TitleAbstractYear(sorted ascending)
the rhodospirillum rubrum cytochrome bc1 complex: peptide composition, prosthetic group content and quinone binding.a cytochrome bc1 complex, essentially free of bacteriochlorophyll, has been purified from the photosynthetic purple non-sulfur bacterium rhodospirillum rubrum. the complex catalyzes electron flow from quinol to cytochrome c (turnover number = 75 s-1) that is inhibited by low concentrations of antimycin a and myxothiazol. the complex contains only three peptide subunits: cytochrome b (mr = 35,000); cytochrome c1 (mr = 31,000) and the rieske iron-sulfur protein (mr = 22,400). em values (ph 7.4) we ...19892548618
characterization of four herbicide-resistant mutants of rhodopseudomonas viridis by genetic analysis, electron paramagnetic resonance, and optical spectroscopy.herbicides of the triazine class block electron transfer in the photosynthetic reaction centers of purple bacteria and psii of higher plants. they are thought to act by competing with one of the electron acceptors, the secondary quinone, qb, for its binding site. several mutants of the purple bacterium rhodopseudomonas viridis resistant to terbutryn [2-(methylthio)-4-(ethylamino)-6-(tert-butylamino)-s-triazine] have been isolated by their ability to grow photosynthetically in the presence of the ...19892550055
identification of a ni- and fe-containing cluster in rhodospirillum rubrum carbon monoxide dehydrogenase.methyl viologen-oxidized carbon monoxide dehydrogenase (codh) from rhodospirillum rubrum exhibits complex epr. comparison to epr of oxidized apo-codh (codh from which ni is lacking) leads to the identification of signals whose intensity is correlated with the presence of ni. 61ni labeling observably broadens the sharpest feature of these signals, as does 57fe. r. rubrum codh thus contains a cluster containing both ni and fe. the epr associated with this cluster is unlike any epr previously attri ...19892550436
purification and partial characterization of glutamine synthetase from the photosynthetic bacterium rhodospirillum rubrum.glutamine synthetase (l-glutamate: ammonia ligase (adp-forming), ec from the photosynthetic bacterium rhodospirillum rubrum grown under nitrogen fixing conditions has been purified to homogeneity. the purification procedure involves affinity chromatography on adp-agarose type 2 as the major purification step. the recovery in the purification is 70%. the specific activity of the purified enzyme is about 10-times higher in the gamma-glutamyl transferase assay than in the coupled biosynthe ...19892562919
regulation of nitrogenase activity by reversible adp ribosylation. 19892575970
r-body-producing bacteria.until 10 years ago, r bodies were known only as diagnostic features by which endosymbionts of paramecia were identified as kappa particles. they were thought to be limited to the cytoplasm of two species in the paramecium aurelia species complex. now, r bodies have been found in free-living bacteria and other paramecium species. the organisms now known to form r bodies include the cytoplasmic kappa endosymbionts of p. biaurelia and p. tetraurelia, the macronuclear kappa endosymbionts of p. cauda ...19892651865
isolation and partial characterization of a cytochrome-o complex from chromatophores of the photosynthetic bacterium rhodospirillum rubrum fr1.a cytochrome-o complex was isolated from chromatophores of photoheterotrophically grown rhodospirillum rubrum fr1. the enzyme was extracted with the non-denaturating detergent taurodeoxycholate and subsequently purified by sucrose-density-gradient centrifugation and gel-permeation hplc. the complex contains two types of cytochromes, one of them cytochrome o, and two copper atoms. it catalyzes the reduction of molecular oxygen, when n,n,n',n'-tetramethyl-p-phenylenediamine or ubiquinol 10 are off ...19892659347
linear optimization of predictors for secondary structure. application to transbilayer segments of membrane proteins.sliding-window averaging of amino acid properties is a standard method for predicting protein secondary structure. for example, transmembrane segments are predicted to occur near the peaks in a hydropathy plot of a membrane protein. such a scheme (linear convolutional recognizer, lcr) assigns a number (weight) to each type of monomer, and then convolutes some window function with the sequence of weights. the window has commonly been rectangular, and the weights derived from singlet amino acid fr ...19892685329
crystal structure of the complex of ribulose-1,5-bisphosphate carboxylase and a transition state analogue, 2-carboxy-d-arabinitol 1,5-bisphosphate.the crystal structure of the binary complex of nonactivated ribulose-1,5-bisphosphate carboxylase/oxygenase from rhodospirillum rubrum and a transition state analogue, 2-carboxy-d-arabinitol 1,5-bisphosphate has been determined to 2.6 a resolution with x-ray crystallographic methods. the transition state analogue binds in a rather extended conformation at the active site. the orientation of the transition state analogue within the active site could be determined from the electron density maps. t ...19892708355
1h-nmr studies of high-potential iron-sulfur protein from the purple phototrophic bacterium, rhodospirillum tenue.the high-potential iron-sulfur protein (hipip) from rhodospirillum tenue (strain 3761) shows only a weak (20-25%) sequence similarity to hipips from chromatium vinosum, ectothiorhodospira halophila and ectothiorhodospira vacuolata, including the strict conservation of only two of the twelve residues assumed to be in the 4fe-4s cluster packing region [tedro, s. m., meyer, t. e. and kamen, m. d. (1979) j. biol. chem. 254, 1495-1500]. in spite of these differences, the general range and distributio ...19892714284
rhodospirillum centenum, sp. nov., a thermotolerant cyst-forming anoxygenic photosynthetic bacterium.a novel non-sulfur purple photosynthetic bacterium, designated rhodospirillum centenum, was isolated from an enrichment culture designed to favor growth of anoxygenic photosynthetic n2-fixing bacteria. r. centenum grows optimally at 40-42 degrees c and has the capacity to produce cytoplasmic 'r bodies', refractile structures not observed hitherto in photosynthetic prokaryotes. the bacterium is also unusual among photosynthetic bacteria in that it forms desiccation-resistant cysts when grown aero ...19892757370
isolation, characterization, and biological activity of ferredoxin-nad+ reductase from the methane oxidizer methylosinus trichosporium ob3b.a ferredoxin-nad+ oxidoreductase (ec has been isolated from extracts of the obligate methanotroph methylosinus trichosporium ob3b. this enzyme was shown to couple electron flow from formate dehydrogenase (nad+ requiring) to ferredoxin. ferredoxin-nad+ reductase was purified to homogeneity by conventional chromatography techniques and was shown to be a flavoprotein with a molecular weight of 36,000 +/- 1,000. this ferredoxin reductase was specific for nadh (km, 125 microm) and coupled e ...19892768195
distribution of delta-aminolevulinic acid biosynthetic pathways among phototrophic bacterial groups.two biosynthetic pathways are known for the universal tetrapyrrole precursor, delta-aminolevulinic acid (ala). in the ala synthase pathway which was first described in animal and some bacterial cells, the pyridoxal phosphate-dependent enzyme ala synthase catalyzes condensation of glycine and succinyl-coa to form ala with the loss of c-1 of glycine as co2. in the five-carbon pathway which was first described in plant and algal cells, the carbon skeleton of glutamate is converted intact to ala in ...19892789025
isolation and characterization of a structural subunit from the core light-harvesting complex of rhodobacter sphaeroides 2.4.1 and puc705-ba.a method for isolating a structural subunit, b825, from the b875 core light-harvesting complex (lhc) of rhodobacter sphaeroides 2.4.1 (wild-type) and a b800-b850(-) mutant, puc705-ba, is presented. this method, based on one developed to prepare a similar subunit, b820, from the core lhc of rhodospirillum rubrum [miller et al., biochemistry 26, 5055-5062 (1987)], requires the dissociation of treated chromatophores with the detergent, octyl-glucoside. a subsequent gel filtration step separates b80 ...19902089436
cellular differentiation in the process of generation of the eukaryotic cell.primitive atmosphere of the earth did not contain oxygen gas (o2) when the proto-cells were generated successfully as the result of chemical evolution and then evolved. therefore, they first had acquired anaerobic energy metabolism, fermentation. the cellular metabolisms have often been formed by reorganizing to combine or recombinate between pre-existing metabolisms and newly born bioreactions. photosynthetic metabolism in eukaryotic chloroplast consists of an electron-transfer photosystem and ...19902103939
an engineered change in substrate specificity of ribulosebisphosphate carboxylase/oxygenase.the potential for altering the specificity of ribulosebisphosphate carboxylase/oxygenase toward gaseous substrates is explored through a modest perturbation of the active site microenvironment. specifically, replacement of active site glu-48 with carboxy-methylcysteine is achieved in a two-step process in which the catalytically incompetent cys-48 mutant protein is first generated and then treated with iodoacetic acid. this regimen of concerted site-directed mutagenesis and chemical modification ...19902104836
spectroscopic characterization of the light-harvesting complex of rhodospirillum rubrum and its structural subunit.the spectroscopic properties of the light-harvesting complex of rhodospirillum rubrum, b873, and a detergent-isolated subunit form, b820, are presented. absorption and circular dichroism spectra suggest excitonically interacting bacteriochlorophyll alpha (bchl alpha) molecules give b820 its unique spectroscopic properties. resonance raman results indicate that bchl alpha is 5-coordinate in both b820 and b873 but that the interactions with the bchl c2 acetyl in b820 and b873 are different. the re ...19902105744
reversible adp-ribosylation is demonstrated to be a regulatory mechanism in prokaryotes by heterologous expression.the primary product of biological nitrogen fixation, ammonia, reversibly regulates nitrogenase activity in a variety of diazotrophs by a process called "nh4(+)-switch-off/on." strong correlative evidence from work in azospirillum lipoferum and rhodospirillum rubrum indicates that this regulation involves both the inactivation of dinitrogenase reductase by dinitrogenase reductase adp-ribosyltransferase and the reactivation by dinitrogenase reductase activating glycohydrolase. the genes encoding t ...19902106680
cloning and expression of dratg genes from azospirillum lipoferum.a genomic library of azospirillum lipoferum was constructed with phage lambda embl4 as vector. from this library, the genes encoding dinitrogenase reductase adp-ribosyltransferase (drat), drat, and dinitrogenase reductase-activating glycohydrolase (drag), drag, were cloned by hybridization with the heterologous probes of rhodospirillum rubrum. as in r. rubrum, drat is located between drag and nifh, the gene encoding dinitrogenase reductase (a substrate for the drag/drat system). in the crude ext ...19902107127
crystallographic refinement and structure of ribulose-1,5-bisphosphate carboxylase from rhodospirillum rubrum at 1.7 a resolution.the amino acid sequence of ribulose-1,5-bisphosphate carboxylase/oxygenase from rhodospirillum rubrum has been fitted to the electron density maps. the resulting protein model has been refined to a nominal resolution of 1.7 a using the constrained-restrained least-squares refinement program of sussman and the restrained least-squares refinement program of hendrickson & konnert. the crystallographic refinement, based on 76,452 reflections with f greater than sigma (f) in the resolution range 5.5 ...19902107319
determination of hopanoid levels in bacteria using high-performance liquid chromatography.a reverse-phase hplc method to detect and quantify levels of hopanoids in bacteria has been developed. chromophores have been introduced by derivatization and the levels of the c35 hopanoids and their conjugates can be measured in bacterial lipid extracts down to picomole levels. some structural variations of the complex lipids were detected after derivatization and were easily purified using the same hplc system. zymomonas mobilis and rhodospirillum rubrum extracts were examined using this syst ...19902109551
activation of the nickel-deficient carbon monoxide dehydrogenase from rhodospirillum rubrum: kinetic characterization and reductant requirement.the requirements for and kinetics of the activation of the nickel-deficient (apo) co dehydrogenase from rhodospirillum rubrum by exogenous nickel have been investigated. the activation is strictly dependent upon the presence of a low-potential one-electron reductant. sodium dithionite and reduced methylviologen (e degrees' = -440 mv) are suitable reductants, whereas reduced indigo carmine (e degrees' = -125 mv) and the two-electron reductants sodium borohydride, nadh, and dithiothreitol are inef ...19902109635
truncation of ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) from rhodospirillum rubrum affects the holoenzyme assembly and activity.truncations of the subunit of ribulose bisphosphate carboxylase/oxygenase (rubisco) from rhodospirillum rubrum were generated by site-directed mutagenesis to examine the role of the c-terminal tail section. removal of the last and the penultimate alpha-helices in the tail section changes the quaternary structure of the protein. electrophoretic and electron microscope analysis revealed that the truncated subunits assemble into an octamer, whereas the wild-type enzyme has a dimeric structure. the ...19902109693
probing the bacteriochlorophyll binding site by reconstitution of the light-harvesting complex of rhodospirillum rubrum with bacteriochlorophyll a analogues.structural features of bacteriochlorophyll (bchl) a that are required for binding to the light-harvesting proteins of rhodospirillum rubrum were determined by testing for reconstitution of the b873 or b820 (structural subunit of b873) light-harvesting complexes with bchl a analogues. the results indicate that the binding site is very specific; of the analogues tested, only derivatives of bchl a with ethyl, phytyl, and geranylgeranyl esterifying alcohols and bchl b (phytyl) successfully reconstit ...19902110819
electron transfer between primary and secondary donors in rhodospirillum rubrum: evidence for a dimeric association of reaction centers.light-induced oxidation of the primary electron donor p and of the secondary donor cytochrome c2 was studied in whole cells of rhodospirillum rubrum in the presence of myxothiazole to slow down their reduction. 1. the primary and secondary electron donors are close to thermodynamic equilibrium during continuous illumination when the rate of the electron transfer is light-limited. this implies a long-range thermodynamic equilibration involving the diffusible cytochrome c2. a different behavior is ...19902112407
[the surface membrane charge of bacteria and its role in serine proteinase secretion by bacillus subtilis cells].univalent, bivalent and trivalent metal cations increase the fluorescence yield of 9-aminoacridine in the suspensions of chromatophores of the purple nonsulfur bacterium rhodospirillum rubrum isolated thylakoid membranes and cells of cyanobacterium anabaena variabilis, cells bacillus subtilis. the active cation concentrations increase about in 10 times with the decrease of their valency by one. it points to the fact that the changes in 9-aminoacridine fluorescence serve for the monitoring of the ...19902112959
comparison of the crystal structures of l2 and l8s8 rubisco suggests a functional role for the small subunit.comparison of the crystal structures of the l2 and l8s8 forms of ribulose-1,5-bisphosphate carboxylase from rhodospirillum rubrum and spinach respectively, reveals a remarkable similarity in the overall architecture of the l2 building blocks in the two enzymes. within the l subunits, no large conformational differences such as domain-domain rotations were found. in spite of a somewhat different packing of the l subunits in the l2 dimer, the active sites of the two enzymes are highly conserved. s ...19902113466
carboxylterminal deletion mutants of ribulosebisphosphate carboxylase from rhodospirillum rubrum.the carboxylterminal octapeptide of ribulosebisphosphate carboxylase from rhodospirillum rubrum, which lacks small subunits, shows homology to a highly conserved region near the amino terminus of the small subunits of hexadecameric ribulosebisphosphate carboxylases, which are composed of large and small subunits. truncations of the r. rubrum enzyme, which partially or completely deleted the region of homology, demonstrated that the region is not an important determinant of the catalytic efficien ...19902114311
the contribution of the carotenoid to the visible circular dichroism of the light-harvesting antenna of rhodospirillum rubrum.the visible c.d. spectrum of wild-type rhodospirillum rubrum shows positive bands [dratz, schultz & sauer (1966) brookhaven symp. biol. 19, 303-318] that are largely due to the b880 antenna pigments, bacteriochlorophyll a and carotenoids. the bacteriochlorophyll c.d. band was absent from the spectrum of r. rubrum g9, a mutant unable to synthesize coloured carotenoids, and could be partly restored by adding extracted carotenoids to freeze-dried membrane vesicles isolated from that mutant. therefo ...19902119174
chromatographic and protein chemical analysis of the ubiquinol-cytochrome c2 oxidoreductase isolated from rhodobacter sphaeroides.the ubiquinol-cytochrome c2 oxidoreductase (cytochrome bc1 complex) purified from chromatophores of rhodobacter sphaeroides consists of four polypeptide subunits corresponding to cytochrome b, c1, and the rieske iron-sulfur protein, as well as a 14-kda polypeptide of unknown function, respectively. in contrast, the complex isolated from rhodospirillum rubrum by the same procedure lacked a polypeptide corresponding to the 14-kda subunit. gel-permeation chromatography of the r. sphaeroides cytochr ...19902153104
molecular cloning, sequencing and expression of cytochrome c2 from rhodospirillum rubrum.cytochrome c2 (mr 12,840) of the purple photosynthetic bacterium rhodospirillum rubrum functions as a mobile electron carrier in the cyclic photosynthetic electron-transport system of this organism. it acts as the electron donor to photochemically oxidized reaction centres and is reduced in turn by electrons from the cytochrome bc1 complex. by using synthetic oligonucleotides based on the known amino acid sequence of the protein, the structural gene (cyca) has been identified and isolated. dna s ...19902154194
versatile protein engineering vectors for mutagenesis, expression and hybrid enzyme formation. 19902158660
soluble cytochromes and a photoactive yellow protein isolated from the moderately halophilic purple phototrophic bacterium, rhodospirillum salexigens.three soluble cytochromes were found in two strains of the halophilic non-sulfur purple bacterium rhodospirillum salexigens. these are cytochromes c2, c and c-551. cytochrome c2 was recognized by the presence of positive charge at the site of electron transfer (measured by laser flash photolysis), although the protein has an overall negative charge (pi = 4.7). cytochrome c2 has a high redox potential (300 mv) and is monomeric (13 kda). cytochrome c was recognized from its characteristic absorpti ...19902158819
assignments of 15n and 1h nmr resonances and a neutral ph ionization in rhodospirillum rubrum cytochrome c2.the phi nh proton and 15n resonances of the ligand histidine of rhodospirillum rubrum fericytochrome c2 are found at 14.7 and 184 ppm, respectively, contradicting the proposal that this proton is absent in the r. rubrum ferricytochrome. substitution of the deuterium atom for this proton causes small upfield shifts of the phi nitrogen in both oxidation states, indicating that the phi nh-peptide carboxyl hydrogen bond is not substantially weakened by the substitution. the proton and 15n resonances ...19902159778
characterization of ph-dependent conformational heterogeneity in rhodospirillum rubrum cytochrome c2 using 15n and 1h nmr.the 15n-enriched ferricytochrome c2 from rhodospirillum rubrum has been studied by 15n and 1h nmr spectroscopy as a function of ph. the 15n resonances of the heme and ligand tau nitrogen are broadened beyond detection because of paramagnetic relaxation. the 15n resonance of the ligand histidine phi nitrogen was unambiguously identified at 184 ppm (ph 5.6). the 15n resonances of the single nonligand histidine are observed only at low ph, as in the ferrocytochrome because of the severe broadening ...19902159779
resonance raman spectroscopy of cytochrome bc1 complexes from rhodospirillum rubrum: initial characterization and reductive titrations.resonance raman spectra of bc1 complexes from rhodospirillum rubrum have been obtained. various resonance conditions and the stoichiometric redox titration of the complex were used to isolate and identify the contributions of the heme c1 and heme b active sites to the observed spectra. the complex was found to partially photoreduce when exposed to laser excitation.19902165419
proton nmr study of the comparative electronic/magnetic properties and dynamics of the acid in equilibrium with alkaline transition in a series of ferricytochromes c'.the proton nmr spectra of ferricytochrome c' from rhodopseudomonas palustris, rhodospirillum molischianum, rhodospirillum rubrum, and chromatium vinosum have been investigated for the purpose of further elucidating the common spectral and/or structural properties for this subclass of cytochromes in the acidic and alkaline forms, and to characterize in detail the dynamics and structural basis for this acid in equilibrium with alkaline transition. the identification of strongly upfield-shifted mes ...19902168882
the pet genes of rhodospirillum rubrum: cloning and sequencing of the genes for the cytochrome bc1-complex.a cytochrome bc1-complex of rs. rubrum was isolated and the three subunits were purified to homogeneity. the n-terminal amino acid sequence of the purified subunits was determined by automatic edman degradation. the pet genes of rhodospirillum rubrum coding for the three subunits of the cytochrome bc1-complex were isolated from a genomic library of rs. rubrum using oligonucleotides specific for conserved regions of the subunits from other organisms and a heterologous probe derived from the genes ...19902176269
nitrogenase in the archaebacterium methanosarcina barkeri 227.the discovery of nitrogen fixation in the archaebacterium methanosarcina barkeri 227 raises questions concerning the similarity of archaebacterial nitrogenases to mo and alternative nitrogenases in eubacteria. a scheme for achieving a 20- to 40-fold partial purification of nitrogenase components from strain 227 was developed by using protamine sulfate precipitation, followed by using a fast protein liquid chromatography apparatus operated inside an anaerobic glove box. as in eubacteria, the nitr ...19902254255
antigenic sites on cytochrome c2 from rhodospirillum rubrum.the antigenic determinants for three monoclonal antibodies against cytochrome c2 from rhodospirillum rubrum were partially characterized by differential chemical modification of free and antibody-bound cytochrome c2 and by cross-reactivity analysis with different antigens. circular dichroism spectroscopy was used to probe the effect of antibody binding on the conformation of cytochrome c2. the binding of two antibodies was strongly dependent on the native folding of the antigen. the first antibo ...19901688799
examination of the intersubunit interaction between glutamate-48 and lysine-168 of ribulose-bisphosphate carboxylase/oxygenase by site-directed mutagenesis.the active site of ribulose-bisphosphate carboxylase/oxygenase is constituted from domains of adjacent subunits and includes an intersubunit electrostatic interaction between lys 168 and glu48, which has been recently identified by x-ray crystallography (andersson, i., knight, s., schneider, g., lindqvist, y., lundqvist, t., brändén, c.-i., and lorimer, g.h. (1989) nature 337, 229-234; lundqvist, t., and schneider, g. (1989) j. biol. chem. 264, 7078-7083). to examine the structural and functiona ...19901969412
atp-dependent and nad-dependent modification of glutamine synthetase from rhodospirillum rubrum in vitro.glutamine synthetase from the photosynthetic bacterium rhodospirillum rubrum is the target of both atp- and nad-dependent modification. incubation of r. rubrum cell supernatant with [alpha-32p]nad results in the labeling of glutamine synthetase and two other unidentified proteins. dinitrogenase reductase adp-ribosyltransferase does not appear to be responsible for the modification of glutamine synthetase or the unidentified proteins. the [alpha-32p]atp- and [alpha-32p] nad-dependent modification ...19901974253
identification of a groes-like chaperonin in mitochondria that facilitates protein folding.mitochondria contain a polypeptide that is functionally equivalent to escherichia coli chaperonin 10 (cpn10; also known as groes). this mitochondrial cpn10 has been identified in beef and rat liver and is able to replace bacterial cpn10 in the chaperonin-dependent reconstitution of chemically denatured ribulose-1,5-bisphosphate carboxylase. thus, like the bacterial homologue, mitochondrial cpn10 facilitates a k(+)- and mg.atp-dependent discharge of unfolded (or partially folded) ribulose bisphos ...19901977163
the cloning and functional characterization of the nifh gene of rhodospirillum rubrum.dinitrogenase reductase (the nifh product) from rhodospirillum rubrum is regulated by a post-translational modification system encoded by dratg. as demonstrated in this report, the cloning, sequencing, and functional characterization of the nifh gene provides a basis for further analysis as well as revealing interesting features of gene organization. the coding regions of nifh and drat are separated by only 400 bp, though the genes are divergently transcribed and differentially regulated. the co ...19901979299
complementation of a pleiotropic nif-gln regulatory mutant of rhodospirillum rubrum by a previously unrecognized azotobacter vinelandii regulatory locus.a spontaneous pleiotropic nif- mutation in rhodospirillum rubrum has been partially characterized biochemically and by complementation analysis with recombinant plasmids carrying azotobacter vinelandii dna in the vicinity of orf12 [jacobson et al. (1989) j. bacteriol 171: 1017-1027]. in addition to being unable to grow on n2 as a nitrogen source the phenotypic characterization of this and other metronidazole enriched spontaneous mutants showed (a) no nitrogenase activity, (b) the absence of nifh ...19901980582
supramolecular arrangement of rhodospirillum rubrum b880 holochrome as studied by radiation inactivation and electron paramagnetic resonance.oxidation of the b880 antenna holochrome gives rise to a 3.8-g linewidth electron paramagnetic resonance (epr) signal that is considerably narrower than the 13-g signal of monomeric bacteriochlorophyll (bchl) cation. radiation inactivation was used to verify a model according to which this linewidth narrowing is due to delocalization over several bchl molecules. chromatophores of the photoreaction centerless mutant f24 of rhodospirillum rubrum were subjected to different doses of gamma-radiation ...199011607076
nitrogenase activity and amounts of nitrogenase proteins in a frankia-alnus incana symbiosis subjected to darkness.effects of prolonged darkness on nitrogenase activity in vivo, nitrogenase activity in vitro, and the amounts of nitrogenase proteins were studied in symbiotic frankia. plants of alnus incana (l.) moench in symbiosis with a local source of frankia were grown for 9 to 10 weeks in an 18/6 hour light/darkness cycle. after 12 hours of a light period, the plants were exposed to darkness for up to 40 hours. nitrogenase activity (acetylene reduction activity) of intact plants was measured repeatedly. f ...199116668058
possible role of the highly conserved amino acids trp-8 and pro-13 in the n-terminal segment of the pigment-binding polypeptide lhi alpha of rhodobacter capsulatus.trp-8 and pro-13 of the rhodobacter capsulatus light-harvesting (lh) i alpha polypeptide are highly conserved among lhi and lhii alpha proteins of several species of the rhodospirillaceae. exchange of trp-8 and pro-13 to other amino acyl residues similar in structure and/or hydrophobicity indicates that trp-8 is involved in the insertion of the lhi alpha polypeptide into the intracytoplasmic membrane (icm). pro-13, however, seems not to participate in the integration process of the lhi alpha pro ...19912065784
phylogenetic analysis and evolution of rnase p rna in proteobacteria.the secondary structures of the eubacterial rnase p rnas are being elucidated by a phylogenetic comparative approach. sequences of genes encoding rnase p rna from each of the recognized subgroups (alpha, beta, gamma, and delta) of the proteobacteria have now been determined. these sequences allow the refinement, to nearly the base pair level, of the phylogenetic model for rnase p rna secondary structure. evolutionary change among the rnase p rnas was found to occur primarily in four discrete str ...19911711030
construction, characterization, and complementation of rhodospirillum rubrum puf region mutants.rhodospirillum rubrum is a facultatively phototrophic bacterium that, under certain growth conditions, forms an intracytoplasmic chromatophore membrane (icm) housing the photochemical apparatus. the puf operon of r. rubrum encodes protein subunits of the photochemical reaction center and the b880 light-harvesting antenna complex. mutant strains of r. rubrum were constructed by interposon mutagenesis through which a kanamycin resistance gene cartridge was inserted into restriction sites and in pl ...19911715861
functional analysis of the putative catalytic bases his-321 and ser-368 of rhodospirillum rubrum ribulose bisphosphate carboxylase/oxygenase by site-directed mutagenesis.numerous candidates have been suggested according to chemical and structural criteria for the active site base of ribulose bisphosphate carboxylase/oxygenase that catalyzes substrate enolization. we evaluate the functional significance of two such candidates, his-321 and ser-368 of the rhodospirillum rubrum enzyme, by site-directed mutagenesis. position 321 mutants retain 3-12% of wild-type rates of both overall carboxylation and the initial enolization, with little effect on km for co2 or ribul ...19911761567
protein engineering of rubisco.modification of the kinetic parameters of enzymes by protein engineering requires extensive knowledge of the structural details of the enzyme and its complexes with different reaction intermediate analogues. such structural studies are described here for rubisco, ribulose-1,5-bisphosphate carboxylase/oxygenase, which catalyzes the initial reactions of two important but competing physiological events in green plants; carbon dioxide fixation and photorespiration. observed functional changes in mut ...19911772628
dna sequencing and complementation/deletion analysis of the bcha-puf operon region of rhodobacter sphaeroides: in vivo mapping of the oxygen-regulated puf promoter.within the photosynthetic gene cluster of rhodobacter sphaeroides the genes encoding light-harvesting lhi and reaction-centre complexes are transcriptionally linked in the order pufbalmx. the region stretching 1.6 kb upstream of pufb has been examined by dna sequencing and by complementation/deletion analysis. these studies demonstrate that three open reading frames are located upstream of pufb. one open reading frame, designated bcha, terminates just inside pufq, which is located proximal to pu ...19911779756
extraction and purification of the beta subunit and an active alpha beta-core complex from the spinach chloroplast cfof1-atp synthase.incubation of rhodospirillum rubrum chromatophores with 2 m licl in the presence of mgatp has been shown to remove their f1 beta subunit leaving inactive but fully reconstitutable beta-less chromatophores (gromet-elhanan, z., and khanashvili, d., (1986) methods enzymol, 126, 528-538). a similar treatment of thoroughly washed spinach thylakoids has now been shown to release the cf1 beta subunit (cf1 beta) together with a complex containing equal amounts of cf1 alpha and cf1 beta (cf1 (alpha beta] ...19911826683
proton-translocating transhydrogenase from photosynthetic bacteria. 19911838340
electron spin echo envelope modulation spectroscopy supports the suggested coordination of two histidine ligands to the rieske fe-s centers of the cytochrome b6f complex of spinach and the cytochrome bc1 complexes of rhodospirillum rubrum, rhodobacter sphaeroides r-26, and bovine heart mitochondria.electron spin echo envelope modulation (eseem) experiments performed on the rieske fe-s clusters of the cytochrome b6f complex of spinach chloroplasts and of the cytochrome bc1 complexes of rhodospirillum rubrum, rhodobacter sphaeroides r-26, and bovine heart mitochondria show modulation components resulting from two distinct classes of 14n ligands. at the g = 1.92 region of the rieske epr spectrum of the cytochrome b6f complex, the measured hyperfine couplings for the two classes of coupled nit ...19911847076
proton-pumping n,n'-dicyclohexylcarbodiimide-sensitive inorganic pyrophosphate synthase from rhodospirillum rubrum: purification, characterization, and reconstitution.a new method has been developed for the isolation of the proton-pumping n,n'-dicyclohexylcarbodiimide-sensitive ppi synthase (h(+)-ppi synthase) from chromatophores of rhodospirillum rubrum. the h(+)-ppi synthase was purified by extraction of chromatophores with a mixture of nonanoyl-n-methylglucamide and cholate, by fractionation with poly(ethylene glycol) 4000, hydroxyapatite chromatography, and affinity chromatography. the purified enzyme is homogeneous and has a specific activity of 20.4 mum ...19911848779
purification and properties of the h(+)-nicotinamide nucleotide transhydrogenase from rhodobacter capsulatus.1. h(+)-transhydrogenase from rhodobacter capsulatus is an integral membrane protein which, unlike the enzyme from rhodospirillum rubrum, does not require the presence of a water-soluble component for activity. 2. the enzyme from rb. capsulatus was solubilised in triton x-100 and subjected to ion-exchange, hydroxyapatite and then gel-exclusion column chromatography. sds/page of the purified enzyme revealed the presence of two polypeptides with apparent mr 53,000 and 48,000. other minor component ...19911849819
attenuated effect of oxygen on photopigment synthesis in rhodospirillum centenum.rhodospirillum centenum resembles typical nonsulfur photosynthetic bacteria in a number of respects, including its ability to grow either anaerobically as a phototroph or aerobically as a heterotroph. we demonstrate, however, that r. centenum is unusual in its ability to synthesize a functional photosynthetic apparatus regardless of the presence of molecular oxygen. aerobically expressed photopigments were shown to be functionally active, as demonstrated by the ability of heterotrophically grown ...19911885527
[the role of propionyl-coa carboxylase in the biosynthesis of antibiotics]. 19911892432
rapid purification and characterization of homoserine dehydrogenase from saccharomyces cerevisiae.homoserine dehydrogenase of saccharomyces cerevisiae has been rapidly purified to homogeneity by heat and acid treatments, ammonium sulfate fractionation, and chromatography on matrex gel red a and q-sepharose columns. the final preparation migrated as a single entity upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a mr of 40,000. the mr of the native enzyme was 81,000 as determined by gel filtration, suggesting that the enzyme is composed of two identical subunits. this feat ...19911897932
crystal structure of the ternary complex of ribulose-1,5-bisphosphate carboxylase, mg(ii), and activator co2 at 2.3-a resolution.the activated ternary complex, enzyme-co2-mg(ii), of the dimeric ribulose-1,5-bisphosphate carboxylase/oxygenase from rhodospirillum rubrum can be prepared in the same crystal form that was used for the crystallographic structure determination of the native nonactivated enzyme (schneider, g., bränden, c.-i., & lorimer, g. (1986) j. mol. biol. 187, 141-143). the three-dimensional structure of the activated enzyme has been determined to a nominal resolution of 2.3 a by protein crystallographic met ...19911899197
probing the primary quinone environment in photosynthetic bacterial reaction centers by light-induced ftir difference spectroscopy.the photoreduction of the primary electron acceptor, qa, has been characterized by light-induced fourier transform infrared difference spectroscopy for rb. sphaeroides reaction centers and for rsp. rubrum and rp. viridis chromatophores. the samples were treated both with redox compounds, which rapidly reduce the photooxidized primary electron p+, and with inhibitors of electron transfer from qa- to the secondary quinone qb. this approach yields spectra free from p and p+ contributions which make ...19911899390
expression of endogenous and foreign ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) genes in a rubisco deletion mutant of rhodobacter sphaeroides.a rhodobacter sphaeroides ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) deletion strain was constructed that was complemented by plasmids containing either the form i or form ii co2 fixation gene cluster. this strain was also complemented by genes encoding foreign rubisco enzymes expressed from a rhodospirillum rubrum rubisco promoter. in r. sphaeroides, the r. rubrum promoter was regulated, resulting in variable levels of disparate rubisco molecules under different growth conditions ...19911900508
dimeric carotenoid interaction in the light-harvesting antenna of purple phototrophic bacteria.the carotenoid content of intracytoplasmic membrane vesicles isolated from purple phototrophic bacteria was reduced to a variable extent by mild extraction with light petroleum. using preparations obtained from rhodobacter capsulatus strains that contained the light harvesting system i (lhi) complex as the only major photosynthetic holochrome, it was shown that the visible circular dichroism of the carotenoids increased with the square of the membrane carotenoid content, as expected from being c ...19911901490
the puh structural gene coding for the h subunit of the rhodospirillum rubrum photoreaction center.the rhodospirillum rubrum structural gene puh, coding for the photoreaction center h polypeptide, and three other putative genes that surround puh were cloned and sequenced. the deduced 257 amino acid h polypeptide has a molecular weight of 27,909, in close agreement with polyacrylamide gel electrophoresis determination. hydropathy plots predict a single hydrophobic alpha helix. the h polypeptide of rhodospirillum rubrum shares only 23% of its residues with all three of the h polypeptides from r ...19911903263
pyruvate is a by-product of catalysis by ribulosebisphosphate carboxylase/oxygenase.pyruvate is a minor product of the reaction catalyzed by ribulosebisphosphate carboxylase/oxygenase from spinach leaves. labeled pyruvate was detected, in addition to the major labeled product, 3-phosphoglycerate, when 14co2 was the substrate. pyruvate production was also measured spectrophotometrically in the presence of lactate dehydrogenase and nadh. the km for co2 of the pyruvate-producing activity was 12.5 microm, similar to the co2 affinity of the 3-phosphoglycerate-producing activity. no ...19911903385
demonstration of a functional requirement for the carbamate nitrogen of ribulosebisphosphate carboxylase/oxygenase by chemical rescue.ribulosebisphosphate carboxylase/oxygenase is reversibly activated by the reaction of co2 with a specific lysyl residue (lys191 of the rhodospirillum rubrum enzyme) to form a carbamate that coordinates an essential mg2+ cation. surprisingly, the lys191----cys mutant protein, in the presence of co2 and mg2+, exhibits tight binding of the reaction intermediate analogue 2-carboxyarabinitol bisphosphate [smith, h. b., larimer, f. w., & hartman, f. c. (1988) biochem. biophys. res. commun. 152, 579-58 ...19911903652
fluorescence polarization and low-temperature absorption spectroscopy of a subunit form of light-harvesting complex i from purple photosynthetic bacteria.measurements of polarized fluorescence and cd were made on light-harvesting complex 1 and a subunit form of this complex from rhodospirillum rubrum, rhodobacter sphaeroides, and rhodobacter capsulatus. the subunit form of lh1, characterized by a near-infrared absorbance band at approximately 820 nm, was obtained by titration of carotenoid-depleted lh1 complexes with the detergent n-octyl beta-d-glucopyranoside as reported by miller et al. (1987) [miller j. f., hinchigeri, s. b., parkes-loach, p. ...19911904275
crystal structure of activated ribulose-1,5-bisphosphate carboxylase complexed with its substrate, ribulose-1,5-bisphosphate.the three-dimensional structure of the complex of ribulose-1,5-bisphosphate carboxylase from rhodospirillum rubrum, co2, mg2+, and ribulose bisphosphate has been determined with x-ray crystallographic methods to 2.6-a resolution. ribulose-1,5-bisphosphate binds across the active site with the two phosphate groups in the two phosphate binding sites of the beta/alpha barrel. the oxygen atoms of the carbamate and the side chain of asp-193 provide the protein ligands to the bound mg2+ ion. the c2 an ...19911905726
identification of an alternative nitrogenase system in rhodospirillum rubrum.a second nitrogenase activity has been demonstrated in rhodospirillum rubrum. this nitrogenase is expressed whenever a strain lacks an active mo nitrogenase because of physiological or genetic inactivation. the alternative nitrogenase is able to support growth on n2 in the absence of fixed n. v does not stimulate, nor does mo or w inhibit, growth or activity under the conditions tested. the proteins responsible for this activity were identified by electrophoretic and immunological properties. th ...19911909322
glycine 100 in the dinitrogenase reductase of rhodospirillum rubrum is required for nitrogen fixation but not for adp-ribosylation.dinitrogenase reductase (rr2) is required for reduction of the molybdenum dinitrogenase in the nitrogen fixation reaction and is the target of posttranslational regulation in rhodospirillum rubrum. this posttranslational regulation involves the adp-ribosylation of rr2. to study the structural requirements for these two functions of rr2, i.e., activity and regulation, two site-directed mutations in nifh, the gene encoding rr2, were constructed and analyzed. the mutations both affected a region of ...19911917849
characterization of the co oxidation/h2 evolution system of rhodospirillum rubrum. role of a 22-kda iron-sulfur protein in mediating electron transfer between carbon monoxide dehydrogenase and hydrogenase.the response of the membrane-associated carbon monoxide dehydrogenase (codh) from rhodospirillum rubrum to solubilization by detergents and organic solvents, the properties of solubilized codh, and the mechanism for coupling co oxidation to hydrogen evolution via a co-induced hydrogenase activity have been investigated. the release of codh by a variety of ionic and nonionic detergents occurs in a redox-dependent fashion: codh is solubilized in the presence of low-potential reductants (dithionite ...19911917963
performance of trickle-bed bioreactors for converting synthesis gas to methane.carbon monoxide, h2, and co2 in synthesis gas can be converted to ch4 by employing a triculture of rhodospirillum rubrum, methanosarcina barkeri, and methanobacterium formicicum. trickle-bed reactors have been found to be effective for this conversion because of their high mass-transfer coefficients. this paper compares results obtained for the conversion of synthesis gas to ch4 in 5-cm- and 16.5-cm-diameter trickle-bed reactors. mass-transfer and scale-up parameters are defined, and light requi ...19911929378
cos degradation by selected co-utilizing bacteria. scientific note. 19911929384
purification and partial characterization of glutamate synthase from rhodospirillum rubrum grown under nitrogen-fixing conditions.glutamate synthase, a key enzyme in ammonia assimilation, has been purified from the photosynthetic bacterium rhodospirillum rubrum. the purification procedure involves ion-exchange chromatography, affinity chromatography and gel filtration. the recovery in the procedure is high (62%) and the specific activity is 21 mumol of nadph oxidized/min per mg. the enzyme is specific for its substrates, and no activity was demonstrated with nadh or nh4+ ions substituting for nadph and glutamine respective ...19911930133
purification and partial characterization of a pyruvate oxidoreductase from the photosynthetic bacterium rhodospirillum rubrum grown under nitrogen-fixing conditions.a pyruvate oxidoreductase with the capacity to support pyruvate-dependent nitrogenase activity in vitro has been purified from the photosynthetic bacterium rhodospirillum rubrum. the enzyme requires coa for activity and is irreversibly inactivated by oxygen. the molecular properties and km values for the substrates have been studied. in supporting nitrogenase activity addition of ferredoxin is required. overall the enzyme is similar to the nif-specific pyruvate: flavodoxin oxidoreductase purifie ...19911930134
mutations in the drat and drag genes of rhodospirillum rubrum result in loss of regulation of nitrogenase by reversible adp-ribosylation.reversible adp-ribosylation of dinitrogenase reductase forms the basis of posttranslational regulation of nitrogenase activity in rhodospirillum rubrum. this report describes the physiological effects of mutations in the genes encoding the enzymes that add and remove the adp-ribosyl moiety. mutants lacking a functional drat gene had no dinitrogenase reductase adp-ribosyltransferase (drat, the drat gene product) activity in vitro and were incapable of modifying dinitrogenase reductase with adp-ri ...19911938894
functional size analysis of pyrophosphatase from rhodospirillum rubrum determined by radiation inactivation.a radiation inactivation technique was employed to determine the functional size of pyrophosphatase (ppase) from the chromatophores of rhodospirillum rubrum. the activities of hydrolysis and synthesis reactions of pyrophosphatase and its coupled proton translocation decayed in a simple exponential function with the increase of radiation dosages. d37 values of 5.2 +/- 0.7 and 5.8 +/- 0.8 mrads were obtained for pyrophosphate hydrolysis and its associated proton translocation yielding molecular ma ...19911645297
sequence variability in bacterial cytochromes c.cytochromes c are proteins that can be defined both phenotypically and by their possession of a characteristic sequence motif. many sequences from bacterial sources are known, and new ones are being reported every year. an analysis can be made as to what fraction of new sequences are members of already known classes or subclasses, and how many map into previously uninhabited regions of sequence space.19911646017
high-resolution 1h- and 15n-nmr studies of rhodospirillum rubrum cytochrome c2.rhodospirillum rubrum cytochrome c2 was uniformly enriched in 15n and studied by 1h- and 15n-nmr spectroscopy. relaxation and noe data allowed determination of the rotational correlation time and indicated more rapid side-chain motion in the native protein and increased segmental motion in the base-denatured protein. the pi nitrogen of the ligand histidine and the indolic nitrogen of the invariant tryptophan both remain protonated and act as proton-donors in hydrogen bonds over a wide ph range a ...19911646025
ligand binding properties of cytochromes c'.the cytochromes c' bind co, alkylisocyanides and cn- with rate and equilibrium constants which are 10(2)- to 10(6)-fold smaller than other high-spin hemoproteins. the decreased affinity for exogenous ligands is largely associated with steric interactions at the heme coordination site. while co and alkylisocyanides bind noncooperatively to the dimeric rhodospirillum molischianum cytochrome c', co, alkylisocyanides and cn- appear to bind cooperatively to the dimeric chromatium vinosum cytochrome c ...19911646027
the rhodospirillum rubrum cytochrome bc1 complex: redox properties, inhibitor sensitivity and proton pumping.a detergent-solubilized, three-subunit-containing cytochrome bc1 complex, isolated from the photosynthetic bacterium r. rubrum, has been shown to be highly sensitive to stigmatellin, myxothiazol, antimycin a and uhdbt, four specific inhibitors of these complexes. oxidation-reduction titrations have allowed the determination of em values for all the electron-carrying prosthetic groups in the complex. antimycin a has been shown to produce a red shift in the alpha-band absorbance maximum of one of ...19911646633
genetic analysis of photosynthesis in rhodospirillum centenum.a genetic system has been developed for studying bacterial photosynthesis in the recently described nonsulfur purple photosynthetic bacterium rhodospirillum centenum. nonphotosynthetic mutants of r. centenum were obtained by enrichment for spontaneous mutations, by ethyl methanesulfonate mutagenesis coupled to penicillin selection on solid medium, and by tn5 transposition mutagenesis with an incp plasmid vector containing a temperature-sensitive origin of replication. in vivo and in vitro charac ...19911648078
molecular structure of cytochrome c2 isolated from rhodobacter capsulatus determined at 2.5 a resolution.the molecular structure of the cytochrome c2, isolated from the purple photosynthetic bacterium rhodobacter capsulatus, has been solved to a nominal resolution of 2.5 a and refined to a crystallographic r-factor of 16.8% for all observed x-ray data. crystals used for this investigation belong to the space group r32 with two molecules in the asymmetric unit and unit cell dimensions of a = b = 100.03 a, c = 162.10 a as expressed in the hexagonal setting. an interpretable electron density map calcu ...19911651396
cytochrome c' of paracoccus denitrificans.cytochrome c' was identified in periplasmic extracts of the paracoccus denitrificans strains lmd 22.21 and lmd 52.44. the cytochrome c' was purified from the latter using the device of sequential molecular exclusion chromatography in the dimeric and monomeric states. although showing the overall spectroscopic features of the cytochrome c' family, the paracoccus cytochrome c' is unusual in having a red-shifted oxidised soret band at 407 nm. also unusual is the midpoint potential of 202 mv, well a ...19911653018
electrostatic effects on the kinetics of electron transfer reactions of cytochrome c caused by binding to negatively charged lipid bilayer vesicles.the effect of binding reduced tuna mitochondrial cytochrome c to negatively charged lipid bilayer vesicles at low ionic strength on the kinetics of electron transfer to various oxidants was studied by stopped-flow spectrophotometry. binding strongly stimulated (up to 100-fold) the rate of reaction with the positively charged cobalt phenanthroline ion, whereas the rate of reaction with the negatively charged ferricyanide ion was greatly inhibited (up to 60-fold), as compared with the same systems ...19911654779
electron transfer proteins of the purple phototrophic bacterium, rhodopseudomonas rutila.the soluble electron transfer protein content of rhodopseudomonas rutila was found to consist of two basic cytochromes and a (4fe-4s) ferredoxin. cytochrome c' was easily identified by its characteristic high spin absorption spectra. the native molecular weight is 29,000 and the subunit is 14,000. cytochrome c-550 has low spin absorption spectra and a high redox potential (376 mv) typical of cytochromes c2. the molecular weight is about 14,000. the ferredoxin is apparently a dimer (43,000) of ap ...19911654788
structural and functional features of pseudomonas cytochrome c peroxidase.the secondary structure of pseudomonas cytochrome c peroxidase (ferrocytochrome c: hydrogen-peroxide oxidoreductase, ec has been predicted from the established amino acid sequence of the enzyme using a chou-fasman-type algorithm. the amount of alpha-helicity thus obtained is in agreement with previously obtained results based on circular dichroic measurements at far uv. the two heme c moieties of the enzyme have earlier been shown to have widely different characteristics, e.g., the red ...19911657179
an improved tn7-based system for the single-copy insertion of cloned genes into chromosomes of gram-negative bacteria.a system is described for the single-copy, stable insertion of cloned dna sequences into the chromosomes of gram- bacteria. two narrow-host-range plasmids form the basis of this system: the 'carrier' plasmid contains the mini tn7-km transposon, into which foreign dna can be cloned; the 'helper' plasmid provides the tn7 transposition functions in trans. both plasmids are readily transferred into gram- bacteria by conjugation. the functionality of this system has been demonstrated in rhodospirillu ...19911661697
immunological cross-reactivity between proton-pumping inorganic pyrophosphatases of widely phylogenic separated species.immunological cross-reactivity among three types of inorganic pyrophosphatases, that is, the proton pumping inorganic pyrophosphate synthase (h(+)-ppi synthase) and the soluble inorganic pyrophosphatase, both from rhodospirillum rubrum, and the vacuolar membrane inorganic pyrophosphatase (h(+)-ppase) from mung bean (vigna radiata), were examined by means of immunoblot analyses. antibodies raised against the mung bean h(+)-ppase cross-reacted with the h(+)-ppi synthase from r. rubrum but not with ...19911662506
an electrochemical assay for the characterization of redox proteins from biological electron transfer chains.a sensitive and quick assay for redox proteins based on electrochemical titrations in a thin-layer electrochemical cell is described. using a combination of modified-electrode and "mediator-enhanced" electrochemistry, equilibration of the cell volume (4 microliters) with the applied potential allows series of spectra as a function of the potential to be recorded rapidly. a complete redox titration between +500 and -600 mv (vs ag/agcl/3 m kcl) in 30-mv intervals takes approximately 2 h. the detec ...19911667456
reactivation of the chloroplast cf1-atpase beta subunit by trace amounts of the cf1 alpha subunit suggests a chaperonin-like activity for cf1 alpha.incubation of tobacco and lettuce thylakoids with 2 m licl in the presence of mgatp removes the beta subunit from their cf1-atpase (cf1 beta) together with varying amounts of the cf1 alpha subunit (cf1 alpha). these 2 m licl extracts, as with the one obtained from spinach thylakoids (avital, s., and gromet-elhanan, z. (1991) j. biol. chem. 266, 7067-7072), could form active hybrid atpases when reconstituted into inactive beta-less rhodospirillum rubrum chromatophores. pure cf1 beta fractions tha ...19911673460
low- and high-activity forms of glutamine synthetase from rhodospirillum rubrum: sensitivity to feed-back effectors and activation of the low-activity form.glutamine synthetase from rhodospirillum rubrum can be isolated in two forms, with low and high activity, respectively, depending on the concentration of combined nitrogen in the medium before harvest. the two forms have been studied with respect to their dependence on mn2+ and mg2+ in both the transferase and the biosynthetic assay. there is no difference in ph optimum between the forms in the biosynthetic assay. in addition the ph-optima for the two cations studied are very close, 7.4 (mg2+) a ...19911683256
mg2+ is an essential activator of hydrolytic activity of membrane-bound pyrophosphatase of rhodospirillum rubrum.the substrate for the hydrolytic activity of membrane-bound pyrophosphatase is the pp(i)-mg2+ complex. the enzyme has no activity when the free mg2+ concentration is lower than 10 microm (at 0.5 mm-pp(i)-mg2+), and therefore free mg2+ is an essential activator of the hydrolytic activity. the km for the substrate changes in response to variation in free mg2+ concentration, from 10.25 to 0.6 mm when free mg2+ is increased from 0.03 to 1.0 mm respectively. the km for mg2+ depends on the substrate c ...19921315519
three-dimensional structure of ferricytochrome c' from rhodospirillum rubrum at 2.8 a resolution.the structure of ferricytochrome c' extracted from rhodospirillum rubrum has been determined by the x-ray crystallographic method. crystals in hexagonal space group p6(1), with unit-cell dimensions a = b = 51.72 a and c = 155.49 a, contain one dimer molecule composed of chemically identical polypeptide chains (monomer i and monomer ii) per asymmetric unit. an electron density map has been calculated at a resolution of 2.8 a by the multiple isomorphous replacement method using four-circle diffrac ...19921316891
isolation and characterisation of a functional alpha beta heterodimer from the atp synthase of rhodospirillum alpha beta heterodimer of the f1-atpase of rhodospirillum rubrum was isolated by extraction of chromatophores with licl. each alpha beta heterodimer contains one tightly bound adp, which is released upon removal of medium mg2+. the dimer can be reversibly dissociated by removal of mg(2+)-ions. the alpha beta heterodimer restores both atp-synthetic and -hydrolytic activities to licl-treated chromatophores, saturation being achieved at approximately 2 mmol alpha beta.mol bchl-1. the heterodimer ...19921327870
evidence of an essential carboxyl residue in membrane-bound pyrophosphatase of rhodospirillum rubrum.chemical modifications with water-soluble carbodiimides (edc and cmc) were performed to elucidate whether some carboxyl residues are involved in the catalytic activity of membrane-bound pyrophosphatase of rhodospirillum rubrum. edc and cmc cause a loss of hydrolytic activity following pseudo-first-order kinetics up to 10 min of reaction. the enzyme was completely protected against edc inhibition by ppi or mg2+, whereas ppi or mg2+ gave partial protection against cmc inactivation. mg-ppi protecte ...19921334073
conformational states of ribulosebisphosphate carboxylase and their interaction with chaperonin 60.conformational states of ribulosebisphosphate carboxylase (rubisco) from rhodospirillum rubrum were examined by far-uv circular dichroism (cd), tryptophan fluorescence, and 1-anilino-naphthalenesulfonate (ans) binding. at ph 2 and low ionic strength (i = 0.01), rubisco adopts an unfolded, monomeric conformation (ua1 state) as judged by far-uv cd and tryptophan fluorescence. as with other acid-unfolded proteins [goto, y., calciano, l. j., & fink, a. l. (1990) proc. natl. acad. sci. u.s.a. 87, 573 ...19921348956
purified chaperonin 60 (groel) interacts with the nonnative states of a multitude of escherichia coli vitro experiments employing the soluble proteins from escherichia coli reveal that about half of them, in their unfolded or partially folded states, but not in their native states, can form stable binary complexes with chaperonin 60 (groel). these complexes can be isolated by gel filtration chromatography and are efficiently discharged upon the addition of mg.atp. binary complex formation is substantially reduced if chaperonin 60 is presaturated with rubisco-i, the folding intermediate of rub ...19921363913
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