TitleAbstractYear(sorted ascending)
characterization of the interaction of dinitrogenase reductase-activating glycohydrolase from rhodospirillum rubrum with bacterial membranes.the interaction of dinitrogenase reductase-activating glycohydrolase (drag) with bacterial membranes and the solubilization of drag in response to nucleotides were characterized. purified drag from rhodospirillum rubrum reversibly bound bacterial pellet fractions from rsp. rubrum and other nitrogen-fixing bacteria. drag saturated the membrane fraction of rsp. rubrum at a concentration of 0.2 mol drag/mol bacteriochlorophyll, suggesting that the drag-binding species is prevalent in the membrane. ...199910398752
refolding of recombinant alpha and beta subunits of the rhodospirillum rubrum f(0)f(1) atp synthase into functional monomers that reconstitute an active alpha(1)beta(1)-dimer.the alpha subunit from the rhodospirillum rubrum f(0)f(1) atp synthase (rrf(1)alpha) was over-expressed in unc operon-deleted escherichia coli strains under various growth conditions only in insoluble inclusion bodies. the functional refolding of urea-solubilized rrf(1)alpha was followed by measuring its ability to stimulate the restoration of atp synthesis and hydrolysis in beta-less r. rubrum chromatophores reconstituted with pure native or recombinant rrf(1)beta [nathanson, l. & gromet-elhana ...199910406951
bacterial photoreceptor with similarity to photoactive yellow protein and plant phytochromes.a phytochrome-like protein called ppr was discovered in the purple photosynthetic bacterium rhodospirillum centenum. ppr has a photoactive yellow protein (pyp) amino-terminal domain, a central domain with similarity to phytochrome, and a carboxyl-terminal histidine kinase domain. reconstitution experiments demonstrate that ppr covalently attaches the blue light-absorbing chromophore p-hydroxycinnamic acid and that it has a photocycle that is spectrally similar to, but kinetically slower than, th ...199910411503
hydrolysis of native poly(hydroxybutyrate) granules (phb), crystalline phb, and artificial amorphous phb granules by intracellular and extracellular depolymerases.native poly(hydroxybutyrate) (phb) granules, purified phb and artificial amorphous phb granules were examined as putative substrates for hydrolysis by the intracellular depolymerase system of rhodospirillum rubrum and the extracellular depolymerase of pseudomonas lemoignei. the r. rubrum depolymerizing system requires pretreatment of granules with a heat stable 'activator' fraction; the activator can be replaced by mild trypsin treatment. artificial granules were prepared with a cationic deterge ...199910416659
ni(2+) transport and accumulation in rhodospirillum rubrum.the cooctj gene products are coexpressed with co-dehydrogenase (codh) and facilitate in vivo nickel insertion into codh. a ni(2+) transport assay was used to monitor uptake and accumulation of (63)ni(2+) into r. rubrum and to observe the effect of mutations in the cooc, coot, and cooj genes on (63)ni(2+) transport and accumulation. cells grown either in the presence or absence of co transported ni(2+) with a k(m) of 19 +/- 4 microm and a v(max) of 310 +/- 22 pmol of ni/min/mg of total protein. i ...199910419953
identification of genes unique to mo-independent nitrogenase systems in diverse diazotrophs.a number of nitrogen-fixing bacteria were screened using pcr for genes (vnfg and anfg) unique to the v-containing nitrogenase (vnf) and the fe-only nitrogenase (anf) systems. products with sequences similar to that of vnfg were obtained from azotobacter paspali and azotobacter salinestris genomic dnas, and products with sequences similar to that of anfg were obtained from azomonas macrocytogenes, rhodospirillum rubrum, and azotobacter paspali dnas. phylogenetic analysis of the deduced amino acid ...199910420583
disordered exciton model for the core light-harvesting antenna of rhodopseudomonas this work we explain the spectral heterogeneity of the absorption band (. biochim. biophys. acta. 1229:373-380), as well as the spectral evolution of pump-probe spectra for membranes of rhodopseudomonas (rps.) viridis. we propose an exciton model for the lh1 antenna of rps. viridis and assume that lh1 consists of 24-32 strongly coupled bchl b molecules that form a ring-like structure with a 12- or 16-fold symmetry. the orientations and pigment-pigment distances of the bchls were taken to be t ...199910423416
recognition of target dna and transcription activation by the co-sensing transcriptional activator cooa.cooa from rhodospirillum rubrum is a heme-based co-sensing transcriptional activator, in which co acts as a physiological effector. in this study, we examined the mechanism of site-specific recognition and transcriptional activation by cooa by elucidating the transcriptional activator activity of the mutant cooa proteins and the chimeric proteins derived from crp and cooa and the promoter activity of the mutant promoters. site-directed mutagenesis has revealed that arg(177), gln(178), and ser(18 ...199910425177
conformation of bacteriochlorophyll molecules in photosynthetic proteins from purple bacteria.fourier transform near-infrared resonance raman spectroscopy can be used to obtain information on the bacteriochlorophyll a (bchl a) molecules responsible for the redmost absorption band in photosynthetic complexes from purple bacteria. this technique is able to distinguish distortions of the bacteriochlorin macrocycle as small as 0.02 a, and a systematic analysis of those vibrational modes sensitive to bchl a macrocycle conformational changes was recently published [näveke et al. (1997) j. rama ...199910460167
amino acid sequences of two high-potential iron-sulfur proteins (hipips) from the moderately halophilic purple phototrophic bacterium, rhodospirillum salinarum.the amino acid sequences of two very different high-potential iron-sulfur protein (hipip) isozymes have been determined from the moderately halophilic purple phototrophic bacterium, rhodospirillum salinarum. iso-1 hipip, which is monomeric and contains 57 amino acid residues, is most similar to the thiobacillus ferrooxidans iron-oxidizing enzyme (45% identity and a 6-residue deletion). on the other hand, iso-2 hipip, which is isolated as an oligomer, contains a peptide chain with 54 amino acid r ...199910462450
nmr characterization of the nadp(h)-binding domain of escherichia coli transhydrogenase: sequential assignment and global fold.the soluble nadp(h)-binding domain of escherichia coli transhydrogenase (186 amino acids, 20.4 kda, rotational correlation time 14 ns) was characterized using nmr techniques. the global fold is similar to that of a classical dinucleotide-binding fold with six parallel beta-strands in a central sheet surrounded by helices and irregular structures, but is lacking both alphad and alphae. the substrate is bound in an extended conformation at the c-terminal end of the parallel beta-sheet and our data ...199910481061
methanobacterium thermoautotrophicum encodes two multisubunit membrane-bound [nife] hydrogenases. transcription of the operons and sequence analysis of the deduced proteins.two gene groups, designated energy converting hydrogenase a (eha) and energy converting hydrogenase b (ehb), each encoding a putative multisubunit membrane-bound [nife] hydrogenase, were identified in the genome of methanobacterium thermoautotrophicum. the length of the transcription units was determined using reverse transcription (rt)-pcr. the eha operon (12.5 kb) and the ehb operon (9.6 kb) were found to be composed of 20 and 17 open reading frames, respectively. competitive rt-pcr was used t ...199910491142
probing the heme axial ligation in the co-sensing cooa protein with magnetic circular dichroism spectroscopy.the combination of uv/visible/near-ir variable-temperature magnetic circular dichroism (vtmcd) and epr spectroscopies has been used to investigate the spin states and axial ligation of the heme group in oxidized, reduced, and co-bound reduced forms of the rhodospirillum rubrum co oxidation transcriptional activator protein (cooa) and its h77y and c75s variants. the energy of the porphyrin(pi)-to-fe(iii) charge-transfer band (8930 cm(-)(1)) and the presence of cysteinate s-to-fe(iii) charge-trans ...199910504250
evidence for the stabilization of nadph relative to nadp(+) on the diii components of proton-translocating transhydrogenases from homo sapiens and from rhodospirillum rubrum by measurement of tryptophan fluorescence.a unique trp residue in the recombinant diii component of transhydrogenase from human heart mitochondria (hsdiii), and an equivalent trp engineered into the diii component of rhodospirillum rubrum transhydrogenase (rrdiii.d155w), are more fluorescent when nadp(+) is bound to the proteins, than when nadph is bound. we have used this to determine the occupancy of the binding site during transhydrogenation reactions catalysed by mixtures of recombinant di from the r. rubrum enzyme and either hsdiii ...199910514549
purification of p(ii) and p(ii)-ump and in vitro studies of regulation of glutamine synthetase in rhodospirillum rubrum.the p(ii) protein from rhodospirillum rubrum was fused with a histidine tag, overexpressed in escherichia coli, and purified by ni(2+)-chelating chromatography. the uridylylated form of the p(ii) protein could be generated in e. coli. the effects on the regulation of glutamine synthetase by p(ii), p(ii)-ump, glutamine, and alpha-ketoglutarate were studied in extracts from r. rubrum grown under different conditions. p(ii) and glutamine were shown to stimulate the atp-dependent inactivation (adeny ...199910515945
expression of p(ii) and glutamine synthetase is regulated by p(ii), the ntrbc products, and processing of the glnba mrna in rhodospirillum rubrum.we have studied the transcription of the glnb and glna genes in rhodospirillum rubrum with firefly luciferase as a reporter enzyme. under nh(4)(+) and n(2) conditions, glnba was cotranscribed from a weak and a strong promoter. in nitrogen-fixing cultures, activity of the latter was highly enhanced by ntrc, but transcription from both promoters occurred under both conditions. there is no promoter controlling transcription of glna alone, supporting our proposal that the glna mrna is produced by pr ...199910515946
characterization by mass spectrometry of poly(3-hydroxyalkanoates) produced by rhodospirillum rubrum from 3-hydroxyacids.the sequence distributions of two microbial copolyesters obtained by fermentation of rhodospirillum rubrum, grown with 3-hydroxyhexanoic or 3-hydroxyheptanoic acids, were determined by analyzing the oligomers prepared by partial pyrolysis or partial methanolysis of these copolyesters using fast atom bombardment mass spectrometry (fab-ms). oligomers up to pentamers were identified in the case of partial pyrolysis and up to tetradecamers in the case of partial methanolysis. the comparison between ...199910517530
h+ -ppases: a tightly membrane-bound family.the earliest known h+-ppase (proton-pumping inorganic pyrophosphatase), the integrally membrane-bound h+-ppi synthase (proton-pumping inorganic pyrophosphate synthase) from rhodospirillum rubrum, is still the only alternative to h+-atp synthase in biological electron transport phosphorylation. cloning of several higher plant vacuolar h+-ppase genes has led to the recognition that the corresponding proteins form a family of extremely similar proton-pumping enzymes. the bacterial h+-ppi synthase a ...199910523139
reduction of selenite and detoxification of elemental selenium by the phototrophic bacterium rhodospirillum rubrum.the effect of selenite on growth kinetics, the ability of cultures to reduce selenite, and the mechanism of detoxification of selenium were investigated by using rhodospirillum rubrum. anoxic photosynthetic cultures were able to completely reduce as much as 1. 5 mm selenite, whereas in aerobic cultures a 0.5 mm selenite concentration was only reduced to about 0.375 mm. the presence of selenite in the culture medium strongly affected cell division. in the presence of a selenite concentration of 1 ...199910543779
a thermostable vacuolar-type membrane pyrophosphatase from the archaeon pyrobaculum aerophilum: implications for the origins of pyrophosphate-energized pumps.vacuolar-type h(+)-translocating pyrophosphatases (v-ppases) have been considered to be restricted to plants, a few species of phototrophic proteobacteria and protists. here, we describe pvp, a thermostable, sequence-divergent v-ppase from the facultatively aerobic hyperthermophilic archaeon pyrobaculum aerophilum. pvp shares only 38% sequence identity with both the prototypical v-ppase from arabidopsis thaliana and the h(+)-ppi synthase from rhodospirillum rubrum, yet possesses most of the stru ...199910556526
certain species of the proteobacteria possess unusual bacteriochlorophyll a environments in their light-harvesting this work, we have examined, using fourier-transform raman (ft-r) spectroscopy, the bacteriochlorophyll a (bchl a) binding sites in light-harvesting (lh) antennae from different species of the proteobacteria that exhibit unusal absorption properties. while the lh1 complexes from erythromicrobium (e.) ramosum (rc-b871) and rhodospirillum centenum (b875) present classic ft-r spectra in the carbonyl high-frequency region, we show that in the blue-shifted lh1 complex, absorbing at 856 nm, from ro ...199910604286
thioredoxin is involved in oxygen-regulated formation of the photosynthetic apparatus of rhodobacter sphaeroides.thioredoxin, a redox active protein, has been previously demonstrated to be essential for growth of the anoxygenic photosynthetic bacterium rhodobacter sphaeroides. in the present study, the involvement of thioredoxin in the formation of the photosynthetic apparatus of r. sphaeroides ws8 was investigated by construction and analysis of a mutant strain disrupted for the chromosomal trxa copy and carrying a plasmid-borne copy of trxa under the control of the hybrid ptrc promoter inducible by iptg ...19999864318
nickel-binding proteins.nickel enzymes are a relatively new class of metalloenzymes. the seven known nickel enzymes are urease, hydrogenase, co-dehydrogenase, methyl-coenzyme m reductase, ni-superoxide dismutase, glyoxalase i and cis-trans isomerase. the requirement for nickel implies the presence of a nickel-processing system, since free transition metals are harmful to the cell. a nickel-processing system involves the recognition and transport of nickel into the cell and the handling of the nickel once it enters the ...199911212309
unprecedented proximal binding of nitric oxide to heme: implications for guanylate cyclase.microbial cytochromes c' contain a 5-coordinate his-ligated heme that forms stable adducts with nitric oxide (no) and carbon monoxide (co), but not with dioxygen. we report the 1.95 and 1.35 a resolution crystal structures of the co- and no-bound forms of the reduced protein from alcaligenes xylosoxidans. no disrupts the his-fe bond and binds in a novel mode to the proximal face of the heme, giving a 5-coordinate species. in contrast, co binds 6-coordinate on the distal side. a second co molecul ...200011060017
maintenance and control of redox poise in rhodobacter capsulatus strains deficient in the calvin-benson-bassham pathway.carbon dioxide serves as the preferred electron acceptor during photoheterotrophic growth of nonsulfur purple photosynthetic bacteria such as rhodobacter capsulatus and rhodobacter sphaeroides. this co2, produced as a result of the oxidation of preferred organic carbon sources, is reduced through reactions of the calvin-benson-bassham reductive pentose phosphate pathway. this pathway is thus crucial to maintain a balanced intracellular oxidation-reduction potential (or redox poise) under photohe ...200011131022
co sensing and regulation of gene expression by the transcriptional activator cooa.the transcriptional activator cooa from rhodospirillum rubrum contains a six-coordinate protoheme that acts as a co sensor in vivo. co is a physiological effector of cooa and replaces one of the axial ligands of the ferrous heme to form the co-bound cooa that is active as the transcriptional activator. cys75 or his77 is coordinated to the ferric and ferrous hemes in cooa, respectively. the redox-controlled ligand exchange between cys75 and his77 proceeds during the change in the redox state of t ...200011132638
energy transfer and charge separation in the purple non-sulfur bacterium roseospirillum parvum.the antenna reaction centre system of the recently described purple non-sulfur bacterium roseospirillum parvum strain 930i was studied with various spectroscopic techniques. the bacterium contains bacteriochlorophyll (bchl) a, 20% of which was esterified with tetrahydrogeranylgeraniol. in the near-infrared, the antenna showed absorption bands at 805 and 909 nm (929 nm at 6 k). fluorescence bands were located at 925 and 954 nm, at 300 and 6 k, respectively. fluorescence excitation spectra and tim ...200011106774
mutations in the beta-subunit thr(159) and glu(184) of the rhodospirillum rubrum f(0)f(1) atp synthase reveal differences in ligands for the coupled mg(2+)- and decoupled ca(2+)-dependent f(0)f(1) the crystal structure of the mitochondrial f(1)-atpase, the beta-thr(163) residue was identified as a ligand to mg(2+) and the beta-glu(188) as directly involved in catalysis. we replaced the equivalent beta-thr(159) of the chromatophore f(0)f(1) atp synthase of rhodospirillum rubrum with ser, ala, or val and the glu(184) with gln or lys. the mutant beta subunits were isolated and tested for their capacity to assemble into a beta-less chromatophore f(0)f(1) and restore its lost activities. al ...200010625625
hybrid rhodospirillum rubrum f(0)f(1) atp synthases containing spinach chloroplast f(1) beta or alpha and beta subunits reveal the essential role of the alpha subunit in atp synthesis and tentoxin sensitivity.trace amounts ( approximately 5%) of the chloroplast alpha subunit were found to be absolutely required for effective restoration of catalytic function to licl-treated chromatophores of rhodospirillum rubrum with the chloroplast beta subunit (avital, s., and gromet-elhanan, z. (1991) j. biol. chem. 266, 7067-7072). to clarify the role of the alpha subunit in the rebinding of beta, restoration of catalytic function, and conferral of sensitivity to the chloroplast-specific inhibitor tentoxin, licl ...200010625626
electronic absorption, epr, and resonance raman spectroscopy of cooa, a co-sensing transcription activator from r. rubrum, reveals a five-coordinate no-heme.electronic absorption, epr, and resonance raman spectroscopies revealed that cooa, the co-sensing transcriptional regulator from rhodospirillum rubrum, reacts with no to form a five-coordinate no-heme. no must therefore displace both of the heme ligands from six-coordinate, low-spin fe(ii)cooa in forming five-coordinate fe(ii)cooa(no). co, in contrast, displaces a single heme ligand from fe(ii)cooa to form six-coordinate fe(ii)cooa(co). of a series of common heme-binding ligands, only co and no ...200010631000
mutagenesis and functional characterization of the glnb, glna, and nifa genes from the photosynthetic bacterium rhodospirillum rubrum.nitrogen fixation is tightly regulated in rhodospirillum rubrum at two different levels: transcriptional regulation of nif expression and posttranslational regulation of dinitrogenase reductase by reversible adp-ribosylation catalyzed by the drat-drag (dinitrogenase reductase adp-ribosyltransferase-dinitrogenase reductase-activating glycohydrolase) system. we report here the characterization of glnb, glna, and nifa mutants and studies of their relationship to the regulation of nitrogen fixation. ...200010648524
regulation of dinitrogenase reductase adp-ribosyltransferase and dinitrogenase reductase-activating glycohydrolase by a redox-dependent conformational change of nitrogenase fe protein.the nitrogenase-regulating enzymes dinitrogenase reductase adp-ribosyltransferase (drat) and dinitrogenase reductase-activating glycohydrolase (drag), from rhodospirillum rubrum, were shown to be sensitive to the redox status of the [fe(4)s(4)](1+/2+) cluster of nitrogenase fe protein from r. rubrum or azotobacter vinelandii. drag had <2% activity with oxidized r. rubrum fe protein relative to activity with reduced fe protein. the activity of drag with oxygen-denatured fe protein or a low molecu ...200010652344
exchanging cofactors in the core antennae from purple bacteria: structure and properties of zn-bacteriopheophytin-containing lh1.the core light-harvesting lh1 complex of rhodospirillum rubrum consists of an assembly of membrane-spanning alpha and beta polypeptides, each of which binds one bacteriochlorophyll (bchl) a molecule. in this work, we describe a technique that allows the replacement of the natural, mg bchl a cofactors present in this protein by zn-bacteriopheophytin (zn-bpheo). this technique makes use of the well-characterized, reversible dissociation of lh1 induced by the detergent beta-octylglucoside. incubati ...200010653655
role of the h protein in assembly of the photochemical reaction center and intracytoplasmic membrane in rhodospirillum rubrum.rhodospirillum rubrum is a model for the study of membrane formation. under conditions of oxygen limitation, this facultatively phototrophic bacterium forms an intracytoplasmic membrane that houses the photochemical apparatus. this apparatus consists of two pigment-protein complexes, the light-harvesting antenna (lh) and photochemical reaction center (rc). the proteins of the photochemical components are encoded by the puf operon (lhalpha, lhbeta, rc-l, and rc-m) and by puha (rc-h). r. rubrum pu ...200010671438
relative orientation of the hemes of the cytochrome bc(1) complexes from rhodobacter sphaeroides, rhodospirillum rubrum, and beef heart mitochondria. a linear dichroism study.the orientation of the chromophores in the cytochrome bc(1) of rhodospirillum rubrum, rhodobacter sphaeroides, and beef heart mitochondria is reported. the combination of redox-resolved absorption spectrophotometry and linear dichroism experiments at low temperature allows the determination of the orientation of the three hemes with respect to the membrane plane. the orientations of the b(h)-and b(l)-hemes of the r. sphaeroides and beef heart mitochondrial complexes are similar to those determin ...200010681500
escape probability and trapping mechanism in purple bacteria: revisited.despite intensive research for decades, the trapping mechanism in the core complex of purple bacteria is still under discussion. in this article, it is attempted to derive a conceptionally simple model that is consistent with all basic experimental observations and that allows definite conclusions on the trapping mechanism. some experimental data reported in the literature are conflicting or incomplete. therefore we repeated two already published experiments like the time-resolved fluorescence d ...200010692545
a novel covalent modification of nitrogenase in a extracts of the unicellular cyanobacterium gloeothece, the fe-protein of nitrogenase can be separated by sds-page into two antigenically identifiable components. unlike the situation in photosynthetic bacteria such as rhodospirillum rubrum, these two forms do not arise from covalent modification of the protein by adp-ribosylation. rather, the fe-protein of gloeothece nitrogenase is subjected to modification by palmitoylation.200010692592
dos, a heme-binding pas protein from escherichia coli, is a direct oxygen sensor.a direct sensor of o(2), the dos protein, has been found in escherichia coli. previously, the only biological sensors known to respond to o(2) by direct and reversible binding were the fixl proteins of rhizobia. a heme-binding region in dos is 60% homologous to the o(2)-sensing pas domain of the fixl protein, but the remainder of dos does not resemble fixl. specifically, the c-terminal domain of dos, presumed to be a regulatory partner that couples to its heme-binding domain, is not a histidine ...200010704219
characterization and cloning of an (r)-specific trans-2,3-enoylacyl-coa hydratase from rhodospirillum rubrum and use of this enzyme for pha production in escherichia (r)-trans-2,3-enoylacyl-coa hydratase was purified to near-homogeneity from rhodospirillum rubrum. protein sequencing of enriched protein fractions allowed the construction of a degenerate oligonucleotide. the gene encoding the (r)-specific hydratase activity was cloned following three rounds of colony hybridization using the oligonucleotide, and overexpression of the gene in e. coli led to the purification of the enzyme to homogeneity. the purified enzyme used crotonyl-coa, trans-2,3-penteno ...200010709984
control of cooa activity by the mutation at the c-terminal end of the heme-binding domain.a constitutively active mutant of a cooa, in which met131 was replaced by leu, was isolated by random mutagenesis. site-directed mutagenesis at position 131 revealed that m131r-cooa was also constitutively active even in the absence of co and that m131p-, m131d-, and m131e-cooa were constitutively inactive regardless of the presence or absence of co. while m131l- and m131e-cooa showed almost the same electronic absorption spectra as those of the wild type in the ferric, ferrous, and co-bound for ...200010714706
stopped-flow reaction kinetics of recombinant components of proton-translocating transhydrogenase with physiological information on the high resolution structure of the membrane proton pump, transhydrogenase, now provides a framework for understanding kinetic descriptions of the enzyme. here, we have studied redox reactions catalyzed by mixtures of the recombinant nad(h)-binding component (di) of rhodospirillum rubrum transhydrogenase, and the recombinant nadp(h)-binding component (diii) of either the r. rubrum enzyme or the human enzyme. by recording changes in the fluorescence emission of native and engi ...200010747934
modeling photoheterotrophic growth kinetics of rhodospirillum rubrum inrectangular photobioreactors.based on a previously established model for radiant light transfer in photobioreactors (pbr), taking into account absorption and scattering of light, a new knowledge model for coupling radiant light energy available and local growth kinetics in pbrs for the photoheterotrophic bacteria rhodospirillum rubrum is discussed. a revised method is presented for the calculation of the absorption and scattering coefficients. the specific characteristics of the electron-transfer chains in such microorganis ...200010753444
the solution structure of rhodobacter sphaeroides lh1beta reveals two helical domains separated by a more flexible region: structural consequences for the lh1, the solution structure of the rhodobacter sphaeroides core light-harvesting complex beta polypeptide solubilised in chloroform:methanol is presented. the structure, determined by homonuclear nmr spectroscopy and distance geometry, comprises two alpha helical regions (residue -34 to -15 and -11 to +6, using the numbering system in which the conserved histidine residue is numbered zero) joined by a more flexible four amino acid residue linker. the c-terminal helix forms the membrane spanning ...200010756106
adp-ribosylation of variants of azotobacter vinelandii dinitrogenase reductase by rhodospirillum rubrum dinitrogenase reductase a number of nitrogen-fixing bacteria, nitrogenase is posttranslationally regulated by reversible adp-ribosylation of dinitrogenase reductase. the structure of the dinitrogenase reductase from azotobacter vinelandii is known. in this study, mutant forms of dinitrogenase reductase from a. vinelandii that are affected in various protein activities were tested for their ability to be adp-ribosylated or to form a complex with dinitrogenase reductase adp-ribosyltransferase (drat) from rhodospirillu ...200010762264
induction of carbon monoxide dehydrogenase to facilitate redox balancing in a ribulose bisphosphate carboxylase/oxygenase-deficient mutant strain of rhodospirillum rubrum.a ribulose-1,5-bisphosphate carboxylase/oxygenase-deficient mutant strain (strain i-19) of rhodospirillum rubrum was capable of growth under photoheterotrophic conditions in the absence of exogenous electron acceptors. these results suggested that alternative means of removing reducing equivalents have been acquired that allow this strain to remove reducing equivalents in the absence of a functional calvin-benson-bassham reductive pentose phosphate pathway. previously, the proton-reducing activi ...200010763751
interaction of photosynthetic pigments with various organic solvents 2. application of magnetic circular dichroism to bacteriochlorophyll a and light-harvesting complex 1.magnetic circular dichroism (mcd) and absorption spectra of metal bacteriochlorin complexes have been measured on bacteriochlorophyll (bchl) a in various solvents and different forms of light-harvesting complexes 1 (lh1 complexes). in hydrophilic organic solvents, the mcd intensity of the q(y)(0-0) transition of bchl a was sensitive to the wavelength of absorption maximum of q(x)(0-0), and the ratio of mcd q(y)(0-0) intensity to the dipole strength (b/d) was inversely proportional to the differe ...200010773156
organization of the pigment molecules in the chlorophyll a/b/c containing alga mantoniella squamata (prasinophyceae) studied by means of absorption, circular and linear dichroism order to obtain information on the organization of the pigment molecules in chlorophyll (chl) a/b/c-containing organisms, we have carried out circular dichroism (cd), linear dichroism (ld) and absorption spectroscopic measurements on intact cells, isolated thylakoids and purified light-harvesting complexes (lhcs) of the prasinophycean alga mantoniella squamata. the cd spectra of the intact cells and isolated thylakoids were predominated by the excitonic bands of the chl a/b/c lhc. however, so ...200010773164
axenic cultivation of anoxygenic phototrophic bacteria, cyanobacteria, and microalgae in a new closed tubular glass photobioreactor.a low-cost closed tubular glass photobioreactor allowing axenic cultivation of phototrophic microorganisms was constructed. standard glass tubes were arranged in a helical array providing a working volume of 80 1. the glass tubes were connected with a degassing chamber, which also provided ports for measuring and regulating oxygen supply, ph, foam, and optical density and for adding substrates and antifoam agents as well as disposing of vent gas. a pump module allowed agitation of the medium in ...200010803892
sequence of pha synthase gene from two strains of rhodospirillum rubrum and in vivo substrate specificity of four pha synthases across two heterologous expression systems.a 3.0-kb genomic fragment has been isolated from rhodospirillum rubrum (atcc 25903) that contains an open reading frame (orf) with strong homology to other known polyhydroxyalkanoate (pha) synthase genes. this orf has lower homology to the r. rubrum strain ha pha synthase than would be expected within the same species. we have conducted a series of heterologous expression studies evaluating the in vivo substrate specificity of pha synthase genes from rhodobacter sphaeroides, ralstonia eutropha ( ...200010803898
[dark metabolism of acetate in rhodospirillum rubrum cells, grown under photoheterotropic conditions].the mechanism of the dark assimilation of acetate in the photoheterotrophically grown nonsulfur bacterium rhodospirillum rubrum was studied. both in the light and in the dark, acetate assimilation in rsp. rubrum cells, which lack the glyoxylate pathway, was accompanied by the excretion of glyoxylate into the growth medium. the assimilation of propionate was accompanied by the excretion of pyruvate. acetate assimilation was found to be stimulated by bicarbonate, pyruvate, the c4-dicarboxylic acid ...200010808482
interactions between the soluble domain i of nicotinamide nucleotide transhydrogenase from rhodospirillum rubrum and transhydrogenase from escherichia coli. effects on catalytic and h+-pumping activities.nicotinamide nucleotide transhydrogenase from escherichia coli is composed of two subunits, the alpha and the beta subunits, each of which contains a hydrophilic domain, domain i and iii, respectively, as well as several transmembrane helices, collectively denoted domain ii. the interactions between domain i from rhodospirillum rubrum (rri) and the intact or the protease-treated enzyme from e. coli was investigated using the separately expressed and purified domain i from r. rubrum, and his-tagg ...200010824114
effects of perturbations of the nitrogenase electron transfer chain on reversible adp-ribosylation of nitrogenase fe protein in klebsiella pneumoniae strains bearing the rhodospirillum rubrum dra operon.the redox state of nitrogenase fe protein is shown to affect regulation of adp-ribosylation in klebsiella pneumoniae strains transformed by plasmids carrying dra genes from rhodospirillum rubrum. the dra operon encodes dinitrogenase reductase adp-ribosyltransferase and dinitrogenase reductase-activating glycohydrolase, enzymes responsible for the reversible inactivation, via adp-ribosylation, of nitrogenase fe protein in r. rubrum. in bacteria containing the dra operon in their chromosomes, inac ...200010850982
purification and characterization of a membrane-bound hydrogenase from the hyperthermophilic archaeon pyrococcus furiosus.highly washed membrane preparations from cells of the hyperthermophilic archaeon pyrococcus furiosus contain high hydrogenase activity (9.4 micromol of h(2) evolved/mg at 80 degrees c) using reduced methyl viologen as the electron donor. the enzyme was solubilized with n-dodecyl-beta-d-maltoside and purified by multistep chromatography in the presence of triton x-100. the purified preparation contained two major proteins (alpha and beta) in an approximate 1:1 ratio with a minimum molecular mass ...200010852873
rhythmic activity of uptake hydrogenase in the prokaryote rhodospirillum rubrum.growth of rhodospirillum rubrum was followed in cultures kept under anoxic conditions at constant temperature in either continuous light (ll, 32 degrees c) or continuous darkness (dd, 32 degrees c and 16 degrees c). in dd, only small modifications of the turbidity were detected; linear regression analysis nevertheless gives a very significant slope (t(34) = 13.07, p < 10(-14), with r2 of 0.834). mean generation times reflected these differences of growth with 11.9+/-0.5 h in ll and 43.2+/-1.1 h ...200010885876
altering the specificity of cooa, the carbon monoxide-sensing transcriptional activator: characterization of cooa variants that bind cyanide in the fe(ii) form with high affinity.cooa is a carbon monoxide- (co-) sensing homodimeric heme protein that activates the transcription of genes required for the anaerobic oxidation of co to co(2) in the phototrophic bacterium rhodospirillum rubrum. in this study, we demonstrate that mutational alteration of the histidine residue (his(77)) that serves as a heme ligand in the fe(ii) form of cooa allows high-affinity binding of cyanide (k(d) approximately 0.4 mm) to the heme. in contrast, neither these same variants in the fe(iii) fo ...200010889037
evidence for a ligand co that is required for catalytic activity of co dehydrogenase from rhodospirillum rubrum.radiolabeling studies support the existence of a nonsubstrate co ligand (co(l)) to the fe atom of the proposed [feni] cluster of carbon monoxide dehydrogenase (codh) from rhodospirillum rubrum. purified codh has variable amounts of co(l) dissociated depending on the extent of handling of the proteins. this dissociated co(l) can be restored by incubation of codh with co, resulting in a 30-40% increase in initial activity relative to as-isolated purified codh. a similar amount of co(l) binding is ...200010891076
crystallization of the di component of transhydrogenase, a proton-translocating membrane protein.nicotinamide nucleotide transhydrogenase couples the exchange of a hydride-ion equivalent between nad(h) and nadp(h) to the translocation of protons across an energy-transducing membrane. peripheral components of 380 and 200 residues bind nad(h) (di) and nadp(h) (diii), respectively, while a third component forms a membrane-spanning region (dii). the nad(h)-binding component di of rhodospirillum rubrum transhydrogenase has been crystallized in a form which diffracts to beyond 3.0 a resolution an ...200010957636
dissociation and recombination between ligands and heme in a co-sensing transcriptional activator cooa. a flash photolysis study.cooa from rhodospirillum rubrum is a transcriptional activator in which a heme prosthetic group acts as a co sensor and regulates the activity of the protein. in this study, the electronic relaxation of the heme, and the concurrent recombination between ligands and the heme at approximately 280 k were examined in an effort to understand the environment around the heme and the dynamics of the ligands. upon photoexcitation of the reduced cooa at 400 nm, electronic relaxation of the heme occurred w ...200010978334
the orf162b sequence of rhodobacter capsulatus encodes a protein required for optimal levels of photosynthetic pigment-protein complexes.the orf162b sequence, the second open reading frame 3' of the reaction center (rc) h protein gene puha in the rhodobacter capsulatus photosynthesis gene cluster, is shown to be transcribed from a promoter located 5' of puha. a nonpolar mutation of orf162b was generated by replacing most of the coding region with an antibiotic resistance cartridge. although the mutant strain initiated rapid photosynthetic growth, growth slowed progressively and cultures often entered a pseudostationary phase. the ...200010986247
protein-protein recognition, hydride transfer and proton pumping in the transhydrogenase complex.membrane-bound ion pumps are involved in metabolic regulation, osmoregulation, cell signalling, nerve transmission and energy transduction. how the ion electrochemical gradient interacts with the scalar chemistry and how the catalytic machinery is gated to ensure high coupling efficiency are fundamental to the mechanism of action of such pumps. transhydrogenase is a conformationally coupled proton pump linking a proton gradient to the redox reaction between nad(h) and nadp(h). the enzyme has thr ...200010997900
solution structure of the nadp(h)-binding component (diii) of proton-translocating transhydrogenase from rhodospirillum rubrum.transhydrogenase is a proton pump found in the membranes of bacteria and animal mitochondria. the solution structure of the expressed, 21.5 kda, nadp(h)-binding component (diii) of transhydrogenase from rhodospirillum rubrum has been solved by nmr methods. this is the first description of the structure of diii from a bacterial source. the protein adopts a rossmann fold: an open, twisted, parallel beta-sheet, flanked by helices. however, the binding of nadp(+) to diii is profoundly different to t ...200011004437
characterization of variants altered at the n-terminal proline, a novel heme-axial ligand in cooa, the co-sensing transcriptional activator.cooa, the carbon monoxide-sensing transcription factor from rhodospirillum rubrum, binds co through a heme moiety resulting in conformational changes that promote dna binding. the crystal structure shows that the n-terminal pro(2) of one subunit (met(1) is removed post-translationally) provides one ligand to the heme of the other subunit in the cooa homodimer. to determine the importance of this novel ligand and the contiguous residues to cooa function, we have altered the n terminus through two ...200011007793
structure of the co sensing transcription activator cooa.cooa is a homodimeric transcription factor that belongs to the catabolite activator protein (cap) family. binding of co to the heme groups of cooa leads to the transcription of genes involved in co oxidation in rhodospirillum rubrum. the 2.6 a structure of reduced (fe2+) cooa reveals that his 77 in both subunits provides one heme ligand while the n-terminal nitrogen of pro 2 from the opposite subunit provides the other ligand. a structural comparison of cooa in the absence of effector and dna (o ...200011017196
genetic analysis of carboxydothermus hydrogenoformans carbon monoxide dehydrogenase genes coof and coos.carboxydothermus hydrogenoformans is an extremely thermophilic, gram-positive bacterium growing on carbon monoxide (co) as single carbon and energy source and producing only h(2) and co(2). carbon monoxide dehydrogenase is a key enzyme for co metabolism. the carbon monoxide dehydrogenase genes coof and coos from c. hydrogenoformans were cloned and sequenced. these genes showed the highest similarity to the coof genes from the archaeon archaeoglobus fulgidus and the coos gene from the bacterium r ...200011024270
interactions of the nadp(h)-binding domain iii of proton-translocating transhydrogenase from escherichia coli with nadp(h) and the nad(h)-binding domain i studied by nmr and site-directed mutagenesis.using the purified nadp(h)-binding domain of proton-translocating escherichia coli transhydrogenase (eciii) overexpressed in (15)n- and (2)h-labeled medium, together with the purified nad(h)-binding domain from e. coli (eci), the interface between eciii and eci, the nadp(h)-binding site and the influence on the interface by nad(p)(h) was investigated in solution by nmr chemical shift mapping. mapping of the nadp(h)-binding site showed that the nadp(h) substrate is bound to eciii in an extended c ...200011027139
a new appraisal of the prokaryotic origin of eukaryotic phytochromes.the evolutionary origin of the phytochromes of eukaryotes is controversial. three cyanobacterial proteins have been described as "phytochrome-like" and have been suggested to be potential ancestors of these essential photoreceptors: cph1 from synechocystis pcc 6803, showing homology to phytochromes along its entire length and known to attach a chromophore; and plpa from synechocystis pcc 6803 and rcae from fremyella diplosiphon, both showing homology to phytochromes most strongly only in the c-t ...200011029065
pigment-protein architecture in the light-harvesting antenna complexes of purple bacteria: does the crystal structure reflect the native pigment-protein arrangement?structural analysis of crystallized peripheral (lh2) and core antenna complexes (lh1) of purple bacteria has revealed circular aggregates of high rotational symmetry (c8, c9 and c16, respectively). quantum-chemical calculations indicate that in particular the waterwheel-like arrangements of pigments should show characteristic structure-sensitive spectroscopic behavior in the near infrared absorption region. laser-spectroscopic data obtained with non-crystallized, isolated lh2 of rhodospirillum m ...200011034303
n2-dependent growth and nitrogenase activity in the metal-metabolizing bacteria, geobacter and magnetospirillum species.cells of geobacter metallireducens, magnetospirillum strain amb-1, magnetospirillum magnetotacticum and magnetospirillum gryphiswaldense showed n2-dependent growth, the first anaerobically with fe(iii) as the electron acceptor, and the latter three species microaerobically in semi-solid oxygen gradient cultures. cells of the magnetospirillum species grown with n2 under microaerobic conditions were magnetotactic and therefore produced magnetosomes. cells of geobacter metallireducens reduced acety ...200011200427
efficient light harvesting through carotenoids.we review the factors that control the efficiency of carotenoid-chlorophyll excitation transfer in photosynthetic light harvesting. for this we summarize first the recently developed theory that describes electronic couplings between carotenoids and chlorophylls and we outline in particular the influence of length of conjugated system and of symmetry breaking on the couplings. we focus hereby on the structurally solved lycopene-bchl system of lh 2 from rhodospirillum molischianum and the peridin ...200016228415
cloning, sequencing and analysis of the pucc genes from rubrivivax gelatinosus strain 151 and rhodopseudomonas acidophila strain 10050.the pucc genes of rubrivivax gelatinosus strain 151 and rhodopseudomonas acidophila strain 10050 have been identified, cloned and sequenced. in rubrivivax gelatinosus the arrangement of the pucc gene with regard to the pucba genes was shown to differ from that found in other species of photosynthetic bacteria. the rhodopseudomonas acidophila pucc was found downstream of four new pucba gene pairs, bringing the sequenced pucba pairs to a total of eight in this strain. the predicted pucc protein se ...200016228472
bacterial photosynthesis begins with quantum-mechanical the antenna system of photosynthetic bacteria, pigments form circular aggregates whose excitations are excitons with quantum-mechanical coherence extending over many pigments. these excitons play crucial roles in light harvesting, storage, and excitation-energy transfer (eet). eet takes place rapidly to and/or from optically forbidden exciton states, without total transition dipole, within the antenna system and to the reaction center. such eets cannot be rationalized by förster's formula, th ...200111933253
a transcriptional regulator of a pristinamycin resistance gene in streptomyces coelicolor.pip is a pristinamycin-induced transcriptional regulator protein detected in many streptomyces species by its ability to specifically bind sequence motifs within the promoter of a streptomyces pristinaespiralis multidrug resistance gene (ptr). to investigate the possible role of pip in regulating multidrug resistance, it was purified from a genetically characterized species, streptomyces coelicolor, utilizing an affinity matrix of the ptr promoter conjugated to magnetic beads. reverse genetics i ...200111050092
component of the rhodospirillum centenum photosensory apparatus with structural and functional similarity to methyl-accepting chemotaxis protein chemoreceptors.photosynthetic bacteria respond to alterations in light conditions by migrating to locations that allows optimal use of light as an energy source. studies have indicated that photosynthesis-driven electron transport functions as an attractant signal for motility among purple photosynthetic bacteria. however, it is unclear just how the motility-based signal transduction system monitors electron flow through photosynthesis-driven electron transport. recently, we have demonstrated that the purple p ...200111114914
role of the dinitrogenase reductase arginine 101 residue in dinitrogenase reductase adp-ribosyltransferase binding, nad binding, and cleavage.dinitrogenase reductase is posttranslationally regulated by dinitrogenase reductase adp-ribosyltransferase (drat) via adp-ribosylation of the arginine 101 residue in some bacteria. rhodospirillum rubrum strains in which the arginine 101 of dinitrogenase reductase was replaced by tyrosine, phenylalanine, or leucine were constructed by site-directed mutagenesis of the nifh gene. the strain containing the r101f form of dinitrogenase reductase retains 91%, the strain containing the r101y form retain ...200111114923
evidence for three distinct hydrogenase activities in rhodospirillum rubrum.inducer, inhibitor, and mutant studies on three hydrogenase activities of rhodospirillum rubrum indicate that they are mediated by three distinct hydrogenase enzymes. uptake hydrogenase mediates h2 uptake to an unknown physiological acceptor or methylene blue and is maximally synthesized during autotrophic growth in light. formate-linked hydrogenase is synthesized primarily during growth in darkness or when light becomes limiting, and links formate oxidation to h2 production. carbon-monoxide-lin ...200111778889
effect of p(ii) and its homolog glnk on reversible adp-ribosylation of dinitrogenase reductase by heterologous expression of the rhodospirillum rubrum dinitrogenase reductase adp-ribosyl transferase-dinitrogenase reductase-activating glycohydrolase regulatory system in klebsiella pneumoniae.reversible adp-ribosylation of dinitrogenase reductase, catalyzed by the dinitrogenase reductase adp-ribosyl transferase-dinitrogenase reductase-activating glycohydrolase (drat-drag) regulatory system, has been characterized in rhodospirillum rubrum and other nitrogen-fixing bacteria. to investigate the mechanisms for the regulation of drat and drag activities, we studied the heterologous expression of r. rubrum dratg in klebsiella pneumoniae glnb and glnk mutants. in k. pneumoniae wild type, th ...200111160092
isolation and characterization of drat mutants that have altered regulatory properties of dinitrogenase reductase adp-ribosyltransferase in rhodospirillum rhodospirillum rubrum, dinitrogenase reductase adp-ribosyltransferase (drat) is responsible for the adp-ribosylation of dinitrogenase reductase in response to the addition of nh(+)(4) or removal from light, resulting in a decrease in nitrogenase activity. drat is itself subject to post-translational regulation; to investigate the mechanism for the regulation of drat activity, random pcr mutagenesis of drat (encoding drat) was performed and mutants with altered drat regulation were screened. t ...200111160813
oligomerization of light-harvesting i antenna peptides of rhodospirillum rubrum.we investigated the oligomerization of the core light-harvesting complex (lh1) of rhodospirillum rubrum from the separated alpha beta bchl(2) subunits (b820) and the oligomerization of the b820 subunit from its monomeric peptides. the full lh1 complex was reversibly associated from b820 subunits by either varying the temperature in the range 277-300 k or by varying the detergent concentration in the buffer from 0.36 to 0.52% n-octyl-beta-d-glucopyranoside. temperature-induced transition measurem ...200111669628
structure of cytochrome c2 from rhodospirillum centenum.cytochrome c(2) from the purple photosynthetic bacterium rhodospirillum centenum has been crystallized by the sitting-drop vapour-diffusion method. the crystals belong to the orthorhombic space group p2(1)2(1)2(1), with unit-cell parameters a = 29.7, b = 59.9, c = 65.4 a, and diffract to a resolution limit of 1.7 a. the fe-atom position was determined from its anomalous scattering contribution and a molecular-replacement solution was calculated. the correctness of the solution was confirmed by p ...200111679712
photophysical characterization of natural means of steady-state fluorescence spectroscopy we explore the photophysics of two lowest lying singlet excited states in two natural 15-cis-carotenoids, namely phytoene and phytofluene, possessing three and five conjugated double bonds (n), respectively. the results are interpreted in relation to the photophysics of all-transcarotenoids with varying n. the fluorescence of phytofluene is more stokes-shifted relative to that of phytoene, and is ascribed to the forbidden s1-->s0 transition, wit ...200111683034
hydrophobicity and prediction of the secondary structure of membrane proteins and peptides.reliability of the hydropathy method to predict the formation of membrane-spanning alpha-helices by integral membrane proteins and peptides whose structure is known from x-ray crystallography is analysed. it is shown that kyte-doolittle hydropathy plots do not predict accurately 22 transmembrane alpha-helices in the reaction centres (rc) of the photosynthetic bacteria rhodopseudomonas viridis and rhodobacter sphaeroides (r-26). the accuracy of prediction for these proteins was improved using an ...200111699870
plastome-encoded bacterial ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) supports photosynthesis and growth in tobacco.the efficiency with which crop plants use their resources of light, water, and fertilizer nitrogen could be enhanced by replacing their co(2)-fixing enzyme, d-ribulose-1,5-bisphosphate carboxylase-oxygenase (rubisco), with more efficient forms, such as those found in some algae, for example. this important challenge has been frustrated by failure of all previous attempts to substitute a fully functional, foreign rubisco (efficient or inefficient) into higher plants. this failure could be caused ...200111724961
effect of carotenoids on the interaction between pigment-protein complexes in membranes of the sulfur photosynthetic bacterium chromatium minutissimum. 200111813560
the dimerization of folded monomers of ribulose 1,5-bisphosphate carboxylase/oxygenase.spontaneous refolding and reconstitution processes of dimeric ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) from rhodospirillum rubrum have been investigated using size-exclusion high performance liquid chromatography (hplc), spectroscopic, and activity measurements. when the unfolded rubisco in guanidine hydrochloride is diluted at 4 degrees c, a folding intermediate (rubisco-i) is rapidly formed, which remains in an unstable monomeric state and gradually develops into folded monome ...200111092881
effects of specific amino acid substitutions on activities of dinitrogenase reductase-activating glycohydrolase from rhodospirillum mutagenesis of the drag gene was used to generate altered forms of dinitrogenase reductase-activating glycohydrolase (drag) with d123a, h142l, h158n, d243g, and e279r substitutions. the amino acid residues h142 and e279 are not required either for the coordination to the metal center or for catalysis since the variants h142l and e279r retained both catalytic and electron paramagnetic resonance spectral properties similar to those of the wild-type enzyme. since drag-h158n and drag-d ...200111544238
the heme pocket afforded by gly117 is crucial for proper heme ligation and activity of cooa.cooa, a co-sensing homodimeric transcription activator from rhodospirillum rubrum, undergoes a conformational change in response to co binding to its heme prosthetic group that allows it to bind specific dna sequences. in a recent structural study (lanzilotta, w. n., schuller, d. j., thorsteinsson, m. v., kerby, r. l., roberts, g. p., and poulos, t. l. (2000) nat. struct. biol. 7, 876-880), it was suggested that co binding to cooa results in a modest repositioning of the c-helices that serve as ...200111551932
detection of bacteria in environmental samples by direct pcr without dna extraction.cultured cells and environmental samples were used directly in pcrs without the isolation of dna. serial dilution was used to eliminate the inhibitory effect of materials in natural samples. primers specific for pmoa, which encodes a subunit of the particulate methane monooxygenase, were used to detect and quantify methanotrophic bacteria by direct most probable number pcr. phototrophic bacteria were detected in environmental samples by direct pcr with primers specific for pufm, and members of t ...200111570503
fast hydride transfer in proton-translocating transhydrogenase revealed in a rapid mixing continuous flow device.transhydrogenase couples the redox reaction between nad(h) and nadp(h) to proton translocation across a membrane. coupling is achieved through changes in protein conformation. upon mixing, the isolated nucleotide-binding components of transhydrogenase (di, which binds nad(h), and diii, which binds nadp(h)) form a catalytic di(2).diii(1) complex, the structure of which was recently solved by x-ray crystallography. the fluorescence from an engineered trp in diii changes when bound nadp(+) is reduc ...200111577115
functional characterization of three glnb homologs in the photosynthetic bacterium rhodospirillum rubrum: roles in sensing ammonium and energy status.the glnb (p(ii)) protein, the product of glnb, has been characterized previously in the photosynthetic bacterium rhodospirillum rubrum. here we describe identification of two other p(ii) homologs in this organism, glnk and glnj. although the sequences of these three homologs are very similar, the molecules have both distinct and overlapping functions in the cell. while glnb is required for activation of nifa activity in r. rubrum, glnk and glnj do not appear to be involved in this process. in co ...200111591658
conformational dynamics of the transcriptional regulator cooa protein studied by subpicosecond mid-infrared vibrational spectroscopy.cooa, which is a transcriptional regulator heme protein allosterically triggered by co, is studied by femtosecond visible-pump mid-ir-probe spectroscopy. transient bleaching upon excitation of the heme in the soret band is detected at approximately 1979 cm(-1), which is the absorption region of the co bound to the heme. the bleach signal shows a nonexponential decay with time constants of 56 and 290 ps, caused by the rebinding of the co to the heme. about 98% of dissociated co recombines geminat ...200111592884
life on carbon monoxide: x-ray structure of rhodospirillum rubrum ni-fe-s carbon monoxide dehydrogenase.a crystal structure of the anaerobic ni-fe-s carbon monoxide dehydrogenase (codh) from rhodospirillum rubrum has been determined to 2.8-a resolution. the codh family, for which the r. rubrum enzyme is the prototype, catalyzes the biological oxidation of co at an unusual ni-fe-s cluster called the c-cluster. the ni-fe-s c-cluster contains a mononuclear site and a four-metal cubane. surprisingly, anomalous dispersion data suggest that the mononuclear site contains fe and not ni, and the four-metal ...200111593006
time-dependent changes in the carotenoid composition and preferential binding of spirilloxanthin to the reaction center and anhydrorhodovibrin to the lh1 antenna complex in rhodobium marinum.carotenoids were isolated from the cells of rhodobium marinum, and their structures were determined by mass spectrometry and 1h nuclear magnetic resonance spectroscopy; the carotenoids include lycopene, rhodopin, anhydrorhodovibrin, rhodovibrin and spirilloxanthin. time-dependent changes in the carotenoid composition in the reaction center (rc) and the light-harvesting complex 1 (lh1) were traced by high-performance liquid chromatography analysis of the extracts. the carotenoid composition chang ...200111594059
an unusual pathway of excitation energy deactivation in carotenoids: singlet-to-triplet conversion on an ultrafast timescale in a photosynthetic antenna.carotenoids are important biomolecules that are ubiquitous in nature and find widespread application in medicine. in photosynthesis, they have a large role in light harvesting (lh) and photoprotection. they exert their lh function by donating their excited singlet state to nearby (bacterio)chlorophyll molecules. in photosynthetic bacteria, the efficiency of this energy transfer process can be as low as 30%. here, we present evidence that an unusual pathway of excited state relaxation in caroteno ...200111226245
a change in ionization of the nadp(h)-binding component (diii) of proton-translocating transhydrogenase regulates both hydride transfer and nucleotide release.transhydrogenase couples the transfer of hydride-ion equivalents between nad(h) and nadp(h) to proton translocation across a membrane. the enzyme has three components: di binds nad(h), diii binds nadp(h) and dii spans the membrane. coupling between transhydrogenation and proton translocation involves changes in the binding of nadp(h). mixtures of isolated di and diii from rhodospirillum rubrum transhydrogenase catalyse a rapid, single-turnover burst of hydride transfer between bound nucleotides; ...200111231296
the crystal structure of an asymmetric complex of the two nucleotide binding components of proton-translocating transhydrogenase.membrane-bound ion translocators have important functions in biology, but their mechanisms of action are often poorly understood. transhydrogenase, found in animal mitochondria and bacteria, links the redox reaction between nad(h) and nadp(h) to proton translocation across a membrane. linkage is achieved through changes in protein conformation at the nucleotide binding sites. the redox reaction takes place between two protein components located on the membrane surface: di, which binds nad(h), an ...200111250201
ribulose-1,5-bisphosphate carboxylase/oxygenase from thermococcus kodakaraensis kod1. 200111265476
formation and properties of hybrid photosynthetic f1-atpases. demonstration of different structural requirements for stimulation and inhibition by tentoxin.a hybrid atpase composed of cloned chloroplast atp synthase beta and gamma subunits (betac and gammac) and the cloned alpha subunit from the rhodospirillum rubrum atp synthase (alphar) was assembled using solubilized inclusion bodies and a simple single-step folding procedure. the catalytic properties of the assembled alpha3rbeta3cgammac were compared to those of the core alpha3cbeta3cgammac complex of the native chloroplast coupling factor 1 (cf1) and to another recently described hybrid enzyme ...200111277942
binding of co at the pro2 side is crucial for the activation of co-sensing transcriptional activator cooa. (1)h nmr spectroscopic studies.cooa is a heme-containing transcriptional activator that anaerobically binds to dna at co atmosphere. to obtain information on the conformational transition of cooa induced by co binding to the heme, we assigned ring current-shifted (1)h nmr signals of cooa using two mutants whose axial ligands of the heme were replaced. in the absence of co, the nmr spectral pattern of h77y cooa, in which the axial histidine (his(77)) was replaced with tyrosine, was similar to that of wild-type cooa. in contras ...200111278259
assembled f1-(alpha beta ) and hybrid f1-alpha 3beta 3gamma -atpases from rhodospirillum rubrum alpha, wild type or mutant beta, and chloroplast gamma subunits. demonstration of mg2+versus ca2+-induced differences in catalytic site structure and function.refolding together the expressed alpha and beta subunits of the rhodospirillum rubrum f(1)(rf(1))-atpase led to assembly of only alpha(1)beta(1) dimers, showing a stable low mgatpase activity. when incubated in the presence of alcl(3), naf and either mgad(t)p or caad(t)p, all dimers associated into closed alpha(3)beta(3) hexamers, which also gained a low caatpase activity. both hexamer atpase activities exhibited identical rates and properties to the open dimer mgatpase. these results indicate t ...200111278351
excitation trap approach to analyze size and pigment-pigment coupling: reconstitution of lh1 antenna of rhodobacter sphaeroides with ni-substituted bacteriochlorophyll.replacement of the central mg in chlorophylls by ni opens an ultrafast (tens of femtoseconds time range) radiationless de-excitation path, while the principal ground-state absorption and coordination properties of the pigment are retained. a method has been developed for substituting the native bacteriochlorophyll a by ni-bacteriochlorophyll a ([ni]-bchl) in the light harvesting antenna of the core complex (lh1) from the purple bacterium, rhodobacter (rb.) sphaeroides, to investigate its unit si ...200111297443
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