| cu(i) analysis of blue copper proteins. | a simple colorimetric test for the cu(i) content in blue copper proteins is described. the procedure is based on the formation of a complex between cu(i) and 2,2'-biquinoline in an acetic acid medium. analyses of spinach plastocyanin, pseudomonas aeruginosa azurin and rhus vernicifera stellacyanin show that the cysteine residue in the type 1 site does not induce cu(ii) reduction under our conditions. there is evidence in laccase samples for the presence of an endogenous reductant that can reduce ... | 1988 | 3223941 |
| peritonitis due to methylobacterium mesophilicum complicating ambulatory peritoneal dialysis--british columbia. | | 1988 | 3242906 |
| the hopanoids of the purple non-sulfur bacteria rhodopseudomonas palustris and rhodopseudomonas acidophila and the absolute configuration of bacteriohopanetetrol. | five complex hopanoids have been detected in the purple non-sulfur bacterium rhodopseudomonas acidophila. next to the polyfunctionalized methylcyclopentane bacteriohopanetetrol ether already isolated from methylobacterium organophilum, 35-carbamoylbacteriohopane-32,33,34-triol, 34,35-dicarbamoylbacteriohopane-32,33-diol and two nucleoside analogues, (22r)-30-(5'-adenosyl)hopane and (22s)-30-(5'-adenosyl)hopane were isolated and identified by spectroscopic and chemical methods. in rhodopseudomona ... | 1988 | 3338464 |
| preliminary x-ray crystallographic study of amicyanin from thiobacillus versutus. | | 1988 | 3351942 |
| preferred sites and pathways for electron transfer in blue copper proteins. | long-range electron transfer reactions proceed within and between metalloproteins at relatively fast rates and with marked specificities. the blue single copper proteins are well known electron carriers with their redox center being of limited accessibility to solvent and solutes. the question of where and how electrons are transferred to and from the copper-ion have been investigated. one experimental approach developed in order to pursue these problems is that of reductively labeling several r ... | 1988 | 3406028 |
| phase determination by multiple-wavelength x-ray diffraction: crystal structure of a basic "blue" copper protein from cucumbers. | a novel x-ray diffraction technique, multiple-wavelength anomalous dispersion (mad) phasing, has been applied to the de novo determination of an unknown protein structure, that of the "blue" copper protein isolated from cucumber seedlings. this method makes use of crystallographic phases determined from measurements made at several wavelengths and has recently been made technically feasible through the use of intense, polychromatic synchrotron radiation together with accurate data collection fro ... | 1988 | 3406739 |
| a 1h-nmr study on the blue copper protein amicyanin from thiobacillus versutus. resonance identifications, structural rearrangements and determination of the electron self-exchange rate constant. | a number of resonances in the 1h-nmr spectra of reduced and oxidised amicyanin from thiobacillus versutus have been identified by one- and two-dimensional nmr techniques. the second-order electron self-exchange rate constant (8.5 x 10(4) m-1.s-1; ph = 7.4; t = 308.5 k) was determined by measuring the line broadening of six singlets in slightly oxidised solutions of the protein. a large increase in electron exchange rate is observed in the presence of ferrocyanide. the copper atom in the reactive ... | 1988 | 3416870 |
| the amino acid sequence of the blue copper protein of alcaligenes faecalis. | the complete amino acid sequence of a blue copper protein from alcaligenes faecalis s-6 has been determined. this protein is clearly homologous to pseudoazurins in achromobacter cycloclastes and pseudomonas am1, more distantly related to plant plastocyanins, and markedly different from the azurin of pseudomonas aeruginosa. yet all of these proteins bind copper, and analogous ligands appear to be involved. | 1986 | 3512305 |
| kinetic studies of the copper nitrite reductase from achromobacter cycloclastes and its interaction with a blue copper protein. | transient state, burst and steady state kinetics of reactions of the blue copper nitrite reductase (nir) and blue copper protein from achromobacter cycloclastes are investigated. the two copper-containing species are reacted with each other and where possible with dithionite, ascorbate and nitrite. both copper proteins are fully reduced by dithionite with both s2o4(2-) and so2-. species active. nir is only partially reduced by ascorbate in an unusual biphasic reaction consistent with complete re ... | 1987 | 3593351 |
| redox properties of the quinoprotein methylamine dehydrogenase from paracoccus denitrificans. | paracoccus denitrificans synthesizes a methylamine dehydrogenase that contains a covalently bound form of pyrroloquinoline quinone as a prosthetic group [husain, m., & davison, v.l. (1987) j. bacteriol. 169, 1712-1717]. anaerobic reductive titration of this enzyme with dithionite proceeded through a semiquinone intermediate with spectral properties quite distinct from those of the oxidized and reduced species. from these data the molar extinction coefficients were calculated at various wavelengt ... | 1987 | 3651442 |
| dna:dna hybridization studies on the pink-pigmented facultative methylotrophs. | the genomic relatedness among 36 strains of pink-pigmented facultatively methylotrophic bacteria (ppfms) was estimated by determination of dna base composition and by dna:dna hybridization studies. a reproducible hybridization system was developed for the rapid analysis of multiple dna samples. results indicated that the ppfms comprise four major and several minor homology groups, and that they should remain grouped in a single genus, methylobacterium. | 1987 | 3655730 |
| type 1, blue copper proteins constitute a respiratory nitrite-reducing system in pseudomonas aureofaciens. | pseudomonas aureofaciens truncates the respiratory reduction of nitrate (denitrification) at the level of n2o. the nitrite reductase from this organism was purified to apparent electrophoretic homogeneity and found to be a blue copper protein. the enzyme contained 2 atoms of copper/85 kda, both detectable by electron paramagnetic resonance (epr) spectroscopy. the protein was dimeric, with subunits of identical size (40 +/- 3 kda). its pi was 6.05. the epr spectrum showed an axial signal g at 2.2 ... | 1987 | 3665926 |
| properties and electron transfer specificity of copper proteins from the denitrifier "achromobacter cycloclastes". | a blue copper protein (mr 12,000) was purified from cells of "achromobacter cycloclastes" grown as a denitrifier. when reduced, the blue copper protein transferred electrons to the copper protein nitrite reductase purified from the same cells, whereas a variety of cytochromes from denitrifiers failed to do so. inclusion of a protease inhibitor, phenylmethylsulfonyl fluoride, in the buffers employed during preparation yielded purified blue copper protein with 18 more amino acid residues and two t ... | 1986 | 3700338 |
| properties of paracoccus denitrificans amicyanin. | paracoccus denitrificans synthesizes an inducible, periplasmic, blue copper protein [husain, m., & davidson, v.l. (1985) j. biol. chem. 260, 14626-14629] that can be classified as an amicyanin on the basis of its ability to accept electrons from methylamine dehydrogenase. the amino acid composition and sequence of the 10 n-terminal residues of this protein have been determined. from these data, it is evident that amicyanin is structurally distinct from azurins as it contains no disulfide bond an ... | 1986 | 3718960 |
| preliminary x-ray crystallographic study of amicyanin from paracoccus denitrificans. | single crystals have been prepared of paracoccus denitrificans amicyanin, a blue copper protein that serves as an electron acceptor for methylamine dehydrogenase. the crystals belong to the monoclinic space group p2(1), and have unit cell parameters a = 20.90 a, b = 56.61 a, c = 27.55 a and beta = 96.41. there is one molecule in the asymmetric unit. the crystals diffract to beyond 1.5 a resolution. | 1986 | 3783676 |
| prokaryotic triterpenoids. 2. 2 beta-methylhopanoids from methylobacterium organophilum and nostoc muscorum, a new series of prokaryotic triterpenoids. | 2 beta-methylhopanoids, a new series of triterpenoids was identified from two prokaryotes. 2 beta-methyldiplopterol was isolated from the methylotrophic bacterium methylobacterium organophilum, and three different 2 beta-methylbacteriohopanepolyols from the cyanobacterium nostoc muscorum. the structures of these compounds was deduced by direct comparison with 2 beta-methyldiplopterol synthesized from 22-hydroxyhopan-3-one. | 1985 | 3926495 |
| prokaryotic triterpenoids. 3. the biosynthesis of 2 beta-methylhopanoids and 3 beta-methylhopanoids of methylobacterium organophilum and acetobacter pasteurianus ssp. pasteurianus. | the incorporation of l-[methyl-3h,14c]methionine or l-(methyl-2h3)methionine into 2 beta-methyldiplopterol of methylobacterium organophilum and various 3 beta-methylhopanoids of acetobacter pasteurianus ssp. pasteurianus showed that all three hydrogen atoms of the transferred methyl group are retained in the triterpenoids. these methylations are compatible with a methylation substrate such as a delta 2-hopanoid in the case of the 2 beta-methylhopanoid biosynthesis and of a delta 2-hopanoid or sq ... | 1985 | 3926496 |
| the role of blue copper proteins in the oxidation of methylamine by an obligate methylotroph. | organism 4025, an obligate methylotroph, when grown on methylamine in the presence of a high concentration of copper, contained high concentrations of methylamine dehydrogenase and two blue copper proteins, amicyanin and an azurin-type protein; these were purified to homogeneity and characterized. the methylamine dehydrogenase is a basic protein (pi 8.8) and consists of light and heavy subunits (mr 14100 and 43000; total mr 112000). this dehydrogenase differed slightly from other methylamine deh ... | 1985 | 3927899 |
| prokaryotic triterpenoids. new bacteriohopanetetrol cyclitol ethers from the methylotrophic bacterium methylobacterium organophilum. | together with bacteriohopanetetrol, which is identical to bacteriohopanetetrol isolated from bacillus acidocaldarius, three other bacteriohopane derivatives were isolated from the methylotrophic bacterium methylobacterium organophilum. three different kinds of polar moieties were found linked to the c-35 hydroxyl group of bacteriohopanetetrol: glucosamine linked through a glycosidic bond and two new polyhydroxylated methylcyclopentanoids differing one from each other by the presence of an amino ... | 1985 | 3928379 |
| the primary structures of pseudomonas am1 amicyanin and pseudoazurin. two new sequence classes of blue copper proteins. | the amino acid sequences of two blue copper proteins from the pink facultative methylotroph pseudomonas am1 (n.c.i.b. 9133) were determined. they each consist of a single polypeptide chain and bind one copper atom. amicyanin contains 99 and pseudoazurin 123 residues. copper-binding sites, consisting of the side chains of two histidine, one cysteine and one methionine residues, can be recognized in each protein by analogy with azurin and plastocyanin, but the spacings of the ligand residues are d ... | 1985 | 4091802 |
| a blue protein as an inactivating factor for nitrite reductase from alcaligenes faecalis strain s-6. | a blue protein with a molecule weight of 12,000 containing 1 atom of type i cu2+ was purified and crystallized from a denitrifying bacterium, alcaligenes faecalis strain s-6, as an inactivating factor for copper-containing nitrite reductase of the same organism. inactivation of the enzyme occurred when the enzyme was incubated aerobically with a catalytic amount of the blue protein in the presence of reducing agents such as cysteine and ascorbate. the blue protein acts as a direct electron donor ... | 1981 | 6263871 |
| amicyanin: an electron acceptor of methylamine dehydrogenase. | | 1981 | 6272760 |
| extension of the model concerning linkage of genes coding for c-1 related functions in methylobacterium organophilum. | evidence is presented which suggests that methylobacterium organophilum contains isoenzymes of phosphoenolpyruvate carboxylase activity. methanol-grown cells contained an acetyl coenzyme a (coa)-insensitive activity which precipitated in a 65 to 75% of saturation ammonium sulfate fraction. succinate-grown cells contained an acetyl-coa-stimulated activity which precipitated in a 55 to 65% of saturation ammonium sulfate fraction. mutants unable to grow on methanol appeared to lack acetyl-coa-insen ... | 1981 | 6786218 |
| obligate methylotrophy: evaluation of dimethyl ether as a c1 compound. | the suitability of dimethyl ether as a c1 compound was examined with the obligate methylobacterium methylococcus capsulatus (texas). the ether did not support growth and was not formed during growth on methane; it was an inhibitor of growth and oxidation of methane and a poor oxidation substrate for cell suspensions. nadh stimulation of methane, but not dimethyl ether, oxidation occurred in cell extracts. | 1982 | 6802804 |
| stereospecificity and other properties of a novel secondary-alcohol-specific alcohol dehydrogenase. | nad-dependent alcohol dehydrogenase from the methanol-grown methylcoccus sp. crl m1 (type i membrane), methylosinus trichosporium ob3b (type ii membrane), methylobacterium organophillum crl 26 (type ii membrane, facultative methylotroph). pseudomonas sp. atcc 21439, and pichia pastoris y-55 are secondary-alcohol-specific and that from p. pastoris y-7556 is not. this novel secondary-alcohol-specific alcohol dehydrogenase (secondary-alcohol dehydrogenase) has been purified from methanol-grown pseu ... | 1981 | 7030736 |
| intermolecular electron transfer from substrate-reduced methylamine dehydrogenase to amicyanin is linked to proton transfer. | within the methylamine dehydrogenase-amicyanin complex, intermolecular electron transfer (et) occurs between tryptophan tryptophylquinone (ttq) and copper. the et reactions from two chemically distinct reduced forms of ttq were studied. the quinol form of ttq was generated by reduction by dithionite. an aminoquinol form of ttq, in which an amino group displaces the carbonyl oxygen, was generated by reduction by the substrate methylamine. thermodynamic analysis of the et reactions suggested that ... | 1995 | 7547947 |
| electron transfer reactions between aromatic amine dehydrogenase and azurin. | binding and electron transfer reactions between the tryptophan tryptophylquinone (ttq) enzyme, aromatic amine dehydrogenase (aadh), and the type i copper protein azurin have been characterized. in steady-state kinetic assays using azurin as an electron acceptor, it was observed that the apparent km for azurin decreased with increasing ionic strength. these results are the opposite of what was observed for the reaction between the ttq enzyme methylamine dehydrogenase (madh) and amicyanin, despite ... | 1995 | 7547967 |
| nucleotide sequence of the mxcq and mxce genes, required for methanol dehydrogenase synthesis in methylobacterium organophilum xx: a two-component regulatory system. | nucleotide sequence analysis of the mxcq and mxce loci, required for the synthesis of methanol dehydrogenase in methylobacterium organophilum xx, has revealed two open reading frames that show significant similarity to sequences of prokaryotic two-component systems, especially mxay and mxax proteins of another methylotrophic bacterium, paracoccus denitrificans. cell-free extracts and dna-column-fractionated proteins from wild-type m. organophilum xx cells grown on methanol or succinate contained ... | 1995 | 7582014 |
| identification and nucleotide sequences of mxaa, mxac, mxak, mxal, and mxad genes from methylobacterium extorquens am1. | the dna sequence for a 4.4-kb hindiii-xhoi methylobacterium extorquens am1 dna fragment that is known to contain three genes (mxaakl) involved in incorporation of calcium into methanol dehydrogenase (i. w. richardson and c. anthony, biochem. j. 287:709-7115, 1992) was determined. five complete open reading frames and two partial open reading frames were found, suggesting that this region contains previously unidentified genes. a combination of sequence analysis, mutant complementation data, and ... | 1995 | 7592474 |
| complex formation with methylamine dehydrogenase affects the pathway of electron transfer from amicyanin to cytochrome c-551i. | methylamine dehydrogenase (madh), amicyanin, and cytochrome c-551i are soluble redox proteins that form a complex in solution (chen, l., durley, r., mathews, f. s., and davidson, v. l. (1994) science 264, 86-90), which is required for the physiologic electron transfer from the tryptophan tryptophylquinone cofactor of madh to heme via the copper center of amicyanin. the reduction of cytochrome by amicyanin within the complex in solution has been demonstrated using rapid scanning stopped-flow spec ... | 1995 | 7592588 |
| mutational analysis of mau genes involved in methylamine metabolism in paracoccus denitrificans. | a chromosomal fragment containing dna downstream from mauc was isolated from paracoccus denitrificans. sequence analysis of this fragment revealed the presence of four open reading frames, all transcribed in the same direction. the products of the putative genes were found to be highly similar to mauj, maug, maum and maun of methylobacterium extorquens am1. using these four mau genes, 11 mau genes have been cloned from p. denitrificans to date. the gene order is maurfbedacjgmn, which is similar ... | 1995 | 7601147 |
| new archaebacterial genes coding for redox proteins: implications for the evolution of aerobic metabolism. | archaebacterial respiratory chains are poorly understood at the molecular level. we have cloned and sequenced a cluster of five new genes from the archaebacterium sulfolobus acidocaldarius, four of them coding for redox proteins: a rieske iron-sulphur protein, a cytochrome b, a subunit ii of cytochrome oxidase and a blue copper protein (sulfocyanin). the fifth gene codes for a hydrophobic protein with no homologue in the databases. the gene organization and biochemical data suggest that all four ... | 1995 | 7608970 |
| binding of monovalent cations to methylamine dehydrogenase in the semiquinone state and its effect on electron transfer. | the binding of monovalent cations to methylamine dehydrogenase in the semiquinone state (madhsq) at a site close to the tryptophan tryptophylquinone (ttq) active center is demonstrated in experiments which show that the radical epr signal of madhsq is considerably broadened in the presence of cs+, nh4+, and, to a smaller extent, na+. the cations also stabilize the semiquinone state, as is evident from the increase of the epr intensity they induce. on the basis of the optical absorbance spectra, ... | 1995 | 7626645 |
| the active site of methanol dehydrogenase contains a disulphide bridge between adjacent cysteine residues. | adjacent cysteine residues can only form disulphide bridges in a distorted structure containing a cis-peptide link. such bridges are extremely uncommon, identified so far in the acetyl choline receptor alone where the structure of the bridge is undetermined. here we present the first molecular description of a disulphide bridge of this type in the quinoprotein methanol dehydrogenase from methylobacterium extorquens. we show that this structure occurs in close proximity to the pyrrolo-quinoline q ... | 1994 | 7656012 |
| synthesis of pyrroloquinoline quinone in vivo and in vitro and detection of an intermediate in the biosynthetic pathway. | in klebsiella pneumoniae, six genes, constituting the pqqabcdef operon, which are required for the synthesis of the cofactor pyrroloquinoline quinone (pqq) have been identified. the role of each of these k. pneumoniae pqq proteins was examined by expression of the cloned pqq genes in escherichia coli, which cannot synthesize pqq. all six pqq genes were required for pqq biosynthesis and excretion into the medium in sufficient amounts to allow growth of e. coli on glucose via the pqq-dependent glu ... | 1995 | 7665488 |
| the tyrosine corner: a feature of most greek key beta-barrel proteins. | the tyr corner is a conformation in which a tyrosine (residue "y") near the beginning or end of an antiparallel beta-strand makes an h bond from its side-chain oh group to the backbone nh and/or co of residue y - 3, y - 4, or y - 5 in the nearby connection. the most common "classic" case is a delta 4 tyr corner (more than 40 examples listed), in which the h bond is to residue y - 4 and the tyr chi 1 is near -60 degrees. y - 2 is almost always a glycine, whose left-handed beta or very extended be ... | 1994 | 7703839 |
| the refined structure of the quinoprotein methanol dehydrogenase from methylobacterium extorquens at 1.94 a. | methanol dehydrogenase (mdh) is a bacterial periplasmic quinoprotein; it has pyrrolo-quinoline quinone (pqq) as its prosthetic group, requires ca2+ for activity and uses cytochrome cl as its electron acceptor. low-resolution structures of mdh have already been determined. | 1995 | 7735834 |
| the role of the novel disulphide ring in the active site of the quinoprotein methanol dehydrogenase from methylobacterium extorquens. | all cysteines in methanol dehydrogenase (mdh) from methylobacterium extorquens are involved in intra-subunit disulphide bridge formation. one of these is between adjacent cysteine residues which form a novel ring structure in the active site. it is readily reduced, the reduced enzyme being inactive in electron transfer to cytochrome cl. the inactivation is not a result of major structural change or to modification of the prosthetic group pyrrolo-quinoline quinone (pqq). the reduced enzyme appear ... | 1995 | 7741704 |
| cloning and characterization of the methylobacterium extorquens polyhydroxyalkanoic-acid-synthase structural gene. | a cosmid gene bank of partially ecori-digested genomic dna from methylobacterium extorquens ibt no. 6 was screened for dna fragments restoring polyhydroxyalkanoic-acid (pha) accumulation in the pha-negative mutant alkaligenes eutrophus h16 phb-4. the m. extorquens pha-synthase structural gene phacmex was mapped on a 23-kbp ecori fragment by complementation studies, by hybridization experiments with heterologous dna probes from a. eutrophus h16 encoding for phaa, phab and phac and by nucleic acid ... | 1993 | 7763712 |
| microbes, enzymes and genes involved in dichloromethane utilization. | dichloromethane (dcm) is efficiently utilized as a carbon and energy source by aerobic, gram-negative, facultative methylotrophic bacteria. it also serves as a sole carbon and energy source for a nitrate-respiring hyphomicrobium sp. and for a strictly anaerobic co-culture of a dcm-fermenting bacterium and an acetogen. the first step of dcm utilization by methylotrophs is catalyzed by dcm dehalogenase which, in a glutathione-dependent substitution reaction, forms inorganic chloride and s-chlorome ... | 1994 | 7765835 |
| a comparison of organochlorine removal from bleached kraft pulp and paper-mill effluents by dehalogenating pseudomonas, ancylobacter and methylobacterium strains. | the relative importance of each of three dechlorinating species to overall organochlorine removal from bleached kraft-mill effluents (bkme) was assessed. ancylobacter aquaticus a7, pseudomonas p1, and methylobacterium cp13, strains indigenous to a bkme treatment system, were tested for growth on chlorinated acetic acids and alcohols, and for adsorbable organic halogen (aox) reduction in batch cultures of sterile bkme from three sources. a. aquaticus a7 exhibited the broadest substrate range, but ... | 1995 | 7765918 |
| the structure of the quinoprotein alcohol dehydrogenase of acetobacter aceti modelled on that of methanol dehydrogenase from methylobacterium extorquens. | the 1.94 a structure of methanol dehydrogenase has been used to provide a model structure for part of a membrane quinohaemoprotein alcohol dehydrogenase. the basic superbarrel structure and the active-site region are retained, indicating essentially similar mechanisms of action, but there are considerable differences in the external loops, particularly those involved in formation of the shallow funnel leading to the active site. | 1995 | 7772016 |
| introduction of a cua site into the blue copper protein amicyanin from thiobacillus versutus. | the c-terminal loop of the blue copper protein amicyanin, which contains three of the four active site ligands, has been replaced with a cua binding loop. the purple protein produced has visible and epr spectra identical to those of a cua centre. recent evidence strongly suggests that the cua centre of cytochrome c oxidase and the a centre of nitrous oxide reductase are similar and are both binuclear. it therefore follows that the purple amicyanin mutant created here also possesses a binuclear c ... | 1995 | 7774723 |
| phenotypic and genetic diversity of chlorine-resistant methylobacterium strains isolated from various environments. | strains of pink-pigmented facultative methylotrophs which were isolated previously from various environments and assigned tentatively to the genus methylobacterium were characterized in comparison with authentic strains of previously known species of this genus. most of the isolates derived from chlorinated water supplies exhibited resistance to chlorine, whereas 29 to 40% of the isolates from air, natural aquatic environments, and clinical materials were chlorine resistant. none of the tested a ... | 1995 | 7793931 |
| the copper-containing dissimilatory nitrite reductase involved in the denitrifying system of the fungus fusarium oxysporum. | a copper-containing nitrite reductase (cu-nir) was purified to homogeneity from the denitrifying fungus fusarium oxysporum. the enzyme seemed to consist of two subunits with almost the same m(r) value of 41,800 and contains two atoms of copper per subunit. the electron paramagnetic resonance spectrum showed that both type 1 and type 2 copper centers are present in the protein, whereas the visible absorption spectrum exhibited a sole and strong absorption maximum at 595 nm, causing a blue but not ... | 1995 | 7876166 |
| the effects of ph and cations on the spectral and kinetic properties of methylamine dehydrogenase from thiobacillus versutus. | the catalytic parameters of thiobacillus versutus methylamine dehydrogenase (madh) with the physiological substrates methylamine and amicyanin show a ph profile that is quite different from the one found in commonly used assays with artificial electron acceptors. the optimum at ph 7.5, observed for kcat in the latter case, is absent with amicyanin as the reoxidizing substrate. with amicyanin kcat scarcely depends on ph; the same is true for the maximal rate of reduction of madh by methylamine (k ... | 1994 | 7918441 |
| identification of a promoter region for mxaf (moxf) from the type i methanotroph, methylobacter albus bg8. | a fragment of methylobacter albus bg8 dna containing mxaf (moxf), the gene encoding the alpha subunit of methanol dehydrogenase, was previously cloned using a fragment of mxaf from methylobacterium extorquens am1 as a probe (stephens et al., j. bacteriol. (1988) 170, 2063-2069). in this study we identified the 5' portion of mxaf of m. albus bg8 and sequenced a 1.7-kb region containing the 5' portion of mxaf and 1.5 kb of upstream dna. the deduced n-terminal amino acid sequence of mxaf was found ... | 1994 | 7926691 |
| genetics of the serine cycle in methylobacterium extorquens am1: cloning, sequence, mutation, and physiological effect of glya, the gene for serine hydroxymethyltransferase. | the gene (glya) of methylobacterium extorquens am1 encoding serine hydroxymethyltransferase (shmt), one of the key enzymes of the serine cycle for c1 assimilation, was isolated by using a synthetic oligonucleotide with a sequence based on amino acid sequence conserved in shmts from different sources. the amino acid sequence deduced from the gene revealed high similarity to those of known shmts. the cloned gene was inactivated by insertion of a kanamycin resistance gene, and recombination of this ... | 1994 | 7961431 |
| genetics of the serine cycle in methylobacterium extorquens am1: identification, sequence, and mutation of three new genes involved in c1 assimilation, orf4, mtka, and mtkb. | in a recent paper we reported the sequence of the beginning of a serine cycle gene cluster on the methylobacterium extorquens am1 chromosome, containing the genes encoding serine glyoxylate aminotransferase (sgaa), hydroxypyruvate reductase (hpra), and 5,10-methylenetetrahydrofolate dehydrogenase (mtda) (l. v. chistoserdova and m. e. lidstrom j. bacteriol. 176:1957-1968, 1994). here we present the sequence of the adjacent downstream region containing three full and one partial open reading frame ... | 1994 | 7961516 |
| transcriptional analysis of pqqd and study of the regulation of pyrroloquinoline quinone biosynthesis in methylobacterium extorquens am1. | methanol dehydrogenase, the enzyme that oxidizes methanol to formaldehyde in gram-negative methylotrophs, contains the prosthetic group pyrroloquinoline quinone (pqq). to begin to analyze how the synthesis of pqq is coordinated with the production of other methanol dehydrogenase components, the transcription of one of the key pqq synthesis genes has been studied. this gene (pqqd) encodes a 29-amino-acid peptide that is thought to be the precursor for pqq biosynthesis. a unique transcription star ... | 1995 | 8002620 |
| blue copper proteins as a model for investigating electron transfer processes within polypeptide matrices. | intramolecular long-range electron transfer (et) processes have been investigated in two types of blue copper proteins; the single-copper protein, azurin and the multi-copper oxidase, ascorbate oxidase. these have several advantages for investigating the parameters that control the above reactions: (1) their sole physiological role is mediating or catalyzing et processes via the evolutionary optimized copper sites. (2) the three-dimensional structures of a considerable number of blue single copp ... | 1994 | 8011935 |
| kinetics of the reduction of wild-type and mutant cytochrome c-550 by methylamine dehydrogenase and amicyanin from thiobacillus versutus. | to elucidate the kinetic properties of the methylamine dehydrogenase (madh) redox chain of thiobacillus versutus the reduction of cytochrome c-550 by madh and amicyanin has been studied. under steady state conditions, the rate constants of the reactions have been determined as a function of the ionic strength, both for wild type cytochrome c-550 and for mutants in which the conserved residue lys14 has been replaced as follows: lys14-->gln (mutant [k14q]cytochrome c-550) and lys14-->glu (mutant [ ... | 1994 | 8020493 |
| genetic organization of the mau gene cluster in methylobacterium extorquens am1: complete nucleotide sequence and generation and characteristics of mau mutants. | the nucleotide sequence of the methylamine utilization (mau) gene region from methylobacterium extorquens am1 was determined. open reading frames for 11 genes (maufbedacjglmn) were found, all transcribed in the same orientation. the maub, maua, and mauc genes encode the periplasmic methylamine dehydrogenase (madh) large and small subunit polypeptides and amicyanin, respectively. the products of maud, maug, maul, and maum were also predicted to be periplasmic. the products of mauf, maue, and maun ... | 1994 | 8021187 |
| organization of the methylamine utilization (mau) genes in methylophilus methylotrophus w3a1-ns. | the organization of genes involved in utilization of methylamine (mau genes) was studied in methylophilus methylotrophus w3a1. the strain used was a nonmucoid variant termed ns (nonslimy). the original mucoid strain was shown to be identical to the ns strains on the basis of chromosomal digest and hybridization patterns. an 8-kb psti fragment of the chromosome from m. methylotrophus w3a1-ns encoding the mau genes was cloned and a 6,533-bp region was sequenced. eight open reading frames were foun ... | 1994 | 8021188 |
| x-ray structure of pqq-dependent methanol dehydrogenase. | the three-dimensional structure of the pqq-dependent quinoprotein, methanol dehydrogenase from methylobacterium extorquens am1, has been determined at 3a resolution. the a2b2 tetrameric enzyme has a large a-chain of almost spherical form with a chain fold in which eight 4-stranded antiparallel b-sheets segments are arranged radially around a pseudo 8-fold molecular symmetry axis. the much smaller b-chain is surprisingly not globular, but has an extended conformation running across the surface of ... | 1994 | 8032156 |
| solution structure of the type 1 blue copper protein amicyanin from thiobacillus versutus. | a three-dimensional solution structure of amicyanin from thiobacillus versutus has been determined by distance geometry and restrained molecular dynamics. a total of 984 experimentally derived constraints were used for the final refinement (881 distance constraints and 103 dihedral angle constraints). stereospecific assignments were made for 17 prochiral beta-methylene protons (33%) and the methyl groups of eight valine residues. fourteen structures were selected to represent the solution struct ... | 1994 | 8035459 |
| an unusual conformation of the methionine haem ligand in cytochrome cl established by two-dimensional 1h-nmr. | a complete relaxation-matrix analysis of noesy cross-peak intensities was used to determine the conformation of the methionine ligand to the haem group in two ferrocytochromes cl from methylophilus methylotrophus and methylobacterium extorquens, including the configuration at the sulphur. the conformation of the axial methionine is of a type reported only for the cytochromes c5 from pseudomonas mendocina and azotobacter vinelandii. although the conformation of the methionine is unusual, the para ... | 1994 | 8055954 |
| genetics of methane and methanol oxidation in gram-negative methylotrophic bacteria. | within the past few years, considerable progress has been made in the understanding of the molecular genetics of methane and methanol oxidation. in order to summarize this progress and to illustrate the important genetic methods employed, this review will focus on several well-studied organisms. these organisms include the gram-negative faculative methylotrophs methylobacterium extorquens, methylobacterium organophilum and paracoccus denitrificans. in addition, the obligate methanotrophs methylo ... | 1993 | 8092853 |
| intergeneric conjugal transfer of escherichia coli/methylobacterium sp. shuttle vector. | to develop a host-vector system for methylobacterium sp. using a construct based on a small indigenous methylotrophic plasmid, the e. coli--methylobacterium sp. shuttle vector pwubr (12.7 kb, apr, tcr) was constructed by joining the e. coli plasmid pbr328 and the cryptic plasmid pwu7 (7.8 kb), isolated from the soil facultative methylotrophic bacterium, methylobacterium sp. strain m17. via mobilization by the pdpt51 r plasmid, belonging to the incp-1 incompatibility group, plasmid pwubr was tran ... | 1993 | 8112692 |
| [high resistance of some oligotrophic bacteria to ionizing radiation]. | the resistance against ionizing radiation of seven cultures of oligotrophic and eutrophic bacteria was investigated in the interval 0-360 gr/h. it is determine that all of tested bacteria are distributed into three groups according to the lever of their resistance. most resistant were: methylobacterium organophilum, pedodermatophilus halotolerans (ld50 = 270 cr/h). these organisms are close to deinococcus radiodurans in the survival. middle resistance shown water-born ring-forming bacteria flect ... | 1993 | 8114644 |
| crystal structure analysis and refinement at 2.15 a resolution of amicyanin, a type i blue copper protein, from thiobacillus versutus. | the crystal structure of the type i blue copper protein amicyanin from thiobacillus versutus has been determined by patterson search techniques on the basis of the molecular model of amicyanin from paracoccus denitrificans, and refined by energy-restrained least-squares methods. amicyanin crystallizes in the trigonal space group p3(2) with unit cell dimensions of a = b = 87.40 a, c = 38.20 a. the asymmetric unit is composed of three independent molecules centred on the crystallographic 3(2) axes ... | 1994 | 8120896 |
| isolation, phenotypic characterization, and complementation analysis of mutants of methylobacterium extorquens am1 unable to synthesize pyrroloquinoline quinone and sequences of pqqd, pqqg, and pqqc. | aerobic gram-negative methylotrophs oxidize methanol to formaldehyde by using a methanol dehydrogenase that has pyrroloquinoline quinone (pqq) as a prosthetic group. seventy-two mutants which are unable to grow on methanol unless the growth medium is supplemented with pqq have been isolated in the facultative methanol utilizer methylobacterium extorquens am1. in addition, 12 previously isolated methanol oxidation mutants of m. extorquens am1 were shown to be able to grow on methanol in the prese ... | 1994 | 8132470 |
| structure of an electron transfer complex: methylamine dehydrogenase, amicyanin, and cytochrome c551i. | the crystal structure of a ternary protein complex has been determined at 2.4 angstrom resolution. the complex is composed of three electron transfer proteins from paracoccus denitrificans, the quinoprotein methylamine dehydrogenase, the blue copper protein amicyanin, and the cytochrome c551i. the central region of the c551i is folded similarly to several small bacterial c-type cytochromes; there is a 45-residue extension at the amino terminus and a 25-residue extension at the carboxyl terminus. ... | 1994 | 8140419 |
| genetics of the serine cycle in methylobacterium extorquens am1: identification of sgaa and mtda and sequences of sgaa, hpra, and mtda. | in a previous paper, we reported identification of the 5' part of hpra of methylobacterium extorquens am1, which encodes the serine cycle enzyme hydroxypyruvate reductase (l. v. chistoserdova and m. e. lidstrom, j. bacteriol. 174:71-77, 1992). here we present the complete sequence of hpra and partial sequence of genes adjacent to hpra. upstream of hpra, the 3' part of an open reading frame was discovered, separated from hpra by 263 bp. this open reading frame was identified as the gene encoding ... | 1994 | 8144463 |
| kinetic and thermodynamic analysis of a physiologic intermolecular electron-transfer reaction between methylamine dehydrogenase and amicyanin. | the quinoprotein methylamine dehydrogenase (madh) and a type i copper protein, amicyanin, form a physiologic complex in which electrons are transferred from tryptophan tryptophylquinone to copper. the reoxidation of madh by amicyanin has been studied by stopped-flow spectroscopy. the rate constant for the electron-transfer (et) reaction and the dissociation constant for the complex have been determined at different temperatures. marcus theory was used to calculate the distance, reorganizational ... | 1994 | 8180195 |
| isolation and characterization of the methylophilus sp. strain dm11 gene encoding dichloromethane dehalogenase/glutathione s-transferase. | the restricted facultative methylotroph methylophilus sp. strain dm11 utilizes dichloromethane as the sole carbon and energy source. it differs from other dichloromethane-utilizing methylotrophs by faster growth on this substrate and by possession of a group b dichloromethane dehalogenase catalyzing dechlorination at a fivefold-higher rate than the group a enzymes of slow-growing strains. we isolated dcma, the structural gene of the strain dm11 dichloromethane dehalogenase, to elucidate its rela ... | 1994 | 8206823 |
| isoprenoid biosynthesis in bacteria: a novel pathway for the early steps leading to isopentenyl diphosphate. | incorporation of 13c-labelled glucose, acetate, pyruvate or erythrose allowed the determination of the origin of the carbon atoms of triterpenoids of the hopane series and/or of the ubiquinones from several bacteria (zymomonas mobilis, methylobacterium fujisawaense, escherichia coli and alicyclobacillus acidoterrestris) confirmed our earlier results obtained by incorporation of 13c-labelled acetate into the hopanoids of other bacteria and led to the identification of a novel biosynthetic route f ... | 1993 | 8240251 |
| haloacetonitriles are low k1 inhibitors of bacterial dichloromethane dehalogenases. | distinct dichloromethane dehalogenases from methylobacterium sp. strain dm4 and methylophilus dm11 were inhibited by low concentrations of haloacetonitriles. chloroacetonitrile (clch2cn) showed maximal inhibition at a stoichiometry of 1 mol inhibitor:1 mol holoenzyme for both enzymes. this stoichiometry is suggestive of one active site per holoenzyme or extreme negative cooperativity amongst the subunits. radiolabelled clch2cn dissociated completely or partially from the two dehalogenases, respe ... | 1993 | 8267624 |
| [isolation of methylobacterium spp. from drinking tank-water and resistance of isolates to chlorine]. | on bacteriological examination of 100 samples of drinking tank water, standard plate count bacteria (36 degrees c, 24 h) and coliforms were not detected, conforming to the water quality criteria under the water supply law. ninety-five percent of test samples had concentrations of residual chlorine exceeding 0.1 mg/l. however, one characteristic heterotroph was isolated from 70% of these water samples. the bacteria showed glucose non-fermentative gram-negative rods and formed pink colonies when c ... | 1993 | 8268478 |
| mutants of methylobacterium extorquens and paracoccus denitrificans deficient in c-type cytochrome biogenesis synthesise the methylamine-dehydrogenase polypeptides but cannot assemble the tryptophan-tryptophylquinone group. | five mutants of methylobacterium extorquens and four mutants of paracoccus denitrificans that have a general defect in c-type cytochrome synthesis also failed to assemble an active methylamine dehydrogenase. in all cases methanol dehydrogenase, another periplasmic enzyme, was fully active. all nine mutant strains accumulated both the heavy and light subunits of methylamine dehydrogenase to essentially wild-type levels. in all nine mutants, the heavy-subunit and light-subunit polypeptides were pr ... | 1993 | 8269962 |
| molecular cloning, chromosomal mapping, and sequence analysis of copper resistance genes from xanthomonas campestris pv. juglandis: homology with small blue copper proteins and multicopper oxidase. | copper-resistant strains of xanthomonas campestris pv. juglandis occur in walnut orchards throughout northern california. the copper resistance genes from a copper-resistant strain c5 of x. campestris pv. juglandis were cloned and located on a 4.9-kb clai fragment, which hybridized only to dna of copper-resistant strains of x. campestris pv. juglandis, and was part of an approximately 20-kb region which was conserved among such strains of x. campestris pv. juglandis. hybridization analysis indic ... | 1994 | 8282694 |
| roseomonas, a new genus associated with bacteremia and other human infections. | in the 1980s, a pink bacterium different from species of the genus methylobacterium was implicated in human infection. using biochemical tests and dna hybridization, we examined 42 strains of pink-pigmented, gram-negative bacteria that were not members of the genus methylobacterium. the isolates included 6 strains each of cdc "pink coccoid" groups i, ii, iii, and iv; 10 isolates from gilardi's "unnamed taxon"; and 8 blood isolates from ill, debilitated, or immunosuppressed patients. the dna hybr ... | 1993 | 8308122 |
| binding constants for a physiologic electron-transfer protein complex between methylamine dehydrogenase and amicyanin. effects of ionic strength and bound copper on binding. | two soluble proteins, methylamine dehydrogenase and amicyanin, form a physiologically relevant complex in which intermolecular electron transfer occurs. to characterize and quantitate the binding of these two weakly-associating proteins, an ultrafiltration binding assay has been developed which involves brief centrifugation of mixtures of proteins in centrifuge concentrators followed by quantitation of proteins on each side of the filtration membrane by hplc. under low ionic strength conditions ... | 1993 | 8347660 |
| a method for extracting rate constants from initial rates of stopped-flow kinetic data: application to a physiological electron-transfer reaction. | the most commonly used methods for analysis of stopped-flow kinetic data require performing a series of measurements in which one reactant is varied at concentrations significantly greater than the concentration of the other reactant. for enzyme-catalysed reactions this may not be possible, because the dissociation constants for the enzyme-substrate complex are often of the same order of magnitude as the high concentrations of enzyme that must frequently be used in stopped-flow studies. an alter ... | 1993 | 8363574 |
| preliminary crystal structure studies of a ternary electron transfer complex between a quinoprotein, a blue copper protein, and a c-type cytochrome. | a ternary electron transfer protein complex has been crystallized and a preliminary structure investigation has been carried out. the complex is composed of a quinoprotein, methylamine dehydrogenase (madh), a blue copper protein, amicyanin, and a c-type cytochrome (c551i). all three proteins were isolated from paracoccus denitrificans. the crystals of the complex are orthorhombic, space group c222(1) with cell dimensions a = 148.81 a, b = 68.85 a, and c = 187.18 a. two types of isomorphous cryst ... | 1993 | 8382992 |
| stoichiometry and spectroscopic identity of copper centers in phenoxazinone synthase: a new addition to the blue copper oxidase family. | phenoxazinone synthase catalyzes the oxidative condensation of two molecules of substituted o-aminophenols to the phenoxazinone chromophore of actinomycin. cyclization occurs with the concomitant reduction of molecular oxygen to water. we have shown that the enzyme requires 4-5 copper atoms/monomer for full activity and the additional copper inhibits the enzyme. the optical absorption spectrum of phenoxazinone synthase is also dependent on the cu per monomer ratio, and the absorption peak at 598 ... | 1993 | 8387816 |
| a novel quinoprotein methanol dehydrogenase containing an additional 32-kilodalton peptide purified from acetobacter methanolicus: identification of the peptide as a moxj product. | acetobacter methanolicus is a unique acetic acid bacterium which has a methanol oxidase respiratory chain in addition to an ethanol oxidase respiratory chain. in this study, two different forms of methanol dehydrogenase (type i and ii mdhs) were purified from a. methanolicus grown on methanol. type i mdh was more basic (pi of 8.0) and smaller (m(r) of 148k) than type ii mdh (pi of 6.7 and m(r) of 177k). type i mdh consisted of alpha and beta subunits of 62 and 10 kda, which has the same alpha 2 ... | 1993 | 8389187 |
| evolution of protein complexity: the blue copper-containing oxidases and related proteins. | the blue copper proteins and their relatives have been compared by sequence alignments, by comparison of three-dimensional structures, and by construction of phylogenetic trees. the group contains proteins varying in size from 100 residues to over 2,300 residues in a single chain, containing from zero to nine copper atoms, and with a broad variation in function ranging from electron carrier proteins and oxidases to the blood coagulation factors v and viii. difference matrices show the sequence d ... | 1993 | 8433378 |
| identification and growth characteristics of pink pigmented oxidative bacteria, methylobacterium mesophilicum and biovars isolated from chlorinated and raw water supplies. | pink pigmented bacteria were isolated from a blood bank water purification unit, a municipal town water supply (tap water), and an island (untreated) ground water source. a total of thirteen strains including two reference strains of pink pigmented bacteria were compared in a numerical phenotypic study using 119 binary characters. three clusters were derived, one major cluster of eleven strains was subdivided into two sub-clusters on the basis of methanol utilization. five strains were facultati ... | 1993 | 8469180 |
| characterization of a flavobacterium glutathione s-transferase gene involved reductive dechlorination. | the gene pcpc, encoding tetrachloro-p-hydroquinone (tech) reductive dehalogenase, was cloned from flavobacterium sp. strain atcc 39723 and sequenced. the gene was identified by hybridization with a degenerate oligonucleotide designed from the n-terminal sequence of the purified protein. an open reading frame of 747 nucleotides was found, which predicts a translational product of 248 amino acids having a molecular weight of 28,263, which agrees favorably with the sodium dodecyl sulfate-polyacryla ... | 1993 | 8478329 |
| crystal structure analysis of amicyanin and apoamicyanin from paracoccus denitrificans at 2.0 a and 1.8 a resolution. | the crystal structure of amicyanin, a cupredoxin isolated from paracoccus denitrificans, has been determined by molecular replacement. the structure has been refined at 2.0 a resolution using energy-restrained least-squares procedures to a crystallographic residual of 15.7%. the copper-free protein, apoamicyanin, has also been refined to 1.8 a resolution with residual 15.5%. the protein is found to have a beta-sandwich topology with nine beta-strands forming two mixed beta-sheets. the secondary ... | 1993 | 8495197 |
| genetics of serine pathway enzymes in methylobacterium extorquens am1: phosphoenolpyruvate carboxylase and malyl coenzyme a lyase. | methylobacterium extorquens am1 is a facultative methylotrophic bacterium that uses the serine pathway for formaldehyde incorporation as its assimilation pathway during growth on one-carbon compounds. a dna region from m. extorquens am1 previously shown to contain genes for the serine pathway enzymes malyl coenzyme a (coa) lyase and hydroxypyruvate reductase has been characterized in more detail. insertion mutagenesis revealed an additional region required for growth on one-carbon compounds, and ... | 1993 | 8509332 |
| identification of methanol-regulated promoter sequences from the facultative methylotrophic bacterium methylobacterium organophilum xx. | a promoter-probe vector (phx200) was constructed using the broad-host-range cosmid pla2917 and a promoterless xyle gene of pseudomonas as the reporter gene. insertion of the cloned promoter fragment of the methanol dehydrogenase large subunit gene moxf (methanol oxidation) in front of the xyle gene in phx200v-47 resulted in high-level expression of the xyle gene product--catechol 2,3-dioxygenase--in methylobacterium organophilum xx. the specific activity of the enzyme was four times higher in me ... | 1993 | 8515233 |
| tn5-directed cloning of pqq genes from pseudomonas fluorescens cha0: mutational inactivation of the genes results in overproduction of the antibiotic pyoluteorin. | pseudomonas fluorescens cha0 produces several secondary metabolites, e.g., the antibiotics pyoluteorin (plt) and 2,4-diacetylphloroglucinol (phl), which are important for the suppression of root diseases caused by soil-borne fungal pathogens. a tn5 insertion mutant of strain cha0, cha625, does not produce phl, shows enhanced plt production on malt agar, and has lost part of the ability to suppress black root rot in tobacco plants and take-all in wheat. we used a rapid, two-step cloning-out proce ... | 1995 | 8526497 |
| methanol oxidation mutants in methylobacterium extorquens am1: identification of new genetic complementation groups. | two-hundred-and-eight new methylobacterium extorquens am1 methanol oxidation (mox) mutants were isolated and placed into complementation groups. complementation analyses identified new mox groups in the mxb and mxc loci and at a new locus, mxd. thirty-seven mutants at the mxb locus were divided into mxbm and mxbd complementation groups on the basis of their complementation pattern. twenty-nine mutants at the mxc locus fell into three complementation groups, mxcb, mxcq and mxce. the direction of ... | 1995 | 8535526 |
| the mxaakl genes of methylobacter albus bg8. | the facultative methanol utilizer methylobacterium extorquens am1 contains at least three genes (mxaa, k and l) that encode functions involved in providing calcium to the holoenzyme of methanol dehydrogenase, the enzyme that oxidizes methanol to formaldehyde in this strain. methane-utilizing bacteria (methanotrophs) also contain methanol dehydrogenase, and evidence suggests that similar methanol oxidation (mox) functions may be present in some of these strains. dna fragments from methylobacteriu ... | 1995 | 8535527 |
| structure of the quinoprotein glucose dehydrogenase of escherichia coli modelled on that of methanol dehydrogenase from methylobacterium extorquens. | the structure of methanol dehydrogenase (mdh) at 0.194 nm (1.94 a) has been used to provide a model structure for part of a membrane quinoprotein glucose dehydrogenase (gdh). the basic superbarrel structure is retained, along with the tryptophan-docking motifs. the active-site regions are similar, but there are important differences, the most important being that gdh lacks the novel disulphide ring structure formed from adjacent cysteines in mdh; in gdh the equivalent region is occupied by his-2 ... | 1995 | 8554505 |
| primary structure and properties of the formyltransferase from the mesophilic methanosarcina barkeri: comparison with the enzymes from thermophilic and hyperthermophilic methanogens. | the ftr gene encoding formylmethanofuran: tetrahydromethanopterin formyltransferase (ftr) from methanosarcina barkeri was cloned, sequenced, and functionally expressed in escherichia coli. the overproduced enzyme was purified eightfold to apparent homogeneity, and its catalytic properties were determined. the primary structure and the hydropathic character of the formyltransferase from methanosarcina barkeri were compared with those of the enzymes from methanobacterium thermoautotrophicum, metha ... | 1996 | 8593103 |
| occurrence of polyhydroxyalkanoic acid granule-associated proteins related to the alcaligenes eutrophus h16 ga24 protein in other bacteria. | fifty different polyhydroxyalkanoic acid (pha)-accumulating bacterial strains were investigated for the occurrence of phasin proteins bound to pha granules and related to the ga24 protein of alcaligenes eutrophus h16, by isolating pha granules and western blot analysis of granule-associated proteins employing antibodies raised against the ga24 protein. it could be demonstrated that th pha granules of many poly(3-hydroxybutyrate)-accumulating bacteria exhibited a similar protein pattern, and a pr ... | 1996 | 8598273 |
| cloning, characterization, and expression of the nitric oxide-generating nitrite reductase and of the blue copper protein genes of achromobacter cycloclastes. | the nitrite reductase (nir) and blue copper protein (bcp) genes have been cloned from achromobacter cycloclastes and characterized. nir gene encodes a protein of 378 amino acid residues including a putative signal peptide of 37 residues. bcp gene encodes a protein of 148 residues with a 24-residue signal peptide. the dna-derived amino acid sequence of nir is in complete agreement with that from edman degradation and the dna coding sequence of bcp is also consistent with its partial n-terminal am ... | 1996 | 8605003 |
| characterization and nucleotide sequence of pqqe and pqqf in methylobacterium extorquens am1. | methylobacterium extorquens am1 pqqef are genes required for synthesis of pyrroloquinoline quinone (pqq). the nucleotide sequence of these genes indicates pqqe belongs to an endopeptidase family, including pqqf of klebsiella pneumoniae, and m. extorquens am1 pqqf has low identity with the same endopeptidase family. m. extorquens am1 pqqe complemented a k. pneumoniae pqqf mutant. | 1996 | 8606199 |
| analysis of the paramagnetic copper(ii) site of amicyanin by 1h nmr spectroscopy. | application of the tailored pulse sequences like super-weft allows the direct observation of the hyperfine-shifted signals of the paramagnetic cu(ii) forms of blue copper proteins in solution. the signals can be assigned by applying 2d nmr techniques, like exsy, to solutions containing a mixture of reduced and oxidized species. the fermi contact shift is separated from the pseudocontact shift on the basis of the known g-tensor anisotropy of the cu(ii) state, allowing the determination of a numbe ... | 1996 | 8608149 |
| enzymatic and electron transfer activities in crystalline protein complexes. | enzymatic and electron transfer activities have been studied by polarized absorption spectroscopy in single crystals of both binary and ternary complexes of methylamine dehydrogenase (madh) with its redox partners. within the crystals, madh oxidizes methylamine, and the electrons are passed from the reduced tryptophan tryptophylquinone (ttq) cofactor to the copper of amicyanin and to the heme of cytochrome c551i via amicyanin. the equilibrium distribution of electrons among the cofactors, and th ... | 1996 | 8621571 |
| tungsten in biological systems. | tungsten (atomic number 74) and the chemically analogous and very similar metal molybdenum (atomic number 42) are minor yet equally abundant elements on this planet. the essential role of molybdenum in biology has been known for decades and molybdoenzymes are ubiquitous. yet, it is only recently that a biological role for tungsten has been established in prokaryotes, although not as yet in eukaryotes. the best characterized organisms with regard to their metabolism of tungsten are certain specie ... | 1996 | 8672295 |
| electron transfer from copper to heme within the methylamine dehydrogenase--amicyanin--cytochrome c-551i complex. | methylamine dehydrogenase (madh), amicyanin, and cytochrome c-551i are soluble redox proteins that form a complex in solution [chen, l., durley, r., mathews, f. s., & davidson, v. l. (1994) science 264, 86-90] which is required for the physiologic electron transfer from the tryptophan tryptophylquinone cofactor of madh to heme via the copper center of amicyanin. the electron transfer reaction from copper to heme within the protein complex has been characterized by transient kinetic and thermodyn ... | 1996 | 8679563 |
| evidence for a tryptophan tryptophylquinone aminosemiquinone intermediate in the physiologic reaction between methylamine dehydrogenase and amicyanin. | the tryptophan tryptophylquinone (ttq) cofactor of methylamine dehydrogenase (madh) is covalently modified by nitrogen during its two-electron reduction by methylamine to form an aminoquinol (n-quinol). it is possible, in vitro, to generate unmodified o-quinol and o-semiquinone forms of madh with dithionite, as well as an n-semiquinone form which contains a substrate-derived nitrogen. rapid-scanning stopped-flow spectroscopy and global kinetic analysis are used to demonstrate that n-semiquinone ... | 1996 | 8688431 |
| redox reactivity of the type 1 copper protein amicyanin from thiobacillus versutus with its physiological partner cytochrome c550 and inter-protein cross-reaction studies. | reduction potentials eo' for the t. versutus amicyanin couple, amcuii/i, were determined at ph values in the range 4.4-9.0 by direct measurement using cyclic voltammetry, and from rate constants for the reactions amcu1 + [co(terpy)2]3+ and [co(terpy)2]2+ + amcuii, using an eo' for the [co(terpy)2]2+/3+ couple of 260 mv. at ph > 7.5 the value obtained is 236 mv, which increases with decreasing ph in keeping with proton inactivation of amcui. together with previously determined eo' values for the ... | 1996 | 8695651 |
| molecular characterization of a chromosomal region involved in the oxidation of acetyl-coa to glyoxylate in the isocitrate-lyase-negative methylotroph methylobacterium extorquens am1. | a region on the methylobacterium extorquens am1 chromosome previously shown to complement a chemically induced mutant (pct48) unable to convert acetyl-coa into glyoxylate was characterized in detail in order to identify the gene(s) involved in the unknown pathway for acetyl-coa oxidation. six complete and two partial orfs were identified by sequencing. sequence comparisons suggested these might code for, respectively, a dehydrogenase of unknown specificity, a polypeptide of at least 15 kda with ... | 1996 | 8704985 |
| immunological characterization of serine-glyoxylate aminotransferase and hydroxypyruvate reductase from a methylotrophic bacterium, hyphomicrobium methylovorum gm2. | immunological characterization of serine-glyoxylate aminotransferase and hydroxypyruvate reductase, key enzymes for the assimilation of one-carbon compounds in methylotrophs, was performed using antibodies raised against these enzymes purified from hyphomicrobium methylovorum gm2. immunodiffusion studies indicated that serine-glyoxylate aminotransferase and hydroxypyruvate reductase of all seven hyphomicrobium strains tested were immunochemically similar. in immunotitration experiments and weste ... | 1996 | 8759789 |
| the cupric geometry of blue copper proteins is not strained. | the geometry of several realistic models of the metal coordination sphere in the blue copper proteins has been optimised using high-level quantum chemical methods. the results show that the optimal vacuum structure of the cu(ii) models is virtually identical to the crystal structure of oxidised blue copper proteins. for the reduced forms, the optimised structure seems to be more tetrahedral than the one found in the proteins, but the energy difference between the two geometries is less than 5 kj ... | 1996 | 8794878 |