| phylogenetic relationships among the chromatiaceae, their taxonomic reclassification and description of the new genera allochromatium, halochromatium, isochromatium, marichromatium, thiococcus, thiohalocapsa and thermochromatium. | sequences of the 16s rdna from all available type strains of chromatium species have been determined and were compared to those of other chromatiaceae, a few selected ectothiorhodospiraceae and escherichia coli. the clear separation of ectothiorhodospiraceae and chromatiaceae is confirmed. most significantly the sequence comparison revealed a genetic divergence between chromatium species originated from freshwater sources and those of truly marine and halophilic nature. major phylogenetic branch ... | 1998 | 9828415 |
| in situ analysis of sulfur in the sulfur globules of phototrophic sulfur bacteria by x-ray absorption near edge spectroscopy. | during the oxidation of sulfide and thiosulfate purple and green sulfur bacteria accumulate globules of 'elemental' sulfur. although essential for a thorough understanding of sulfur metabolism in these organisms, the exact chemical nature of the stored sulfur is still unclear. we applied sulfur k-edge x-ray absorption near edge spectroscopy (xanes) to probe the forms of sulfur in intact cells. comparing xanes spectra of allochromatium vinosum, thiocapsa roseopersicina, marichromatium purpuratum, ... | 1999 | 10434064 |
| an unusual arrangement of pur and lpx genes in the photosynthetic purple sulfur bacterium allochromatium vinosum. | the nucleotide sequence of a 1634 bp dna fragment from the photosynthetic purple sulfur bacterium allochromatium vinosum contains one complete and two partial open reading frames. sequence comparisons to genes from other organisms suggest that this a. vinosum dna fragment contains, starting from the 5' end, the following: (1) 234 bp at the 3' end of the a. vinosum purh gene, coding for 78 amino acids at the c-terminus of the bi-functional 5'-phosphoribosyl-5-aminoimidazole-4-carboxamide formyltr ... | 1999 | 10532315 |
| genes involved in hydrogen and sulfur metabolism in phototrophic sulfur bacteria. | the dsr genes and the hydsl operon are present as separate entities in phototrophic sulfur oxidizers of the genera allochromatium, marichromatium, thiocapsa and thiocystis and are organized similarly as in allochromatium vinosum and thiocapsa roseopersicina, respectively. the dsra gene, encoding the alpha subunit of 'reverse' siroheme sulfite reductase, is also present in two species of green sulfur bacteria pointing to an important and universal role of this enzyme and probably other proteins e ... | 1999 | 10556728 |
| sulfide:quinone oxidoreductase in membranes of the hyperthermophilic bacterium aquifex aeolicus (vf5). | the sulfide-dependent reduction of exogenous ubiquinone by membranes of the hyperthermophilic chemotrophic bacterium aquifex aeolicus (vf5), the sulfide-dependent consumption of oxygen and the reduction of cytochromes by sulfide in membranes were studied. sulfide reduced decyl-ubiquinone with a maximal rate of up to 3.5 micromol (mg protein)(-1) min(-1) at 20 degrees c. rates of 220 nmol (mg protein)(-1) min(-1)] for the sulfide-dependent consumption of oxygen and 480 nmol (mg protein)(-1) min(- ... | 2000 | 10816041 |
| characterization of the cys gene locus from allochromatium vinosum indicates an unusual sulfate assimilation pathway. | homologues of the genes cysb, cysi, cysh, cysd, cysn, and seld were identified in the genome of the phototrophic purple sulfur bacterium allochromatium vinosum (formerly chromatium vinosum). on the basis of amino acid comparisons these genes encode a ferredoxin-dependent siroheme-sulfite reductase (cysi), a plant-type assimilatory aps reductase without thioredoxin domain (cysh), the two different subunits of heterodimeric atp sulfurylase (cysdn), a transcriptional regulator (cysb) and a selenoph ... | 2000 | 10939523 |
| novel genes of the sox gene cluster, mutagenesis of the flavoprotein soxf, and evidence for a general sulfur-oxidizing system in paracoccus pantotrophus gb17. | the novel genes soxfgh were identified, completing the sox gene cluster of paracoccus pantotrophus coding for enzymes involved in lithotrophic sulfur oxidation. the periplasmic soxf, soxg, and soxh proteins were induced by thiosulfate and purified to homogeneity from the soluble fraction. soxf coded for a protein of 420 amino acids with a signal peptide containing a twin-arginine motif. soxf was 37% identical to the flavoprotein fccb of flavocytochrome c sulfide dehydrogenase of allochromatium v ... | 2001 | 11443084 |
| a novel system for heterologous expression of flavocytochrome c in phototrophic bacteria using the allochromatium vinosum rbca promoter. | flavocytochrome c-sulfide dehydrogenase (fcsd), an enzyme that catalyzes the reversible conversion of sulfide to elemental sulfur in vitro, is common to bacteria that utilize reduced sulfur compounds as electron donors in the process of carbon dioxide fixation. fcsd is a heterodimer containing two different cofactors, a flavin (fad) and one or two heme c groups, located on the separate protein subunits. efforts to produce the holoproteins of the soluble allochromatium vinosum fcsd and the membra ... | 2001 | 11479699 |
| class i and iii polyhydroxyalkanoate synthases from ralstonia eutropha and allochromatium vinosum: characterization and substrate specificity studies. | class i and iii polyhydroxyalkanoate (pha) synthases catalyze the conversion of beta-hydroxybutyryl coenzyme a (hbcoa) to polyhydroxybutyrate. the class i pha synthase from ralstonia eutropha has been purified by numerous labs with reported specific activities that vary between 1 and 160 u/mg. an n-terminal (his)6-pha synthase was constructed and purified with specific activity of 40 u/mg. the variable activity is shown to be related to the protein's propensity to aggregate and not to incomplete ... | 2001 | 11566031 |
| in vivo role of adenosine-5'-phosphosulfate reductase in the purple sulfur bacterium allochromatium vinosum. | adenosine-5'-phosphosulfate (aps) reductase participates in the oxidation of sulfite to aps in allochromatium vinosum. oxidation of sulfite via the aps pathway yields atp through substrate-level phosphorylation. an alternative enzyme for the oxidation of sulfite to sulfate, sulfite:acceptor oxidoreductase, has also been reported in ach. vinosum. oxidation of sulfite through this enzyme does not yield atp. aps reductase is expressed constitutively in ach. vinosum, suggesting that it performs an i ... | 2001 | 11685375 |
| the [nife] hydrogenase from allochromatium vinosum studied in epr-detectable states: h/d exchange experiments that yield new information about the structure of the active site. | in this study we report on thus-far unobserved proton hyperfine couplings in the well-known epr signals of [nife] hydrogenases. the preparation of the enzyme in several highly homogeneous states allowed us to carefully re-examine the ni(u)*, ni(r)*, ni(a)-c* and ni(a)-l* epr signals which are present in most [nife] hydrogenases. at high resolution (modulation amplitude 0.57 g), clear indications for hyperfine interactions were observed in the g(z) line of the ni(r)* epr signal. the hyperfine pat ... | 2001 | 11713683 |
| purification and characterization of a membrane-bound enzyme complex from the sulfate-reducing archaeon archaeoglobus fulgidus related to heterodisulfide reductase from methanogenic archaea. | heterodisulfide reductase (hdr) is a unique disulfide reductase that plays a key role in the energy metabolism of methanogenic archaea. the genome of the sulfate-reducing archaeon archaeoglobus fulgidus encodes several proteins of unknown function with high sequence similarity to the catalytic subunit of hdr. here we report on the purification of a multisubunit membrane-bound enzyme complex from a. fulgidus that contains a subunit related to the catalytic subunit of hdr. the purified enzyme is a ... | 2002 | 11952791 |
| direct comparison of the electrocatalytic oxidation of hydrogen by an enzyme and a platinum catalyst. | it is shown that for molecules of allochromatium vinosum [nife]-hydrogenase adsorbed on a pyrolytic graphite electrode the nickel-iron active site catalyzes hydrogen oxidation at a diffusion-controlled rate matching that achieved by platinum. | 2002 | 12123018 |
| enzyme electrokinetics: hydrogen evolution and oxidation by allochromatium vinosum [nife]-hydrogenase. | the mechanism of catalytic hydrogen evolution and oxidation by allochromatium vinosum [nife]-hydrogenase has been studied by protein film voltammetry (pfv) with the enzyme adsorbed at a pyrolytic graphite edge electrode. by analyzing the entire shapes of catalytic voltammograms, the energetics of the catalytic cycles (reduction potentials and acidity constants of the active states), including the detailed profiles of activity against ph and the sequences of proton and electron transfers, have be ... | 2002 | 12501202 |
| membrane targeting of a folded and cofactor-containing protein. | targeting of proteins to and translocation across the membranes is a fundamental biological process in all organisms. in bacteria, the twin arginine translocation (tat) system can transport folded proteins. here, we demonstrate in vivo that the high potential iron-sulfur protein (hipip) from allochromatium vinosum is translocated into the periplasmic space by the tat system of escherichia coli. in vitro, reconstituted hipip precursor (preholohipip) was targeted to inverted membrane vesicles from ... | 2003 | 12631279 |
| enzyme electrokinetics: electrochemical studies of the anaerobic interconversions between active and inactive states of allochromatium vinosum [nife]-hydrogenase. | the cycling between active and inactive states of the catalytic center of [nife]-hydrogenase from allochromatium vinosum has been investigated by dynamic electrochemical techniques. adsorbed on a rotating disk pyrolytic graphite "edge" electrode, the enzyme is highly electroactive: this allows precise manipulations of the complex redox chemistry and facilitates quantitative measurements of the interconversions between active catalytic states and the inactive oxidized form ni(r) (also called ni-b ... | 2003 | 12848556 |
| structural studies on a twin-arginine signal sequence. | translocation of folded proteins across biological membranes can be mediated by the so-called 'twin-arginine translocation' (tat) system. to be translocated, tat substrates require n-terminal signal sequences which usually contain the eponymous twin-arginine motif. here we report the first structural analysis of a twin-arginine signal sequence, the signal sequence of the high potential iron-sulfur protein from allochromatium vinosum. nuclear magnetic resonance (nmr) analyses of amide proton reso ... | 2003 | 12935879 |
| electron transfer from hipip to the photooxidized tetraheme cytochrome subunit of allochromatium vinosum reaction center: new insights from site-directed mutagenesis and computational studies. | the kinetics of electron transfer from reduced high-potential iron-sulfur protein (hipip) to the photooxidized tetraheme cytochrome c subunit (thc) bound to the photosynthetic reaction center (rc) from the purple sulfur bacterium allochromatium vinosum were studied under controlled redox conditions by flash absorption spectroscopy. at ambient redox potential eh = +200 mv, where only the high-potential (hp) hemes of the thc are reduced, the electron transfer from hipip to photooxidized hp heme(s) ... | 2004 | 14717598 |
| crystallization of 4-hydroxybenzoyl-coa reductase and the structure of its electron donor ferredoxin. | 4-hydroxybenzoyl-coa reductase (4-hbcr) is a central enzyme in the metabolism of phenolic compounds in anaerobic bacteria. the enzyme catalyzes the reductive removal of the phenolic hydroxyl group from 4-hydroxybenzoyl-coa, yielding benzoyl-coa and water. 4-hbcr belongs to the xanthine oxidase (xo) family of molybdenum enzymes which occur as heterodimers, (alphabetagamma)(2). 4-hbcr contains two molybdopterins, four [2fe-2s] and two [4fe-4s] clusters and two fads. a low-potential allochromatium ... | 2004 | 14747735 |
| reactions of h2, co, and o2 with active [nife]-hydrogenase from allochromatium vinosum. a stopped-flow infrared study. | the ni-fe site in the active membrane-bound [nife]-hydrogenase from allochromatium vinosum can exist in three different redox states. in the most oxidized state (ni(a)-s) the nickel is divalent. the most reduced state (ni(a)-sr) likewise has ni(2+), while the intermediate state (ni(a)-c) has ni(3+). the transitions between these states have been studied by stopped-flow fourier transform infrared spectroscopy. it is inferred from the data that the ni(a)-s --> ni(a)-c* and ni(a)-c* --> ni(a)-sr tr ... | 2004 | 15157115 |
| hydrogen-induced activation of the [nife]-hydrogenase from allochromatium vinosum as studied by stopped-flow infrared spectroscopy. | the reaction between hydrogen and the [nife]-hydrogenase from allochromatium vinosum in its inactive form has been studied by stopped-flow infrared spectroscopy. the data, for the first time, clearly show that at room temperature enzyme in the unready state, either oxidized or reduced, does not react with hydrogen. enzyme in the ready state reacts with hydrogen after a lag phase of about six seconds, whereby a specific reduction of the enzyme occurs. the lag phase and the rate of reduction of th ... | 2004 | 15157116 |
| the activation of the [nife]-hydrogenase from allochromatium vinosum. an infrared spectro-electrochemical study. | the membrane-bound [nife]-hydrogenase from allochromatium vinosum can occur in several inactive or active states. this study presents the first systematic infrared characterisation of the a. vinosum enzyme, with emphasis on the spectro-electrochemical properties of the inactive/active transition. this transition involves an energy barrier, which can be overcome at elevated temperatures. the reduced ready enzyme can exist in two different inactive states, which are in an apparent acid-base equili ... | 2004 | 15243788 |
| characterization and expression of genes from the rubisco gene cluster of the chemoautotrophic symbiont of solemya velum: cbblsqo. | chemoautotrophic endosymbionts residing in solemya velum gills provide this shallow water clam with most of its nutritional requirements. the cbb gene cluster of the s. velum symbiont, including cbbl and cbbs, which encode the large and small subunits of the carbon-fixing enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco), was cloned and expressed in escherichia coli. the recombinant rubisco had a high specific activity, approximately 3 micromol min(-1) mg protein (-1), and a kco2 ... | 2004 | 15316720 |
| the role of the sulfur globule proteins of allochromatium vinosum: mutagenesis of the sulfur globule protein genes and expression studies by real-time rt-pcr. | during oxidation of reduced sulfur compounds, the purple sulfur bacterium allochromatium vinosum stores sulfur in the periplasm in the form of intracellular sulfur globules. the sulfur in the globules is enclosed by a protein envelope that consists of the homologous 10.5-kda proteins sgpa and sgpb and the smaller 8.5-kda sgpc. reporter gene fusions of sgpa and alkaline phosphatase showed the constitutive expression of sgpa in a. vinosum and yielded additional evidence for the periplasmic localiz ... | 2004 | 15340792 |
| electrochemical potential-step investigations of the aerobic interconversions of [nife]-hydrogenase from allochromatium vinosum: insights into the puzzling difference between unready and ready oxidized inactive states. | dynamic electrochemical studies, incorporating catalytic voltammetry and detailed potential-step manipulations, provide compelling evidence that the oxidized inactive state of [nife]-hydrogenases termed unready (or ni-a) contains a product of partial reduction of o(2) that is trapped in the active site. | 2004 | 15535717 |
| the biosynthetic routes for carbon monoxide and cyanide in the ni-fe active site of hydrogenases are different. | the incorporation of carbon into the carbon monoxide and cyanide ligands of [nife]-hydrogenases has been investigated by using (13)c labelling in infrared studies of the allochromatium vinosum enzyme and by (14)c labelling experiments with overproduced hyp proteins from escherichia coli. the results suggest that the biosynthetic routes of the carbon monoxide and cyanide ligands in [nife]-hydrogenases are different. | 2005 | 15642360 |
| successful recombinant production of allochromatium vinosum cytochrome c' requires coexpression of cmm genes in heme-rich escherichia coli jcb712. | cytochrome c' from the purple photosynthetic bacterium allochromatium vinosum (ccp) displays a unique, reversible dimer-to-monomer transition upon binding of no, co, and cn(-). this small, four helix bundle protein represents an attractive model for the study of other heme protein biosensors, provided a recombinant expression system is available. here we report the development of an efficient expression system for ccp that makes use of a maltose binding protein fusion strategy to enhance peripla ... | 2005 | 15649399 |
| detection of intermediates from the polymerization reaction catalyzed by a d302a mutant of class iii polyhydroxyalkanoate (pha) synthase. | polyhydroxybutyrate (phb) synthases catalyze the polymerization of (r)-3-hydroxybutyryl-coa (hb-coa) into high molecular weight phb, biodegradable polymers. the class iii phb synthase from allochromatium vinosum is composed of a 1:1 mixture of two approximately 40 kda proteins: phac and phae. previous studies using site-directed mutagenesis and a saturated trimer of hydroxybutyryl-coa have suggested the importance of c149 (in covalent catalysis), h331 (in activation of c149), and d302 (in hydrox ... | 2005 | 15683234 |
| novel genes of the dsr gene cluster and evidence for close interaction of dsr proteins during sulfur oxidation in the phototrophic sulfur bacterium allochromatium vinosum. | seven new genes designated dsrljopnsr were identified immediately downstream of dsrabefhcmk, completing the dsr gene cluster of the phototrophic sulfur bacterium allochromatium vinosum d (dsm 180(t)). interposon mutagenesis proved an essential role of the encoded proteins for the oxidation of intracellular sulfur, an obligate intermediate during the oxidation of sulfide and thiosulfate. while dsrr and dsrs encode cytoplasmic proteins of unknown function, the other genes encode a predicted nadph: ... | 2005 | 15687204 |
| oxygen tolerance of the h2-sensing [nife] hydrogenase from ralstonia eutropha h16 is based on limited access of oxygen to the active site. | hydrogenases, abundant proteins in the microbial world, catalyze cleavage of h2 into protons and electrons or the evolution of h2 by proton reduction. hydrogen metabolism predominantly occurs in anoxic environments mediated by hydrogenases, which are sensitive to inhibition by oxygen. those microorganisms, which thrive in oxic habitats, contain hydrogenases that operate in the presence of oxygen. we have selected the h2-sensing regulatory [nife] hydrogenase of ralstonia eutropha h16 to investiga ... | 2005 | 15849358 |
| investigating metalloenzyme reactions using electrochemical sweeps and steps: fine control and measurements with reactants ranging from ions to gases. | protein film voltammetry is a powerful method for probing the chemistry of redox-active sites in metalloproteins. the technique affords precise potential control over a tiny quantity of material that is manipulated on an electrode surface, providing information on ligand- or metal-exchange reactions coupled to electron transfer. this is illustrated by examples of transformations of the iron-sulfur clusters in ferredoxins. protein film voltammetry is particularly advantageous in studies of metall ... | 2005 | 15859247 |
| the mechanism of activation of a [nife]-hydrogenase by electrons, hydrogen, and carbon monoxide. | activation of the oxidized inactive state (termed unready or ni(u)) of the [nife]-hydrogenase from allochromatium vinosum requires removal of an unidentified oxidizing entity [o], produced by partial reduction of o(2). dynamic electrochemical kinetic studies, subjecting enzyme molecules on an electrode to sequences of potential steps and gas injections, establish the order of events in an otherwise complex sequence of reactions that involves more than one intermediate retaining [o] or its redox ... | 2005 | 15869280 |
| class iii polyhydroxybutyrate synthase: involvement in chain termination and reinitiation. | polyhydroxybutyrate (phb) synthase catalyzes the polymerization of (r)-3-hydroxybutyryl-coa (coa = coenzyme a) into high molecular weight phb. recombinant wild-type (wt) class iii synthase from allochromatium vinosum (phacphae(av)), antibodies to this synthase and to phb, and [(14)c]hydroxybutyryl-coa (hb-coa) have been used to detect oligomeric hydroxybutyrate (hb) units covalently bound to the synthase using sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. although a distrib ... | 2005 | 15938626 |
| reconstitution of photosynthetic reaction centers and core antenna-reaction center complexes in liposomes and their thermal stability. | photosynthetic reaction centers (rcs) and their core light-harvesting complexes (lh1-rcs), purified from a thermophile, thermochromatium (t.) tepidum, and a mesophile, allochromatium (a.) vinosum, were reconstituted into liposomes. the rc and the lh1-rc in the reconstituted liposomes were found intact from the absorption spectra at about 4 and 40 degrees c respectively. the thermal stability of the rcs of t. tepidum in the liposome was dependent on whether they were surrounded directly by lipids ... | 2005 | 15973044 |
| in vitro analysis of the chain termination reaction in the synthesis of poly-(r)-beta-hydroxybutyrate by the class iii synthase from allochromatium vinosum. | allochromatium vinosum polyhydroxyalkanoate synthase catalyzes formation of poly-(r)-3-hydroxybutyrate (phb) from (r)-3-hydroxybutyryl-coenzyme a (hb-coa). (r)-3-hydroxybutyryl-n-acetylcysteamine (hb-nac) is an alternative substrate for this synthase in vitro, with a turnover 1% that of hb-coa. with hb-nac, the molecular weight (m(w)) of phb produced at substrate-to-enzyme ratios of 1500-15 000 is approximately 75 kda. (1)h nmr shows that phb produced has hydroxybutyrate at the alcohol end and n ... | 2005 | 16004452 |
| characterization of purple sulfur bacteria from the south andros black hole cave system: highlights taxonomic problems for ecological studies among the genera allochromatium and thiocapsa. | a dense 1 m thick layer of phototrophic purple sulfur bacteria is present at the pycnocline (17.8 m depth) in the meromictic south andros black hole cave system (bahamas). two purple sulfur bacteria present in samples collected from this layer have been identified as belonging to the family chromatiaceae. one isolate (bh-1), pink coloured, is non-motile, non-gas vacuolated, 2-3 microm in diameter and surrounded by a capsule. the other isolates (bh-2 and bh-2.4), reddish-brown coloured, are small ... | 2005 | 16011763 |
| the puf operon of the purple sulfur bacterium amoebobacter purpureus: structure, transcription and phylogenetic analysis. | the puf operon, encoding photosynthetic reaction center and light-harvesting genes, of the purple sulfur phototrophic bacterium amoebobacter purpureus was cloned and sequenced. this revealed an unusual operon structure of the genes pufb1 a1 lmcb2 a2 b3 a3. the sequence represents the second complete puf operon available for chromatiaceae. so far, additional sets of light-harvesting 1 (lh1) genes, pufb2 a2 and pufb3 a3 in the region downstream of pufc have only been described for allochromatium v ... | 2005 | 16025309 |
| [the phototrophic community found in lake khilganta (an alkaline saline lake located in the southeastern transbaikal region)]. | the structure of the phototrophic community found in lake khilganta (the agin-buryat autonomous area), a shallow saline soda lake (depth, 35-45 cm; water mineralization, 45 g/l; alkalinity, 30 mg-equiv/l; ph 9.5) has been studied. the bottom of the lake is covered with a 10- to 15-mm microbial mat, whose basis is formed by the filamentous cyanobacterium microcoleus chthonoplastes. the mat exhibits pronounced layering and contains a significant amount of minerals. six zones, which have characteri ... | 2005 | 16119856 |
| purification and characterization of the polypeptides of core light-harvesting complexes from purple sulfur bacteria. | although the polypeptides of core light-harvesting complexes (lh1) from many purple nonsulfur bacteria have been well characterized, little information is available on the polypeptides of lh1 from purple sulfur photosynthetic organisms. we present here the results of isolation and characterization of lh1 polypeptides from two purple sulfur bacteria, thermochromatium (tch.) tepidum and allochromatium (ach.) vinosum. native lh1 complexes were extracted and purified in a reaction center (rc)-associ ... | 2003 | 16245044 |
| transcription of three sets of genes coding for the core light-harvesting proteins in the purple sulfur bacterium, allochromatium vinosum. | the nucleotide sequence of the puf operon coding for the subunits of the photosynthetic reaction center and the core light-harvesting complex (lh1) of the purple sulfur bacterium, allochromatium (a.) vinosum (formally chromatium vinosum), was completely determined. unlike other known puf operons, which contain only one set of genes coding for the lh1 apoproteins, pufb and pufa, the a. vinosum puf operon included three sets of pufb and pufa genes with a gene order of pufb (1) a (1) lmcb (2) a (2) ... | 2002 | 16245138 |
| formation of bacteriochlorophyll form b820 in light harvesting 2 complexes from purple sulfur bacteria treated with dioxane. | treatment of some sulfur bacteria (allochromatium minutissimum, thiorhodospira sibirica, and ectothiorhodospira halovacuolata wn22) with dioxane results in formation of the bacteriochlorophyll form b820 in the light harvesting complex lh2. this form characterized by absorption maximum at 820 nm has the same absorption spectrum as b820 subcomplex from lh1 complex. appearance of the b820 form was accompanied by a sharp decrease in absorption in the carotenoid region. this phenomenon observed in al ... | 2005 | 16271027 |
| reconstitution of okenone into light harvesting complexes from allochromatium minutissimum. | okenone was reconstituted into light harvesting (lh) complexes of the purple photosynthetic bacterium allochromatium minutissimum possessing the spirilloxanthin pathway for carotenoid biosynthesis. suppression of this pathway by diphenylamine, an inhibitor of carotenogenesis, yielded nearly carotenoidless complexes preserving their native spectral properties. using a previously developed technique, okenone was readily reconstituted into lh1 complex (>90%) whereas its reconstitution into lh2 comp ... | 2005 | 16336182 |
| the structure of the 2[4fe-4s] ferredoxin from pseudomonas aeruginosa at 1.32-a resolution: comparison with other high-resolution structures of ferredoxins and contributing structural features to reduction potential values. | the structure of the 2[4fe-4s] ferredoxin (pafd) from pseudomonas aeruginosa, which belongs to the allochromatium vinosum (alvin) subfamily, has been determined by x-ray crystallography at 1.32-a resolution, which is the highest up to now for a member of this subfamily of fds. the main structural features of pafd are similar to those of alvinfd. however, the significantly higher resolution of the pafd structure makes possible a reliable comparison with available high-resolution structures of [4f ... | 2006 | 16596388 |
| an outer membrane protein a (ompa) homologue from the photosynthetic purple sulfur bacterium allochromatium vinosum. | a 991 bp dna fragment, consisting of a 225 amino acid reading frame homologous to outer membrane protein coding ompa gene, was cloned from a purple sulfur bacterium allochromatium vinosum. the homology analysis revealed up to 51% similarity to other bacterial species. the absence of branching within diazotrophs or other taxonomically related groups shows the structural importance of the protein regardless of the metabolism and evolution of the species. | 2007 | 16644194 |
| expression of foreign type i ribulose-1,5-bisphosphate carboxylase/ oxygenase (ec 4.1.1.39) stimulates photosynthesis in cyanobacterium synechococcus pcc7942 cells. | a reporter gene assay revealed that promoters derived from synechococcus pcc7942 (s.7942) psbai and synechocystis pcc6803 (s.6803) psbaii were suitable for the expression of foreign ribulose-bisphosphate carboxylase (rubisco; ec 4.1.1.39) in s.7942 cells. transformational vectors with a promoter and a foreign rubisco gene, cvrbc originated from allochromatium vinosum, were constructed on a binary vector, puc303, and introduced to s.7942 cells. when the cvrbc was expressed with the s.7942 psbai p ... | 2006 | 16741604 |
| ghp, a new c-type green heme protein from halochromatium salexigens and other proteobacteria. | we have isolated a minor soluble green-colored heme protein (ghp) from the purple sulfur bacterium, halochromatium salexigens, which contains a c-type heme. a similar protein has also been observed in the purple bacteria allochromatium vinosum and rhodopseudomonas cryptolactis. this protein has wavelength maxima at 355, 420, and 540 nm and remains unchanged upon addition of sodium dithionite or potassium ferricyanide, indicating either an unusually low or high redox potential, respectively. the ... | 2006 | 16817906 |
| siro(haem)amide in allochromatium vinosum and relevance of dsrl and dsrn, a homolog of cobyrinic acid a,c-diamide synthase, for sulphur oxidation. | in the purple sulphur bacterium allochromatium vinosum, the prosthetic group of dissimilatory sulphite reductase (dsrab) was identified as siroamide, an amidated form of the classical sirohaem. the genes dsrab are the first two of a large cluster of genes necessary for the oxidation of sulphur globules stored intracellularly during growth on sulphide and thiosulphate. dsrn is homologous to cobyrinic acid a,c diamide synthase and may therefore catalyze glutamine-dependent amidation of sirohaem. i ... | 2006 | 16907720 |
| importance of the dsrmkjop complex for sulfur oxidation in allochromatium vinosum and phylogenetic analysis of related complexes in other prokaryotes. | in the phototrophic sulfur bacterium allochromatium vinosum, sulfur of oxidation state zero stored in intracellular sulfur globules is an obligate intermediate during the oxidation of sulfide and thiosulfate. the proteins encoded in the dissimilatory sulfite reductase (dsr) locus are essential for the oxidation of the stored sulfur. dsrmkjop form a membrane-spanning complex proposed to accept electrons from or to deliver electrons to cytoplasmic sulfur-oxidizing proteins. in frame deletion mutag ... | 2006 | 16924482 |
| characterization of a hoxefuyh type of [nife] hydrogenase from allochromatium vinosum and some epr and ir properties of the hydrogenase module. | a soluble hydrogenase from allochromatium vinosum was purified. it consisted of a large (m (r) = 52 kda) and a small (m (r) = 23 kda) subunit. the genes encoding for both subunits were identified. they belong to an open reading frame where they are preceded by three more genes. a dna fragment containing all five genes was cloned and sequenced. the deduced amino acid sequences of the products characterized the complex as a member of the hoxefuyh type of [nife] hydrogenases. detailed sequence anal ... | 2007 | 16969669 |
| thiosulphate oxidation in the phototrophic sulphur bacterium allochromatium vinosum. | two different pathways for thiosulphate oxidation are present in the purple sulphur bacterium allochromatium vinosum: oxidation to tetrathionate and complete oxidation to sulphate with obligatory formation of sulphur globules as intermediates. the tetrathionate:sulphate ratio is strongly ph-dependent with tetrathionate formation being preferred under acidic conditions. thiosulphate dehydrogenase, a constitutively expressed monomeric 30 kda c-type cytochrome with a ph optimum at ph 4.2 catalyses ... | 2006 | 16995898 |
| electrochemical investigations of the interconversions between catalytic and inhibited states of the [fefe]-hydrogenase from desulfovibrio desulfuricans. | studies of the catalytic properties of the [fefe]-hydrogenase from desulfovibrio desulfuricans by protein film voltammetry, under a h2 atmosphere, reveal and establish a variety of interesting properties not observed or measured quantitatively with other techniques. the catalytic bias (inherent ability to oxidize hydrogen vs reduce protons) is quantified over a wide ph range: the enzyme is proficient at both h2 oxidation (from ph > 6) and h2 production (ph < 6). hydrogen production is inhibited ... | 2006 | 17177431 |
| electron transfer and ligand binding to cytochrome c' immobilized on self-assembled monolayers. | we have successfully immobilized allochromatium vinosum cytochrome c' on carboxylic acid-terminated thiol monolayers on gold and have investigated its electron-transfer and ligand binding properties. immobilization could only be achieved for ph's ranging from 3.5 to 5.5, reflecting the fact that the protein is only sufficiently positively charged below ph 5.5 (pi = 4.9). upon immobilization, the protein retains a near-native conformation, as is suggested by the observed potential of 85 mv vs she ... | 2007 | 17209627 |
| sulfide removal and elemental sulfur recycling from a sulfide-polluted medium by allochromatium vinosum strain 21d. | phototrophic purple sulfur bacteria oxidize sulfide to elemental sulfur, which is stored as intracellular sulfur globules. the mutant allochromatium vinosum strain 21d, containing an inactivated dsrb gene, is unable to further oxidize intracellularly stored sulfur to sulfate. this mutant was used as a biocatalyst in a biotechnological process to eliminate sulfide from synthetic wastewater and to recycle elemental sulfur as a raw material. for this purpose, the mutant was grown in an illuminated ... | 2006 | 17236158 |
| utilization of solid "elemental" sulfur by the phototrophic purple sulfur bacterium allochromatium vinosum: a sulfur k-edge x-ray absorption spectroscopy study. | the purple sulfur bacterium allochromatium vinosum can use elemental sulfur as an electron donor for anoxygenic photosynthesis. the elemental sulfur is taken up, transformed into intracellular sulfur globules and oxidized to sulfate. commercially available "elemental" sulfur usually consists of the two species cyclo-octasulfur and polymeric sulfur. the authors investigated whether only one sulfur species is used or at least preferred when alc. vinosum takes up elemental sulfur and forms globules ... | 2007 | 17379736 |
| ligand-induced monomerization of allochromatium vinosum cytochrome c' studied using native mass spectrometry and fluorescence resonance energy transfer. | cytochrome c' from allochromatium vinosum is an attractive model protein to study ligand-induced conformational changes. this homodimeric protein dissociates into monomers upon binding of no, co or cn(-) to the iron of its covalently attached heme group. while ligand binding to the heme has been well characterized using a variety of spectroscopic techniques, direct monitoring of the subsequent monomerization has not been reported previously. here we have explored two biophysical techniques to si ... | 2007 | 17546467 |
| phylogeny of the alpha and beta subunits of the dissimilatory adenosine-5'-phosphosulfate (aps) reductase from sulfate-reducing prokaryotes--origin and evolution of the dissimilatory sulfate-reduction pathway. | newly developed pcr assays were used to pcr-amplify and sequence fragments of the dissimilatory adenosine-5'-phosphosulfate (aps) reductase genes (aprba) comprising nearly the entire gene locus (2.2-2.4 kb, equal to 92-94 % of the protein coding sequence) from 75 sulfate-reducing prokaryotes (srp) of a taxonomically wide range. comparative phylogenetic analysis included all determined and publicly available aprba sequences from srp and selected homologous sequences of sulfur-oxidizing bacteria ( ... | 2007 | 17600048 |
| phototrophic purple sulfur bacteria as heat engines in the south andros black hole. | photosynthetic organisms normally endeavor to optimize the efficiency of their light-harvesting apparatus. however, here we describe two bacterial isolates belonging to the genera allochromatium and thiocapsa that demonstrate a novel adaptation by optimizing their external growth conditions at the expense of photosynthetic efficiency. in the south andros black hole, bahamas, a dense l-m thick layer of these anoxygenic purple sulfur bacteria is present at a depth of 17.8 m. in this layer the wate ... | 2008 | 17906940 |
| cloning, expression, purification, crystallization and preliminary x-ray diffraction analysis of dsrefh from allochromatium vinosum. | in purple sulfur bacteria, the proteins encoded by dsr genes play an essential role in the oxidation of intracellular sulfur, which is an obligate intermediate during the oxidation of sulfide and thiosulfate. one such gene product, dsrefh from allochromatium vinosum, has been cloned, expressed, purified and crystallized. synchrotron data were collected to 2.5 a from a crystal of selenomethionine-substituted dsrefh. the crystal belongs to the primitive monoclinic space group p2(1), with unit-cell ... | 2007 | 17909298 |
| phylogeny and evolution of the family ectothiorhodospiraceae based on comparison of 16s rrna, cbbl and nifh gene sequences. | the occurrence of genes encoding nitrogenase and ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) was investigated in the members of the family ectothiorhodospiraceae. this family forms a separate phylogenetic lineage within the gammaproteobacteria according to 16s rrna gene sequence analysis and mostly includes photo- and chemoautotrophic halophilic and haloalkaliphilic bacteria. the cbbl gene encoding the large subunit of 'green-like' form i rubisco was found in all strains, except th ... | 2007 | 17911316 |
| carotenoid-photosensitized oxidation of bacteriochlorophyll dimers in light-harvesting complexes b800-850 in allochromatium minutissimum cells. | | 2007 | 18064826 |
| allochromatium renukae sp. nov. | an ovoid to rod-shaped, phototrophic, purple sulfur bacterium, designated strain ja136(t), was isolated in pure culture from brackish water near kakinada, india, in a medium that contained 2 % nacl (w/v). cells were gram-negative and motile by means of a single polar flagellum. strain ja136(t) had no absolute salt requirement for growth but was able to tolerate up to 4 % nacl (w/v). intracellular photosynthetic membranes were of the vesicular type. bacteriochlorophyll a and the carotenoid lycope ... | 2008 | 18218939 |
| femtosecond spectroscopy of native and carotenoidless purple-bacterial lh2 clarifies functions of carotenoids. | eet between the two circular bacteriochlorophyll compartments b800 and b850 in native (containing the carotenoid rhodopin) and carotenoidless lh2 isolated from the photosynthetic purple sulfur bacterium allochromatium minutissimum was investigated by femtosecond time-resolved transient absorption spectroscopy. both samples were excited with 120-fs laser pulses at 800 nm, and spectral evolution was followed in the 720-955 nm range at different delay times. no dependence of transient absorption in ... | 2008 | 18339744 |
| polymyxin-coated au and carbon nanotube electrodes for stable [nife]-hydrogenase film voltammetry. | we report on the use of polymyxin (pm), a cyclic cationic lipodecapeptide, as an electrode modifier for studying protein film voltammetry (pfv) on au and single-walled carbon nanotube (swnt) electrodes. pretreating the electrodes with pm allows for the subsequent immobilization of an active submonolayer of [nife]-hydrogenase from allochromatium vinosum ( av h2ase). probed by cyclic voltammetry (cv), the adsorbed enzyme exhibits characteristic electrocatalytic behavior that is stable for several ... | 2008 | 18459755 |
| allochromatium vinosum dsrc: solution-state nmr structure, redox properties, and interaction with dsrefh, a protein essential for purple sulfur bacterial sulfur oxidation. | sequenced genomes of dissimilatory sulfur-oxidizing and sulfate-reducing bacteria containing genes coding for dsrab, the enzyme dissimilatory sulfite reductase, inevitably also contain the gene coding for the 12-kda dsrc protein. dsrc is thought to have a yet unidentified role associated with the activity of dsrab. here we report the solution structure of dsrc from the sulfur-oxidizing purple sulfur bacterium allochromatium vinosum determined with nmr spectroscopy in reducing conditions, and we ... | 2008 | 18656485 |
| x-ray absorption spectroscopy as a probe of microbial sulfur biochemistry: the nature of bacterial sulfur globules revisited. | the chemical nature of the sulfur in bacterial sulfur globules has been the subject of controversy for a number of years. sulfur k-edge x-ray absorption spectroscopy (xas) is a powerful technique for probing the chemical forms of sulfur in situ, but two groups have used it with very different conclusions. the root of the controversy lies with the different detection strategies used by the two groups, which result in very different spectra. this paper seeks to resolve the controversy. we experime ... | 2008 | 18676668 |
| purification, crystallization and preliminary x-ray analysis of the membrane-bound [nife] hydrogenase from allochromatium vinosum. | the membrane-bound [nife] hydrogenase is a unique metalloprotein that is able to catalyze the reversible oxidation of hydrogen to protons and electrons during a complex reaction cycle. the [nife] hydrogenase was isolated from the photosynthetic purple sulfur bacterium allochromatium vinosum and its crystallization and preliminary x-ray analysis are reported. it was crystallized by the hanging-drop vapour-diffusion method using sodium citrate and imidazole as crystallization agents. the crystals ... | 2008 | 18678940 |
| the peripheral light-harvesting complexes from purple sulfur bacteria have different 'ring' sizes. | the integral membrane light-harvesting (lh) proteins from purple photosynthetic bacteria form circular oligomers of an elementary unit that is composed of two very hydrophobic polypeptides, termed alpha and beta. these apoprotein dimers are known to associate into closed circular arrays of 8, 9 and 16 alpha/beta-mers. we report the existence of peripheral lh proteins purified from allochromatium vinosum with two intermediate ring sizes and postulate that one is a 13 alpha/beta-mer. this shows th ... | 2008 | 18840433 |
| sulfur metabolism in phototrophic sulfur bacteria. | phototrophic sulfur bacteria are characterized by oxidizing various inorganic sulfur compounds for use as electron donors in carbon dioxide fixation during anoxygenic photosynthetic growth. these bacteria are divided into the purple sulfur bacteria (psb) and the green sulfur bacteria (gsb). they utilize various combinations of sulfide, elemental sulfur, and thiosulfate and sometimes also ferrous iron and hydrogen as electron donors. this review focuses on the dissimilatory and assimilatory metab ... | 2009 | 18929068 |
| structural and molecular genetic insight into a widespread sulfur oxidation pathway. | many environmentally important photo- and chemolithoautotrophic bacteria accumulate globules of polymeric, water-insoluble sulfur as a transient product during oxidation of reduced sulfur compounds. oxidation of this sulfur requires the concerted action of dsr proteins. however, individual functions and interplay of these proteins are largely unclear. we proved with a deltadsre mutant experiment that the cytoplasmic alpha2beta2gamma2-structured protein dsrefh is absolutely essential for the oxid ... | 2008 | 18952098 |
| thiophaeococcus mangrovi gen. nov., sp. nov., a photosynthetic, marine gammaproteobacterium isolated from the bhitarkanika mangrove forest of india. | a coccoid, phototrophic purple sulfur bacterium was isolated in pure culture from a mud sample collected from brackish water in the bhitarkanika mangrove forest of orissa, india, in a medium containing 2 % nacl (w/v). this bacterium, strain ja304(t), was gram-negative and had a requirement for nacl. intracellular photosynthetic membranes were of the vesicular type. the colour of the phototrophically grown culture was saddle-brown. bacteriochlorophyll a and the carotenoid lycopene were present as ... | 2008 | 18984710 |
| heterogeneity of carotenoid content and composition in lh2 of the purple sulphur bacterium allochromatium minutissimum grown under carotenoid-biosynthesis inhibition. | the effects brought about by growing allochromatium (alc.) minutissimum in the presence of different concentrations of the carotenoid (car) biosynthetic inhibitor diphenylamine (dpa) have been investigated. a decrease of car content (from approximately 70% to >5%) in the membranes was accompanied by an increase of the percentage of (immature) cars with reduced numbers of conjugated c=c bonds (from neurosporene to phytoene). based on the obtained results and the analysis of literature data, the c ... | 2008 | 18998236 |
| [distribution of bacteriochlorophyll between the pigment-protein complexes of the sulfur photosynthesizing bacterium allochromatium minutissimum depending on light intensity at different temperatures]. | variation of the distribution of bacteriochlorophyll a (bchl a) between external antenna (lh2) and core complexes (lhl + rc) of the photosynthetic membrane of the sulfur bacterium allochromatium minutissimum was studied at light intensities of 5 and 90 wt/m2 in the temperature range of 12-43 degrees c. the increase of light intensity was shown to result in a 1.5- to 2-times increase of a photosynthetic unit (psu). psu sizes pass through a maximum depending on growth temperature, and the increase ... | 2008 | 19004340 |
| toward single-enzyme molecule electrochemistry: [nife]-hydrogenase protein film voltammetry at nanoelectrodes. | we have scaled down electrochemical assays of redox-active enzymes enabling us to study small numbers of molecules. our approach is based on lithographically fabricated au nanoelectrodes with dimensions down to ca. 70 x 70 nm(2). we first present a detailed characterization of the electrodes using a combination of scanning electron microscopy, cyclic voltammetry, and finite-element modeling. we then demonstrate the viability of the approach by focusing on the highly active [nife]-hydrogenase fro ... | 2008 | 19206284 |
| insight into the protein and solvent contributions to the reduction potentials of [4fe-4s]2+/+ clusters: crystal structures of the allochromatium vinosum ferredoxin variants c57a and v13g and the homologous escherichia coli ferredoxin. | the crystal structures of the c57a and v13g molecular variants of allochromatium vinosum 2[4fe-4s] ferredoxin (alvinfd) and that of the homologous ferredoxin from escherichia coli (ecfd) have been determined at 1.05-, 1.48-, and 1.65-a resolution, respectively. the present structures combined with cyclic voltammetry studies establish clear effects of the degree of exposure of the cluster with the lowest reduction potential (cluster i) towards less negative reduction potentials (e degrees ). this ... | 2009 | 19290553 |
| interaction between sox proteins of two physiologically distinct bacteria and a new protein involved in thiosulfate oxidation. | organisms using the thiosulfate-oxidizing sox enzyme system fall into two groups: group 1 forms sulfur globules as intermediates (allochromatium vinosum), group 2 does not (paracoccus pantotrophus). while several components of their sox systems are quite similar, i.e. the proteins soxxa, soxyz and soxb, they differ by sox(cd)(2) which is absent in sulfur globule-forming organisms. still, the respective enzymes are partly exchangeable in vitro: p. pantotrophus sox enzymes work productively with a ... | 2009 | 19303410 |
| allochromatium phaeobacterium sp. nov. | a rod-shaped, phototrophic, purple sulfur bacterium was isolated in pure culture from brackish water near bheemli, visakhapatnam, india, in a medium that contained 2 % nacl (w/v). strain ja144(t) was gram-negative and motile. it did not require salt, but tolerated up to 3 % nacl (w/v). intracellular photosynthetic membranes were of the vesicular type. bacteriochlorophyll a and carotenoids that probably belonged to the rhodopinal series were present as photosynthetic pigments. strain ja144(t) was ... | 2009 | 19329600 |
| unexpected extracellular and intracellular sulfur species during growth of allochromatium vinosum with reduced sulfur compounds. | before its uptake and oxidation by purple sulfur bacteria, elemental sulfur probably first has to be mobilized. to obtain more insight into this mobilization process in the phototrophic purple sulfur bacterium allochromatium vinosum, we used hplc analysis and x-ray absorption near-edge structure (xanes) spectroscopy for the detection and identification of sulfur compounds in culture supernatants and bacterial cells. we intended to identify soluble sulfur compounds that specifically occur during ... | 2009 | 19423634 |
| altered composition of ralstonia eutropha poly(hydroxyalkanoate) through expression of pha synthase from allochromatium vinosum atcc 35206. | the class iii poly(hydroxyalkanoate) synthase (phas) genes (phac and phae) of a photosynthetic bacterium, allochromatium vinosum atcc 35206, were cloned, sequenced and expressed in a heterologous host. pcr coupled with a chromosomal gene-walking method was used to clone and subsequently sequence the contiguous phac (1,068 bps) and phae (1,065 bps) genes of a. vinosum atcc 35206. blastp search of protein databases showed that the gene-products of phac and phae are different (<66% identities) from ... | 2009 | 19557308 |
| increased biological hydrogen production by deletion of hydrogen-uptake system in photosynthetic bacteria. | hydrogenases are the key enzymes for the biological hydrogen production, which can be classified as h(2)-uptake hydrogenase and h(2)-production hydrogenase. the genes encoding a membrane-bound [nife]-hydrogenase (mbh), which is mainly responsible for hydrogen uptake, from the photosynthetic bacterium allochromatium vinosum was cloned and sequenced. it consist of two structural genes (hyds, hydl) and two intergenic genes (isp1, isp2), which are therefore organized as hyds-isp1-isp2-hydl. this is ... | 2009 | 19560910 |
| two-photon excitation spectroscopy of carotenoid-containing and carotenoid-depleted lh2 complexes from purple bacteria. | we applied two-photon fluorescence excitation spectroscopy to lh2 complex from purple bacteria allochromatium minutissimum and rhodobacter sphaeroides . bacteriochlorophyll fluorescence was measured under two-photon excitation of the samples within the 1200-1500 nm region. spectra were obtained for both carotenoid-containing and -depleted complexes of each bacterium to allow their direct comparison. the depletion of carotenoids did not alter the two-photon excitation spectra of either bacteria. ... | 2009 | 19650635 |
| detection of covalent and noncovalent intermediates in the polymerization reaction catalyzed by a c149s class iii polyhydroxybutyrate synthase. | polyhydroxybutyrate (phb) synthases catalyze the conversion of 3-hydroxybutyryl coenzyme a (hbcoa) to phb with a molecular mass of 1.5 mda. the class iii synthase from allochromatium vinosum is a tetramer of phaephac (each 40 kda). the polymerization involves covalent catalysis using c149 of phac with one phb chain per phaec dimer. two mechanisms for elongation have been proposed. the first involves an active site composed of two monomers in which the growing hydroxybutyrate (hb) chain alternate ... | 2009 | 19711985 |
| the speciation of soluble sulphur compounds in bacterial culture fluids by x-ray absorption near edge structure spectroscopy. | over the last decade x-ray absorption near edge structure (xanes) spectroscopy has been used in an increasing number of microbiological studies. in addition to other applications it has served as a valuable tool for the investigation of the sulphur globules deposited intra- or extracellularly by certain photo- and chemotrophic sulphur-oxidizing (sox) bacteria. for xanes measurements, these deposits can easily be concentrated by filtration or sedimentation through centrifugation. however, during ... | 2009 | 19950470 |
| regulation of dsr genes encoding proteins responsible for the oxidation of stored sulfur in allochromatium vinosum. | sulfur globules are formed as obligatory intermediates during the oxidation of reduced sulfur compounds in many environmentally important photo- and chemolithoautotrophic bacteria. it is well established that the so-called dsr proteins are essential for the oxidation of zero-valent sulfur accumulated in the globules; however, hardly anything is known about the regulation of dsr gene expression. here, we present a closer look at the regulation of the dsr genes in the phototrophic sulfur bacterium ... | 2010 | 20007651 |
| self-interaction chromatography as a tool for optimizing conditions for membrane protein crystallization. | the second virial coefficient, or b value, is a measurement of how well a protein interacts with itself in solution. these interactions can lead to protein crystallization or precipitation, depending on their strength, with a narrow range of b values (the 'crystallization slot') being known to promote crystallization. a convenient method of determining the b value is by self-interaction chromatography. this paper describes how the light-harvesting complex 1-reaction centre core complex from allo ... | 2010 | 20057048 |
| dsrr, a novel isca-like protein lacking iron- and fe-s-binding functions, involved in the regulation of sulfur oxidation in allochromatium vinosum. | in the purple sulfur bacterium allochromatium vinosum, the reverse-acting dissimilatory sulfite reductase (dsrab) is the key enzyme responsible for the oxidation of intracellular sulfur globules. the genes dsrab are the first and the gene dsrr is the penultimate of the 15 genes of the dsr operon in a. vinosum. genes homologous to dsrr occur in a number of other environmentally important sulfur-oxidizing bacteria utilizing dsr proteins. dsrr exhibits sequence similarities to a-type scaffolds, lik ... | 2010 | 20061482 |
| a new structure-based classification of sulfide:quinone oxidoreductases. | sulfide:quinone oxidoreductases (sqr) are ubiquitous membrane-bound flavoproteins involved in sulfide detoxification, in sulfide-dependent energy conservation processes and potenatially in the homeostasis of the neurotransmitter sulfide. the first 2 structures of sqrs from the bacterium aquifex aeolicus (marcia et al., proc natl acad sci usa 2009; 106:9625-9630) and the archaeon acidianus ambivalens (brito et al., biochemistry 2009; 48:5613-5622) were determined recently by x-ray crystallography ... | 2010 | 20077566 |
| beyond the genome: functional studies of phototrophic sulfur oxidation. | the increasing availability of complete genomic sequences for cultured phototrophic bacteria and assembled metagenomes from environments dominated by phototrophs has reinforced the need for a "post-genomic" analytical effort to test models of cellular structure and function proposed from genomic data. comparative genomics has produced a testable model for pathways of sulfur compound oxidation in the phototrophic bacteria. in the case of sulfide, two enzymes are predicted to oxidize sulfide: sulf ... | 2010 | 20532738 |
| bd oxidase homologue of photosynthetic purple sulfur bacterium allochromatium vinosum is co-transcribed with a nitrogen fixation related gene. | purple sulfur bacteria, which are known to be the most ancient among anoxygenic phototrophs, play an important role in the global sulfur cycle. allochromatium vinosum oxidizes reduced sulfur compounds such as hydrogen sulfide, elemental sulfur and thiosulfide. at low oxygen concentrations, a. vinosum can grow chemotrophically using oxygen as the terminal electron acceptor. being also a nitrogen fixer, a. vinosum is faced with the paradox of co-existence of aerobic metabolism and nitrogen fixatio ... | 2011 | 20577808 |
| the crystal structure of the [nife] hydrogenase from the photosynthetic bacterium allochromatium vinosum: characterization of the oxidized enzyme (ni-a state). | the crystal structure of the membrane-associated [nife] hydrogenase from allochromatium vinosum has been determined to 2.1 å resolution. electron paramagnetic resonance (epr) and fourier transform infrared spectroscopy on dissolved crystals showed that it is present in the ni-a state (>90%). the structure of the a. vinosum [nife] hydrogenase shows significant similarities with [nife] hydrogenase structures derived from desulfovibrio species. the amino acid sequence identity is ∼ 50%. the bimetal ... | 2010 | 20673834 |
| dsrj, an essential part of the dsrmkjop transmembrane complex in the purple sulfur bacterium allochromatium vinosum, is an unusual triheme cytochrome c. | the dsrmkjop transmembrane complex has a most important function in dissimilatory sulfur metabolism, not only in many sulfur-oxidizing organisms but also in sulfate-reducing prokaryotes. here, we focused on an individual component of this complex, the triheme cytochrome c dsrj from the purple sulfur bacterium allochromatium vinosum. in a. vinosum, the signal peptide of dsrj is not cleaved off but serves as a membrane anchor. sequence analysis suggested the presence of three heme c species with b ... | 2010 | 20726534 |
| biochemical characterization of individual components of the allochromatium vinosum dsrmkjop transmembrane complex aids understanding of complex function in vivo. | the dsrmkjop transmembrane complex has a most important function in dissimilatory sulfur metabolism and consists of cytoplasmic, periplasmic, and membrane integral proteins carrying fes centers and b- and c-type cytochromes as cofactors. in this study, the complex was isolated from the purple sulfur bacterium allochromatium vinosum and individual components were characterized as recombinant proteins. the two integral membrane proteins dsrm and dsrp were successfully produced in escherichia coli ... | 2010 | 20952577 |
| five novel acid-tolerant oligotrophic thiosulfate-metabolizing chemolithotrophic acid mine drainage strains affiliated with the genus burkholderia of betaproteobacteria and identification of two novel soxb gene homologues. | five acid-tolerant thiosulfate-metabolizing bacteria were isolated from acid mine drainage samples from garubathan, india. 16s rrna gene analysis revealed that the strains were affiliated with the genus burkholderia of the class of betaproteobacteria. comparative 16s rrna gene sequence analyses indicated that the strains designated as gah1 and gah2 produced a separate phylogenetic branch having burkholderia pyrrocinia atcc 51958(t) (96-98%) as the closest relative. strains gah4 and burkholderia ... | 2011 | 21349327 |
| heterologous synthesis of cytochrome c' by escherichia coli is not dependent on the system i cytochrome c biogenesis machinery. | hydrogenophilus thermoluteolus cytochrome c' (phcp) has typical spectral properties previously observed for other cytochromes c', which comprise ambler's class ii cytochromes c. the phcp protein sequence (135 amino acids) deduced from the cloned gene is the most homologous (55% identity) to that of cytochrome c' from allochromatium vinosum (avcp). these findings indicate that phcp forms a four-helix bundle structure, similar to avcp. strikingly, phcp with a covalently bound heme was heterologous ... | 2011 | 21554540 |
| metatranscriptomic analysis of sulfur oxidation genes in the endosymbiont of solemya velum. | thioautotrophic endosymbionts in the domain bacteria mediate key sulfur transformations in marine reducing environments. however, the molecular pathways underlying symbiont metabolism and the extent to which these pathways are expressed in situ are poorly characterized for almost all symbioses. this is largely due to the difficulty of culturing symbionts apart from their hosts. here, we use pyrosequencing of community rna transcripts (i.e., the metatranscriptome) to characterize enzymes of dissi ... | 2011 | 21738524 |
| the genus allochromatium (chromatiales chromatiaceae) revisited: a study on its intragenic structure based on multilocus sequence analysis (mlsa) and dna-dna hybridization (ddh). | in this study, the taxonomic status of anoxygenic photosynthetic bacteria belonging to the genus allochromatium is revisited. the inter- and intraspecies relationship of seven allochromatium strains, including a set of well described type strains, were examined by dna-dna hybridization (ddh) and multilocus sequence analysis (mlsa) using segments of seven protein-coding genes. the re-sequencing of the 16s rrna, the internal transcriber spacer (its), multi-gene analysis and ddh comparison indicate ... | 2011 | 21885227 |
| regulation of dissimilatory sulfur oxidation in the purple sulfur bacterium allochromatium vinosum. | in the purple sulfur bacterium allochromatium vinosum, thiosulfate oxidation is strictly dependent on the presence of three periplasmic sox proteins encoded by the soxbxak and soxyz genes. it is also well documented that proteins encoded in the dissimilatory sulfite reductase (dsr) operon, dsrabefhcmkljopnrs, are essential for the oxidation of sulfur that is stored intracellularly as an obligatory intermediate during the oxidation of thiosulfate and sulfide. until recently, detailed knowledge ab ... | 2011 | 21927612 |