) techniques were considered as a method for the detection and identification of srb. antisera were prepared against whole cells of different species o ... | 2001 | 11400049 |
| identifying regulators of transcription in an obligate intracellular pathogen: a metal-dependent repressor in chlamydia trachomatis. | a prominent feature exhibited by chlamydia trachomatis growing in an iron-limiting environment is a differential pattern of protein expression. in many bacteria, iron-responsive proteins are regulated at the level of transcription by a family of repressors resembling the escherichia coli ferric uptake regulator (fur) protein. although the chlamydial genome sequencing project did not unveil an obvious fur homologue, a detailed examination indicated five unassigned open reading frames (orfs) that ... | 2001 | 11401709 |
| relativistic dft calculations of the paramagnetic intermediates of [nife] hydrogenase. implications for the enzymatic mechanism. | | 2001 | 11403633 |
| isolation of desulfomicrobium orale sp. nov. and desulfovibrio strain ny682, oral sulfate-reducing bacteria involved in human periodontal disease. | the species of sulfate-reducing bacteria that prevail in sites affected by periodontal disease may be different from those commonly occurring in the digestive tracts of healthy individuals. ten strains of mesophilic sulfate-reducing bacteria (srb) were isolated from subgingival plaque in periodontal lesions of ten patients with periodontitis. characterization on the basis of morphological, physiological and phylogenetic properties demonstrated two distinct types of oral srb. one strain was a cur ... | 2001 | 11411671 |
| identification of a small tetraheme cytochrome c and a flavocytochrome c as two of the principal soluble cytochromes c in shewanella oneidensis strain mr1. | two abundant, low-redox-potential cytochromes c were purified from the facultative anaerobe shewanella oneidensis strain mr1 grown anaerobically with fumarate. the small cytochrome was completely sequenced, and the genes coding for both proteins were cloned and sequenced. the small cytochrome c contains 91 residues and four heme binding sites. it is most similar to the cytochromes c from shewanella frigidimarina (formerly shewanella putrefaciens) ncimb400 and the unclassified bacterial strain h1 ... | 2001 | 11425747 |
| mechanistic study of microbial control of hydrogen sulfide production in oil reservoirs. | microbial control of biogenic production of hydrogen sulfide in oil fields was studied in a model system consisting of pure cultures of the nitrate-reducing, sulfide-oxidizing bacterium (nr-sob) thiomicrospira sp. strain cvo and the sulfate-reducing bacterium (srb) desulfovibrio sp. strain lac6, as well as in microbial cultures enriched from produced water of a canadian oil reservoir. the presence of nitrate at concentrations up to 20 mm had little effect on the rate of sulfate reduction by a pu ... | 2001 | 11427944 |
| molecular characterization of desulfovibrio gigas neelaredoxin, a protein involved in oxygen detoxification in anaerobes. | desulfovibrio gigas neelaredoxin is an iron-containing protein of 15 kda, having a single iron site with a his(4)cys coordination. neelaredoxins and homologous proteins are widespread in anaerobic prokaryotes and have superoxide-scavenging activity. to further understand its role in anaerobes, its genomic organization and expression in d. gigas were studied and its ability to complement escherichia coli superoxide dismutase deletion mutant was assessed. in d. gigas, neelaredoxin is transcribed a ... | 2001 | 11443075 |
| identification of the gene encoding nadh-rubredoxin oxidoreductase in clostridium acetobutylicum. | nadh-rubredoxin oxidoreductase (nror), a flavoprotein from the obligately anaerobe clostridium acetobutylicum is encoded by an orf (nror) of 1140 nucleotides. whereas primary structure analysis reveals that nror has amino acid sequence patterns homologous with those involved in fad and nad-binding, the enzyme is distantly related to other flavoproteins in the databank. nror is highly active for reducing clostridial rubredoxin (rd) especially against c. acetobutylicum rd with an efficiency (k(cat ... | 2001 | 11444870 |
| use of 16s rrna-targeted oligonucleotide probes to investigate the distribution of sulphate-reducing bacteria in estuarine sediments. | the distribution of sulphate-reducing bacteria (srbs) in three anaerobic sediments, one predominantly freshwater and low sulphate and two predominantly marine and high sulphate, on the river tama, tokyo, japan, was investigated using 16s rrna-targeted oligonucleotide probes. hybridisation results and sulphate reduction measurements indicated that srbs are a minor part of the bacterial population in the freshwater sediments. only desulfobulbus and desulfobacterium were detected, representing 1.6% ... | 2001 | 11451520 |
| the genetic organization of desulfovibrio desulphuricans atcc 27774 bacterioferritin and rubredoxin-2 genes: involvement of rubredoxin in iron metabolism. | the anaerobic bacterium desulfovibrio desulphuricans atcc 27774 contains a unique bacterioferritin, isolated with a stable di-iron centre and having iron-coproporphyrin iii as its haem cofactor, as well as a type 2 rubredoxin with an unusual spacing of four amino acid residues between the first two binding cysteines. the genes encoding for these two proteins were cloned and sequenced. the deduced amino acid sequence of the bacterioferritin shows that it is among the most divergent members of thi ... | 2001 | 11454214 |
| crystallographic and ftir spectroscopic evidence of changes in fe coordination upon reduction of the active site of the fe-only hydrogenase from desulfovibrio desulfuricans. | fe-only hydrogenases, as well as their nife counterparts, display unusual intrinsic high-frequency ir bands that have been assigned to co and cn(-) ligation to iron in their active sites. ftir experiments performed on the fe-only hydrogenase from desulfovibrio desulfuricans indicate that upon reduction of the active oxidized form, there is a major shift of one of these bands that is provoked, most likely, by the change of a co ligand from a bridging position to a terminal one. indeed, the crysta ... | 2001 | 11456758 |
| mössbauer characterization of the iron-sulfur clusters in desulfovibrio vulgaris hydrogenase. | the periplasmic hydrogenase of desulfovibrio vulgaris (hildenbourough) is an all fe-containing hydrogenase. it contains two ferredoxin type [4fe-4s] clusters, termed the f clusters, and a catalytic h cluster. recent x-ray crystallographic studies on two fe hydrogenases revealed that the h cluster is composed of two sub-clusters, a [4fe-4s] cluster ([4fe-4s](h)) and a binuclear fe cluster ([2fe](h)), bridged by a cysteine sulfur. the aerobically purified d. vulgaris hydrogenase is stable in air. ... | 2001 | 11456963 |
| modeling the active sites in metalloenzymes. 3. density functional calculations on models for [fe]-hydrogenase: structures and vibrational frequencies of the observed redox forms and the reaction mechanism at the diiron active center. | optimized structures for the redox species of the diiron active site in [fe]-hydrogenase as observed by ftir and for species in the catalytic cycle for the reversible h(2) oxidation have been determined by density-functional calculations on the active site model, [(l)(co)(cn)fe(mu-pdt)(mu-co)fe(co)(cn)(l')](q)(l = h(2)o, co, h(2), h(-); pdt = sch(2)ch(2)ch(2)s, l' = ch(3)s(-), ch(3)sh; q = 0, 1-, 2-, 3-). analytical dft frequencies on model complexes (mu-pdt)fe(2)(co)(6) and [(mu-pdt)fe(2)(co)(4 ... | 2001 | 11457105 |
| a capable bridging ligand for fe-only hydrogenase: density functional calculations of a low-energy route for heterolytic cleavage and formation of dihydrogen. | | 2001 | 11457119 |
| self-consistent karplus parametrization of 3j couplings depending on the polypeptide side-chain torsion chi1. | recently proposed self-consistent 3j coupling analysis (schmidt, j. m.; blümel, m.; löhr, f.; rüterjans, h. j. biomol. nmr 1999, 14, 1-12) has been carried out to calibrate karplus parameters constituting the empirical dependence of 3j coupling constants on the chi1 dihedral angle in amino acid side chains. the procedure involves simultaneous least-squares optimization of six sets of three karplus coefficients related to all six 3j coupling types accessible in 15n,13c-labeled proteins. a simple ... | 2001 | 11459487 |
| in the facultative sulphate/nitrate reducer desulfovibrio desulfuricans atcc 27774, the nine-haem cytochrome c is part of a membrane-bound redox complex mainly expressed in sulphate-grown cells. | the bacterium desulfovibrio desulfuricans atcc 27774 belongs to the group of sulphate reducers also capable of utilising nitrate as its terminal electron acceptor for anaerobic growth. one of the complex multihaem proteins found in nitrate- or sulphate-grown cells of desulfovibrio desulfuricans atcc 27774 is the nine-haem cytochrome c. the present work shows that the gene encoding for desulfovibrio desulfuricans atcc 27774 nine-haem cytochrome c is part of an operon formed by the gene cluster 9h ... | 2001 | 11470160 |
| the mechanism of superoxide scavenging by archaeoglobus fulgidus neelaredoxin. | neelaredoxin is a mononuclear iron protein widespread among prokaryotic anaerobes and facultative aerobes, including human pathogens. it has superoxide scavenging activity, but the exact mechanism by which this process occurs has been controversial. in this report, we present the study of the reaction of superoxide with the reduced form of neelaredoxin from the hyperthermophilic archaeon archaeoglobus fulgidus by pulse radiolysis. this protein reduces superoxide very efficiently (k = 1.5 x 10(9) ... | 2001 | 11489883 |
| crystal structures of a novel ferric reductase from the hyperthermophilic archaeon archaeoglobus fulgidus and its complex with nadp+. | studies performed within the last decade have indicated that microbial reduction of fe(iii) to fe(ii) is a biologically significant process. the ferric reductase (fer) from archaeoglobus fulgidus is the first reported archaeal ferric reductase and it catalyzes the flavin-mediated reduction of ferric iron complexes using nad(p)h as the electron donor. based on its catalytic activity, the a. fulgidus fer resembles the bacterial and eukaryotic assimilatory type of ferric reductases. however, the hi ... | 2001 | 11525168 |
| biological degradation of 2,4,6-trinitrotoluene. | nitroaromatic compounds are xenobiotics that have found multiple applications in the synthesis of foams, pharmaceuticals, pesticides, and explosives. these compounds are toxic and recalcitrant and are degraded relatively slowly in the environment by microorganisms. 2,4,6-trinitrotoluene (tnt) is the most widely used nitroaromatic compound. certain strains of pseudomonas and fungi can use tnt as a nitrogen source through the removal of nitrogen as nitrite from tnt under aerobic conditions and the ... | 2001 | 11527999 |
| assignment of fatty acid-beta-oxidizing syntrophic bacteria to syntrophomonadaceae fam. nov. on the basis of 16s rrna sequence analyses. | after enrichment from chinese rural anaerobic digestor sludge, anaerobic, sporing and nonsporing, saturated fatty acid-beta-oxidizing syntrophic bacteria were isolated as cocultures with h2- and formate-utilizing methanospirillum hungatei or desulfovibrio sp. strain g-11. the syntrophs degraded c4 to c8 saturated fatty acids, including isobutyrate and 2-methylbutyrate. they were adapted to grow on crotonate and were isolated as pure cultures. the crotonate-grown pure cultures alone did not gr ... | 1993 | 11536533 |
| 34s/32s fractionation in sulfur cycles catalyzed by anaerobic bacteria. | stable isotopic distributions in the sulfur cycle were studied with pure and mixed cultures of the anaerobic bacteria, chlorobium vibrioforme and desulfovibrio vulgaris. d. vulgaris and c. vibrioforme can catalyze three reactions constituting a complete anaerobic sulfur cycle: reduction of sulfate to sulfide (d. vulgaris), oxidation of sulfide to elemental sulfur (c. vibrioforme), and oxidation of sulfur to sulfate (c. vibrioforme). in all experiments, the first and last reactions favored con ... | 1988 | 11536596 |
| conformational component in the coupled transfer of multiple electrons and protons in a monomeric tetraheme cytochrome. | cell metabolism relies on energy transduction usually performed by complex membrane-spanning proteins that couple different chemical processes, e.g. electron and proton transfer in proton-pumps. there is great interest in determining at the molecular level the structural details that control these energy transduction events, particularly those involving multiple electrons and protons, because tight control is required to avoid the production of dangerous reactive intermediates. tetraheme cytochr ... | 2001 | 11551953 |
| antimicrobial susceptibilities of clinical desulfovibrio isolates. | the antimicrobial susceptibilities of 16 clinical isolates of desulfovibrio spp. were determined. all or most isolates were susceptible to imipenem (mic(90) [mic at which 90% of the isolates tested were inhibited], 0.5 microg/ml), metronidazole (mic(90), 0.25 microg/ml), clindamycin (mic(90), 4 microg/ml), and chloramphenicol (mic(90), 16 microg/ml) but were resistant or intermediate to penicillin g (mic(90), 64 microg/ml), piperacillin (mic(90), 256 microg/ml), piperacillin-tazobactam (mic(90), ... | 2001 | 11557495 |
| [formation of microbial populations on the surface of protective coatings]. | formation of microbial cenosis on the surface of polyethylene-, polyurethane- and oil-bitumen-based protective coatings was studied in dynamics during 1, 3, 7, 14 and 21 days. it has been shown that the biofilm was formed on the protective materials during 14 days and consisted of ammonifying, denitrifying, hydrocarbon-oxidizing and sulphate-reducing bacteria referred to pseudomonas, arthrobacter, bacillus and kesulfovibrio genera. the bacteria which form the biofilm on coatings possess high den ... | 2001 | 11558243 |
| a role for rubredoxin in oxidative stress protection in desulfovibrio vulgaris: catalytic electron transfer to rubrerythrin and two-iron superoxide reductase. | desulfovibrio vulgaris rubredoxin, which contains a single [fe(scys)4] site, is shown to be a catalytically competent electron donor to two enzymes from the same organism, namely, rubrerythrin and two-iron superoxide reductase (a.k.a. rubredoxin oxidoreductase or desulfoferrodoxin). these two enzymes have been implicated in catalytic reduction of hydrogen peroxide and superoxide, respectively, during periods of oxidative stress in d. vulgaris, but their proximal electron donors had not been char ... | 2001 | 11566030 |
| reduction of technetium(vii) by desulfovibrio fructosovorans is mediated by the nickel-iron hydrogenase. | resting cells of the sulfate-reducing bacterium desulfovibrio fructosovorans grown in the absence of sulfate had a very high tc(vii)-reducing activity, which led to the formation of an insoluble black precipitate. the involvement of a periplasmic hydrogenase in tc(vii) reduction was indicated (i) by the requirement for hydrogen as an electron donor, (ii) by the tolerance of this activity to oxygen, and (iii) by the inhibition of this activity by cu(ii). moreover, a mutant carrying a deletion in ... | 2001 | 11571159 |
| direct detection of 16s rrna in soil extracts by using oligonucleotide microarrays. | we report on the development and validation of a simple microarray method for the direct detection of intact 16s rrna from unpurified soil extracts. total rnas from geobacter chapellei and desulfovibrio desulfuricans were hybridized to an oligonucleotide array consisting of universal and species-specific 16s rrna probes. pcr-amplified products from geobacter and desulfovibrio were easily and specifically detected under a range of hybridization times, temperatures, and buffers. however, reproduci ... | 2001 | 11571176 |
| copper-induced inhibition of growth of desulfovibrio desulfuricans g20: assessment of its toxicity and correlation with those of zinc and lead. | the toxicity of copper [cu(ii)] to sulfate-reducing bacteria (srb) was studied by using desulfovibrio desulfuricans g20 in a medium (mtm) developed specifically to test metal toxicity to srb (r. k. sani, g. geesey, and b. m. peyton, adv. environ. res. 5:269-276, 2001). the effects of cu(ii) toxicity were observed in terms of inhibition in total cell protein, longer lag times, lower specific growth rates, and in some cases no measurable growth. at only 6 microm, cu(ii) reduced the maximum specifi ... | 2001 | 11571183 |
| control of biogenic h(2)s production with nitrite and molybdate. | the effects of the metabolic inhibitors, sodium nitrite and ammonium molybdate, on production of h(2)s by a pure culture of the sulfate-reducing bacterium (srb) desulfovibrio sp. strain lac6 and a consortium of srb, enriched from produced water of a canadian oil field, were investigated. addition of 0.1 mm nitrite or 0.024 mm molybdate at the start of growth prevented the production of h(2)s by strain lac6. with exponentially growing cultures, higher levels of inhibitors, 0.25 mm nitrite or 0.09 ... | 2001 | 11571618 |
| effect of hydrogen-bond networks in controlling reduction potentials in desulfovibrio vulgaris (hildenborough) cytochrome c3 probed by site-specific mutagenesis. | cytochromes c3 isolated from desulfovibrio spp. are periplasmic proteins that play a central role in energy transduction by coupling the transfer of electrons and protons from hydrogenase. comparison between the oxidized and reduced structures of cytochrome c3 isolated from desulfovibrio vulgaris (hildenborough) show that the residue threonine 24, located in the vicinity of heme iii, reorients between these two states [messias, a. c., kastrau, d. h. w., costa, h. s., legall, j., turner, d. l., s ... | 2001 | 11583171 |
| impact of nitrate-mediated microbial control of souring in oil reservoirs on the extent of corrosion. | the effect of microbial control of souring on the extent of corrosion was studied in a model system consisting of pure cultures of the nitrate-reducing, sulfide-oxidizing bacterium (nr-sob) thiomicrospira sp. strain cvo and the sulfate-reducing bacterium (srb) desulfovibrio sp. strain lac6, as well as in an srb consortium enriched from produced water from a canadian oil reservoir. the average corrosion rate induced by the srb consortium (1.4 g x m(-2) x day(-1)) was faster than that observed in ... | 2001 | 11587574 |
| [extracellular metabolites of hydrocarbon-oxidizing bacteria as a substrate for sulfate reduction]. | the relationship between bacterial oxidation of hydrocarbons and sulfate reduction was studied in the experimental system with liquid paraffin was used as a source of organic compounds inoculated with silt taken from a reservoir. pseudomonads dominated in the hydrocarbon-oxidizing silt bacteriocenosis. however, rhodococcus and arthrobacteria amounted to not more than 3%. arthrobacteria dominated the microbial association formed in the paraffin film of the model system. sulfate-reducing bacteria ... | 2001 | 11605466 |
| influence of sulfur metalation on the accessibility of the ni(ii/i) couple in [n,n'-bis(2-mercaptoethyl)-1,5-diazacyclooctanato]nickel(ii): insight into the redox properties of [nife]-hydrogenase. | a redox model study of [nife] hydrogenase has examined a series of five polymetallics based on the metalation of the dithiolate complex [1,5-bis(mercaptoethyl)-1,5-diazacyclooctane]ni(ii), ni-1. crystal structures of three polymetallics of the series have been reported earlier: [(ni-1)(2)()ni]cl(2)(), [(ni-1)(2)()fecl(2)()](2)(), and [(ni-1)(3)()(zncl)(2)()]cl(2)(). two are described here: [(ni-1)(2)()pd]cl(2)().2h(2)()ocrystallizes in the monoclinic system, space group p2(1)/c with cell constan ... | 1996 | 11666411 |
| freeze-quench magnetic circular dichroism spectroscopic study of the "very rapid" intermediate in xanthine oxidase. | freeze-quench magnetic circular dichroism spectroscopy (mcd) has been used to trap and study the excited-state electronic structure of the mo(v) active site in a xanthine oxidase intermediate generated with substoichiometric concentrations of the slow substrate 2-hydroxy-6-methylpurine. epr spectroscopy has shown that the intermediate observed in the mcd experiment is the "very rapid" intermediate, which lies on the main catalytic pathway. the low-energy (< approximately 30 000 cm(-1)) c-term mc ... | 1999 | 11671238 |
| modeling nickel hydrogenases: synthesis and structure of a distorted octahedral complex with an unprecedented [nis(4)h(2)] core. | | 2001 | 11681879 |
| role of a highly conserved ypitp motif in 2-oxoacid:ferredoxin oxidoreductase: heterologous expression of the gene from sulfolobus sp.strain 7, and characterization of the recombinant and variant enzymes. | 2-oxoacid:ferredoxin oxidoreductase from sulfolobus sp. strain 7, an aerobic and thermoacidophilic crenoarchaeon, catalyses the coenzyme a-dependent oxidative decarboxylation of pyruvate and 2-oxoglutarate, a cognate zn-7fe-ferredoxin serving as an electron acceptor. it comprises two subunits, a (632 amino acids) and b (305 amino acids). to further elucidate its structure and function, we constructed a gene expression system. the wild-type recombinant enzyme was indistinguishable from the natura ... | 2001 | 11683888 |
| periplasmic oxygen reduction by desulfovibrio species. | washed cells of desulfovibrio vulgaris strain marburg (dsm 2119) reduced oxygen to water with h(2) as electron donor at a mean rate of 253 nmol o(2) min(-1) (mg protein)(-1). after separating the periplasm from the cells, more than 60% of the cytochrome c activity and 90% of the oxygen-reducing activity were found in the periplasmic fraction. oxygen reduction and the reduction of cytochrome c with h(2) were inhibited by cucl(2). after further separation of the periplasm by ultrafiltration (exclu ... | 2001 | 11685376 |
| both ph and carbon flux influence the level of rubredoxin in clostridium butyricum. | the rubredoxin expression level in clostridium butyricum dsm 5431 grown in continuous culture was monitored using primer extension analyses of the rub gene and a specific enzymatic assay of the iron-sulfur protein. in this way, we showed that variations in rubredoxin content and in rub mrna level were influenced by the ph of the culture and were directly dependent on the carbon flux. the maximum rubredoxin level reached 1227.3 pmol (mg of proteins)(-1) (i.e. 0.7% of the total protein content) un ... | 2001 | 11685512 |
| nmr structure of desulfovibrio gigas rubredoxin: a model for studying protein stabilization by compatible solutes. | rubredoxins are small, soluble proteins that display a wide variation in thermostability, despite having a high degree of sequence similarity they also vary in the extent to which they are stabilized by solutes such as diglycerol phosphate. hence, they provide excellent models for studying the mechanisms of thermostabilization. nuclear magnetic resonance (nmr) spectroscopy can be used to investigate interactions between molecules, as well as subtle changes in conformation in solution, and also p ... | 2001 | 11699644 |
| improved measurement of (3)j(h(alpha)(i),n(i+1)) coupling constants in h(2)o dissolved proteins. | a modification to the recently proposed alpha/beta-hn(co)ca-j trosy pulse sequence (p. permi et al., j. magn. reson. 146, 255-259 (2000)) makes it possible to determine (3)j(h(alpha)(i), n(i+1)) coupling constants from a single e.cosy-type cross-peak pattern rather than from two (1)h(alpha) spin-state-edited subspectra. advantages are increased (15)n resolution, critical to extracting accurate (1)h(alpha)-(15)n coupling constants, and minimized differential relaxation due to nested (13)c(alpha) ... | 2001 | 11700083 |
| modeling the active sites in metalloenzymes 5. the heterolytic bond cleavage of h(2) in the [nife] hydrogenase of desulfovibrio gigas by a nucleophilic addition mechanism. | the h(2) activation catalyzed by an fe(ii)-ni(iii) model of the [nife] hydrogenase of desulfovibrio gigas has been investigated by density functional theory (dft/b3lyp) calculations on the neutral and anionic active site complexes, [(co)(cn)(2)fe(mu-sh)(2)ni(sh)(sh(2))](0) and [(co)(cn)(2)fe(mu-sh)(2)ni(sh)(2)](-). the results suggest that the reaction proceeds by a nucleophilic addition mechanism that cleaves the h-h bond heterolytically. the terminal cysteine residue cys530 in the [nife] hydro ... | 2001 | 11703120 |
| structure refinement of the aldehyde oxidoreductase from desulfovibrio gigas (mop) at 1.28 a. | the sulfate-reducing bacterium aldehyde oxidoreductase from desulfovibrio gigas (mop) is a member of the xanthine oxidase family of enzymes. it has 907 residues on a single polypeptide chain, a molybdopterin cytosine dinucleotide (mcd) cofactor and two [2fe-2s] iron-sulfur clusters. synchrotron data to almost atomic resolution were collected for improved cryo-cooled crystals of this enzyme in the oxidized form. the cell constants of a=b=141.78 a and c=160.87 a are about 2% shorter than those of ... | 2001 | 11713686 |
| characterization of recombinant desulfovibrio gigas ferredoxin. | dg ferredoxin gene was cloned using the polymerase chain reaction (pcr), inserted into vector pt7-7, and overexpressed in escherichia coli (e. coli) grown in aerobic media. the recombinant protein is a dimer and contains a [3fe-4s] cluster per monomer. epr and (1)h nmr data of recombinant and wild-type protein are compared. | 2001 | 11716522 |
| comparative biology of incq and incq-like plasmids. | plasmids belonging to escherichia coli incompatibility group q are relatively small (approximately 5 to 15 kb) and able to replicate in a remarkably broad range of bacterial hosts. these include gram-positive bacteria such as brevibacterium and mycobacterium and gram-negative bacteria such as agrobacterium, desulfovibrio, and cyanobacteria. these plasmids are mobilized by several self-transmissible plasmids into an even more diverse range of organisms including yeasts, plants, and animal cells. ... | 2001 | 11729261 |
| influence of electrochemical properties in determining the sensitivity of [4fe-4s] clusters in proteins to oxidative damage. | interconversion between [4fe-4s] cubane and [3fe-4s] cuboidal states represents one of the simplest structural changes an iron-sulphur cluster can undertake. this reaction is implicated in oxidative damage and in modulation of the activity and regulation of certain enzymes, and it is therefore important to understand the factors governing cluster stability and the processes that activate cluster conversion. in the present study, protein film voltammetry has been used to induce and monitor the ox ... | 2001 | 11736664 |
| molecular lego: design of molecular assemblies of p450 enzymes for nanobiotechnology. | this paper reports on the application of the molecular lego approach to p450 enzymes. protein domains are used as catalytic (p450 bm3 haem domain and human p450 2e1) or electron transfer (flavodoxin and p450 bm3 reductase) modules. the objectives are to build assemblies with improved electrochemical properties, to construct soluble human p450 enzymes, and to generate libraries of new p450 catalytic modules based on p450 bm3. a rationally designed, gene-fused assembly (bmp-fld) was obtained from ... | 2002 | 11742744 |
| crystal structure of the free radical intermediate of pyruvate:ferredoxin oxidoreductase. | in anaerobic organisms, the decarboxylation of pyruvate, a crucial component of intermediary metabolism, is catalyzed by the metalloenzyme pyruvate: ferredoxin oxidoreductase (pfor) resulting in the generation of low potential electrons and the subsequent acetylation of coenzyme a (coa). pfor is the only enzyme for which a stable acetyl thiamine diphosphate (thdp)-based free radical reaction intermediate has been identified. the 1.87 a-resolution structure of the radical form of pfor from desulf ... | 2001 | 11752578 |
| physical, chemical, and microbiological characteristics of microbial mats (kopara) in the south pacific atolls of french polynesia. | microbial mats that develop in shallow brackish and hyposaline ponds in the rims of two french polynesian atolls (rangiroa and tetiaroa) were intensively investigated during the past three years. comparative assessment of these mats (called kopara in polynesian language) showed remarkable similarities in their composition and structure. due to the lack of iron, the color of the cyanobacterial pigments produced remained visible through the entire depth of the mats (20-40 cm depth), with alternate ... | 2001 | 11766060 |
| phylogenetic identification and substrate uptake patterns of sulfate-reducing bacteria inhabiting an oxic-anoxic sewer biofilm determined by combining microautoradiography and fluorescent in situ hybridization. | we simultaneously determined the phylogenetic identification and substrate uptake patterns of sulfate-reducing bacteria (srb) inhabiting a sewer biofilm with oxygen, nitrate, or sulfate as an electron acceptor by combining microautoradiography and fluorescent in situ hybridization (mar-fish) with family- and genus-specific 16s rrna probes. the mar-fish analysis revealed that desulfobulbus hybridized with probe 660 was a dominant srb subgroup in this sewer biofilm, accounting for 23% of the total ... | 2002 | 11772645 |
| 17o endor detection of a solvent-derived ni-(oh(x))-fe bridge that is lost upon activation of the hydrogenase from desulfovibrio gigas. | crystallographic studies of the hydrogenases (hases) from desulfovibrio gigas (dg) and desulfovibrio vulgaris miyazaki (dvm) have revealed heterodinuclear nickel-iron active centers in both enzymes. the structures, which represent the as-isolated (unready) ni-a (s = (1)/(2)) enzyme state, disclose a nonprotein ligand (labeled as x) bridging the two metals. the bridging atom was suggested to be an oxygenic (o(2)(-) or oh(-)) species in dg hase and an inorganic sulfide in dvm hase. to determine th ... | 2002 | 11782180 |