Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| quinolones and their n-oxides as inhibitors of mitochondrial complexes i and iii. | 4(1h)-quinolones (2-alkyl- (1), 2-alkyl-3-methyl- (2), 2-methyl-3-alkyl- (3), 1-hydroxy-2-methyl-3-alkyl- (4) and 1-hydroxy-2-alkyl- (5)) with n-alkyl side chains varying from c5 to c17 have been synthesized and tested for biological activity in mitochondrial complexes. whereas all quinolones were efficient inhibitors of electron transport in the cytochrome b/c1-complex from either beef heart or rhodospirillum rubrum, in complex i from beef heart quinolones 1 and 2 only were highly active. in a ... | 1997 | 9030270 |
| high cyclic transhydrogenase activity catalyzed by expressed and reconstituted nucleotide-binding domains of rhodospirillum rubrum transhydrogenase. | the hydrophilic, extramembranous domains i (alpha 1 subunit) and iii of the rhodospirillum rubrum nicotinamide nucleotide transhydrogenase were expressed in escherichia coli and purified therefrom as soluble proteins. these domains bind nad(h) and nadp(h). respectively, and together they form the enzyme's catalytic site. we have demonstrated recently that the isolated domains i and iii of the bovine transhydrogenase (or domain i of r. rubrum plus domain iii of the bovine enzyme) reconstitute to ... | 1997 | 9030266 |
| two-dimensional crystallization of the light-harvesting i-reaction centre photounit from rhodospirillum rubrum. | a stoichiometric unit of the light-harvesting complex i and the reaction centre (lhi-rc complex) has been isolated from a carotenoid-less mutant of the purple non-sulphur bacterium rhodospirillum rubrum by mild solubilization of photosynthetic membranes with the phospholipid detergent diheptylphosphatidylcholine. dialysis of the isolated lhi-rc complexes in the presence of added dioleoyl-sn-phosphatidylcholine produced ordered two-dimensional crystals. digital image processing revealed that the ... | 1997 | 9020974 |
| a 3-hydroxy-3-methylglutaryl-coa lyase gene in the photosynthetic bacterium rhodospirillum rubrum. | a 1.2 kb long dna segment from rhodospirillum rubrum has been sequenced (embl/genbank accession number: u41280). this dna segment includes the first sequenced gene for a putative 3-hydroxy-3-methylglutaryl-coa (hmg-coa) lyase, termed hmgl, from a photosynthetic organism. the sequenced segment also contains a ribosome-binding site and two clusters of possible-35 and -10 promotor sequences preceding the hmgl gene. translation of the gene would yield a 303 amino-acid-long protein with a calculated ... | 1997 | 9003443 |
| a global two component signal transduction system that integrates the control of photosynthesis, carbon dioxide assimilation, and nitrogen fixation. | photosynthesis, biological nitrogen fixation, and carbon dioxide assimilation are three fundamental biological processes catalyzed by photosynthetic bacteria. in the present study, it is shown that mutant strains of the nonsulfur purple photosynthetic bacteria rhodospirillum rubrum and rhodobacter sphaeroides, containing a blockage in the primary co2 assimilatory pathway, derepress the synthesis of components of the nitrogen fixation enzyme complex and abrogate normal control mechanisms. the abs ... | 1996 | 8962083 |
| unleashing hydrogenase activity in carbon monoxide dehydrogenase/acetyl-coa synthase and pyruvate:ferredoxin oxidoreductase. | these results demonstrate that two well-studied metalloenzymes, carbon monoxide dehydrogenase/acetyl-coa synthase (codh/acs) and pyruvate:ferredoxin oxidoreductase (pfor), can reduce protons to h2 and, at much lower rates, oxidize h2 to protons and electrons. to our knowledge, this if the first time that pfor has been shown to have hydrogenase activity. codh/acs and pfor evolved h2 at maximum rates when co and pyruvate were the electron donors, respectively, and when electron acceptors are absen ... | 1996 | 8961945 |
| control of nitrogen fixation by oxygen in purple nonsulfur bacteria | some members of the facultatively phototrophic bacteria are able to grow diazotrophically in the presence of oxygen. as in other diazotrophs, the nitrogenase of the phototrophic bacteria is highly sensitive to oxygen; therefore, both the function and the expression of nitrogenase are strictly controlled by oxygen. this review focuses on the different levels of oxygen control in the two most extensively studied facultatively phototrophic bacteria, rhodospirillum rubrum and rhodobacter capsulatus. ... | 1996 | 8952942 |
| a novel heme protein that acts as a carbon monoxide-dependent transcriptional activator in rhodospirillum rubrum. | the gene coding for a carbon monoxide-dependent transcriptional activator (cooa) in rhodospirillum rubrum has been expressed in e. coli, and the recombinant cooa has been purified. cooa contains b-type heme which may act as a co sensor in vivo. co-bound cooa was formed when reduced cooa was reacted with co, but not in the case of oxidized cooa. cooa is the first example of the heme protein acting as a dna-binding transcriptional activator. | 1996 | 8941349 |
| facilitation of the terminal proton transfer reaction of ribulose 1,5-bisphosphate carboxylase/oxygenase by active-site lys166. | the terminal step in the carboxylation pathway catalyzed by ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) is stereospecific protonation of the c-2 aci-acid of 3-phosphoglycerate (pga). x-ray crystallographic results favor the epsilon-amino group of lys166 as the proton donor in this step [knight et al. (1990) j. mol. biol. 215, 113]. nonetheless, position-166 mutants are able to catalyze forward processing of isolated 2-carboxy-3-ketoarabinitol 1,5-bisphosphate (ckabp), the carboxyla ... | 1996 | 8909282 |
| properties of the purified, recombinant, nadp(h)-binding domain iii of the proton-translocating nicotinamide nucleotide transhydrogenase from rhodospirillum rubrum. | transhydrogenase comprises three domains. domains i and iii are peripheral to the membrane and possess the nad(h)- and nadp(h)-binding sites, respectively, and domain ii spans the membrane. domain iii of transhydrogenase from rhodospirillum rubrum was expressed at high levels in escherichia coli, and purified. the purified protein was associated with substoichiometric quantities of tightly bound nadp+ and nadph. fluorescence spectra of the domain iii protein revealed emissions due to tyr residue ... | 1996 | 8898902 |
| characterization of the region encoding the co-induced hydrogenase of rhodospirillum rubrum. | in the photosynthetic bacterium rhodospirillum rubrum, the presence of carbon monoxide (co) induces expression of several proteins. these include carbon monoxide dehydrogenase (codh) and a co-tolerant hydrogenase. together these enzymes catalyze the following conversion: co + h2o --> co2 + h2. this system enables r. rubrum to grow in the dark on co as the sole energy source. expression of this system has been shown previously to be regulated at the transcriptional level by co. we have now identi ... | 1996 | 8892819 |
| mutants that show increased sensitivity to hydrogen peroxide reveal an important role for the pentose phosphate pathway in protection of yeast against oxidative stress. | we have isolated several mutants of saccharomyces cerevisiae that are sensitive to oxidative stress in a screen for elevated sensitivity to hydrogen peroxide. two of the sixteen complementation groups obtained correspond to structural genes encoding enzymes of the pentose phosphate pathway. allelism of the pos10 mutation (pos for peroxide sensitivity) to the zwf1/met1 mutants in the structural gene for glucose 6-phosphate dehydrogenase was reported previously. the second mutation, pos18, was com ... | 1996 | 8879247 |
| development of gene transfer methods for rubrivivax gelatinosus s1: construction, characterization and complementation of a puf operon deletion strain. | gene transfer systems were developed in rubrivivax (rx.) gelatinosus s1. first, a system for conjugative transfer of mobilizable plasmids from escherichia coli to rx. gelatinosus s1 was established. secondly, optimal conditions for the transformation of rx. gelatinosus s1 by electroporation were determined. a delta puf strain was constructed. complementation with the puf operon from a wild-type strain cloned in a replicative plasmid restored photosynthetic growth. two insertion strains were also ... | 1996 | 8879238 |
| melatonin immunoreactivity in the photosynthetic prokaryote rhodospirillum rubrum: implications for an ancient antioxidant system. | rhodospirillum rubrum is a spiral anoxygenic photosynthetic bacterium that can exist under either aerobic or anaerobic conditions. the organism thrives in the presence of light or complete darkness and represents one of the oldest species of living organisms, possibly 2-3.5 billion years old. the success of this prokaryotic species may be attributed to the evolution of certain indole compounds that offer protection against life-threatening oxygen radicals produced by an evolutionary harsh enviro ... | 1995 | 8867786 |
| biological electron transfer. | many oxidoreductases are constructed from (a) local sites of strongly coupled substrate-redox cofactor partners participating in exchange of electron pairs, (b) electron pair/single electron transducing redox centers, and (c) nonadiabatic, long-distance, single-electron tunneling between weakly coupled redox centers. the latter is the subject of an expanding experimental program that seeks to manipulate, test, and apply the parameters of theory. new results from the photosynthetic reaction cente ... | 1995 | 8847340 |
| the effects of decyl aurachins c and d on the respiratory electron flow of facultative phototrophic bacteria. | decyl aurachins c and d are two synthetic compounds related to the natural products aurachins c and d extracted from stigmatella aurantiaca. titrations of a range of partial respiratory activities in membranes from facultative phototrophs indicate that decyl aurachin c is more effective than aurachin d in inhibiting the quinol oxidase. decyl aurachin c also affects the nadh-ubiquinone oxidoreductase of rhodobacter capsulatus and the cytochrome bc1 complexes of rb.capsulatus and rhodospirillum ce ... | 1996 | 8843334 |
| comparison of the hydrolysis of zn-ppi2- and the mgppi2- as substrates and the effect of free cations upon membrane-bound pyrophosphatase of rhodospirillum rubrum. | the hydrolytic activity of chromatophore membrane-bound pyrophosphatase with zn-ppi2- as substrate was studied and compared with mg-ppi2- hydrolysis. the ph profile of zn-ppi2- hydrolysis is a bell shaped curve with an optimum at 5.25. this behavior is different from the sigmoidal profile obtained for mg-ppi2- hydrolysis, which has a plateau from ph 6.5 to 9.0. zn-ppi2- hydrolytic activity is inhibited by 1-butanol and methylene-diphosphate but not by naf. the enzyme has no activity when free zn ... | 1995 | 8834776 |
| effect of the pufq-pufb intercistronic region on puf mrna stability in rhodobacter capsulatus. | differential expression of genes localized within the polycistronic puf operon of rhodobacter capsulatus is partly due to altered stabilities of individual mrna segments. we show that the 5' untranslated region (utr) of pufb contributes to the unusual longevity of the 0.5 kb light-harvesting (lh) i specific pufba mrna and of the 2.7 kb pufbalmx mrna. three stem-loop structures have been identified within the pufq-pufb intercistronic region by means of rna secondary-structure analysis in vitro an ... | 1996 | 8809769 |
| two-dimensional structure of light harvesting complex ii (lhii) from the purple bacterium rhodovulum sulfidophilum and comparison with lhii from rhodopseudomonas acidophila. | within the membranes of photosynthetic bacteria, up to three types of light harvesting complexes (lhi, lhii, lhiii) are found. these complexes absorb photons and transfer the excitation energy to the photosynthetic reaction centre. the lh complexes comprise units that contain alpha and beta polypeptides with associated pigment molecules. | 1996 | 8805531 |
| a perturbed two-level model for exciton trapping in small photosynthetic systems. | the study of exciton trapping in photosynthetic systems provides significant information about migration kinetics within the light harvesting antenna (lha) and the reaction center (rc). we discuss two random walk models for systems with weakly coupled pigments, with a focus on the application to small systems (10-40 pigments/rc). details of the exciton transfer to and from the rc are taken into consideration, as well as migration within the lha and quenching in the rc. the first model is obtaine ... | 1996 | 8789084 |
| posttranslational regulation of nitrogenase activity by fixed nitrogen in azotobacter chroococcum. | using anti-(fe protein) antibody raised against the fe protein of the photosynthetic bacterium rhodospirillum rubrum, it was found that the fe protein component of nitrogenase (ec 1.18.2.1) from azotobacter chroococcum cells subjected to an ammonium shock, and hence with an inactive nitrogenase, appeared as a doublet in western blot analysis of cell extracts. the fe protein incorporated [32p]phosphate and [3h]adenine in response to ammonium treatment, and l-methionine-dl-sulfoximine, an inhibito ... | 1996 | 8781527 |
| the binding of nucleotides to domain i proteins of the proton-translocating transhydrogenases from rhodospirillum rubrum and escherichia coli as measured by equilibrium dialysis. | transhydrogenase catalyses the transfer of reducing equivalents between nad(h) and nadp(h) coupled to the translocation of protons across a membrane. the nad(h)-binding domain of transhydrogenase (domain i protein) from rhodospirillum rubrum and from escherichia coli were overexpressed and purified. nucleotide binding to the domain i proteins was determined by equilibrium dialysis. nadh and its analogue, acetylpyridine adenine dinucleotide (reduced form), bound with relatively high affinity (kd ... | 1996 | 8774721 |
| light-harvesting mechanisms in purple photosynthetic bacteria. | the processes by which photosynthetic bacteria capture light and transfer the energy to the reaction centre continue to be studied using an array of methodologies, both physical and biological. with the publication this year of the crystal structure of the lh2 complex from rhodopseudomonas acidophila and the projection structure of the lh1 complex from rhodospirillum rubrum, structural models now exist for all the components in the bacterial photosynthetic apparatus. | 1995 | 8749368 |
| the crystal structure of the light-harvesting complex ii (b800-850) from rhodospirillum molischianum. | the light-harvesting complexes ii (lh-2s) are integral membrane proteins that form ring-like structures, oligomers of alpha beta-heterodimers, in the photosynthetic membranes of purple bacteria. they contain a large number of chromophores organized optimally for light absorption and rapid light energy migration. recently, the structure of the nonameric lh-2 of rhodopseudomonas acidophila has been determined; we report here the crystal structure of the octameric lh-2 from rhodospirillum molischia ... | 1996 | 8736556 |
| identification and sequence of a nifj-like gene in rhodospirillum rubrum: partial characterization of a mutant unaffected in nitrogen fixation. | a nifj-like gene was identified in the photosynthetic purple non-sulphur bacterium rhodospirillum rubrum. a dna segment hybridizing to klebsiella pneumoniae nifj was isolated, the gene was inactivated, and a mutant strain, snj-1, was constructed by allele replacement. the mutation was confirmed by dna sequencing. northern blotting and by the lack of pyruvate oxidoreductase activity. this is the first report of a nifj-like gene in photosynthetic bacteria. unexpectedly, snj-1 was capable of nitrog ... | 1996 | 8736535 |
| rubisco in marine symbiotic dinoflagellates: form ii enzymes in eukaryotic oxygenic phototrophs encoded by a nuclear multigene family. | genes encoding ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) were cloned from dinoflagellate symbionts (symbiodinium spp) of the giant clam tridacna gigas and characterized. strikingly, symbiodinium rubisco is completely different from other eukaryotic (form i) rubiscos: it is a form ii enzyme that is approximately 65% identical to rubisco from rhodospirillum rubrum (rubisco forms i and ii are approximately 25 to 30% identical); it is nuclear encoded by a multigene family; and the pr ... | 1996 | 8721755 |
| transcription of the glnb and glna genes in the photosynthetic bacterium rhodospirillum rubrum. | the pii protein, encoded by glnb, has a central role in the control of nitrogen metabolism in nitrogen-fixing prokaryotes. the glnb gene of rhodospirillum rubrum was isolated and sequenced. the deduced amino acid sequence had very high sequence identity to other pii proteins. the glna gene, encoding glutamine synthetase, was located 135 bp downstream of glnb and was partially sequenced. glnb is cotranscribed with glna from a promoter with high similarity to the sigma 54-dependent promoter consen ... | 1996 | 8704966 |
| evidence for a proximal histidine interaction in the structure of cytochromes c in solution: a resonance raman study. | soret-excited resonance raman (rr) spectra of oxidized and reduced cytochromes ć from rhodospirillum molischianum and rhodobacter sphaeroides, in solution, are reported. the spectra of the type i ferricytochromes ć in both species contain different extents of two forms. one of these is readily assignable to a "normal" five-coordinated high-spin heme. the second species with v3 and v10 modes at 1502 and 1635 cm-1, respectively, is attributed to a five-coordinated intermediate-spin heme. the rr da ... | 1996 | 8703928 |
| formation of the light-harvesting complex i (b870) of anoxygenic phototrophic purple bacteria. | the light-harvesting (lh) complex i (b870) of anoxygenic photosynthetic purple bacteria is the oligomeric form of its subunit b820 consisting of the low-molecular-weight polypeptides alpha, beta, bacteriochlorophyll (bchl), and carotenoids in the stoichiometric ratio [alpha1 beta1 (bchl2) crt1-2]n. lhi surrounds the photochemical reaction center (rc). the major absorption band of the lhi complex is species-specific and is found at 870-890 nm; those of the subunit and the monomeric bchl a (dissol ... | 1996 | 8703191 |
| molecular cloning, dna sequence and transcriptional analysis of the rhodospirillum molischianum b800/850 light-harvesting genes. | the amino acid sequences of the b800/850 light-harvesting proteins from rhodospirillum molischianum were determined by edman degradation. on the basis of these amino acid sequences, two degenerated oligonucleotides were synthesized and used for pcr of genomic dna. the resulting 150 bp dna fragment was cloned, sequenced and used for subsequent southern blot analysis of digested genomic dna. a 2.3 kbp ecori fragment strongly hybridized to the probe and a size selected genomic library from genomic ... | 1996 | 8695630 |
| high-resolution crystal structures of two polymorphs of cytochrome c' from the purple phototrophic bacterium rhodobacter capsulatus. | the structures of two polymorphs of cytochrome c' from rhodobacter capsulatus (rccp) strain m110 have been determined by the molecular replacement method. iron anomalous scattering data were used to confirm the molecular replacement solution. the structures were refined at 1.72 angstrom and 2.0 angstrom resolution to r-values of 15.0% and 16.3%, respectively. the rccp molecule is a dimer and each of the identical 129 residue subunits folds as a four-helical bundle with a covalently bound heme gr ... | 1996 | 8676382 |
| a peptidoglycan binding domain in the porin-associated protein (pap) of rhodospirillum rubrum fr1. | the porin-associated protein of rhodospirillum rubrum fr1 was found to contain a peptidoglycan binding motif. a partial fragment of 179 amino acids, obtained by cleavage of pap with trypsin, asp-n protease, and cnbr, was sequenced. substantial sequence homology was found of the c-terminal part (residues 126-179) of porin-associated protein with ompa, the peptidoglycan-associated lipoprotein of several bacteria, protein f of pseudomonas aeruginosa, and piii of neisseria gonorrhoeae, the latter be ... | 1996 | 8674970 |
| the xanthopsins: a new family of eubacterial blue-light photoreceptors. | photoactive yellow protein (pyp) is a photoreceptor that has been isolated from three halophilic phototrophic purple bacteria. the pyp from ectothiorhodospira halophila bn9626 is the only member for which the sequence has been reported at the dna level. here we describe the cloning and sequencing of the genes encoding the pyps from e.halophila sl-1 (type strain) and rhodospirillum salexigens. the latter protein contains, like the e.halophila pyp, the chromophore trans p-coumaric acid, as we show ... | 1996 | 8670821 |
| expression of the puf operon in an aerobic photosynthetic bacterium, roseobacter denitrificans. | the effects of oxygen and light on the expression of the puf operon were investigated in roseobacter denitrificans in a comparison with those in rhodobacter sphaeroides. in darkness, the levels of the total puf mrna in ros. denitrificans were about 1.3 times those in rb. sphaeroides at low concentrations of oxygen, reflecting the accumulation of bacteriochlorophyll and carotenoids. the oxygen tension, up to 94% saturation of dissolved oxygen, did not affect the levels of the total puf transcript ... | 1996 | 8665093 |
| rubisco, an old challenge with new perspectives. | 1996 | 8663895 | |
| the alpha beta dimer-catalytic unit of the f1-atpase. | 1995 | 8654713 | |
| axial heme ligation in the cytochrome bc1 complexes of mitochondrial and photosynthetic membranes. a near-infrared magnetic circular dichroism and electron paramagnetic resonance study. | the combination of epr and low-temperature near-ir magnetic circular dichroism spectroscopies have been used to investigate the axial ligation of the cytochromes in the cytochrome bc1 complexes from bovine heart mitochondria, rhodobacter capsulatus, rhodobacter sphaeroides, and rhodospirillum rubrum, and the purified cytochromes c1 from bovine heart mitochondria, rb. capsulatus and rb. sphaeroides. the possibility of axial ligation of cytochrome c1 by the amino terminus of the polypeptide was al ... | 1996 | 8645697 |
| deletion of a b800-850 light-harvesting complex in rhodospirillum molischianum dsm119 leads to "revertants" expressing a b800-820 complex: insights into pigment binding. | a b800-850 light-harvesting complex (also called lh2) deficient strain of rhodospirillum molischianum was constructed by replacing a portion of the lh2 gene cluster by a kanamycin resistance gene cartridge. the lh2 deficient strain was characterized spectroscopically and by southern blot analysis. surprisingly, pseudorevertants were obtained which express a b800-820 complex which could not be observed in the wild type. this b800-820 complex was isolated and characterized. it consists of an alpha ... | 1996 | 8639597 |
| directed mutagenesis of the rhodobacter capsulatus puha gene and orf 214: pleiotropic effects on photosynthetic reaction center and light-harvesting 1 complexes. | rhodobacter capsulatus puha mutant strains containing either a nonpolar, translationally in-frame deletion or a polar insertion of an antibiotic resistance cartridge were constructed and evaluated for their photosynthetic growth properties, absorption spectroscopy profiles, and chromatophore protein compositions. both types of mutants were found to be incapable of photosynthetic growth and deficient in the reaction center (rc) and light-harvesting 1 (lh1) complexes. the translationally in-frame ... | 1996 | 8636035 |
| purification and characterization of the alternative nitrogenase from the photosynthetic bacterium rhodospirillum rubrum. | the alternative nitrogenase from a nifh mutant of the photosynthetic bacterium rhodospirillum rubrum has been purified and characterized. the dinitrogenase protein (anf1) contains three subunits in an apparent alpha2beta2gamma2 structure and contains fe but no mo or v. a factor capable of activating apo-dinitrogenase (lacking the femo cofactor) from azotobacter vinelandii was extracted from the alternative dinitrogenase protein with n-methylformamide. the electron paramagnetic resonance (epr) si ... | 1996 | 8631723 |
| presence of a second mechanism for the posttranslational regulation of nitrogenase activity in azospirillum brasilense in response to ammonium. | although adp-ribosylation of dinitrogenase reductase plays a significant role in the regulation of nitrogenase activity in azospirillum brasilense, it is not the only mechanism of that regulation. the replacement of an arginine residue at position 101 in the dinitrogenase reductase eliminated this adp-ribosylation and revealed another regulatory system. while the constructed mutants had a low nitrogenase activity, nh4+ still partially inhibited their nitrogenase activity, independent of the dini ... | 1996 | 8631686 |
| mutation of tyr235 in the nad(h)-binding subunit of the proton-translocating nicotinamide nucleotide transhydrogenase of rhodospirillum rubrum affects the conformational dynamics of a mobile loop and lowers the catalytic activity of the enzyme. | the tyr residue in the mobile loop region of the soluble, domain i polypeptide (called ths) of the proton-translocating transhydrogenase from rhodospirillum rubrum has been substituted by asn and by phe. the recombinant proteins were expressed at high levels in escherichia coli and purified to homogeneity. the two well defined resonances at 6.82 and 7.12ppm, observed in the one-dimensional proton nmr spectrum of wild-type protein, and previously attributed to the tyr residue, were absent in both ... | 1996 | 8626569 |
| interaction of nucleotides with the nad(h)-binding domain of the proton-translocating transhydrogenase of rhodospirillum rubrum. | transhydrogenase catalyzes the reduction of nadp+ by nadh coupled to the translocation of protons across a membrane. the polypeptide composition of the enzyme in rhodospirillum rubrum is unique in that the nad(h)-binding domain (called ths) exists as a separate polypeptide. ths was expressed in escherichia coli and purified. the binding of nucleotide substrates and analogues to ths was examined by one-dimensional proton nuclear magnetic resonance (nmr) spectroscopy and by measuring the quenching ... | 1996 | 8626568 |
| spectroelectrochemical characterization of the metal centers in carbon monoxide dehydrogenase (codh) and nickel-deficient codh from rhodospirillum rubrum. | carbon-monoxide dehydrogenase (codh) from rhodospirillum rubrum contains two metal centers: a ni-x-[fe4s4]2+/1+ cluster (c-center) that serves as the cooxidation site and a standard [fe4s4]2+/1+ cluster (b-center) that mediates electron flow from the c-center to external electron acceptors. four states of the c-center were previously identified in electron paramagnetic resonance (epr) and mössbauer studies. in this report, epr-redox titrations demonstrate that the fully oxidized, diamagnetic for ... | 1996 | 8626477 |
| characterization of the co-induced, co-tolerant hydrogenase from rhodospirillum rubrum and the gene encoding the large subunit of the enzyme. | in the presence of carbon monoxide, the photosynthetic bacterium rhodospirillum rubrum induces expression of proteins which allow the organism to metabolize carbon monoxide in the net reaction co + h2o --> co2 + h2. these proteins include the enzymes carbon monoxide dehydrogenase (codh) and a co-tolerant hydrogenase. in this paper, we present the complete amino acid sequence for the large subunit of this hydrogenase and describe the properties of the crude enzyme in relation to other known hydro ... | 1996 | 8626276 |
| consequences for the organization of reaction center-light harvesting antenna 1 (lh1) core complexes of rhodobacter sphaeroides arising from deletion of amino acid residues from the c terminus of the lh1 alpha polypeptide. | the light harvesting antenna 1 (lh1) complex of rhodobacter sphaeroides is intimately associated with the reaction center (rc) as part of the reaction center rc-lh1 core complex. the pufa gene has been modified such that between 5 and 16 amino acid residues were progressively deleted from the c terminus of the lh1 alpha polypeptide. the two largest deletions produced strains which were deficient in lh1. the remaining four deletion mutants exhibited significant reductions in the average level of ... | 1996 | 8621732 |
| cloning, sequencing and transcriptional regulation of the drat and drag genes of azospirillum lipoferum fs. | from azospirillum lipoferum (al) fs, a nitrogen-fixing bacterium isolated from the rhizosphere of rice, we cloned and sequenced drat, encoding dinitrogenase reductase adp-ribosyltransferase, and drag, encoding dinitrogenase reductase-activating glycohydrolase. the nucleotide sequences of dratg showed extensive similarity to the same genes from azospirillum brasilense, rhodospirillum rubrum and rhodobacter capsulatus, and they are assumed to be co-transcribed as a single operon. when this dratg o ... | 1996 | 8621068 |
| kinetic characterization of the hydrolytic activity of the h+-pyrophosphatase of rhodospirillum rubrum in membrane-bound and isolated states. | substrate hydrolysis by the h+-pyrophosphatase (pyrophosphate phosphohydrolase, h+-ppase) of the photosynthetic bacterium rhodospirillum rubrum follows a two-pathway reaction scheme in which preformed 1:1 and 1:2 . enzyme . mg2+ complexes (emg and emg2) convert dimagnesium pyrophosphate (the substrate). this scheme is applicable to isolated enzyme, uncoupled chromatophores and chromatophores energized by a k+/valinomycin diffusion potential. tris and other amine buffers exert a specific effect o ... | 1996 | 8617255 |
| cloning of the amphibolic calvin cycle/oppp enzyme d-ribulose-5-phosphate 3-epimerase (ec 5.1.3.1) from spinach chloroplasts: functional and evolutionary aspects. | exploiting the differential expression of genes for calvin cycle enzymes in bundle-sheath and mesophyll cells of the c4 plant sorghum bicolor l., we isolated via subtractive hybridization a molecular probe for the calvin cycle enzyme d-ribulose-5-phosphate 3-epimerase (r5p3e)(ec 5.1.3.1), with the help of which several full-size cdnas were isolated from spinach. functional identity of the encoded mature subunit was shown by r5p3e activity found in affinity-purified glutatione s-transferase fusio ... | 1995 | 8616224 |
| sequence evidence for strong conservation of the photoactive yellow proteins from the halophilic phototrophic bacteria chromatium salexigens and rhodospirillum salexigens. | the photoactive yellow proteins (pyp) have been found to date only in three species of halophilic purple phototrophic bacteria. they have photochemical activity remarkably similar to that of the bacteria rhodopsins. in contrast to rhodopsins, however, the pyps are small water-soluble proteins. we now report the complete amino acid sequences of rhodospirillum salexigens and chromatium salexigens pyp which allow comparison with the known sequence and three-dimensional structure of the prototypic p ... | 1996 | 8611556 |
| comparison of the structural requirements for bacteriochlorophyll binding in the core light-harvesting complexes of rhodospirillum rubrum and rhodospirillum sphaeroides using reconstitution methodology with bacteriochlorophyll analogs. | bacteriochlorophyll (bchl) structural requirements for formation of the core light-harvesting complex (lh1) and its structural subunit complex were examined by reconstitution with bchl analogs and the alpha- and beta-polypeptides of rhodospirillum rubrum and rhodobacter sphaeroides. comparable results were obtained with most of the bchl analogs and the polypeptides of each bacterium, indicating the conservation of bchl binding sites. these systems showed the following common requirements for for ... | 1996 | 8608148 |
| 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 |
| estimation of the h+/h- ratio of the reaction catalysed by the nicotinamide nucleotide transhydrogenase in chromatophores from over-expressing strains of rhodospirillum rubrum and in liposomes inlaid with the purified bovine enzyme. | two strains of rhodospirillum rubrum were constructed in which, by a gene dosage effect, the transhydrogenase activity of isolated chromatophores was increased 7-10-fold and 15-20-fold, respectively. the h+/h- ratio (the ratio of protons translocated per hydride ion equivalent transferred from nadph to an nad+ analogue, acetyl pyridine adenine dinucleotide), determined by a spectroscopic technique, was approximately 1.0 for chromatophores from the over-expressing strains, but was only approximat ... | 1996 | 8573594 |
| characterization of a co-responsive transcriptional activator from rhodospirillum rubrum. | in rhodospirillum rubrum, co induces the expression of at least two transcripts that encode an enzyme system for co oxidation. this regulon is positively regulated by cooa, which is a member of the camp receptor protein family of transcriptional regulators. the transcriptional start site of one of the transcripts (coofsctj) has been identified by primer extension. the ability of cooa to bind to this promoter in vitro was characterized with dnase i footprinting experiments using extracts of a coo ... | 1996 | 8550545 |
| spectroscopic characterization of nitrosylheme in nitric oxide complexes of ferric and ferrous cytochrome c' from photosynthetic bacteria. | reactions of ferric and ferrous cytochromes c' from four photosynthetic bacteria (rhodobacter capsulatus atcc 11166, rhodopseudomonas palustris atcc 17001, rhodospirillum rubrum atcc 11170, and chromatium vinosum atcc 17899) with nitric oxide have been investigated by electronic absorption and electron paramagnetic resonance spectroscopies. the heme iron(iii) of these ferric cytochromes c' has been recently reported to be in a quantum mechanically admixed (s = 5/2, 3/2) state [fujii, s., yoshimu ... | 1996 | 8547347 |
| predicting the structure of the light-harvesting complex ii of rhodospirillum molischianum. | we attempted to predict through computer modeling the structure of the light-harvesting complex ii (lh-ii) of rhodospirillum molischianum, before the impending publication of the structure of a homologous protein solved by means of x-ray diffraction. the protein studied is an integral membrane protein of 16 independent polypeptides, 8 alpha-apoproteins and 8 beta-apoproteins, which aggregate and bind to 24 bacteriochlorophyll-a's and 12 lycopenes. available diffraction data of a crystal of the p ... | 1995 | 8528066 |
| nonlinear annihilation of excitations in photosynthetic systems. | the theory of the singlet-singlet annihilation in quasi-homogeneous photosynthetic antenna systems is developed further. in the new model, the following important contributions are taken into account: 1) the finite excitation pulse duration, 2) the occupation of higher excited states during the annihilation, 3) excitation correlation effects, and 4) the effect of local heating. the main emphasis is concentrated on the analysis of pump-probe kinetic measurements demonstrating the first two above ... | 1995 | 8519966 |
| direct observation of sub-picosecond equilibration of excitation energy in the light-harvesting antenna of rhodospirillum rubrum. | excitation energy transfer in the light-harvesting antenna of rhodospirillum rubrum was studied at room temperature using sub-picosecond transient absorption measurements. upon excitation of rs. rubrum membranes with a 200 fs, 600 nm laser flash in the qx transition of the bacteriochlorophyll-a (bchl-a) absorption, the induced transient absorption changes in the qy region were monitored. in rs. rubrum membranes the observed delta od spectrum exhibits ground state bleaching, excited state absorpt ... | 1995 | 8519962 |
| occurrence and purification of the photoactive yellow protein of ectothiorhodospira halophila (pyp) and of immunologically related proteins of rhodospirillum salexigens and chromatium salexigens and intracellular localization of pyp. | the photoactive yellow protein of ectothiohodospira halophila (pyp) was purified to homogeneity by an advanced method and applied as an affinity ligand for the isolation of an anti-pyp igg fraction which was used for immunoscreening. the distribution of proteins immunologically related to pyp was investigated in protein fractions of 51 strains from 38 species of non-halophilic and halophilic phototrophic and chemotrophic eubacteria and archaeobacteria. strong immunoreactive bands indicating the ... | 1995 | 8519800 |
| two-dimensional crystallization of the light-harvesting complex from rhodospirillum rubrum. | homogeneous detergent-solubilized b873 light-harvesting complexes from a carotenoid-less mutant of the purple non-sulfur bacterium, rhodospirillum rubrum g9, were reassembled spontaneously into two-dimensional (2d) hexagonal arrays during extensive and controlled dialysis. as the complexes contain only 1 to 2 mol phospholipid per mol alpha beta dimer, the arrays formed by a self assembly process are primary due to protein-protein interactions. the hexagonal lattices were analyzed by negative sta ... | 1993 | 8510160 |
| unexpected similarities of the b800-850 light-harvesting complex from rhodospirillum molischianum to the b870 light-harvesting complexes from other purple photosynthetic bacteria. | the b800-850 light-harvesting complex (also called lh2) was isolated from photosynthetic membranes of rhodospirillum molischianum dsm 119 using molecular sieve and ion-exchange chromatography. its two bacteriochlorophyll a-binding polypeptides (alpha-subunit and beta-subunit) were purified with a reverse-phase hplc system. the complete amino acid sequences of both subunits have been determined. the alpha- and beta-subunits consist of 56 and 45 amino acids, respectively, corresponding to molecula ... | 1993 | 8504081 |
| site-specific mutations in a loop region of the c-terminal domain of the large subunit of ribulose bisphosphate carboxylase/oxygenase that influence substrate partitioning. | amino acids composing a flexible loop (loop 6) of the eight-stranded barrel domain of the l-subunit of synechococcus ribulose bisphosphate carboxylase/oxygenase (ec 4.1.1.39) involved in reaction intermediate stabilization have been modified by site-specific mutagenesis. changes at positions both distant and within the active site affect overall catalysis and substrate partitioning. most significantly, replacement of the active site lys (lys-334) with arg at the apex of the loop almost completel ... | 1993 | 8463309 |
| gene expression of the b875 light-harvesting prepolypeptides from rhodospirillum rubrum in escherichia coli. | the gene coding for the prepolypeptides of alpha and beta, obtained as a 429 bp fragment from chromosomal dna of rhodospirillum rubrum s1 by polymerase chain reaction amplification, were cloned in tandem into the high-level expression vector potsnco 12 for expression in escherichia coli. the vector potsnco12 is a derivative of the pas vector system, which contains the strong lambda pl promotor and is under tight control by the ci857 repressor encoded by the expression strain ar58. induction of t ... | 1993 | 8451297 |
| role of phenylalanine-327 in the closure of loop 6 of ribulosebisphosphate carboxylase/oxygenase from rhodospirillum rubrum. | phenylalanine-327 of ribulosebisphosphate carboxylase/oxygenase (rubisco) from rhodospirillum rubrum was mutated to tryptophan, leucine, valine, alanine, and glycine, and was also deleted. the least active mutant, the deletion mutant, exhibits less than 0.5% of the carboxylase activity of the wild-type enzyme. steady-state kinetic analysis of f327-->leu, val, ala, gly mutant enzymes reveals that kcat and the co2/o2 specificity are unchanged while km(rubp) (rubp = ribulose 1,5-bisphosphate) is dr ... | 1993 | 8448152 |
| expression study with the escherichia coli lep gene for leader peptidase in phototrophic purple bacteria. | synthesis and assembly of leader peptidase of escherichia coli (signal peptidase i), was studied by heterologous expression of its lep gene in three species of phototrophic purple bacteria. cell extracts of the recipient species showed neither cross reaction with antibodies against e. coli leader peptidase nor cleavage of the model substrate m13-procoat in vitro. the lep gene was transferred via conjugation using the plasmid expression vector for phototrophic bacteria pjaj9. plasmid-borne leader ... | 1993 | 8439231 |
| inhibition of proton-translocating transhydrogenase from photosynthetic bacteria by n,n'-dicyclohexylcarbodiimide. | the effects of n,n'-dicyclohexylcarbodiimide [(chxn)2c] on the proton-translocating enzyme, nad(p) h(+)-transhydrogenase (h(+)-thase), from two species of phototrophic bacteria have been investigated. the polypeptides of h(+)-thase from rhodobacter capsulatus are membrane-associated, requiring detergent to maintain solubility. the enzyme from rhodospirillum rubrum, however, has a water soluble polypeptide (ths) and a membrane-associated component (thm) which, separately, have no activity but whi ... | 1993 | 8436126 |
| precise location of the cu(ii)-inhibitory binding site in higher plant and bacterial photosynthetic reaction centers as probed by light-induced absorption changes. | light-dependent absorption change at 325 nm, ascribed to qa activity, was strongly reduced in the presence of cu(ii) in oxygen-evolving core complex. this change was much less affected in the presence of the herbicide 3-(3,4-dichlorophenyl)-1,1-dimethylurea (dcmu), indicating that the cu(ii)-binding site is different from that of the dcmu and that cu(ii) blocks qa reduction. cu(ii) did not eliminate the absorption change at 545 nm, ascribed to pheophytin reduction, in na2s2o4-treated oxygen-evol ... | 1993 | 8420944 |
| the structure and function of omega loop a replacements in cytochrome c. | the structural and functional consequences of replacing omega-loop a (residues 18-32) in yeast iso-1-cytochrome c with the corresponding loop of rhodospirillum rubrum cytochrome c2 have been examined. the three-dimensional structure of this loop replacement mutant repa2 cytochrome c, and a second mutant repa2(val 20) cytochrome c in which residue 20 was back substituted to valine, were determined using x-ray diffraction techniques. a change in the molecular packing is evident in the repa2 mutant ... | 1993 | 8401228 |
| molecular cloning and sequencing of the ferredoxin i fdxn gene of the photosynthetic bacterium rhodospirillum rubrum. | using an oligonucleotide probe derived from the amino acid sequence of rhodospirillum rubrum ferredoxin i, the gene (fdxn) was identified, cloned and sequenced. the fdxn coding region is 183 nucleotides which codes for a 61 amino acid (7267 da) protein. phylogenetic comparisons between the r. rubrum fdi and other 8fe-8s nif-coupled ferredoxins showed only moderate degrees of similarity between the amino acid sequences. r. rubrum fdi synthesis was stimulated by nif derepressing conditions, but wa ... | 1993 | 8399287 |
| differential sensitivity of membrane-associated pyrophosphatases to inhibition by diphosphonates and fluoride delineates two classes of enzyme. | 1,1-diphosphonate analogs of pyrophosphate, containing an amino or a hydroxyl group on the bridge carbon atom, are potent inhibitors of the h(+)-translocating pyrophosphatases of chromatophores prepared from the bacterium rhodospirillum rubrum and vacuolar membrane vesicles prepared from the plant vigna radiata. the inhibition constant for aminomethylenediphosphonate, which binds competitively with respect to substrate, is below 2 microm. rat liver mitochondrial pyrophosphatase is two orders of ... | 1993 | 8392953 |
| reversible dissociation and conformational stability of dimeric ribulose bisphosphate carboxylase. | dimer-monomer dissociation of ribulosebisphosphate carboxylase/oxygenase from rhodospirillum rubrum was investigated using hydrostatic pressure in the range 1-2 kbar to promote dissociation. intrinsic fluorescence emission and polarization, along with the polarization of the fluorescence of single-labeled aedans conjugates, were used to follow the dissociation. full reversibility after dissociation was observed to depend on the presence of small ligands: glycerol, mg2+, and nahco3, the last two ... | 1993 | 8388254 |
| an open reading frame in the rhodospirillum rubrum plasmid, pky1, similar to alga, encoding the bifunctional enzyme phosphomannose isomerase-guanosine diphospho-d-mannose pyrophosphorylase (pmi-gmp). | the nucleotide sequence of a bglii fragment (3188 bp) from the plasmid pky1 of rhodospirillum rubrum was determined. a significant similarity was found between the amino acid sequences deduced from the nucleotide sequence of bglii fragment with that of alga, encoding the bifunctional enzyme with both the activities of phosphomannose isomerase and guanosine diphospho-d-mannose pyrophosphorylase of pseudomonas aeruginosa. | 1993 | 8383539 |
| pathway of proton transfer in bacterial reaction centers: second-site mutation asn-m44-->asp restores electron and proton transfer in reaction centers from the photosynthetically deficient asp-l213-->asn mutant of rhodobacter sphaeroides. | site-directed mutagenesis of the photosynthetic reaction center (rc) from rhodobacter sphaeroides has shown asp-213 of the l subunit (asp-l213) to be important for photosynthetic viability. replacement of asp-l213 with asn resulted in a photosynthetically deficient mutant, due to the 10(4)-fold slower rate for the proton-coupled electron transfer reaction qa-qb- + 2h+-->qaqbh2 (k(2)ab). the detrimental effect of asn-l213 is surprising since rcs from rhodopseudomonas viridis, rhodospirillum rubru ... | 1993 | 8381964 |
| modulation of the proton-translocation stoichiometry of h(+)-atp synthases in two phototrophic prokaryotes by external ph. | the stoichiometry between proton translocation and atp synthesis/hydrolysis was studied in two different photosynthetic prokaryotes, the thermophilic cyanobacterium synechococcus 6716 and the purple bacterium rhodospirillum rubrum. the h+/atp ratio was determined by acid-base transitions as a function of the external ph. the h+/atp ratio of the synechococcus 6716 atp synthase was found to increase with increasing ph. in contrast, in r. rubrum this ratio decreased with increasing ph. these result ... | 1993 | 8379927 |
| excitonic interactions in the light-harvesting antenna of photosynthetic purple bacteria and their influence on picosecond absorbance difference spectra. | a new model of the light-harvesting antenna (core complex) of purple photosynthetic bacteria is proposed based on excitonic interactions in circular aggregates of bacteriochlorophyll molecules. the calculated absorbance difference spectra of circular aggregates demonstrate all special features observed in the experimental spectra of purple bacteria. in particular, the absorption changes with high amplitude of bleaching at the long-wavelength side of the absorption band at different excitation en ... | 1993 | 8370458 |
| a role for the epsilon-amino group of lysine-334 of ribulose-1,5-bisphosphate carboxylase in the addition of carbon dioxide to the 2,3-enediol(ate) of ribulose 1,5-bisphosphate. | earlier structural and functional studies of ribulose-1,5-bisphosphate carboxylase/oxygenase imply that k334 facilitates the addition of gaseous substrate to the 2,3-enediol(ate) derived from ribulose 1,5-bisphosphate. crystallographic analysis of the activated spinach enzyme [knight et al. (1990) j. mol. biol. 215, 113-160] shows that the lysyl side chain is appropriately positioned to stabilize the transition state for the addition of co2 to the enediol(ate). furthermore, despite total impairm ... | 1993 | 8369274 |
| amplification of ribulose biphosphate carboxylase/oxygenase large subunit (rubisco lsu) gene fragments from thiobacillus ferrooxidans and a moderate thermophile using polymerase chain reaction. | southern blot analysis of dna from an iron-oxidising moderate thermophile nmw-6 and from thiobacillus ferrooxidans strain tfi-35 demonstrated sequences homologous to the rubisco lsu gene of synechococcus. dna fragments (457 bp) encoding part of the rubisco lsu gene (amino acids 73-200) were amplified from the genomic dna of thiobacillus ferrooxidans and the moderate thermophile nmw-6 using the polymerase chain reaction (pcr) technique (saiki et al. (1985) science 233, 1350-1354). a comparison wi ... | 1993 | 8357616 |
| complementation analysis and regulation of co2 fixation gene expression in a ribulose 1,5-bisphosphate carboxylase-oxygenase deletion strain of rhodospirillum rubrum. | a ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) deletion strain of rhodospirillum rubrum that was incapable of photolithoautotrophic growth was constructed. photoheterotrophic growth, however, was possible for the r. rubrum rubisco deletion strain when oxidized carbon compounds such as malate were supplied. the r. rubrum rubisco-deficient strain was not complemented to photolithoautotrophic growth by various r. rubrum dna fragments that contain the gene encoding rubisco, cbbm. when t ... | 1993 | 8349547 |
| picosecond dynamics of excitations in light-harvesting complex b800-850 from chromatium minutissimum studied using fluorescence spectrochronography. | the picosecond dynamics of excitations in the isolated b800-850 light-harvesting complex of the purple sulfur bacterium chromatium minutissimum has been studied using picosecond fluorescence spectrochronography. a short-lived component of about 20 ps lifetime has been found at 77k at the short wavelength part of the b850 fluorescence spectrum similar to that previously described for the core antenna bacteriochlorophyll band b880 of rhodospirillum rubrum. evidence has been presented indicating th ... | 1993 | 8335097 |
| purification of form l2 rubisco from a marine obligately autotrophic hydrogen-oxidizing bacterium, hydrogenovibrio marinus strain mh-110. | ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) was purified from an obligately autotrophic hydrogen-oxidizing bacterium, hydrogenovibrio marinus mh-110. the protein has a m(r) value of approximately 110,000, and is composed of two identical subunits of 55,000. to our knowledge, the existence of l2-form rubisco in a chemolithoautotrophic bacterium is first reported in this paper. the n-terminal amino acid sequence determination of the purified enzyme showed high homology with those of ... | 1993 | 8319883 |
| the source and characteristics of chemiluminescence associated with the oxygenase reaction catalyzed by mn(2+)-ribulosebisphosphate carboxylase. | we confirm the observation of mogel and mcfadden (mogel, s.n., and mcfadden, b. a. (1990) biochemistry 29, 8333-8337) that ribulosebisphosphate carboxylase/oxygenase (rubisco) exhibits chemiluminescence while catalyzing its oxygenase reaction in the presence of mn2+. however, our results with the spinach and rhodospirillum rubrum enzymes differ markedly in the following respects. 1) chemiluminescence intensity was directly proportional to enzyme concentration and behaved as if representing the r ... | 1993 | 8314755 |
| the dratg gene region of rhodobacter capsulatus is required for post-translational regulation of both the molybdenum and the alternative nitrogenase. | synthetic oligonucleotides, which were designed according to amino acid sequences conserved between rhodospirillum rubrum and azospirillum brasilense drat and drag, respectively, were used to identify the corresponding genes of rhodobacter capsulatus. sequence analysis of a 1904 bp dna fragment proved the existence of r. capsulatus drat and drag. these two genes were separated by 11 bp only, suggesting that r. capsulatus drat and drag were part of one transcriptional unit. in contrast to r. rubr ... | 1993 | 8277250 |
| atpase of rhodospirillum rubrum requires three functional copies of beta subunit as determined by radiation inactivation analysis. | radiation inactivation analysis yielded a functional unit of 170 +/- 26 kda as beta subunit of atpase was irradiated and then reconstituted to beta-depleted chromatophores of rhodospirillum rubrum. a functional size of 132 +/- 17 kda for the beta-depleted atpase moiety involved in atp hydrolysis reaction was also determined. when both purified beta subunit and beta-depleted chromatophore were irradiated separately, reconstituted, and then activity measured, the functional mass was 312 +/- 50 kda ... | 1993 | 8260936 |
| perturbation of reaction-intermediate partitioning by a site-directed mutant of ribulose-bisphosphate carboxylase/oxygenase. | to explore the roles of active-site glu48 of ribulose-bisphosphate carboxylase/oxygenase from rhodospirillum rubrum, the e48q mutant has been characterized with respect to kinetics and product distribution. although the kcat for carboxylase activity is only 0.6% of the wild-type value, the mutant retains full activity in catalyzing the conversion of the carboxylated reaction intermediate to 3-phosphoglycerate and retains 10% of the normal activity in catalyzing the enolization of ribulose bispho ... | 1993 | 8253788 |
| atomic structure of a cytochrome c' with an unusual ligand-controlled dimer dissociation at 1.8 a resolution. | the crystallographic structure of cytochrome c' from the purple phototrophic bacterium chromatium vinosum (cvcp) has been determined at 1.8 a resolution using multiple isomorphous replacement. the molecule is a dimer, with each 131-residue chain folding as a four-helical bundle incorporating a covalently bound heme group at the core. this structure is the third of the ubiquitous cytochromes c' to be solved and is similar to the known structures of cytochrome c' from r. molischianum (rmcp) and r. ... | 1993 | 8230224 |
| photolithoautotrophic growth and control of co2 fixation in rhodobacter sphaeroides and rhodospirillum rubrum in the absence of ribulose bisphosphate carboxylase-oxygenase. | rhodospirillum rubrum and rhodobacter sphaeroides were shown to be capable of photolithoautotrophic growth in the absence of the reductive pentose phosphate (calvin) cycle. ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) deletion strains were incapable of photolithoautotrophic growth using hydrogen as an electron donor but were able to grow in the absence of organic carbon using less reduced inorganic electron donors, i.e., thiosulfate or sulfide. wild-type r. rubrum grown in the prese ... | 1993 | 8226655 |
| the ratio of protons translocated/hydride ion equivalent transferred by nicotinamide nucleotide transhydrogenase in chromatophores from rhodospirillum rubrum. | the reduction of acetylpyridine adenine dinucleotide (acpdad+, an nad+ analogue) by nadph, in chromatophores treated with valinomycin, was accompanied by alkalinisation of the external medium, as measured by the absorbance change of added cresol red, a simple, non-binding ph indicator. experiments with a stopped-flow spectrophotometer showed that initial (linear) rates of alkalinisation persisted for 1-2s. from the results of experiments in which h+ uptake was driven by a series of short flashes ... | 1993 | 8223619 |
| surface charge modifications do not affect the hydrolytic activity of membrane-bound pyrophosphatase of rhodospirillum rubrum. | the surface charge of the membrane of chromatophores of rhodospirillum rubrum was modified by two methods: fusion of liposomes with the membrane of the chromatophore by changing the ph and by incubating chromatophores in the presence of cationic or anionic detergents. the hydrolytic activity of membrane-bound pyrophosphatase, on surface charge modified chromatophores, did not change the km of the enzyme for its substrate (mg-ppi2-) nor the activation effect of free mg2+ on the hydrolytic activit ... | 1993 | 8220258 |
| construction of a synechocystis pcc6803 mutant suitable for the study of variant hexadecameric ribulose bisphosphate carboxylase/oxygenase enzymes. | the cyanobacterium synechocystis pcc6803 was chosen as a target organism for construction of a suitable photosynthetic host to enable selection of variant plant-like ribulose bisphosphate carboxylase/oxygenase (rubisco) enzymes. the dna region containing the operon encoding rubisco (rbc) was cloned, sequenced and used for the construction of a transformation vector bearing flanking sequences to the rbc genes. this vector was utilized for the construction of a cyanobacterial rbc null mutant in wh ... | 1993 | 8219082 |
| synthesis of quinolones and acridones and their inhibitory activity in nadh-dehydrogenases and cytochrome b/c1-complexes. | 1994 | 8206292 | |
| picosecond absorbance difference spectra of the antenna of photosynthetic purple bacteria. the influence of exciton interactions and librations. | the influence of exciton interactions and pseudolocal librational modes on the relaxation of photo-induced absorption changes of the light-harvesting antenna of the photosynthetic purple bacterium, rhodospirillum rubrum, was studied in the ps time domain. a hypothesis is put forward that the long-lived librational modes can occur in the circular aggregate of light-harvesting bacteriochlorophyll molecules of the core antenna. the model spectra obtained quantitatively fit the shape of the photo-in ... | 1994 | 8200456 |
| amino acid sequence similarities between the vacuolar proton-pumping inorganic pyrophosphatase and the c-subunit of f0f1-atpases. | comparison of the arabidopsis thaliana vacuolar proton-pumping inorganic pyrophosphatase with three f0f1-atpase c-subunits revealed a strong similarity between a stretch containing amino acids 227-245 of the h(+)-ppase and a transmembrane alpha-helix of the c-subunits which contains the glutamate which binds n,n'-dicyclohexylcarbodiimide. | 1993 | 8199778 |
| chemical rescue by exogenous amines of a site-directed mutant of ribulose 1,5-bisphosphate carboxylase/oxygenase that lacks a key lysyl residue. | ligand binding to ribulose 1,5-bisphosphate carboxylase/oxygenase immobilizes the flexible loop 6 of the beta/alpha barrel domain in its closed conformation. lys329, located at the apex of this loop, interacts electrostatically with glu48 of the adjacent subunit and with the co2-derived carboxylate of the carboxylated reaction intermediate [knight et al. (1990) j. mol. biol. 215, 113-160]. previous studies have implicated lys329 in the addition of co2 to the initial enediol(ate) intermediate: mu ... | 1994 | 8180178 |
| anaerobic bacteria from hypersaline environments. | strictly anaerobic halophiles, namely fermentative, sulfate-reducing, homoacetogenic, phototrophic, and methanogenic bacteria are involved in the oxidation of organic carbon in hypersaline environments. to date, six anaerobic fermentative genera, containing nine species, have been described. two of them are homoacetogens. six species belong to the family haloanaerobiaceae, as indicated by their unique 16s rrna oligonucleotide sequences. desulfohalobium retbaense and desulfovibrio halophilus repr ... | 1994 | 8177169 |
| thermodynamics of membrane polypeptide oligomerization in light-harvesting complexes and associated structural changes. | investigation of the equilibrium between the dissociated b777 form of the light-harvesting complex of rhodospirillum rubrum and the oligomeric b820 form demonstrates that the b777 form consists of bacteriochlorophyll a (bchl) bound to the alpha or beta polypeptide chains; this binding appears to be reasonably stable at room temperature with little dissociation to free bchl and polypeptides. analysis of the reaction order for the b777 association reaction to form b820 shows that this reaction req ... | 1994 | 8176735 |
| beta-elimination of phosphate from reaction intermediates by site-directed mutants of ribulose-bisphosphate carboxylase/oxygenase. | five residues (thr-53, asn-54, gly-370, gly-393, and gly-394) of rhodospirillum rubrum ribulose-bisphosphate carboxylase/oxygenase are positioned to serve as hydrogen-bond donors for the c1 phosphate of ribulose bisphosphate and thereby constrain conformational flexibility of the initial enediol(ate) intermediate (knight, s., andersson, i., and brändén, c.-i. (1990) j. mol. biol. 215, 113-160). to study the functional contributions of the residues implicated in ribulose bisphosphate binding and ... | 1994 | 8157638 |
| energy transfer in the inhomogeneously broadened core antenna of purple bacteria: a simultaneous fit of low-intensity picosecond absorption and fluorescence kinetics. | the excited state decay kinetics of chromatophores of the purple photosynthetic bacterium rhodospirillum rubrum have been recorded at 77 k using picosecond absorption difference spectroscopy under strict annihilation free conditions. the kinetics are shown to be strongly detection wavelength dependent. a simultaneous kinetic modeling of these experiments together with earlier fluorescence kinetics by numerical integration of the appropriate master equation is performed. this model, which account ... | 1994 | 8130341 |
| identification of the myxococcus xanthus 59-kda membrane-associated gtp-binding protein as a proton-translocating atpase. | five gtp-binding proteins have been detected in myxococcus xanthus by photoaffinity cross-linking with azido-gtp [muñoz-dorado et al., j. biol. chem. 265 (1990a) 2702-2706]. one of them, the 59-kda membrane-associated gtp-binding protein, has been purified. the n-terminal sequence of a 10-kda fragment from the protease v8 digestion of the purified protein has been determined and degenerate oligodeoxyribonucleotides based on that sequence have been used to isolate and clone the gene that encodes ... | 1994 | 8125291 |
| posttranslational modification of nitrogenase. differences between the purple bacterium rhodospirillum rubrum and the cyanobacterium anabaena variabilis. | in the photosynthetic bacteria rhodospirillum rubrum and rhodopseudomonas capsulatus post-translational regulation of nitrogenase is due to adp-ribosylation of the fe-protein, the dinitrogenase reductase [burris, r. h. (1991) j. biol. chem. 266, 9339-9342]. this mechanism has been assumed to be responsible for nitrogenase modification in a variety of organisms. in the present study, we examined whether adp-ribosylation holds true for the filamentous cyanobacterium anabaena variabilis. genes codi ... | 1994 | 8119279 |
| cloning and sequencing of the genes for the proton-translocating nicotinamide nucleotide transhydrogenase from rhodospirillum rubrum and the implications for the domain structure of the enzyme. | the genes for the proton-translocating nicotinamide nucleotide transhydrogenase from rhodospirillum rubrum have been cloned using a probe constructed with the polymerase chain reaction, genomic dna as target and oligonucleotide primers corresponding to amino acid sequence obtained from the purified soluble subunit. there is a cluster of three genes, designated pntaa, pntab and pntb, whose translation products indicate polypeptides of 384, 139 and 464 amino acids, respectively. this contrasts wit ... | 1994 | 8075801 |