PMID(sorted descending)
photosynthetic deficiency of a pufx deletion mutant of rhodobacter sphaeroides is suppressed by point mutations in the light-harvesting complex genes pufb or pufa.the pufx gene of the facultative phototroph rhodobacter sphaeroides encodes a membrane protein that is required for photoheterotrophic growth. deletion of pufx impairs the photosynthetic generation of a transmembrane potential, suggesting a role for the pufx protein in light-driven cyclic electron transfer [farchaus, j. w., et al. (1992) embo j. 11, 2779-2788]. here we describe the isolation and characterization of 65 spontaneous suppressor mutants in which photosynthetic competence was restored ...19948068653
energy migration and trapping in a spectrally and spatially inhomogeneous light-harvesting this paper, we analyze the process of excitation energy migration and trapping by reaction centres in photosynthesis and discuss the mechanisms that may provide an overall description of this process in the photosynthetic bacterium rhodospirillum (rs.) rubrum and related organisms. a wide range of values have been published for the pigment to pigment transfer rate varying from less than 1 ps up to 10 ps. these differences occur because the interpretation of trapping measurements depend on the ...19948061207
interaction between cytochrome c2 and reaction centers from purple bacteria.the kinetics of electron transfer of cytochrome c2 from rhodobacter sphaeroides, rhodobacter capsulatus, and rhodospirillum centenum to reaction centers from rb. sphaeroides and rb. capsulatus have been measured. observed in the kinetics of decay of the oxidized donor are a rapid first-order rate and one or more slower rates that are due to diffusion-limited complex formation. for reaction centers from rb. sphaeroides, the fast component had time constants of 1.0 and 0.5 microsecond for cytochro ...19948031763
the photoactive yellow protein from ectothiorhodospira halophila as studied with a highly specific polyclonal antiserum: (intra)cellular localization, regulation of expression, and taxonomic distribution of cross-reacting proteins.a rabbit antiserum was raised against the photoactive yellow protein (pyp) from ectothiorhodospira halophila and purified by adsorption experiments to obtain a highly specific polyclonal antiserum. this antiserum was used to obtain the following results. (i) in e. halophila, pyp can be isolated from the fraction of soluble proteins. in the intact cell, however, pyp appeared to be associated with (intra)cytoplasmic membranes, as was concluded from analysis of immunogold-labelled thin sections of ...19948021174
a structural role for arginine in proteins: multiple hydrogen bonds to backbone carbonyl oxygens.we propose that arginine side chains often play a previously unappreciated general structural role in the maintenance of tertiary structure in proteins, wherein the positively charged guanidinium group forms multiple hydrogen bonds to backbone carbonyl oxygens. using as a criterion for a "structural" arginine one that forms 4 or more hydrogen bonds to 3 or more backbone carbonyl oxygens, we have used molecular graphics to locate arginines of interest in 4 proteins: arg 180 in thermus thermophilu ...19948003972
the effect of sulfite on the atp hydrolysis and synthesis activity of membrane-bound h(+)-atp synthase from various species.the action of sulfite on atp hydrolysis and synthesis activities is investigated in membrane vesicles prepared from the cyanobacterium synechococcus 6716, chromatophores from the photosynthetic purple bacterium rhodospirillum rubrum, membrane vesicles from the related non-photosynthetic bacterium paracoccus denitrificans, and bovine heart submitochondrial particles. without any further pretreatment atp hydrolysis is stimulated by sulfite in all four membrane preparations. typically atp synthesis ...19948002977
changes in the nad(p)h concentration caused by addition of nitrogenase 'switch-off' effectors in rhodospirillum rubrum g-9, as measured by fluorescence.the effect of nitrogenase 'switch-off' effectors on the concentration of nad(p)h in rhodospirillum rubrum g-9 was investigated by fluorescence. a rapid decrease in fluorescence was observed when cells, either n2-grown or nitrogen-starved, were subjected to the effectors, but not when sodium chloride or tris buffer was added. no effects on the fluorescence were observed in non-nitrogen fixing cultures except when nad+ was added. the results strongly indicate that the redox state of the pyridine n ...19947988717
characterization of a light-responding trans-activator responsible for differentially controlling reaction center and light-harvesting-i gene expression in rhodobacter capsulatus.the purple nonsulfur photosynthetic bacterium rhodobacter capsulatus regulates synthesis of its photosystem in response to two environmental stimuli, oxygen tension and light intensity. here we describe the identification and characterization of the trans-acting regulatory gene hvra, which we show is involved in differentially controlling reaction center and light-harvesting gene expression in response to alterations in light intensity. an hvra mutant strain is shown to lack the capability to tr ...19947961455
an improved procedure and new vectors for transposon tn5 mutagenesis of the phototrophic bacterium rhodospirillum rubrum.a detailed examination of vectors and procedures used for tn5 mutagenesis of the phototrophic purple non-sulfur bacterium rhodospirillum rubrum has been performed. the mobilizable tn5 suicide vectors currently available show a frequency of tn5 mutagenesis for r. rubrum of approx. 10(-7)-10(-8), approx. 100-1000-fold lower than observed for the related bacteria rhodobacter capsulatus and rhodobacter sphaeroides. using the blue-to-red reversion of a blue-green mutant, r. rubrum st6, containing a s ...19947959072
reconstitution of a functional photosynthetic receptor complex with isolated subunits of core light-harvesting complex and reaction centers.the b820 subunit form of the core light-harvesting complex lhi, isolated from the photosynthetic bacterium rhodospirillum rubrum, was combined in a reassociation assay with the reaction center (rc) isolated from the same or related bacteria. this reassociation produced a photoreceptor complex (prc) which appeared, by absorption spectroscopy, circular dichroism measurements, and kinetic absorption spectroscopy measuring transient photochanges, as analogous to the prc in the intact bacteria. energ ...19947947741
purification and characterization of an oxygen-stable form of dinitrogenase reductase-activating glycohydrolase from rhodospirillum rubrum.dinitrogenase reductase-activating glycohydrolase (drag) is responsible for removing the adp-ribose moiety from post-translationally inactivated nitrogenase of rhodospirillum rubrum. using drag purified from an overexpressing strain (ur276), further properties of this enzyme were studied, including its u.v.-visible and fluorescence spectra and its stability in air. drag appears to require no covalently bound inorganic cofactors for its activity or regulation. previously, purified drag was found ...19947945205
molecular characterization of two spontaneous antimycin a resistant mutants of rhodospirillum rubrum.antimycin a is an inhibitor of cytochrome bc1 complexes acting at the quinone reducing site (qi) of the cytochrome b subunit. we report here the isolation and molecular characterization of two spontaneous mutants of the purple non-sulfur bacterium rhodospirillum rubrum resistant to this inhibitor. in the two mutants antimycin a resistance was found to be conferred by replacement of an aspartate residue at position 243 of the cytochrome b polypeptide chain, in one case by histidine and in the oth ...19947918532
comparative study of reaction centers from photosynthetic purple bacteria: electron paramagnetic resonance and electron nuclear double resonance spectroscopy.reaction centers (rcs) from four species of purple bacteria, rhodobacter sphaeroides, rhodobacter capsulatus, rhodospirillum rubrum, and the recently discovered bacterium rhodospirillum centenum, have been characterized by optical spectroscopy [wang, s., lin, x., woodbury, n. w., & allen, j. p. (1994) photosynth. res. (submitted for publication)] and magnetic resonance spectroscopy. all rcs contain a bacteriochlorophyll (bchl) a dimer as the primary donor. for rb. sphaeroides and rs. rubrum the ...19947918428
characterization of antimycin resistant mutants of rhodospirillum rubrum. 19947911439
bacteriophage t4 encodes a co-chaperonin that can substitute for escherichia coli groes in protein folding.several bacteriophages use the escherichia coli groes and groel chaperonins for folding and assembly of their morphogenetic structures. bacteriophage t4 is unusual in that it encodes a specialized protein (gp31) that is thought to interact with the host groel and to be absolutely required for the correct assembly of the major capsid protein (gp23) in vivo. here we show that despite the absence of amino-acid sequence similarity between gp31 and groes, gp31 can functionally substitute for the groe ...19947908418
reversible adp-ribosylation as a mechanism of enzyme regulation in procaryotes.several cases of adp-ribosylation of endogenous proteins in procaryotes have been discovered and investigated. the most thoroughly studied example is the reversible adp-ribosylation of the dinitrogenase reductase from the photosynthetic bacterium rhodospirillum rubrum and related bacteria. a dinitrogenase reductase adp-ribosyltransferase (drat) and a dinitrogenase reductase adp-ribose glycohydrolase (drag) from r. rubrum have been isolated and characterized. the genes for these proteins have bee ...19947898454
tight nucleotide binding sites and atpase activities of the rhodospirillum rubrum rrf1-atpase as compared to spinach chloroplast cf1-atpase.solubilized rhodospirillum rubrum rrf1-atpase, depleted of loosely bound nucleotides, retains 2.6 mol of tightly bound atp and adp/mol of enzyme. incubation of the depleted rrf1 with mg(2+)-atp or mg(2+)-amp-pnp, followed by passage through two successive sephadex centrifuge columns, results in retention of a maximal number of 4 mol of tightly bound nucleotides/mol of rrf1. they include 1.5 mol of nonexchangeable atp, whereas all tightly bound adp is fully exchangeable. a similar retention of on ...19947896772
amino acid sequences of cytochromes c2 and c' from the moderately halophilic purple phototrophic bacterium rhodospirillum salexigens.rhodospirillum salexigens is a moderately halophilic purple phototrophic bacterium which grows optimally in 8% nacl. the amino acid sequences of the two principal soluble cytochromes c have been determined. one of these is a cytochrome c2, similar in size to mitochondrial cytochrome c. while clearly of the same sequence class as mitochondrial cytochrome c and the proteins from several other gram-negative bacteria, it does not show particular affinity to any already known sequence in terms of the ...19947893810
reconstitution of the bacterial core light-harvesting complexes of rhodobacter sphaeroides and rhodospirillum rubrum with isolated alpha- and beta-polypeptides, bacteriochlorophyll alpha, and carotenoid.methodology has been developed to reconstitute carotenoids and bacteriochlorophyll alpha with isolated light-harvesting complex i (lhi) polypeptides of both rhodobacter sphaeroides and rhodospirillum rubrum. reconstitution techniques first developed in this laboratory using the lhi polypeptides of r. rubrum, r. sphaeroides, and rhodobacter capsulatus reproduced bacteriochlorophyll alpha spectral properties characteristic of lhi complexes lacking carotenoids. in this study, carotenoids are suppli ...19957890709
stability of the asymmetric escherichia coli chaperonin complex. guanidine chloride causes rapid dissociation.the chaperonin proteins, groel14 and groes7, inhibit protein aggregation and assist in protein folding in a potassium/atp-dependent manner. in vitro, assays for chaperonin activity typically involve adding a denatured substrate protein to the chaperonins and measuring the appearance of correctly folded substrate protein. the influence of denaturant is generally ignored. low concentrations of guanidinium chloride (< 100 mm) had a profound effect on the activity/structure of the chaperonins. guani ...19957890652
the 8.5 a projection map of the light-harvesting complex i from rhodospirillum rubrum reveals a ring composed of 16 subunits.two-dimensional crystals from light-harvesting complex i (lhc i) of the purple non-sulfur bacterium rhodospirillum rubrum have been reconstituted from detergent-solubilized protein complexes. frozen-hydrated samples have been analysed by electron microscopy. the crystals diffract beyond 8 a and a projection map was calculated to 8.5 a. the projection map shows 16 subunits in a 116 a diameter ring with a 68 a hole in the centre. these dimensions are sufficient to incorporate a reaction centre in ...19957882966
molecular relationship of an atypical azospirillum strain 4t to other azospirillum species.dna/dna hybridization, plasmid content and partial 16s rdna sequence were determined to confirm the relationship between two azospirillum strains, 4b and 4t, isolated from the same rice rhizosphere. the partial 16s rdna sequence was determined for 9 strains belonging to 5 azospirillum species which included azospirillum lipoferum strains 4b and 4t, and was compared to a set of ribosomal sequences from other bacteria of the alpha subdivision of the proteobacteria. four azospirillum species sequen ...19947871242
differentiation of brucella abortus bv. 1, 2, and 4, brucella melitensis, brucella ovis, and brucella suis bv. 1 by pcr.several pcr assays which identify the genus brucella but do not discriminate among species have been reported. we describe a pcr assay that comprises five oligonucleotide primers which can identify selected biovars of four species of brucella. individual biovars within a species are not differentiated. the assay can identify three biovars (1, 2, and 4) of b. abortus, all three biovars of b. melitensis, biovar 1 of b. suis, and all b. ovis biovars. these biovars include all of the brucella specie ...19947852552
enzymatic and chemical cleavage of the core light-harvesting polypeptides of photosynthetic bacteria: determination of the minimal polypeptide size and structure required for subunit and light-harvesting complex ascertain the minimal structural requirements for formation of the subunit and core light-harvesting complex (lh1), the alpha- and beta-polypeptides of the lh1 from three purple photosynthetic bacteria were enzymatically or chemically truncated or modified. these polypeptides were then used in reconstitution experiments with bacteriochlorophyll a (bchla), and the formation of subunit and lh1 complexes was evaluated using absorbance and circular dichroism spectroscopies. truncation or modifica ...19957849015
energy-transducing nicotinamide nucleotide transhydrogenase: nucleotide sequences of the genes and predicted amino acid sequences of the subunits of the enzyme from rhodospirillum rubrum.based on the amino acid sequence of the n-terminus of the soluble subunit of the rhodospirillum rubrum nicotinamide nucleotide transhydrogenase, two oligonucleotide primers were synthesized and used to amplify the corresponding dna segment (110 base pairs) by the polymerase chain reaction. using this pcr product as a probe, one clone with the insert of 6.4 kbp was isolated from a genomic library of r. rubrum and sequenced. this sequence contained three open reading frames, constituting the genes ...19947844118
h+/ppi stoichiometry of membrane-bound pyrophosphatase of rhodospirillum rubrum.two kinetic methods have been used to measure the h+/ppi stoichiometry in the chromatophores of the photosynthetic bacteria rhodospirillum rubrum. in the first method, the fluorescent probe acridine orange was employed to infer the proton pump activity at the steady state of the delta ph generation. at this point the translocation of protons by the h(+)-ppiase in one direction is balanced exactly by the leak of protons in the opposite direction. pyrophosphatase activity was then quickly stopped ...19957840646
posttranslational regulation of nitrogenase in rhodospirillum rubrum strains overexpressing the regulatory enzymes dinitrogenase reductase adp-ribosyltransferase and dinitrogenase reductase activating glycohydrolase.rhodospirillum rubrum strains that overexpress the enzymes involved in posttranslational nitrogenase regulation, dinitrogenase reductase adp-ribosyltransferase (drat) and dinitrogenase reductase activating glycohydrolase (drag), were constructed, and the effect of this overexpression on in vivo drat and drag regulation was investigated. broad-host-range plasmid constructs containing a fusion of the r. rubrum nifh promoter and translation initiation sequences to the second codon of drat, the firs ...19957836296
characterization of an aerobic repressor that coordinately regulates bacteriochlorophyll, carotenoid, and light harvesting-ii expression in rhodobacter capsulatus.for most species of purple photosynthetic bacteria, the presence of molecular oxygen represses synthesis of carotenoids and bacteriochlorophyll. in this study we characterize a strain of rhodobacter capsulatus, db469, which contains a genomic disruption of an open reading frame in the photosynthesis gene cluster termed orf469. characterization of the steady-state level of bacteriochlorophyll synthesis demonstrates that disruption of orf469 results in a 2.5-fold increase in aerobic synthesis of b ...19957768793
cloning and sequence of the l2 form of rubisco from a marine obligately autotrophic hydrogen-oxidizing bacterium, hydrogenovibrio marinus strain mh-110.a form ii ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) gene was isolated and sequenced from a marine hydrogen-oxidizing bacterium, hydrogenovibrio marinus strain mh-110. to our knowledge, this is the first report for the sequence of a form ii (l2-form) rubisco gene derived from a chemolithoautotrophic bacterium. the form ii rubisco gene coded for 463 amino acid residues (1389 bp, m(r) = 50,655). the deduced amino acid sequence had high homology with those of the l2-form rubisco of r ...19947765489
identification and partial sequence of the bcha gene of rhodospirillum rubrum.the dna sequence was determined for a region upstream of the puf operon of rhodospirillum rubrum. a partial orf was identified. the dna sequence and the inferred amino acid sequences were aligned with those of bcha of rhodobacter capsulatus and other phototrophic bacteria. based on this alignment and genetic evidence, this orf was identified as r. rubrum bcha, which encodes an enzyme involved in bacteriochlorophyll biosynthesis. an additional orf was identified in the intergenic region between b ...19937763790
a signature of the oxygenase intermediate in catalysis by ribulose-bisphosphate carboxylase/oxygenase as provided by a site-directed uncharacterized minor transient product, observed in our earlier studies of substrate turnover by the e48q mutant of rhodospirillum rubrum ribulose-bisphosphate carboxylase/oxygenase (lee, e. h., harpel, m. r., chen, y.-r., and hartman, f. c. (1993) j. biol. chem. 268, 26583-26591), becomes a major product when it is trapped and stabilized with borate as an additive to the reaction mixture. chemical characterization establishes this novel product as d-glycero-2,3-pentodiulose 1,5-bisphosphate ...19957744819
evidence that some dinoflagellates contain a ribulose-1,5-bisphosphate carboxylase/oxygenase related to that of the alpha-proteobacteria.the ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) large subunit from several dinoflagellates has a structure similar to that of the form ii enzyme from rhodospirillum and rhodobacter species rather than the form i rubisco of eukaryotic algae and higher plants. the dinoflagellate rubisco was identified on native polyacrylamide gels by autoradiographic detection of the stable rubisco-[2'-14c]-2-carboxy-d-arabinitol 1,5-bisphosphate complex. the antibody to the symbiodinium sp. large su ...19957740046
properties of the soluble polypeptide of the proton-translocating transhydrogenase from rhodospirillum rubrum obtained by expression in escherichia coli.transhydrogenase, which catalyses the reduction of nadp+ by nadh coupled to proton translocation across a membrane, may be unique in the photosynthetic bacterium rhodospirillum rubrum. unlike the homologous enzyme from animal mitochondria and other bacterial sources, it has a water-soluble polypeptide, which exists as a dimer (ths), that can be reversibly dissociated from the membrane component [williams, r., cotton, n. p. j., thomas, c. m. & jackson, j. b. (1994) microbiology, 140, 1595-1604]. ...19957737169
comparison studies of dinitrogenase reductase adp-ribosyl transferase/dinitrogenase reductase activating glycohydrolase regulatory systems in rhodospirillum rubrum and azospirillum brasilense.reversible adp ribosylation of dinitrogenase reductase, catalyzed by the dinitrogenase reductase adp-ribosyl transferase (drat)/dinitrogenase reductase activating glycohydrolase (drag) regulatory system, has been characterized in both rhodospirillum rubrum and azospirillum brasilense. although the general functions of drat and drag are very similar in these two organisms, there are a number of interesting differences, e.g., in the timing and extent of the regulatory response to different stimuli ...19957730264
reactivity of carbon monoxide dehydrogenase from rhodospirillum rubrum with carbon dioxide, carbonyl sulfide, and carbon disulfide.the reactivities of co2 and the related compounds cos and cs2 with the nickel- and iron- sulfur-containing carbon monoxide dehydrogenase (codh) from rhodospirillum rubrum have been investigated. both co2 and cos were substrates for codh in a reductant-dependent reaction resulting in the formation of co. co2 was reduced to co and h2o, while cos was reduced to co and h2s. co was a potent inhibitor of co2 reduction at dissolved concentrations as low as 1 microm, but this inhibition could be prevent ...19957727395
conformational properties of four peptides corresponding to alpha-helical regions of rhodospirillum cytochrome c2 and bovine calcium binding protein.four peptides corresponding to alpha-helical regions delimited by residues 63-73 and 97-112 of cytochrome c2 (rhodospirillum) and residues 24-36 and 45-55 of bovine calcium binding protein are predicted to be alpha-helical by a recently developed method [rooman, m., kocher, j.p., & wodak, s.j. (1991) j. mol. biol. 221, 961-979], synthesized by solid phase methods, and purified by hplc, and their solution conformations are determined by nmr and cd. the observed conformational properties of these ...19947727367
carbon monoxide-dependent growth of rhodospirillum rubrum.under dark, anaerobic conditions in the presence of sufficient nickel, rhodospirillum rubrum grows with a doubling time of under 5 h by coupling the oxidation of co to the reduction of h+ to h2. co-dependent growth of r. rubrum ur294, bearing a kanamycin resistance cassette in cooc, depends on a medium nickel level ninefold higher than that required for optimal growth of coo+ strains.19957721719
carbon monoxide-induced activation of gene expression in rhodospirillum rubrum requires the product of cooa, a member of the cyclic amp receptor protein family of transcriptional regulators.induction of the co-oxidizing system of the photosynthetic bacterium rhodospirillum rubrum is regulated at the level of gene expression by the presence of co. in this paper, we describe the identification of a gene that is required for co-induced gene expression. an 11-kb deletion of the region adjacent to the previously characterized coofsctj region resulted in a mutant unable to synthesize co dehydrogenase in response to co and unable to grow utilizing co as an energy source. a 2.5-kb region t ...19957721706
mechanistic insights provided by deletion of a flexible loop at the active site of ribulose-1,5-bisphosphate carboxylase/ evaluate the functions of flexible loop 6 at the active site of rhodospirillum rubrum d-ribulose-1,5-bisphosphate carboxylase/oxygenase, the loop was truncated by cassette mutagenesis, whereby seven residues of the twelve-residue loop were excised and replaced by two glycyl residues. the purified loop-deletion mutant was totally devoid of carboxylase activity, but retained substantial catalytic competency in the enolization of ribulose bisphosphate (the initial step in the overall carboxylase ...19957718555
macroscopic phototactic behavior of the purple photosynthetic bacterium rhodospirillum centenum.most photosynthetic microorganisms have the capability of photosensing light quality and intensity. movement of motile photosynthetic microorganisms to locales that offer optimal physical and chemical conditions for light-dependent growth provides obvious selective advantages. among phototrophs, many cyanobacteria and algae migrate towards or away from the direction of light, a process termed phototaxis. in contrast, anoxygenic photosynthetic bacteria are believed to respond to changes in light ...19957710317
studies on reconstitution of the rhodospirillum rubrum nicotinamide nucleotide transhydrogenase.the energy-transducing nicotinamide nucleotide transhydrogenase of rhodospirillum rubrum is composed of 3 subunits alpha 1, alpha 2 and beta, with m(r) values, respectively, of 40.3, 14.9 and 47.8 kda. subunit alpha 1 is water-soluble, loosely bound to chromatophores, and can be easily and reversibly removed. subunits alpha 2 and beta are integral membrane proteins, and their removal from chromatophores requires the use of detergents. treatment of chromatophores with various detergents inhibited ...19947696982
evolutionary relationships among magnetospirillum strains inferred from phylogenetic analysis of 16s rdna sequences.we have investigated the evolutionary relationships between two facultatively anaerobic magnetospirillum strains (amb-1 and mgt-1) and fastidious, obligately microaerophilic species, such as magnetospirillum magnetotacticum, using a molecular phylogenetic approach. genomic dna from strains mgt-1 and amb-1 was used as a template for amplification of the genes coding for 16s rrna (16s rdna) by the polymerase chain reaction. amplified dna fragments were sequenced (1,424 bp) and compared with sequen ...19937691800
electron paramagnetic resonance studies of ferric cytochrome c' from photosynthetic bacteria.electronic ground nature of ferric cytochromes c' isolated from five photosynthetic bacteria. chromatium vinosum atcc 17899, rhodobacter capsulatus atcc 11166, rhodopseudomonas palustris atcc 17001, rhodospirillum molischianum atcc 14031, and rhodospirillum rubrum atcc 11170 has been investigated by electron paramagnetic resonance (epr) spectroscopy. epr spectra indicate that the electronic ground state of five ferric cytochromes c' is a quantum mechanical admixed-spin state of a high spin (s = ...19957669805
oxygenation mechanism of ribulose-bisphosphate carboxylase/oxygenase. structure and origin of 2-carboxytetritol 1,4-bisphosphate, a novel o2-dependent side product generated by a site-directed mutagenesis has implicated active-site lys329 of rhodospirillum rubrum ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) in promoting the reaction of co2 with the 2,3-enediol of ribulose bisphosphate and in stabilizing carboxylation intermediates [hartman, f. c., & lee, e. h. (1989) j. biol. chem. 264, 11784-11789; lorimer, g. h., chen, y.-r., & hartman, f. c. (1993) biochemistry 32, 9018-9024]. although the k329a mutant is greatly impaired in carboxylation, it catalyzes fo ...19957669788
effect of an ntrbc mutation on the posttranslational regulation of nitrogenase activity in rhodospirillum rubrum.homologs of ntrb and ntrc genes from rhodospirillum rubrum were cloned and sequenced. a mutant lacking ntrbc was constructed, and this mutant has normal nitrogenase activity under nif-derepressing conditions, indicating that ntrbc are not necessary for the expression of the nif genes in r. rubrum. however, the post-translational regulation of nitrogenase activity by adp-ribosylation in response to nh4+ was partially abolished in this mutant. more surprisingly, the regulation of nitrogenase activ ...19957665521
theory of fluorescence induction in photosystem ii: derivation of analytical expressions in a model including exciton-radical-pair equilibrium and restricted energy transfer between photosynthetic units.the theoretical relationships between the fluorescence and photochemical yields of ps ii and the fraction of open reaction centers are examined in a general model endowed with the following features: i) a homogeneous, infinite ps ii domain; ii) exciton-radical-pair equilibrium; and iii) different rates of exciton transfer between core and peripheral antenna beds. simple analytical relations are derived for the yields and their time courses in induction experiments. the introduction of the excito ...19957647250
mutation of the ser2 codon of the light-harvesting b870 alpha polypeptide of rhodobacter capsulatus partially suppresses the pufx phenotype.the exact function of the pufx gene product of rhodobacter capsulatus is uncertain, but deletion of the pufx gene renders cells incapable of phototrophic growth on a minimal medium, and photosynthetic electron transfer is impaired in vitro. however, suppressor mutants that are able to grow phototropically are readily isolated. two such suppressor mutants were characterized as to their phototrophic growth properties, their fluorescence at different incident light intensities, the integrity of the ...19957642484
spectroscopic properties of the light-harvesting complexes from rhodospirillum molischianum.spectroscopic properties, including low-temperature absorbance, linear and circular dichroism and site-selection fluorescence of the antenna complexes from rhodospirillum molischianum have been determined. the unique 'lh1-like' character of the amino acid sequence from lh2 of this bacterium is reflected in the circular dichroism of the b850 band of this complex. the wavelength dependence of the polarization of the lh2 complex shows an unusual shape that is attributed to the octameric state of th ...19957619833
phylogeny of the genus azospirillum based on 16s rdna sequence.the 16s rdna of 17 strains of azospirillum, 14 assigned to one of the known species a. amazonense, a. brasilense, a. halopraeferens, a. irakense and a. lipoferum, and the other three of uncertain taxonomic position, was sequenced after polymerase chain reaction amplification and analysed in order to investigate the phylogenetic relationships at the intra-generic and super-generic level. the phylogenetic analysis confirms that the genus azospirillum constitutes a phylogenetically separate entity ...19957607400
direct evidence for secondary loss of mitochondria in entamoeba histolytica.archezoan protists are though to represent lineages that diverged from other eukaryotes before acquisition of the mitochondrion and other organelles. the parasite entamoeba histolytica was originally included in this group. ribosomal rna based phylogenies, however, place e. histolytica on a comparatively recent branch of the eukaryotic tree, implying that its ancestors had these structures. in this study, direct evidence for secondary loss of mitochondrial function was obtained by isolating two ...19957604025
construction of a 2.8-megabase yeast artificial chromosome contig and cloning of the human methylthioadenosine phosphorylase gene from the tumor suppressor region on 9p21.many human malignant cells lack methylthioadenosine phosphorylase (mtap) enzyme activity. the gene (mtap) encoding this enzyme was previously mapped to the short arm of chromosome 9, band p21-22, a region that is frequently deleted in multiple tumor types. to clone candidate tumor suppressor genes from the deleted region on 9p21-22, we have constructed a long-range physical map of 2.8 megabases for 9p21 by using overlapping yeast artificial chromosome and cosmid clones. this map includes the typ ...19957604019
reversible super-reduction of the cubane [4fe-4s](3+;2+;1+) in the high-potential iron-sulfur protein under non-denaturing conditions. epr spectroscopic and electrochemical studies.the reversible 2 x 1 e- reduction of the cubane cluster from oxidized to reduced to super-reduced states ([4fe-4s]3+<-->[4fe-4s]2+<-->[4fe-4s]1+) was studied in high-potential iron-sulfur proteins (hipips). super-reduction to the 1+ state was not observed in any of the seven hipips tested during cyclic voltammetry (down to -0.95 v). however, equilibration at low potential (ph 7.5) of rhodopila globiformis hipip yields a transient peak around -0.47 v due to the oxidation of super-reduced hipip ad ...19957588720
the single-ring thermoanaerobacter brockii chaperonin 60 (tbr-el7) dimerizes to tbr-el14.tbr-es7 under protein folding conditions.chaperone proteins assist in the folding of some newly synthesized proteins and inhibit protein aggregation. the thermoanaerobacter brockii chaperonin proteins (tbr-el and tbr-es) have recently been purified and characterized [truscott, w.n., høj, p. b., & scopes, r. k. (1994) eur. j. biochem. 222, 277-284]; tbr-el was a single seven-membered toroid, unlike most groels which exist as double toroids. using high-resolution gel filtration chromatography, we have resolved the purified tbr-el into si ...19957578105
influence of charge and polarity on the redox potentials of high-potential iron-sulfur proteins: evidence for the existence of two groups.we have investigated the hipips from ectothiorhodospira vacuolata (iso-1 and iso-2), chromatium vinosum, rhodocyclus gelatinosus, rhodocyclus tenuis (strain 2761), rhodopila globiformis, and rhodospirillum salinarum (iso-2) by direct electrochemistry. using a glassy carbon electrode with a negatively charged surface, direct, unpromoted electrochemistry is possible with the positively charged hipips. with the negatively charged hipips, the positively charged and flexible bridging promoter poly(l- ...19957578075
purification, primary structure, and evolution of cytochrome c-550 from the magnetic bacterium, magnetospirillum magnetotacticum.cytochrome c-550 was purified from magnetospirillum magnetotacticum to an electrophoretically homogeneous state, and some of its properties were determined. the cytochrome showed absorption peaks at 528 and 409 nm in the oxidized form, and at 550, 521, and 414 nm in the reduced form. its midpoint redox potential at ph 7.0 was determined to be +289 mv. the primary structure of cytochrome c-550 was determined. cytochrome c is composed of 97 amino acid residues, and its molecular weight was calcula ...19957575096
conformational dynamics of a mobile loop in the nad(h)-binding subunit of proton-translocating transhydrogenases from rhodospirillum rubrum and escherichia coli.transhydrogenase catalyses the reversible transfer of reducing equivalents between nad(h) and nadp(h) to the translocation of protons across a membrane. uniquely in rhodospirillum rubrum, the nad(h)-binding subunit (called ths) exists as a separate subunit which can be reversibly dissociated from the membrane-located subunits. we have expressed the gene for r. rubrum ths in escherichia coli to yield large quantities of protein. low concentrations of either trypsin or endoproteinase lys-c lead to ...19957556167
4-hydroxyphenethyl alcohol--a new cytokinin-like substance from the phototrophic purple bacterium rhodospirillum rubrum 1r.three compounds with cytokinin activity have been isolated from the medium of rhodospirillum rubrum grown photosynthetically. two n-6 aminopurine cytokinins revealed in the medium were identical with those obtained from r. rubrum cells previously. the third compound with cytokinin activity in amaranthus caudatus bioassay proved to be a simple phenolic compound with elemental composition c8h10o2. this cytokinin-like substance according to absorption spectra, mass spectrometry and 1h nmr spectra d ...19957539770
expression of tfx and sensitivity to the rhizobial peptide antibiotic trifolitoxin in a taxonomically distinct group of alpha-proteobacteria including the animal pathogen brucella abortus.three phylogenetically distinct groups within the alpha-proteobacteria which differ in trifolitoxin sensitivity are described. trifolitoxin sensitivity was found in strains of agrobacterium, brucella, mycoplana, ochrobactrum, phyllobacterium, rhodobacter, rhodopseudomonas, rhodospirillum, and rhizobium. strains of agrobacterium, brucella, phyllobacterium, rhizobium, and rhodospirillum were capable of producing trifolitoxin upon conjugal transfer of tfxabcdefg.19947527627
ionic channel activity induced by fusion of rhodospirillum rubrum chromatophores with a planar bilayer lipid membrane.the present work concerns mechanisms of ionic conductivity of photosynthetic membranes. it is shown that reconstitution of vesicles of photosynthetic membranes (chromatophores) of purple bacteria rhodospirillum rubrum into a planar bilayer lipid membrane leads to fluctuations of current showing the existence of a channel with a predominant conductance of approximately 230 ps in the presence of 100 mm kcl. measurements under the conditions of kcl gradient prove that this channel is cation selecti ...19947506216
proton-translocating nicotinamide nucleotide transhydrogenase. reconstitution of the extramembranous nucleotide-binding domains.the nicotinamide nucleotide transhydrogenase of bovine mitochondria is a homodimer of monomer m(r) = 109,065. the monomer is composed of three domains, an nh2-terminal 430-residue-long hydrophilic domain i that binds nad(h), a central 400-residue-long hydrophobic domain ii that is largely membrane intercalated and carries the enzyme's proton channel, and a cooh-terminal 200-residue-long hydrophilic domain iii that binds nadp(h). domains i and iii protrude into the mitochondrial matrix, where the ...19957499307
lipopolysaccharide of rhodospirillum salinarum 40: structural studies on the core and lipid a region.the structural elucidation of lipid a of the cell wall lipopolysaccharide (lps) of rhodospirillum salinarum 40 by chemical methods and laser desorption mass spectrometry revealed the presence of a mixed lipid a composed of three different 1,4'bisphosphorylated beta (1 --> 6)-linked backbone hexosaminyl-hexosamine disaccharides, i.e. those composed of glcn --> glcn, 2,3-diamino-2,3-dideoxy-d-glc-(dag --> dag, and dag --> glcn. lipid a of r. salinarum contained preferentially 3-oh-18:0 and 3-oh-14 ...19957487334
structure of the heptose region of lipopolysaccharies from rhodospirillum tenue.there is a common structure (core region) in the lipopolysaccharides of rhodospirillum tenue. it is composed of a branched trisaccharide of l-glycero-d-mannoheptose (and of 2-keto-3-deoxyoctonate), as revealed by methylation analyses of degraded polysaccharides of four different r. tenue strains. the structure is similar or might even be identical to the inner core of enterobacterial o antigens. in addition, each of the four r. tenue lipopolysaccharides contains a strain-specific region that con ...19817462142
primary structures of high potential, four-iron-sulfur ferredoxins from the pruple sulfur photosynthetic bacteria, thiocapsa roseopersicina and chromatium gracile. 19817451471
labeling of chromatophore membranes and reaction centers from the photosynthetic bacterium rhodospirillum rubrum with the hydrophobic marker 5-[125i]iodonaphthyl-1-azide..chromatophores of the photosynthetic bacterium rhodospirillum rubrum and isolated reaction centers were labeled with the lipophilic membrane marker 5-[125i]iodonaphthyl-1-azide. the two smaller reaction center proteins l and m bind more label than the larger subunit h, a fact supporting the proposed localisation of the 3 subunits obtained with hydrophilic labels. besides these integral proteins the lipids, among them mainly the pigments and the quinones, are highly labeled suggesting a hydrophob ...19807397129
2-carboxy-d-hexitol 1,6-bisophosphate: an inhibitor of d-ribulose 1,5-bisphosphate carbosylase/oxygenase. 19807362236
radioprotective and haemopoietic effects of some lipopolysaccharides from rhodospirillaceae species in mice.lipopolysaccharides (lps) from various rhodopseudomonas and rhodospirillum species were tested for their radioprotective efficiency against x-irradiation and for their influence on the growth of spleen colony forming units (cfu-s) in mice. the lps from rhodopseudomonas gelatinosa dr2 gave a high survival rate. it also favoured cfu-s formation and erythroid differentiation.19817327249
[isolation and properties of the pigment-protein complex (protochlorophyllide - holochrome) from etiolated leaves of corn sprouts].a pigment -- protein complex was isolated from etiolated leaves of corn sprouts using treatment by the detergent triton x-100, ultracentrifugation and gel-filtration. the complex has a molecular weight of 50000 and upon illumination can convert protochlorophyllide (pchld) into chlorophyllide (chld). the low temperature fluorescence spectra of dark preparations reveal maxima of pchld 632 (photo-inactive form) and pchld 653 (photo-active form). upon illumination pchld 653 is converted into chld 68 ...19817248372
dinitrogen-fixing bacteria: computer-assisted identification of soil isolates.dinitrogen-fixing (acetylene-reducing) bacteria may be readily isolated from soils but extensive biochemical or immunobiological testing, or both, are required to identify them absolutely. a computer-assisted scheme for identification of nine genera of dinitrogen-fixing bacteria was developed and tested. the computer program is based on interpretation of the 70 biochemical tests of the api 20e and 50e, supplemented with tests for acetylene reduction, nitrate and nitrite reduction, catalase, oxid ...19807214218
polar lipids in phototrophic bacteria of the rhodospirillaceae and chromatiaceae families.the polar lipids of photosynthetic purple bacteria of the genera chromatium, thiocapsa, thiocystis, ectothiorhodospira, rhodopseudomonas, rhodospirillum, and rhodomicrobium were analyzed. characteristic compositions of the polar lipids were found for most of the rhodospirillaceae and chromatiaceae species. phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin were the major phospholipids in most species. phosphatidylcholine was present as a major component in all species of the genus e ...19827076618
peptidoglycan of rhodopseudomonas viridis: partial lack of n-acetyl substitution of glucosamine.a lack of at least 70% of n-acetyl substitution of glucosamine in the glycan strands of the peptidoglycan from the gram-negative bacterium rhodopseudomonas viridis is reported. a disaccharide, very likely glcn beta(1 leads to 4) mur, was observed in hydrolysates of the isolated peptidoglycan. the disaccharide was not observed when peptidoglycan was n-acetylated before hydrolysis. the peptidoglycan of r. viridis was resistant to lysozyme but became sensitive after n-acetylation with acetic anhydr ...19827054141
composition and development of the bacterial photosynthetic apparatus. 19817032006
nitrogen metabolism in the phototrophic bacteria rhodocyclus purpureus and rhodospirillum tenue.studies of the nitrogen nutrition and pathways of ammonia assimilation in rhodocyclus purpureus and rhodospirillum tenue have shown that these two seemingly related bacteria differ considerably in aspects of their nitrogen metabolism. when grown photoheterotrophically with malate as carbon source, r. purpureus utilized only nh4+ or glutamine as sole nitrogen sources and was unable to fix n2. by contrast, r. tenue was found to utilize a variety of amino acids as nitrogen sources and was a good n2 ...19836863218
consensus structure and evolution of 5s rrna.a consensus structure model of 5s rrna presenting all conserved nucleotides in fixed positions has been deduced from the primary and secondary structure of 71 eubacterial, archaebacterial, eukaryotic cytosolic and organellar molecules. phylogenetically related groups of molecules are characterized by nucleotide deletions in helices iii, iv and v, and by potential base pair interactions in helix iv. the group-specific deletions are correlated with the early branching pattern of a dendrogram calcu ...19836835839
purification and sequencing of cyanogen bromide fragments from ribulosebisphosphate carboxylase/oxygenase from rhodospirillum rubrum. 19826819814
purification and properties of chlorophyllase from greened rye seedlings.1. chlorophyllase [ec] was extracted from the acetone-dried powder of the chloroplasts of greened rye seedlings with 1% cholate, and purified 870-fold with a yield of about 30%. the purification procedure was composed of fractionations with acetone and ammonium sulfate, and hydrophobic chromatography on a phenyl-sepharose cl-4b column. 2. the purified enzyme was pure as analyzed by molecular-sieve chromatography and isoelectric electrophoresis. it had an isoelectric point of 4.5 and a m ...19826819291
protein liganding to the activator cation of ribulosebisphosphate carboxylase.spinach leaf ribulosebisphosphate carboxylase forms a quaternary complex with co2, carboxyarabinitol bisphosphate, and cr2+ or co2+. oxidation of the cation in these complexes produces a protein--cation adduct which is sufficiently stable to be chromatographically isolated after enzyme denaturation. while stoichiometric levels of slowly exchanging cation can be specifically trapped after addition of protein denaturants as well as a vast molar excess of mg2+, neither co2 nor carboxyarabinitol bis ...19826818984
ribulosebisphosphate carboxylase/oxygenase from rhodospirillum rubrum. 19826818424
change in subunit composition of the iron protein of nitrogenase from rhodospirillum rubrum during activation and inactivation of iron protein.the subunit composition of the fe protein of nitrogenase from rhodospirillum rubrum during activation and inactivation was investigated. it was found that the upper subunit (on gel electrophoresis) of the two-subunit fe protein was converted into the lower subunit during activation in vitro. when the fe protein was inactivated in vivo by the addition of nh4cl and alpha-oxoglutarate to the cells, a phosphate-labelled upper band appeared. during activation in vitro by the activating enzyme, some o ...19826816216
heat activation of the fe protein of nitrogenase from rhodospirillum rubrum.the fe protein of nitrogenase from rhodospirillum rubrum isolated in the inactive form was found to be activated in vitro by heating. this heat activation was dependent upon temperature, ph, and enzyme concentration. during activation by heating, a change in the subunit composition of fe protein was observed on sodium dodecyl sulfate gels. the upper subunit decreases and the lower subunit increased. all components of the modifying group on inactive fe protein appear to be lost upon heat activati ...19826815184
pyruvate-dependent diauxic growth of rhodospirillum rubrum in light.when rhodospirillum rubrum mutant c was first exposed to radiant energy after long-term anaerobic dark growth, the cells often exhibited a diauxic growth response. this happened with pyruvate in the medium and when cultures were exposed to a less-than-growth-saturating white light intensity of about 6,460 lx. under the growth-saturating light condition, mutant c photometabolized and growth was not affected by na hypophosphite, an inhibitor of pyruvate fermentation. in lower intensity light, in w ...19826815163
cytochemical localization and measurement of aerobic 3,3'-diaminobenzidine oxidation reactions in photosynthetically grown rhodospirillum rubrum.photoheterotrophically grown rhodospirillum rubrum mutant c oxidized 3,3'-diaminobenzidine (dab) by two aerobic reactions. one reaction was light dependent. the other respiratory reaction occurred in the dark and could be inhibited by 0.1 m kcn. dab was not oxidized under anaerobic conditions. cytochemical results, obtained by reacting viable cells with dab, indicated that the two reactions were associated with different regions of the cellular membrane system. under dark conditions, oxidized da ...19826813374
expression of the activating enzyme and fe protein of nitrogenase from rhodospirillum rubrum.activating enzyme (ae) is responsible for the in vitro activation of inactive fe protein of nitrogenase from rhodospirillum rubrum cells cultured anaerobically with glutamate as the n source. the expression of fe protein and ae was examined in r. rubrum cultured photosynthetically or aerobically on media containing malate as the carbon source. one of the following n sources was used in each culture: glutamate, glutamine, limiting ammonia, high ammonia, glutamate plus histidine, and high ammonia ...19826813314
purification and mn2+ activation of rhodospirillum rubrum nitrogenase activating enzyme.the fe protein activating enzyme for rhodospirillum rubrum nitrogenase was purified to approximately 90% homogeneity, using de52-cellulose chromatography and sucrose density gradient centrifugation. activating enzyme consists of a single polypeptide of molecular weight approximately 24,000. atp was required for catalytic activity, but was relatively ineffective in the absence of mg2+. when the concentration of mgatp2- was held in excess, there was an additional requirement for a free divalent me ...19826813313
comparison of active and inactive forms of iron protein from rhodospirillum rubrum.the fe protein of nitrogenase from rhodospirillum rubrum was purified in its active and inactive forms. it is shown that the inactive form exists as a two-subunit modified form of the enzyme as previously reported [ludden & burris (1978) biochem. j. 175, 251--259]. in contrast, the active form exists as a single-subunit unmodified form of the enzyme. the upper subunit (on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis) of the inactive form was shown to contain at least the phosphate ...19826810874
[adenylate cyclase from a phototrophic organism]. 19826809439
photosynthetic bacterial reaction centers: interactions among the bacteriochlorophylls and bacteriopheophytins. 19826808895
effect of light intensity and inhibitors of nitrogen assimilation on nh4+ inhibition of nitrogenase activity in rhodospirillum rubrum and anabaena sp.nitrogenase activity in rhodospirillum rubrum was inhibited by nh4+ more rapidly in low light than in high light. furthermore, the nitrogenase of cells exposed to phosphorylation uncouplers was inhibited by nh4+ more rapidly than was the nitrogenase of controls without an uncoupler. these observations suggest that high levels of photosynthate inhibit the nitrogenase inactivation system. l-methionine-dl-sulfoximine, a glutamine synthetase inhibitor, prevented nh4+ from inhibiting nitrogenase acti ...19826807962
[reversible effect of intensive light on photobiochemical properties of rhodospirillum rubrum chromatophores].the effect of high intensity (photosynthesis-saturating) light on the optical properties of the bacteriochlorophyll and the light-induced h+ uptake by r. rubrum chromatophores was studied. it was shown that under aerobic conditions illumination causes reversible inhibition (in the dark) of the chromatophore ability for the light-induced uptake of h+, a reversible inhibition of the photosynthetical reaction center function and irreversible bleaching of the antennal bacteriochlorophyll. a kinetic ...19826805518
efficiency of light-driven metabolite transport in the photosynthetic bacterium rhodospirillum evaluation of the efficiency of the l-alanine and l-malate transport systems was undertaken with the photosynthetic bacterium rhodospirillum rubrum grown on the amino acid whose uptake was measured. an all-glass apparatus was constructed for measuring transport activity under anaerobic conditions. l-alanine transport activity decreased under conditions of mg2+ depletion. when cells were allowed to become inactive by suspending them in the dark in mg2+-free buffer, full activity could be resto ...19826804443
development and growth of photosynthetic membranes of rhodospirillum cell-free extracts from low-aeration suspensions of rhodospirillum rubrum strain g-9, bacteriochlorophyll a was distributed in two bands after rate-zone sedimentation in sucrose density gradients. from the physicochemical properties of these fractions, it was concluded that the upper band consisted of small membrane fragments, whereas the major band was composed of fragmented vesicular intracytoplasmic membrane (chromatophores). after a pulse with l-[35s]methionine, apparent polypeptide subun ...19826804438
[analysis of the kinetics of transitional processes in biophysical research using a minicomputer]. 19826803850
reexamination of the binding site for pyridoxal 5'-phosphate in ribulosebisphosphate carboxylase/oxygenase from rhodospirillum rubrum.the high specificity of pyridoxal 5'-phosphate (plp) for an essential lysyl residue of ribulosebisphosphate carboxylase/oxygenase was confirmed, but half-of-sites reactivity was not observed in contrast to an earlier report [robison, p. d., whitman, w. b., waddill, f., riggs, a. f., & tabita, f. r. (1980) biochemistry 19, 4848-4853]. subsequent to reduction with [3h]borohydride and tryptic digestion of the enzyme inactivated by plp, the sole labeled peptide was purified by successive chromatogra ...19826803834
2-bromoacetylaminopentitol 1,5-bisphosphate as an affinity label for ribulose bisphosphate carboxylase/oxygenase from rhodospirillum rubrum.2-bromoacetylaminopentitol 1,5-bisphosphate (bracnh-pentitol-p2) (an epimeric mixture of 2-bromoacetylamino-2-deoxy-d-ribitol bisphosphate and 2-bromoacetylamino-2-deoxy-d-arabinitol 1,5-bisphosphate) has been synthesized from d-ribulose 1,5-bisphosphate by reductive amination with sodium cyanoborohydride followed by bromoacetylation of the resultant amine with bromoacetyl bromide. under conditions that favor full activation of the enzyme, ribulose bisphosphate carboxylase/oxygenase from rhodosp ...19826801050
regulation of rhodospirillum rubrum nitrogenase activity. properties and interconversion of active and inactive fe protein. 19826801038
photooxidase system of rhodospirillum rubrum iii. the role of rhodoquinone and ubiquinone in the activity of preparations of chromatophores and photoreaction centers.the role of rhodoquinone and ubiquinone in the oxygen photoreducing (photooxidase) activity of rhodospirillum rubrum was investigated. the sole addition of purified rhodoquinone restored photooxidase activity in isolated chromatophores which had been extracted with organic solvents and which were apparently free of secondary acceptor ubiquinone. rhodoquinone also enhanced photooxidase activity in photoreaction center preparations from which secondary ubiquinone seemed to have been removed. those ...19826800786
modification of active site histidine in ribulosebisphosphate carboxylase/oxygenase. 19826800404
borate inhibits activation of inactive dinitrogenase reductase from rhodospirillum rubrum.borate and aminophenylboronic acid were tested as inhibitors of activation of inactive dinitrogenase reductase from rhodospirillum rubrum. inhibition was specific for activation because activity of the active form of the enzyme was not inhibited. inhibition showed the ph-dependence expected if borate inhibits by binding to cis-hydroxy groups of the modifying group found on the inactive enzyme.19816798967
propionate formation in rhodospirillum rubrum under anaerobic dark conditions.experiments with 14c labelled propionyl-coa, methylmalonyl-coa and succinyl-coa showed that these compounds are intermediates of propionate synthesis in fermentative metabolism of rhodospirillum rubrum. the rate of propionate and succinate production is dependent on the co2 concentration of the medium. there is, however, no evidence for a transcarboxylation, and high concentrations of propionate in the medium did not inhibit propionate synthesis as in the case in propionibacteria. pep-carboxykin ...19816798770
[carbamyl phosphate and citrulline formation by phototrophic bacteria].the purple bacteria ectothiorhodospira shaposhnikovii and rhodospirillum rubrum are capable of synthesizing citrulline in the presence of ammonium hydrocarbonate, ornithine, atp and mg2+ ions. citrulline biosynthesis by these phototrophic bacteria is presumed to be catalysed by carbamate kinase and ornithine transcarbamoylase. therefore, certain phototrophic bacteria can assimilate carbon dioxide and ammonia for biosynthesis of amino acids, in particular, citrulline and, apparently, arginine.19816798373
fermentation and anaerobic respiration by rhodospirillum rubrum and rhodopseudomonas capsulata.rhodospirillum rubrum and rhodopseudomonas capsulata were able to grow anaerobically in the dark either by a strict mixed-acid fermentation of sugars or, in the presence of an appropriate electron acceptor, by an energy-linked anaerobic respiration. both species fermented fructose without the addition of accessory oxidants, but required the initial presence of bicarbonate before fermentative growth could begin. major products of r. rubrum fermentation were succinate, acetate, propionate, formate ...19826798016
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