TitleAbstractYear(sorted ascending)
nucleotide sequence of cdna clones encoding the beta subunit of mitochondrial atp synthase from the green alga chlamydomonas reinhardtii: the precursor protein encoded by the cdna contains both an n-terminal presequence and a c-terminal extension.cdna and genomic clones encoding the beta subunit of mitochondrial atp synthase from chlamydomonas reinhardtii have been isolated using heterologous dna probes from the photosynthetic bacterium rhodospirillum rubrum. the protein encoded by the cdna is 79-83% identical to corresponding proteins from higher-plant and mammalian mitochondria, and 75% identical to the r. rubrum protein. it contains both an n-terminal presequence and a unique c-terminal extension. the presequence, which is the first m ...19921386535
tentoxin sensitivity of chloroplasts determined by codon 83 of beta subunit of proton-atpase.tentoxin is a naturally occurring phytotoxic peptide that causes seedling chlorosis and arrests growth in sensitive plants and algae. in vitro, it inhibits activity of the beta subunit of the plastid proton-adenosine triphosphatase (atpase) from sensitive species. plastid atpb genes from six closely related, tentoxin-sensitive or -resistant nicotiana species differ at codon 83, according to their response to the toxin: glutamate correlated with resistance and aspartate correlated with sensitivit ...19921387730
in vitro activation of dinitrogenase reductase from the cyanobacterium anabaena variabilis (atcc 29413).nitrogenase of the heterocystous cyanobacterium anabaena variabilis was inactivated in vivo (s. reich, h. almon, and p. böger, fems microbiol. lett. 34:53-56, 1986). partially purified and modified (inactivated) dinitrogenase reductase (fe-protein) of such cells was reactivated by isolated membrane fractions of a. variabilis or of rhodospirillum rubrum, and acetylene reduction was measured. reactivation requires atp, mg2+, and mn2+. the activating principle is localized in the heterocyst and was ...19921400166
prokaryotic triterpenoids: o-alpha-d-glucuronopyranosyl bacteriohopanetetrol, a novel hopanoid from the bacterium rhodospirillum rubrum.a novel hopanoid bearing a glucuronopyranosyl residue linked via an alpha-glycosidic bond to the hydroxyl group of c-35 in bacteriohopanetetrol was isolated, from the type strain of rhodospirillum rubrum as well as from a mutant lacking blue carotenoid.19921417769
surface-enhanced raman scattering spectroscopy of photosynthetic membranes and complexes. 19921435308
[the evolutionary changes in the amino acid sequences and properties of the atp-synthase in chloroplasts, mitochondria and bacteria].studies have been made on atpase from chloroplasts, cyanobacteria and mitochondria of higher plants and animals. no intraspecies and interspecies variability of chloroplast and mitochondrial atpase was found with respect to ph optimum of the activity, to specificity to cations as substrate components, to sensitivity to stimulating and inhibiting anions and ethanol, to optimal stimulating ethanol concentration. intergenus variation of these properties of atpase from chloroplasts, plant mitochondr ...19921441793
conservation of the photosynthesis gene cluster in rhodospirillum centenum.intraspecies and intergenus complementation analysis were utilized to demonstrate that photosynthesis genes are clustered in distantly related purple photosynthetic bacteria. specifically, we show that the linkage order for genes involved in bacteriochlorophyll and carotenoid biosynthesis in rhodospirillum centenum are arranged essentially as in rhodobacter capsulatus and rhodobacter sphaeroides. in addition, the location and relative distance observed between the puf and puh operons which encod ...19921447976
restoration of the wild-type locus in an rubp carboxylase/oxygenase mutant of synechocystis pcc 6803 via targeted gene recombination.the interaction between homologous dna sequences, distant from each other in the chromosome, was examined in the cyanobacterium synechocystis pcc 6803. most of the rbcl gene encoding the large subunit of ribulose bisphosphate carboxylase/oxygenase (rubisco) was duplicated in the genome by a targeted insertion of a 3'-truncated gene copy into the psb a-i locus. both rbcl genes, in the psb a-i region and at the rbc locus, were non-functional; the former due to the 3' truncation, and the latter due ...19921465099
molecular basis for biosynthesis and accumulation of polyhydroxyalkanoic acids in bacteria.the current knowledge on the structure and on the organization of polyhydroxyalkanoic acid (pha)-biosynthetic genes from a wide range of different bacteria, which rely on different pathways for biosynthesis of this storage polyesters, is provided. molecular data will be shown for genes of alcaligenes eutrophus, purple non-sulfur bacteria, such as rhodospirillum rubrum, purple sulfur bacteria, such as chromatium vinosum, pseudomonads belonging to rrna homology group i, such as pseudomonas aerugin ...19921476773
cloning of poly(3-hydroxybutyric acid) synthase genes of rhodobacter sphaeroides and rhodospirillum rubrum and heterologous expression in alcaligenes eutrophus.from genomic libraries of the purple non-sulfur bacteria rhodospirillum rubrum ha and rhodobacter sphaeroides atcc 17023 in the broad-host range cosmid pvk100, we cloned a 15- and a 14-kbp hindiii restriction fragment, respectively. each of these fragments restored the ability to accumulate poly(3-hydroxybutyrate) (phb), in the phb-negative mutant alcaligenes eutrophus phb-4. these hybrid cosmids also complemented phb-negative mutants derived from wild-type r. rubrum or r. sphaeroides. both frag ...19921499989
dynamics of energy transfer and trapping in the light-harvesting antenna of rhodopseudomonas low intensity picosecond absorption spectroscopy it is shown that the exciton lifetime in the light-harvesting antenna of rhodopseudomonas (rps.) viridis membranes with photochemically active reaction centers at room temperature is 60 +/- 10 ps. this lifetime reflects the overall trapping rate of the excitation energy by the reaction center. with photochemically inactive reaction centers, in the presence of p+, the exciton lifetime increases to 150 +/- 15 ps. prereducing the secondary electro ...19921504241
studies on the effect of nad(h) on nitrogenase activity in rhodospirillum rubrum.the effect of nad(p) and analogs of this nucleotide on nitrogenase activity in rhodospirillum rubrum has been studied. addition of nad+ to nitrogen fixing rsp. rubrum leads to inhibition of nitrogenase. nadp+ has the same effect but nadh or analogs modified in the nicotinamide portion do not cause inhibition. in contrast to ammonium ions, addition of nad+ leads to inhibition of nitrogenase in cells that have been n-starved under argon. the inhibitory effect of nad+ is more pronounced at lower li ...19921510568
purification and characterization of glutathione reductase from rhodospirillum rubrum.glutathione reductase (nad(p)h:gssg oxidoreductase ec was purified 1160-fold to homogeneity from the nonsulfurous purple bacteria rhodospirillum rubrum (wild type). specific activity of the pure preparation was 102 u/mg. the enzyme displayed a typical flavoprotein absorption spectrum with maxima at 274,365, and 459 nm and an absorbance ratio a280/a459 of 7.6. the amino acid analysis revealed an unusually high content of glycine and arginine residues. titration of the enzyme with 5,5'-d ...19921524433
enhanced co2/o2 specificity of a site-directed mutant of ribulose-bisphosphate carboxylase/oxygenase.the co2/o2 specificity factor of ribulose-bisphosphate carboxylase/oxygenase partially determines the efficiency of photosynthetic carbon assimilation. heretofore, engineered alterations of the enzyme have only decreased the selectivity for co2 utilization. we show that alanyl replacement of active-site ser-368 of the rhodospirillum rubrum carboxylase enhances the carboxylation selectivity approximately 1.6-fold over the wild-type level. this enhancement reflects a greater relative decline in ox ...19921551863
characterization of lhi- and lhi+ rhodobacter capsulatus pufa mutants.the nh2 termini of light-harvesting complex i (lhi) polypeptides alpha and beta of rhodobacter capsulatus are thought to be involved in the assembly of the lhi complex. for a more detailed study of the role of the nh2-terminal segment of the lhi alpha protein in insertion into the intracytoplasmic membrane (icm) of r. capsulatus, amino acids 6 to 8, 9 to 11, 12 and 13, or 14 and 15 of the lhi alpha protein were deleted. additionally, the hydrophobic stretch of the amino acids 7 to 11 was lengthe ...19921569029
role of asparagine-111 at the active site of ribulose-1,5-bisphosphate carboxylase/oxygenase from rhodospirillum rubrum as explored by site-directed mutagenesis.crystallographic studies of ribulose-1,5-bisphosphate carboxylase/oxygenase from rhodospirillum rubrum suggest that active-site asn111 interacts with mg2+ and/or substrate (lundqvist, t., and schneider, g. (1991) j. biol. chem. 266, 12604-12611). to examine possible catalytic roles of asn111, we have used site-directed mutagenesis to replace it with a glutaminyl, aspartyl, seryl, or lysyl residue. although the mutant proteins are devoid of detectable carboxylase activity, their ability to form a ...19921569095
cloning, sequencing, mutagenesis, and functional characterization of drat and drag genes from azospirillum brasilense.the azospirillum brasilense drat gene, encoding dinitrogenase reductase atp-ribosyltransferase, and drag gene, encoding dinitrogenase reductase activating glycohydrolase, were cloned and sequenced. two genes were contiguous on the a. brasilense chromosome and showed extensive similarity to the same genes from rhodospirillum rubrum. analysis of mutations introduced into the dra region on the a. brasilense chromosome showed that mutants affected in drat were incapable of regulating nitrogenase act ...19921577701
on the structure of the nickel/iron/sulfur center of the carbon monoxide dehydrogenase from rhodospirillum rubrum: an x-ray absorption spectroscopy study.the nickel/iron/sulfur center of the carbon monoxide dehydrogenase (carbon monoxide:(acceptor)oxidoreductase; ec enzyme from rhodospirillum rubrum (rr-codh) was studied by x-ray absorption spectroscopy at the ni k edge. extended x-ray absorption fine structure data show that the first ni coordination shell consists of 2 s atoms at 2.23 a and 2-3 n/o atoms at 1.87 a. the edge structure indicates a distorted tetrahedral or five-coordinate ni environment in both oxidized and reduced rr-co ...19921584775
mutation of asparagine 111 of rubisco from rhodospirillum rubrum alters the carboxylase/oxygenase specificity.the conserved asparagine 111 of ribulose-1,5-bisphosphate carboxylase/oxygenase from the photosynthetic bacteria rhodospirillum rubrum was identified as a candidate for a side-chain that might be involved in the carboxylase/oxygenase specificity. it was replaced by site-directed mutagenesis with aspartic acid, leucine, glutamine or glycine residues. the mutant enzymes exhibit a very low carboxylase activity compared with the wild-type enzyme. the values of km(rubp) and kcat for asn111----gly, th ...19921602488
electrostatic fields at the active site of ribulose-1,5-bisphosphate carboxylase.a macroscopic approach has been employed to calculate the electrostatic potential field of nonactivated ribulose-1,5-bisphosphate carboxylase and of some complexes of the enzyme with activator and substrate. the overall electrostatic field of the l2-type enzyme from the photosynthetic bacterium rhodospirillum rubrum shows that the core of the dimer, consisting of the two c-terminal domains, has a predominantly positive potential. these domains provide the binding sites for the negatively charged ...19921603801
substitution of asp193 to asn at the active site of ribulose-1,5-bisphosphate carboxylase results in conformational changes.the crystal structure of a mutant of ribulose bisphosphate carboxylase/oxygenase from rhodospirillium rubrum, where asp193, one of the ligands of the magnesium ion at the activator site, is replaced by asn, has been determined to a nominal resolution of 0.26 nm. the mutation of asp to asn induces both local and global conformation changes as follows. the side chain of asn193 moves away from the active site and interacts with main-chain oxygen of residue 165, located in the neighbouring strand be ...19921606957
the relation between the soluble factor associated with h(+)-transhydrogenase of rhodospirillum rubrum and the enzyme from mitochondria and escherichia coli.although in mitochondria, escherichia coli and rhodobacter capsulatus the h(+)-transhydrogenases are intrinsic membrane proteins, in rhodospirillum rubrum a water-soluble component (ths) and a membrane-bound component are together required for activity. ths was selectively removed from chromatophore membranes of rhs. rubrum and was purified to homogeneity by precipitation with (nh4)2so4 and ion-exchange, affinity dye and gel exclusion chromatography. the latter indicated an mr of approx. 74,000 ...19921610876
enhancement of carotenoid-to-chlorophyll singlet energy transfer by carotenoid-carotenoid interaction.the apparent quantum yield of singlet-singlet spirilloxanthin-to-bacteriochlorophyll a energy transfer increases linearly with the residual spirilloxanthin content in rhodospirillum rubrum membrane vesicles from which this carotenoid has been partially removed. since it has been previously shown that carotenoid-carotenoid interaction is a linear function of the residual spirilloxanthin level in the major pigment-protein complex of those vesicles (zurdo, j., r. m. lozano, c. fernandez-cabrera, an ...19921617133
direct electrochemical studies of hydrogenase and co dehydrogenase.the reduction potentials of two relatively high-molecular-mass enzymes were determined directly at an edge pyrolytic graphite electrode by using square-wave voltammetry. the equilibrium reduction potential versus standard hydrogen electrode was determined for clostridium pasteurianum hydrogenase i (e'0 = -377 +/- 10 mv; molecular mass 60 kda) and rhodospirillum rubrum carbon monoxide dehydrogenase (e'0 = -418 +/- 7 mv; molecular mass 62 kda). the reduction potential of each enzyme was ph-indepen ...19921637298
genetic and physiological characterization of the rhodospirillum rubrum carbon monoxide dehydrogenase system.a 3.7-kb dna region encoding part of the rhodospirillum rubrum co oxidation (coo) system was identified by using oligonucleotide probes. sequence analysis of the cloned region indicated four complete or partial open reading frames (orfs) with acceptable codon usage. the complete orfs, the 573-bp coof and the 1,920-bp coos, encode an fe/s protein and the ni-containing carbon monoxide dehydrogenase (codh), respectively. the four 4-cysteine motifs encoded by coof are typical of a class of proteins ...19921644755
mutations affecting nitrogenase switch-off in rhodobacter vivo 'switch-off' and subsequent reactivation of nitrogenase activity in rhodobacter capsulatus or rhodospirillum rubrum in response to a variety of environmental stimuli, including the addition of fixed nitrogen, is thought to be due to the action of two nitrogenase fe protein modifying activities; drat (dinitrogenase reductase adp-ribosyl transferase) and drag (dinitrogenase reductase-activating glycohydrolase). here it is demonstrated that strains, including one mutated in glnb, that const ...19921730034
simple determination of the co(2)/o(2) specificity of ribulose-1,5-bisphosphate carboxylase/oxygenase by the specific radioactivity of [c]glycerate 3-phosphate.a new method is presented for measurement of the co(2)/o(2) specificity factor of ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco). the [(14)c]3-phosphoglycerate (pga) from the rubisco carboxylase reaction and its dilution by the rubisco oxygenase reaction was monitored by directly measuring the specific radioactivity of pga. (14)co(2) fixation with rubisco occurred under two reaction conditions: carboxylase with oxygenase with 40 micromolar co(2) in o(2)-saturated water and carboxylase ...199216668709
kinetic model of primary energy transfer and trapping in photosynthetic membranes.the picosecond time-domain incoherent singlet excitation transfer and trapping kinetics in core antenna of photosynthetic bacteria are studied in case of low excitation intensities by numerical integration of the appropriate master equation in a wide temperature range of 4-300 k. the essential features of our two-dimensional-lattice model are as follows: förster excitation transfer theory, spectral heterogeneity of both the light-harvesting antenna and the reaction center, treatment of temperatu ...199219431849
on the long-wavelength component of the light-harvesting complex of some photosynthetic bacteria.the effect of the presence of a minor antenna component in light-harvesting complexes of photosynthetic bacteria is investigated with numerical simulation employing the transition probability matrix method. a model antenna system of hexagonal symmetry is adopted, using as a working hypothesis that the minor component forms a ring around the trap. three cases have been considered: (a) the minor component is isoenergetic with the trap, which is at lower energy than the antennas (the "supertrap"), ...199219431850
modification of the fe protein of nitrogenase in natural populations of trichodesmium thiebautii.the fe protein of nitrogenase in the marine nonheterocystous cyanobacterium trichodesmium thiebautii is interconverted between two forms, which is reminiscent of the adp-ribosylation described in the purple bacterium rhodospirillum rubrum. in natural populations of t. thiebautii during the day, when nitrogenase activity (na) is present and while photosynthetic rates are high, a low-molecular-mass form of the fe protein is present. in the late afternoon, the low-molecular-mass form is partially c ...199316348883
photosynthetic fractionation of the stable isotopes of oxygen and carbon.isotope discrimination during photosynthetic exchange of o2 and co2 was measured using enzyme, thylakoid, and whole cell preparations. evolved oxygen from isolated spinach thylakoids was isotopically identical (within analytical error) to its source water. similar results were obtained with anacystis nidulans richter and phaeodactylum tricornutum bohlin cultures purged with helium. for consumptive reactions, discrimination ([delta], where 1 + [delta]/1000 equals the isotope effect, k16/k18 or k1 ...199312231663
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
construction of a synechocystis pcc6803 mutant suitable for the study of variant hexadecameric ribulose bisphosphate carboxylase/oxygenase enzymes.the cyanobacterium synechocystis pcc6803 was chosen as a target organism for construction of a suitable photosynthetic host to enable selection of variant plant-like ribulose bisphosphate carboxylase/oxygenase (rubisco) enzymes. the dna region containing the operon encoding rubisco (rbc) was cloned, sequenced and used for the construction of a transformation vector bearing flanking sequences to the rbc genes. this vector was utilized for the construction of a cyanobacterial rbc null mutant in wh ...19938219082
surface charge modifications do not affect the hydrolytic activity of membrane-bound pyrophosphatase of rhodospirillum rubrum.the surface charge of the membrane of chromatophores of rhodospirillum rubrum was modified by two methods: fusion of liposomes with the membrane of the chromatophore by changing the ph and by incubating chromatophores in the presence of cationic or anionic detergents. the hydrolytic activity of membrane-bound pyrophosphatase, on surface charge modified chromatophores, did not change the km of the enzyme for its substrate (mg-ppi2-) nor the activation effect of free mg2+ on the hydrolytic activit ...19938220258
the ratio of protons translocated/hydride ion equivalent transferred by nicotinamide nucleotide transhydrogenase in chromatophores from rhodospirillum rubrum.the reduction of acetylpyridine adenine dinucleotide (acpdad+, an nad+ analogue) by nadph, in chromatophores treated with valinomycin, was accompanied by alkalinisation of the external medium, as measured by the absorbance change of added cresol red, a simple, non-binding ph indicator. experiments with a stopped-flow spectrophotometer showed that initial (linear) rates of alkalinisation persisted for 1-2s. from the results of experiments in which h+ uptake was driven by a series of short flashes ...19938223619
photolithoautotrophic growth and control of co2 fixation in rhodobacter sphaeroides and rhodospirillum rubrum in the absence of ribulose bisphosphate carboxylase-oxygenase.rhodospirillum rubrum and rhodobacter sphaeroides were shown to be capable of photolithoautotrophic growth in the absence of the reductive pentose phosphate (calvin) cycle. ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) deletion strains were incapable of photolithoautotrophic growth using hydrogen as an electron donor but were able to grow in the absence of organic carbon using less reduced inorganic electron donors, i.e., thiosulfate or sulfide. wild-type r. rubrum grown in the prese ...19938226655
atomic structure of a cytochrome c' with an unusual ligand-controlled dimer dissociation at 1.8 a resolution.the crystallographic structure of cytochrome c' from the purple phototrophic bacterium chromatium vinosum (cvcp) has been determined at 1.8 a resolution using multiple isomorphous replacement. the molecule is a dimer, with each 131-residue chain folding as a four-helical bundle incorporating a covalently bound heme group at the core. this structure is the third of the ubiquitous cytochromes c' to be solved and is similar to the known structures of cytochrome c' from r. molischianum (rmcp) and r. ...19938230224
perturbation of reaction-intermediate partitioning by a site-directed mutant of ribulose-bisphosphate carboxylase/ explore the roles of active-site glu48 of ribulose-bisphosphate carboxylase/oxygenase from rhodospirillum rubrum, the e48q mutant has been characterized with respect to kinetics and product distribution. although the kcat for carboxylase activity is only 0.6% of the wild-type value, the mutant retains full activity in catalyzing the conversion of the carboxylated reaction intermediate to 3-phosphoglycerate and retains 10% of the normal activity in catalyzing the enolization of ribulose bispho ...19938253788
atpase of rhodospirillum rubrum requires three functional copies of beta subunit as determined by radiation inactivation analysis.radiation inactivation analysis yielded a functional unit of 170 +/- 26 kda as beta subunit of atpase was irradiated and then reconstituted to beta-depleted chromatophores of rhodospirillum rubrum. a functional size of 132 +/- 17 kda for the beta-depleted atpase moiety involved in atp hydrolysis reaction was also determined. when both purified beta subunit and beta-depleted chromatophore were irradiated separately, reconstituted, and then activity measured, the functional mass was 312 +/- 50 kda ...19938260936
the dratg gene region of rhodobacter capsulatus is required for post-translational regulation of both the molybdenum and the alternative nitrogenase.synthetic oligonucleotides, which were designed according to amino acid sequences conserved between rhodospirillum rubrum and azospirillum brasilense drat and drag, respectively, were used to identify the corresponding genes of rhodobacter capsulatus. sequence analysis of a 1904 bp dna fragment proved the existence of r. capsulatus drat and drag. these two genes were separated by 11 bp only, suggesting that r. capsulatus drat and drag were part of one transcriptional unit. in contrast to r. rubr ...19938277250
the source and characteristics of chemiluminescence associated with the oxygenase reaction catalyzed by mn(2+)-ribulosebisphosphate carboxylase.we confirm the observation of mogel and mcfadden (mogel, s.n., and mcfadden, b. a. (1990) biochemistry 29, 8333-8337) that ribulosebisphosphate carboxylase/oxygenase (rubisco) exhibits chemiluminescence while catalyzing its oxygenase reaction in the presence of mn2+. however, our results with the spinach and rhodospirillum rubrum enzymes differ markedly in the following respects. 1) chemiluminescence intensity was directly proportional to enzyme concentration and behaved as if representing the r ...19938314755
purification of form l2 rubisco from a marine obligately autotrophic hydrogen-oxidizing bacterium, hydrogenovibrio marinus strain mh-110.ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) was purified from an obligately autotrophic hydrogen-oxidizing bacterium, hydrogenovibrio marinus mh-110. the protein has a m(r) value of approximately 110,000, and is composed of two identical subunits of 55,000. to our knowledge, the existence of l2-form rubisco in a chemolithoautotrophic bacterium is first reported in this paper. the n-terminal amino acid sequence determination of the purified enzyme showed high homology with those of ...19938319883
picosecond dynamics of excitations in light-harvesting complex b800-850 from chromatium minutissimum studied using fluorescence spectrochronography.the picosecond dynamics of excitations in the isolated b800-850 light-harvesting complex of the purple sulfur bacterium chromatium minutissimum has been studied using picosecond fluorescence spectrochronography. a short-lived component of about 20 ps lifetime has been found at 77k at the short wavelength part of the b850 fluorescence spectrum similar to that previously described for the core antenna bacteriochlorophyll band b880 of rhodospirillum rubrum. evidence has been presented indicating th ...19938335097
complementation analysis and regulation of co2 fixation gene expression in a ribulose 1,5-bisphosphate carboxylase-oxygenase deletion strain of rhodospirillum rubrum.a ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) deletion strain of rhodospirillum rubrum that was incapable of photolithoautotrophic growth was constructed. photoheterotrophic growth, however, was possible for the r. rubrum rubisco deletion strain when oxidized carbon compounds such as malate were supplied. the r. rubrum rubisco-deficient strain was not complemented to photolithoautotrophic growth by various r. rubrum dna fragments that contain the gene encoding rubisco, cbbm. when t ...19938349547
amplification of ribulose biphosphate carboxylase/oxygenase large subunit (rubisco lsu) gene fragments from thiobacillus ferrooxidans and a moderate thermophile using polymerase chain reaction.southern blot analysis of dna from an iron-oxidising moderate thermophile nmw-6 and from thiobacillus ferrooxidans strain tfi-35 demonstrated sequences homologous to the rubisco lsu gene of synechococcus. dna fragments (457 bp) encoding part of the rubisco lsu gene (amino acids 73-200) were amplified from the genomic dna of thiobacillus ferrooxidans and the moderate thermophile nmw-6 using the polymerase chain reaction (pcr) technique (saiki et al. (1985) science 233, 1350-1354). a comparison wi ...19938357616
a role for the epsilon-amino group of lysine-334 of ribulose-1,5-bisphosphate carboxylase in the addition of carbon dioxide to the 2,3-enediol(ate) of ribulose 1,5-bisphosphate.earlier structural and functional studies of ribulose-1,5-bisphosphate carboxylase/oxygenase imply that k334 facilitates the addition of gaseous substrate to the 2,3-enediol(ate) derived from ribulose 1,5-bisphosphate. crystallographic analysis of the activated spinach enzyme [knight et al. (1990) j. mol. biol. 215, 113-160] shows that the lysyl side chain is appropriately positioned to stabilize the transition state for the addition of co2 to the enediol(ate). furthermore, despite total impairm ...19938369274
excitonic interactions in the light-harvesting antenna of photosynthetic purple bacteria and their influence on picosecond absorbance difference spectra.a new model of the light-harvesting antenna (core complex) of purple photosynthetic bacteria is proposed based on excitonic interactions in circular aggregates of bacteriochlorophyll molecules. the calculated absorbance difference spectra of circular aggregates demonstrate all special features observed in the experimental spectra of purple bacteria. in particular, the absorption changes with high amplitude of bleaching at the long-wavelength side of the absorption band at different excitation en ...19938370458
modulation of the proton-translocation stoichiometry of h(+)-atp synthases in two phototrophic prokaryotes by external ph.the stoichiometry between proton translocation and atp synthesis/hydrolysis was studied in two different photosynthetic prokaryotes, the thermophilic cyanobacterium synechococcus 6716 and the purple bacterium rhodospirillum rubrum. the h+/atp ratio was determined by acid-base transitions as a function of the external ph. the h+/atp ratio of the synechococcus 6716 atp synthase was found to increase with increasing ph. in contrast, in r. rubrum this ratio decreased with increasing ph. these result ...19938379927
pathway of proton transfer in bacterial reaction centers: second-site mutation asn-m44-->asp restores electron and proton transfer in reaction centers from the photosynthetically deficient asp-l213-->asn mutant of rhodobacter mutagenesis of the photosynthetic reaction center (rc) from rhodobacter sphaeroides has shown asp-213 of the l subunit (asp-l213) to be important for photosynthetic viability. replacement of asp-l213 with asn resulted in a photosynthetically deficient mutant, due to the 10(4)-fold slower rate for the proton-coupled electron transfer reaction qa-qb- + 2h+-->qaqbh2 (k(2)ab). the detrimental effect of asn-l213 is surprising since rcs from rhodopseudomonas viridis, rhodospirillum rubru ...19938381964
an open reading frame in the rhodospirillum rubrum plasmid, pky1, similar to alga, encoding the bifunctional enzyme phosphomannose isomerase-guanosine diphospho-d-mannose pyrophosphorylase (pmi-gmp).the nucleotide sequence of a bglii fragment (3188 bp) from the plasmid pky1 of rhodospirillum rubrum was determined. a significant similarity was found between the amino acid sequences deduced from the nucleotide sequence of bglii fragment with that of alga, encoding the bifunctional enzyme with both the activities of phosphomannose isomerase and guanosine diphospho-d-mannose pyrophosphorylase of pseudomonas aeruginosa.19938383539
reversible dissociation and conformational stability of dimeric ribulose bisphosphate carboxylase.dimer-monomer dissociation of ribulosebisphosphate carboxylase/oxygenase from rhodospirillum rubrum was investigated using hydrostatic pressure in the range 1-2 kbar to promote dissociation. intrinsic fluorescence emission and polarization, along with the polarization of the fluorescence of single-labeled aedans conjugates, were used to follow the dissociation. full reversibility after dissociation was observed to depend on the presence of small ligands: glycerol, mg2+, and nahco3, the last two ...19938388254
differential sensitivity of membrane-associated pyrophosphatases to inhibition by diphosphonates and fluoride delineates two classes of enzyme.1,1-diphosphonate analogs of pyrophosphate, containing an amino or a hydroxyl group on the bridge carbon atom, are potent inhibitors of the h(+)-translocating pyrophosphatases of chromatophores prepared from the bacterium rhodospirillum rubrum and vacuolar membrane vesicles prepared from the plant vigna radiata. the inhibition constant for aminomethylenediphosphonate, which binds competitively with respect to substrate, is below 2 microm. rat liver mitochondrial pyrophosphatase is two orders of ...19938392953
molecular cloning and sequencing of the ferredoxin i fdxn gene of the photosynthetic bacterium rhodospirillum rubrum.using an oligonucleotide probe derived from the amino acid sequence of rhodospirillum rubrum ferredoxin i, the gene (fdxn) was identified, cloned and sequenced. the fdxn coding region is 183 nucleotides which codes for a 61 amino acid (7267 da) protein. phylogenetic comparisons between the r. rubrum fdi and other 8fe-8s nif-coupled ferredoxins showed only moderate degrees of similarity between the amino acid sequences. r. rubrum fdi synthesis was stimulated by nif derepressing conditions, but wa ...19938399287
the structure and function of omega loop a replacements in cytochrome c.the structural and functional consequences of replacing omega-loop a (residues 18-32) in yeast iso-1-cytochrome c with the corresponding loop of rhodospirillum rubrum cytochrome c2 have been examined. the three-dimensional structure of this loop replacement mutant repa2 cytochrome c, and a second mutant repa2(val 20) cytochrome c in which residue 20 was back substituted to valine, were determined using x-ray diffraction techniques. a change in the molecular packing is evident in the repa2 mutant ...19938401228
precise location of the cu(ii)-inhibitory binding site in higher plant and bacterial photosynthetic reaction centers as probed by light-induced absorption changes.light-dependent absorption change at 325 nm, ascribed to qa activity, was strongly reduced in the presence of cu(ii) in oxygen-evolving core complex. this change was much less affected in the presence of the herbicide 3-(3,4-dichlorophenyl)-1,1-dimethylurea (dcmu), indicating that the cu(ii)-binding site is different from that of the dcmu and that cu(ii) blocks qa reduction. cu(ii) did not eliminate the absorption change at 545 nm, ascribed to pheophytin reduction, in na2s2o4-treated oxygen-evol ...19938420944
inhibition of proton-translocating transhydrogenase from photosynthetic bacteria by n,n'-dicyclohexylcarbodiimide.the effects of n,n'-dicyclohexylcarbodiimide [(chxn)2c] on the proton-translocating enzyme, nad(p) h(+)-transhydrogenase (h(+)-thase), from two species of phototrophic bacteria have been investigated. the polypeptides of h(+)-thase from rhodobacter capsulatus are membrane-associated, requiring detergent to maintain solubility. the enzyme from rhodospirillum rubrum, however, has a water soluble polypeptide (ths) and a membrane-associated component (thm) which, separately, have no activity but whi ...19938436126
expression study with the escherichia coli lep gene for leader peptidase in phototrophic purple bacteria.synthesis and assembly of leader peptidase of escherichia coli (signal peptidase i), was studied by heterologous expression of its lep gene in three species of phototrophic purple bacteria. cell extracts of the recipient species showed neither cross reaction with antibodies against e. coli leader peptidase nor cleavage of the model substrate m13-procoat in vitro. the lep gene was transferred via conjugation using the plasmid expression vector for phototrophic bacteria pjaj9. plasmid-borne leader ...19938439231
role of phenylalanine-327 in the closure of loop 6 of ribulosebisphosphate carboxylase/oxygenase from rhodospirillum rubrum.phenylalanine-327 of ribulosebisphosphate carboxylase/oxygenase (rubisco) from rhodospirillum rubrum was mutated to tryptophan, leucine, valine, alanine, and glycine, and was also deleted. the least active mutant, the deletion mutant, exhibits less than 0.5% of the carboxylase activity of the wild-type enzyme. steady-state kinetic analysis of f327-->leu, val, ala, gly mutant enzymes reveals that kcat and the co2/o2 specificity are unchanged while km(rubp) (rubp = ribulose 1,5-bisphosphate) is dr ...19938448152
gene expression of the b875 light-harvesting prepolypeptides from rhodospirillum rubrum in escherichia coli.the gene coding for the prepolypeptides of alpha and beta, obtained as a 429 bp fragment from chromosomal dna of rhodospirillum rubrum s1 by polymerase chain reaction amplification, were cloned in tandem into the high-level expression vector potsnco 12 for expression in escherichia coli. the vector potsnco12 is a derivative of the pas vector system, which contains the strong lambda pl promotor and is under tight control by the ci857 repressor encoded by the expression strain ar58. induction of t ...19938451297
site-specific mutations in a loop region of the c-terminal domain of the large subunit of ribulose bisphosphate carboxylase/oxygenase that influence substrate partitioning.amino acids composing a flexible loop (loop 6) of the eight-stranded barrel domain of the l-subunit of synechococcus ribulose bisphosphate carboxylase/oxygenase (ec involved in reaction intermediate stabilization have been modified by site-specific mutagenesis. changes at positions both distant and within the active site affect overall catalysis and substrate partitioning. most significantly, replacement of the active site lys (lys-334) with arg at the apex of the loop almost completel ...19938463309
unexpected similarities of the b800-850 light-harvesting complex from rhodospirillum molischianum to the b870 light-harvesting complexes from other purple photosynthetic bacteria.the b800-850 light-harvesting complex (also called lh2) was isolated from photosynthetic membranes of rhodospirillum molischianum dsm 119 using molecular sieve and ion-exchange chromatography. its two bacteriochlorophyll a-binding polypeptides (alpha-subunit and beta-subunit) were purified with a reverse-phase hplc system. the complete amino acid sequences of both subunits have been determined. the alpha- and beta-subunits consist of 56 and 45 amino acids, respectively, corresponding to molecula ...19938504081
two-dimensional crystallization of the light-harvesting complex from rhodospirillum rubrum.homogeneous detergent-solubilized b873 light-harvesting complexes from a carotenoid-less mutant of the purple non-sulfur bacterium, rhodospirillum rubrum g9, were reassembled spontaneously into two-dimensional (2d) hexagonal arrays during extensive and controlled dialysis. as the complexes contain only 1 to 2 mol phospholipid per mol alpha beta dimer, the arrays formed by a self assembly process are primary due to protein-protein interactions. the hexagonal lattices were analyzed by negative sta ...19938510160
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
amino acid sequence similarities between the vacuolar proton-pumping inorganic pyrophosphatase and the c-subunit of f0f1-atpases.comparison of the arabidopsis thaliana vacuolar proton-pumping inorganic pyrophosphatase with three f0f1-atpase c-subunits revealed a strong similarity between a stretch containing amino acids 227-245 of the h(+)-ppase and a transmembrane alpha-helix of the c-subunits which contains the glutamate which binds n,n'-dicyclohexylcarbodiimide.19938199778
picosecond absorbance difference spectra of the antenna of photosynthetic purple bacteria. the influence of exciton interactions and librations.the influence of exciton interactions and pseudolocal librational modes on the relaxation of photo-induced absorption changes of the light-harvesting antenna of the photosynthetic purple bacterium, rhodospirillum rubrum, was studied in the ps time domain. a hypothesis is put forward that the long-lived librational modes can occur in the circular aggregate of light-harvesting bacteriochlorophyll molecules of the core antenna. the model spectra obtained quantitatively fit the shape of the photo-in ...19948200456
synthesis of quinolones and acridones and their inhibitory activity in nadh-dehydrogenases and cytochrome b/c1-complexes. 19948206292
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
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
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
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
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
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
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
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
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
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
characterization of antimycin resistant mutants of rhodospirillum rubrum. 19947911439
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
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
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
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
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
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
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
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
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 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
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
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
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
cloning and sequencing of the genes for the proton-translocating nicotinamide nucleotide transhydrogenase from rhodospirillum rubrum and the implications for the domain structure of the enzyme.the genes for the proton-translocating nicotinamide nucleotide transhydrogenase from rhodospirillum rubrum have been cloned using a probe constructed with the polymerase chain reaction, genomic dna as target and oligonucleotide primers corresponding to amino acid sequence obtained from the purified soluble subunit. there is a cluster of three genes, designated pntaa, pntab and pntb, whose translation products indicate polypeptides of 384, 139 and 464 amino acids, respectively. this contrasts wit ...19948075801
posttranslational modification of nitrogenase. differences between the purple bacterium rhodospirillum rubrum and the cyanobacterium anabaena the photosynthetic bacteria rhodospirillum rubrum and rhodopseudomonas capsulatus post-translational regulation of nitrogenase is due to adp-ribosylation of the fe-protein, the dinitrogenase reductase [burris, r. h. (1991) j. biol. chem. 266, 9339-9342]. this mechanism has been assumed to be responsible for nitrogenase modification in a variety of organisms. in the present study, we examined whether adp-ribosylation holds true for the filamentous cyanobacterium anabaena variabilis. genes codi ...19948119279
identification of the myxococcus xanthus 59-kda membrane-associated gtp-binding protein as a proton-translocating atpase.five gtp-binding proteins have been detected in myxococcus xanthus by photoaffinity cross-linking with azido-gtp [muñoz-dorado et al., j. biol. chem. 265 (1990a) 2702-2706]. one of them, the 59-kda membrane-associated gtp-binding protein, has been purified. the n-terminal sequence of a 10-kda fragment from the protease v8 digestion of the purified protein has been determined and degenerate oligodeoxyribonucleotides based on that sequence have been used to isolate and clone the gene that encodes ...19948125291
energy transfer in the inhomogeneously broadened core antenna of purple bacteria: a simultaneous fit of low-intensity picosecond absorption and fluorescence kinetics.the excited state decay kinetics of chromatophores of the purple photosynthetic bacterium rhodospirillum rubrum have been recorded at 77 k using picosecond absorption difference spectroscopy under strict annihilation free conditions. the kinetics are shown to be strongly detection wavelength dependent. a simultaneous kinetic modeling of these experiments together with earlier fluorescence kinetics by numerical integration of the appropriate master equation is performed. this model, which account ...19948130341
beta-elimination of phosphate from reaction intermediates by site-directed mutants of ribulose-bisphosphate carboxylase/oxygenase.five residues (thr-53, asn-54, gly-370, gly-393, and gly-394) of rhodospirillum rubrum ribulose-bisphosphate carboxylase/oxygenase are positioned to serve as hydrogen-bond donors for the c1 phosphate of ribulose bisphosphate and thereby constrain conformational flexibility of the initial enediol(ate) intermediate (knight, s., andersson, i., and brändén, c.-i. (1990) j. mol. biol. 215, 113-160). to study the functional contributions of the residues implicated in ribulose bisphosphate binding and ...19948157638
thermodynamics of membrane polypeptide oligomerization in light-harvesting complexes and associated structural changes.investigation of the equilibrium between the dissociated b777 form of the light-harvesting complex of rhodospirillum rubrum and the oligomeric b820 form demonstrates that the b777 form consists of bacteriochlorophyll a (bchl) bound to the alpha or beta polypeptide chains; this binding appears to be reasonably stable at room temperature with little dissociation to free bchl and polypeptides. analysis of the reaction order for the b777 association reaction to form b820 shows that this reaction req ...19948176735
anaerobic bacteria from hypersaline environments.strictly anaerobic halophiles, namely fermentative, sulfate-reducing, homoacetogenic, phototrophic, and methanogenic bacteria are involved in the oxidation of organic carbon in hypersaline environments. to date, six anaerobic fermentative genera, containing nine species, have been described. two of them are homoacetogens. six species belong to the family haloanaerobiaceae, as indicated by their unique 16s rrna oligonucleotide sequences. desulfohalobium retbaense and desulfovibrio halophilus repr ...19948177169
chemical rescue by exogenous amines of a site-directed mutant of ribulose 1,5-bisphosphate carboxylase/oxygenase that lacks a key lysyl residue.ligand binding to ribulose 1,5-bisphosphate carboxylase/oxygenase immobilizes the flexible loop 6 of the beta/alpha barrel domain in its closed conformation. lys329, located at the apex of this loop, interacts electrostatically with glu48 of the adjacent subunit and with the co2-derived carboxylate of the carboxylated reaction intermediate [knight et al. (1990) j. mol. biol. 215, 113-160]. previous studies have implicated lys329 in the addition of co2 to the initial enediol(ate) intermediate: mu ...19948180178
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
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
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