| purification of highly active cytochrome bc1 complexes from phylogenetically diverse species by a single chromatographic procedure. | a method has been developed for purification of highly active ubiquinol-cytochrome c oxidoreductase (cytochrome bc1) complexes from wild-type rhodobacter sphaeroides, rhodobacter capsulatus mt1131, bovine heart and yeast mitochondria. this is the first report of the isolation of cytochrome bc1 complex from a wild-type strain of rb. sphaeroides and from any strain of rb. capsulatus. the purification involves extraction of membranes with dodecyl maltoside and two successive deae column chromatogra ... | 1987 | 3032252 |
| the cytochrome bc1 complex of rhodobacter sphaeroides can restore cytochrome c2-independent photosynthetic growth to a rhodobacter capsulatus mutant lacking cytochrome bc1. | plasmids encoding the structural genes for the rhodobacter capsulatus and rhodobacter sphaeroides cytochrome (cyt) bc1 complexes were introduced into strains of r. capsulatus lacking the cyt bc1 complex, with and without cyt c2. the r. capsulatus merodiploids contained higher than wild-type levels of cyt bc1 complex, as evidenced by immunological and spectroscopic analyses. on the other hand, the r. sphaeroides-r. capsulatus hybrid merodiploids produced only barely detectable amounts of r. sphae ... | 1989 | 2553670 |
| effects of light, oxygen, and substrates on steady-state levels of mrna coding for ribulose-1,5-bisphosphate carboxylase and light-harvesting and reaction center polypeptides in rhodopseudomonas sphaeroides. | the mrna levels specific for ribulose-1,5-bisphosphate carboxylase, light-harvesting i polypeptides alpha and beta, and reaction center polypeptides l and m were assayed by use of a series of dna probes specific for each cognate mrna. both the steady-state amounts and sizes of the specific mrnas were measured as a function of the light intensity incident to the culture, the presence or absence of oxygen, and the type of substrate present in the growth medium. northern hybridization revealed at l ... | 1985 | 2581935 |
| flash-induced proton release in rhodopseudomonas sphaeroides spheroplasts. | proton release by flash excitations was measured with right-side-out vesicles prepared from rhodopseudomonas sphaeroides by lysozyme-edta treatment followed by hypotonic treatment. absorbance change at 586 nm in the presence of bromcresol purple was measured to monitor the ph change. in the presence of horse heart cytochrome c, which catalyzes the electron transfer from the cytochrome b-c1 complex to the primary electron donor, the single-turnover flash elicited release of about two protons per ... | 1987 | 3032925 |
| purification and some characteristics of nitrous oxide reductase from paracoccus denitrificans. | nitrous oxide reductase from the denitrifying bacterium paracoccus denitrificans has been purified very nearly to homogeneity by an anaerobic procedure that results in a product with high specific activity. the enzyme is a dimer of about mr 144,000 composed of two subunits of apparently equal mr and contains 4 mol of cu per mol of subunit. the isoelectric point is 4.3; specific activity at 25 degrees c, ph 7.1, is 122 mumol x min-1 x mg of protein-1; and km is about 7 microm n2o under the same c ... | 1987 | 3032972 |
| construction of a transposon containing a gene for polygalacturonate trans-eliminase from klebsiella oxytoca. | a dna fragment containing a klebsiella oxytoca gene for polygalacturonate trans-eliminase was cloned into the kanamycin resistance transposon tn5. this new transposon, designated tn5-pga+, had a transposition frequency of 1 x 10(-6). the broad host range plasmid pr751::tn5-pga+ was conjugally transferred to a variety of genetic backgrounds. the ability to degrade polygalacturonate was expressed in aeromonas hydrophila, alcaligenes eutrophus, azotomonas insolita, escherichia coli, pseudomonas put ... | 1987 | 3034186 |
| organization and expression of genes for photosynthetic pigments-protein complexes in photosynthetic bacteria. | | 1989 | 2653478 |
| the primary structures of the core antenna polypeptides from rhodopseudomonas marina. | the antenna complex b880 of rp. marina has been isolated by applying ion-exchange chromatography on whatman de-52 resin and sucrose density centrifugation of ldao-solubilized photosynthetic membranes. the antenna polypeptides b880-alpha and b880-beta were prepared by organic solvent extraction of extensively dialyzed and freeze-dried b880 antenna complex material or photosynthetic membranes. gel filtration on sephadex lh-60 and ion-exchange chromatography on whatman de-32 resin in the presence o ... | 1989 | 2669779 |
| organization of phosphoribulokinase and ribulose bisphosphate carboxylase/oxygenase genes in rhodopseudomonas (rhodobacter) sphaeroides. | a heterologous phosphoribulokinase (prk) gene probe was used to analyze two recombinant plasmids isolated from a rhodopseudomonas (rhodobacter) sphaeroides gene library. these plasmids were previously shown to carry the genes for form i and form ii ribulose 1,5-bisphosphate carboxylase/oxygenase (rubpc/o). southern blot hybridization analysis indicated that there were two prk genes linked to the rubpc/o coding sequences. restriction mapping showed the arrangement of the duplicate sets of prk and ... | 1987 | 3038848 |
| reaction centers from rhodopseudomonas sphaeroides in reconstituted phospholipid vesicles. i. structural studies. | reaction centers (rcs) from rhodopseudomonas sphaeroides were reconstituted into asolectin vesicles by cosonication. equilibrium centrifugation on sucrose gradients showed that the vesicles were homogeneous in density (i.e., lipid-to-protein ratio) when reconstituted at a molar lipid-to-protein ratio between 500 to 1000. at lower ratios, a considerable fraction of rcs was not incorporated into closed vesicles, while at higher ratios, an increasing population of liposomes was protein-free. the av ... | 1987 | 3040696 |
| reaction centers from rhodopseudomonas sphaeroides in reconstituted phospholipid vesicles. ii. light-induced proton translocation. | unidirectional light-dependent proton translocation was demonstrated in a suspension of reconstituted reaction center (rc) vesicles supplemented with cytochrome c and 2,3-dimethoxy-5-methyl-1,4-benzoquinone (uq0), a lipid- and water-soluble quinone. proton translocation was detected only at alkaline ph. the ph dependence can be accounted for by the slow redox reaction between the reduced quinone (uq0h2) and oxidized cytochrome c. this conclusion is based on (i) the ph dependence of partial react ... | 1987 | 3040697 |
| electron transfer in a genetically modified bacterial reaction center containing a heterodimer. | time-resolved optical measurements encompassing the femtoseconds to seconds time scales have been used to investigate rhodobacter capsulatus reaction centers (rcs) in which the histidine residue at position 200 on the m polypeptide has been changed to a leucine by site-directed mutagenesis. the hism200----leu rc, which has a heterodimer consisting of a bacteriochlorophyll and a bacteriopheophytin, is capable of the primary photochemistry observed in wild-type rb. capsulatus rcs, but with an over ... | 1988 | 3051000 |
| structure of the reaction center from rhodobacter sphaeroides r-26: protein-cofactor (quinones and fe2+) interactions. | the three-dimensional structure of the reaction center (rc) from rhodobacter sphaeroides has been determined by x-ray diffraction to a resolution of 2.8 a with an r value of 24%. the interactions of the protein with the primary quinone, qa, secondary quinone, qb, and the nonheme iron are described and compared to those of rcs from rhodopseudomonas viridis. structural differences between the qa and qb environments that contribute to the function of the quinones (the electron transfer from qa- to ... | 1988 | 3054889 |
| pleiotropic effects of localized rhodobacter capsulatus puf operon deletions on production of light-absorbing pigment-protein complexes. | the polycistronic puf operon of rhodobacter capsulatus encodes protein components for the photosynthetic reaction center and one of the two antenna complexes involved in the capture of light energy. we report here that deletions within specific puf genes alter the synthesis and/or assembly in the photosynthetic membranes of pigment-protein complexes not affected genetically by the deletion. the pufx gene is required for normal ratios of antenna complexes, and its deletion results in an increase ... | 1988 | 3056917 |
| electron transfer in monolayer assemblies and energy storage in photosynthetic bacteria. | | 1988 | 3074639 |
| reaction centers of photosynthetic bacteria. | | 1988 | 3076277 |
| different lipid a types in lipopolysaccharides of phototrophic and related non-phototrophic bacteria. | lipid a analyses confirm not only the present taxa of the purple nonsulfur bacteria (formerly rhodospirillaceae), but also phylogenetical relatedness of distinct phototrophic to distinct non-phototrophic bacteria, as was suggested by cataloguing 16s rrna. for example, lipid a with ester-bound 3-oh-10:0 and the rare amide-linked 3-oxo-14:0 is common to the phototrophic rhodobacter capsulatus and rhodobacter sphaeroides and also to paracoccus denitrificans and thiobacillus versutus. 'lipid adag' ( ... | 1988 | 3078741 |
| crystallization and characterization of two crystal forms of the b800-850 light-harvesting complex from rhodopseudomonas acidophila strain 10050. | two different crystal forms of the b800-850-antenna complex from rhodopseudomonas acidophila strain 10050 have been grown. this complex is an integral membrane protein and is isolated as an oligomeric assembly with a molecular weight of approximately 84 kda. this assembly contains six alpha/beta apoprotein pairs, 18 molecules of bacteriochlorophyll a and nine molecules of carotenoid. the first crystal form has dimensions unit cell a = b = 75.8 a, c = 97.5 a with the space group p4 and diffracts ... | 1989 | 2685328 |
| purple-bacterial light-harvesting complexes. | | 1986 | 3082693 |
| the metabolism of carbaryl by three bacterial isolates, pseudomonas spp. (ncib 12042 & 12043) and rhodococcus sp. (ncib 12038) from garden soil. | at an alkaline ph and in aqueous solution, carbaryl hydrolyses to form 1-naphthol, methylamine and carbon dioxide, but it is much more stable at an acid ph. two bacterial isolated from garden soil, pseudomonas sp. (ncib 12042) and rhodococcus sp. (ncib 12038), could grow on carbaryl as sole carbon and nitrogen source at ph 6.8 but failed to metabolize carbaryl rapidly. both could use 1-naphthol as sole carbon source and ncib 12042 metabolized 1-naphthol via salicylic acid which induced higher ex ... | 1986 | 3086270 |
| nanosecond fluorescence from chromatophores of rhodopseudomonas sphaeroides and rhodospirillum rubrum. | single-photon counting techniques were used to measure the fluorescence decay from rhodopseudomonas sphaeroides and rhodospirillum rubrum chromatophores after excitation with a 25-ps, 600-nm laser pulse. electron transfer was blocked beyond the initial radical-pair state (pf) by chemical reduction of the quinone that serves as the next electron acceptor. under these conditions, the fluorescence decays with multiphasic kinetics and at least three exponential decay components are required to descr ... | 1986 | 3087422 |
| some important concepts in the current theories of electron transfer in biological systems. | the main concepts pertinent to the current theories of electron transfer in biological systems are briefly presented. the different models used to evaluate the purely electronic factors of the transfer are reviewed. | 1986 | 3089326 |
| expression of cellulase genes in rhodobacter capsulatus by use of plasmid expression vectors. | broad-host-range plasmid vectors were constructed for expression of heterologous genes in the photosynthetic bacterium rhodobacter capsulatus. these plasmids utilize an rk2-derived replicon for maintenance and conjugative transfer and the r. capsulatus rxca promoter to obtain transcription of genes within appropriately positioned dna fragments. the expression vectors were used to obtain synthesis of endoglucanase and exoglucanase in r. capsulatus from cellulase genes present on exogenously deriv ... | 1986 | 3090019 |
| organization of the genes for nitrogen fixation in photosynthetic bacteria and cyanobacteria. | | 1986 | 3096194 |
| in vivo regulation of form i ribulose 1,5-bisphosphate carboxylase/oxygenase from rhodopseudomonas sphaeroides. | when autotrophically grown cells of rhodopseudomonas (rhodobacter) sphaeroides were supplied with an organic carbon source, the activity of ribulose 1,5-bisphosphate carboxylase/oxygenase (rubpc/o) decreased 30 to 60%. the extent of inactivation varied depending on the level of derepression of form i and form ii rubpc/o, and on the nature of the organic carbon source, pyruvate being the most effective. raising the concentration of co2 in the gas phase of autotrophic cultures brought about a simi ... | 1987 | 3107471 |
| malate dehydrogenase in phototrophic purple bacteria: purification, molecular weight, and quaternary structure. | the citric acid cycle enzyme malate dehydrogenase was purified to homogeneity from the nonsulfur purple bacteria rhodobacter capsulatus, rhodospirillum rubrum, rhodomicrobium vannielii, and rhodocyclus purpureus. malate dehydrogenase was purified from each species by either a single- or a two-step protocol: triazine dye affinity chromatography was the key step in purification of malate dehydrogenase in all cases. purification of malate dehydrogenase resulted in a 130- to 240-fold increase in mal ... | 1987 | 3114237 |
| dna repair systems in the phototrophic bacterium rhodobacter capsulatus. | uv irradiation and mitomycin c exposure trigger a protease-activity-dependent inhibition of cell division in rhodobacter capsulatus, which begins about 2 h after the treatment is applied. uv irradiation also induces a dose-dependent mutagenesis with a maximal rate between 5 and 10 j m-2, with increased synthesis of a protein of mr approximately 30,000 between 2 and 3 h after uv irradiation. in addition, r. capsulatus has an efficient photoreactivation system that reverses the lethal effects of u ... | 1987 | 3116168 |
| analysis of the rhodobacter capsulatus puf operon. location of the oxygen-regulated promoter region and the identification of an additional puf-encoded gene. | in an attempt to identify features of an oxygen-regulated promoter, we have determined the location of transcription initiation for the puf operon. the position for the oxygen-regulated promoter was demonstrated by several independent means to be located 699 base pairs (bp) upstream from the pufb structural gene. dna sequence analysis of the promoter region demonstrates the presence of a 26-base pair region of dyad symmetry followed by a sequence containing homology to promoters which use the rn ... | 1988 | 3127391 |
| prokaryotic hopanoids: the biosynthesis of the bacteriohopane skeleton. formation of isoprenic units from two distinct acetate pools and a novel type of carbon/carbon linkage between a triterpene and d-ribose. | incorporation of 13c-labelled acetate into the hopanoids of the purple non-sulfur bacteria rhodopseudomonas palustris and rhodopseudomonas acidophila and the facultative methylotroph methylobacterium organophilum showed that the bacteriohopane skeleton is built from an unique carbon/carbon linkage between the triterpenic hopane moiety and the c-5 carbon of a d-ribose derivative arising from the non-oxidative pentose phosphate pathway. furthermore a probable compartmentation of the acetate metabo ... | 1988 | 3136017 |
| malate dehydrogenases in phototrophic purple bacteria. thermal stability, amino acid composition and immunological properties. | purified malate dehydrogenases from four species of non-sulphur purple phototrophic bacteria were examined for their heat-stability, amino acid composition and antigenic relationships. malate dehydrogenase from rhodospirillum rubrum, rhodobacter capsulatus and rhodomicrobium vannielii (which are all tetrameric proteins) had an unusually high glycine content, but the enzyme from rhodocyclus purpureus (which is a dimer) did not. r. rubrum malate dehydrogenase was extremely heat-stable relative to ... | 1988 | 3137931 |
| membrane proteins. detergent ringing true as a model for membranes. | | 1989 | 2770865 |
| rhodobacter capsulatus puf operon encodes a regulatory protein (pufq) for bacteriochlorophyll biosynthesis. | biosynthesis of the photochemical apparatus by purple nonsulfur photosynthetic bacteria is known to be inhibited by molecular oxygen and high light intensity. polypeptides that bind bacteriochlorophyll (bchl) to form the light-harvesting i (lh-i) and reaction-center (rc) complexes are encoded by a single transcriptional unit termed the puf operon. in this investigation we demonstrate that the first structural gene in the puf operon (pufq) of rhodobacter capsulatus encodes a protein that is requi ... | 1988 | 3174621 |
| structure of the reaction center from rhodobacter sphaeroides r-26 and 2.4.1: protein-cofactor (bacteriochlorophyll, bacteriopheophytin, and carotenoid) interactions. | the three-dimensional structures of the cofactors and protein subunits of the reaction center (rc) from the carotenoidless mutant strain of rhodobacter sphaeroides r-26 and the wild-type strain 2.4.1 have been determined by x-ray diffraction to resolutions of 2.8 a and 3.0 a with r values of 24% and 26%, respectively. the bacteriochlorophyll dimer (d), bacteriochlorophyll monomers (b), and bacteriopheophytin monomers (phi) form two branches, a and b, that are approximately related by a twofold s ... | 1988 | 3186702 |
| ammonia-constitutive nitrogen fixation mutants of rhodobacter capsulatus. | mutants of r. capsulatus that express nif genes constitutively with respect to ammonia were studied in order to define better the circuit that regulates nif gene transcription. one mutant class could be complemented in trans by a cosmid clone containing a wild-type gene (nifr5) defined by tn5 inserts as being no longer than 1.6 kb. the nifr5 gene is unlinked to previously described nif genes. a second mutant class could not be complemented by the wild-type cosmid library. for one mutant in this ... | 1988 | 3215528 |
| mechanism of puf mrna degradation: the role of an intercistronic stem-loop structure. | the puf photosynthesis operon of rhodobacter capsulatus encodes two major classes of mrna: operon-length pufbalmx transcripts and short pufba messages. the pufba messages, which end in a large intercistronic stem-loop structure, are long-lived processing products of the puf operon transcripts. decay of the labile puflmx segment of the operon-length transcripts begins with non-random endonucleolytic cleavage well downstream of the intercistronic hairpin structure. this hairpin, which is necessary ... | 1988 | 3243429 |
| location of fatty acids in lipid a obtained from lipopolysaccharide of rhodopseudomonas sphaeroides atcc 17023. | monophosphoryl lipid a (mla) obtained from the lipopolysaccharide of rhodopseudomonas sphaeroides atcc 17023 was initially purified by silicic acid column chromatography to yield a single major pentaacyl mla fraction. this fraction was methylated and further purified by reverse-phase high performance liquid chromatography to yield three prominent peak fractions. laser desorption mass spectrometry of these three fractions allowed us to complete the important structural analysis of lipid a from th ... | 1988 | 3258599 |
| anaerobic phototrophic metabolism of 3-chlorobenzoate by rhodopseudomonas palustris ws17. | a mixed phototrophic culture was found to reductively metabolize 3-chlorobenzoate in the presence of benzoate following adaptation for a period of 7 weeks. the dominant bacterial isolate from this mixed culture, identified as rhodopseudomonas palustris ws17, metabolized 3-chlorobenzoate completely in the presence of benzoate and light and in the absence of oxygen. [14c]3-chlorobenzoate was converted to 14co2 and cell 3-chlorobenzoate metabolism is a common phenomenon in this species. | 1990 | 2128012 |
| o2-dependent nitrogenase switch-off in rhodobacter capsulatus e1f1. | nitrogenase of rhodobacter capsulatus e1f1 (formerly known as rhodopseudomonas capsulata e1f1) was partially resistant to o2 inactivation in vivo. this inactivation was reversed by restoring anaerobic conditions, was independent from de novo protein synthesis and its extent was decreased upon preincubation of the cells with dioxygen at low pressures and also in the presence of h2. illuminated cells exhibited a low rate of o2 uptake which was enhanced in the presence of h2, particularly in cells ... | 1987 | 3268290 |
| adaptive response to simple alkylating agents in the phototrophic bacteria rhodobacter capsulatus and r.sphaeroides. | the presence of an adaptive response to low doses of alkylating chemicals in the phototrophic bacteria rhodobacter sphaeroides and r.capsulatus has been studied. results obtained show that both strains display this repair response against the challenge doses of n-methyl-n'-nitro-n-nitrosoguanidine (mnng), when they are pretreated with low doses of this compound for 120 min. the adaptive response of both r.sphaeroides and r.capsulatus induced an increase of cell survival and a decrease of mutagen ... | 1988 | 3288840 |
| photochemical electron transfer reactions in the acceptor complex of reaction centers of rhodopseudomonas spheroides treated with sodium dodecyl sulfate. | we have compared some photochemical properties of the reaction-center complex of rhodopseudomonas spheroides (wild-type) treated with various amounts of either sodium dodecyl sulfate (sds) or dodecyl dimethylamine n-oxide. in the presence of the latter, the native structure and activity of the reaction center are preserved even at high concentrations of detergent. in contrast, sds denatures the protein. it does this by a cooperative process, as shown by the sigmoidal relationship between primary ... | 1987 | 3297697 |
| structure of the reaction center from rhodobacter sphaeroides r-26: the cofactors. | the three-dimensional structure of the cofactors of the reaction center of rhodobacter sphaeroides r-26 has been determined by x-ray diffraction and refined at a resolution of 2.8 a with an r value of 26%. the main features of the structure are similar to the ones determined for rhodopseudomonas viridis [michel, h., epp, o. & deisenhofer, j. (1986) embo j. 5, 2445-2451]. the cofactors are arranged along two branches, which are approximately related to each other by a 2-fold symmetry axis. the st ... | 1987 | 3303032 |
| electron microscopical investigation of citrate lyase single molecules. | electron micrographs of citrate lyase from rhodopseudomonas gelatinosa and klebsiella aerogenes reveal two characteristic molecular forms. the "basket" form and the "star" form were subjected to two-dimensional image reconstruction using a technique involving averaging of superposed single molecular images after rotational correlation. a three-dimensional image reconstruction shows that the images of these forms can be interconverted by rotation and that they therefore represent different views ... | 1987 | 3304340 |
| membrane topography of anaerobic carbon monoxide oxidation in rhodocyclus gelatinosus. | rhodocyclus gelatinosus 1 grows anaerobically in the dark at the expense of carbon monoxide. topographical studies with methyl viologen as the membrane probe indicated that co oxidation and h2 production sites were on the cytoplasmic side of the cell membrane. membrane-associated hydrogen gas production appeared to be a unidirectional reaction. in the dark, strain 1 whole cells oxidized co and incorporated about 306 pmol of 32pi into atp per min per mg of protein. with co as the sole energy-yiel ... | 1987 | 3308854 |
| the stark effect in reaction centers from rhodobacter sphaeroides r-26 and rhodopseudomonas viridis. | the effect of an electric field on the optical absorption (stark effect) of reaction centers (rcs) from rhodobacter sphaeroides and rhodopseudomonas viridis embedded in films of poly(vinyl alcohol) was measured. the infrared bands were investigated at 295 k and 77 k. in rcs from rp. viridis at 77 k six peaks (at 982, 849, 835, 818, 803, and 787 nm), associated with the qy transitions of the six pigments, were resolved; in addition, a small broad band at 865 nm was resolved. in rcs from rb. sphae ... | 1987 | 3313396 |
| primary structure of the reaction center from rhodopseudomonas sphaeroides. | the reaction center is a pigment-protein complex that mediates the initial photochemical steps of photosynthesis. the amino-terminal sequences of the l, m, and h subunits and the nucleotide and derived amino acid sequences of the l and m structural genes from rhodopseudomonas sphaeroides have previously been determined. we report here the sequence of the h subunit, completing the primary structure determination of the reaction center from r. sphaeroides. the nucleotide sequence of the gene encod ... | 1986 | 3329732 |
| the hopanoids of the purple non-sulfur bacteria rhodopseudomonas palustris and rhodopseudomonas acidophila and the absolute configuration of bacteriohopanetetrol. | five complex hopanoids have been detected in the purple non-sulfur bacterium rhodopseudomonas acidophila. next to the polyfunctionalized methylcyclopentane bacteriohopanetetrol ether already isolated from methylobacterium organophilum, 35-carbamoylbacteriohopane-32,33,34-triol, 34,35-dicarbamoylbacteriohopane-32,33-diol and two nucleoside analogues, (22r)-30-(5'-adenosyl)hopane and (22s)-30-(5'-adenosyl)hopane were isolated and identified by spectroscopic and chemical methods. in rhodopseudomona ... | 1988 | 3338464 |
| the action of the sesquiterpenic benzoquinone, perezone, on electron transport in biological membranes. | perezone (2-(1,5-dimethyl-4-hexenyl)-3-hydroxymethyl-p-benzoquinone) is a sesquiterpenic benzoquinone isolated from roots of plants of the genus perezia. it exhibits oxido-reduction characteristics which suggest that the compound can be used for studies of the electron transfer chain of rat liver mitochondria. perezone at 50 microm inhibits mitochondrial electron transport through a process which differs from that of rotenone, amytal, and antimycin a. the inhibition is temperature dependent; at ... | 1988 | 3341744 |
| purification and properties of benzoate-coenzyme a ligase, a rhodopseudomonas palustris enzyme involved in the anaerobic degradation of benzoate. | a soluble benzoate-coenzyme a (coa) ligase was purified from the phototrophic bacterium rhodopseudomonas palustris. synthesis of the enzyme was induced when cells were grown anaerobically in light with benzoate as the sole carbon source. purification by chromatography successively on hydroxylapatite, phenyl-sepharose, and hydroxylapatite yielded an electrophoretically homogeneous enzyme preparation with a specific activity of 25 mumol/min per mg of protein and a molecular weight of 60,000. the p ... | 1988 | 3350788 |
| identification of a new bradyrhizobium japonicum gene (frxa) encoding a ferredoxinlike protein. | an open reading frame of 74 codons was identified downstream of the nifb gene of bradyrhizobium japonicum 110. the predicted amino acid sequence shared 63% similarity with the rhodopseudomonas palustris ferredoxin i sequence. we propose to name the gene frxa. the frxa gene was found to be cotranscribed with the nifb gene. an insertion mutation within frxa hardly affected nitrogen fixation activity. | 1988 | 3350797 |
| the complete amino acid sequences of the b800-850 antenna polypeptides from rhodopseudomonas acidophila strain 7750. | spectrally pure b800-850 light harvesting complexes of rhodopseudomonas acidophila 7750 were prepared by chromatography of ldao-solubilised photosynthetic membranes on whatmann de-52 ion exchange resin. two low molecular mass polypeptides (alpha, beta) have been isolated by organic solvent extraction of the lyophilised b800-850 light harvesting complexes. their primary structures were determined by liquid phase sequencer runs, by the sequence analyses of c-terminal o-iodosobenzoic acid fragments ... | 1988 | 3376519 |
| isolation of a rhodobacter capsulatus mutant that lacks c-type cytochromes and excretes porphyrins. | a rhodobacter capsulatus mutant lacking cytochrome oxidase activity was isolated by tn5 mutagenesis. difference spectroscopy of crude extracts and extracted c-type cytochromes demonstrated that this mutant completely lacked all c-type cytochromes. the strain did, however, synthesize normal amounts of b-type cytochromes and nonheme iron. this mutant also excreted large amounts of coproporphyrin and protoporphyrin and synthesized reduced amounts of bacteriochlorophyll, suggesting a link between th ... | 1990 | 2155198 |
| transcription of the rhodobacter capsulatus nifhdk operon is modulated by the nitrogen source. construction of plasmid expression vectors based on the nifhdk promoter. | we characterized the rhodobacter capsulatus nifhdk promoter by nucleotide sequencing and nuclease s1 analysis of mrna-protected dna probes. comparison of this promoter to nifp and ntrp promoters from other species reveals extensive homology to the canonical nifp consensus sequence. using lac fusions we have demonstrated that transcription of the nifhdk operon is totally repressed when the growth medium is supplemented with ammonia, becomes fully derepressed in ammonia-free medium, and proceeds a ... | 1988 | 3410321 |
| degradation of puflmx mrna in rhodobacter capsulatus is initiated by nonrandom endonucleolytic cleavage. | differential expression of genes within the puf photosynthesis operon of rhodobacter capsulatus is achieved primarily through marked segmental differences in stability within the polycistronic puf operon transcripts. the comparatively stable pufba segment of these transcripts outlives the labile puflmx segment and accumulates as an abundant puf mrna degradation intermediate. here we present further evidence that degradation of pufbalmx mrna is initiated by endonucleolytic cleavage within the sho ... | 1990 | 2165480 |
| biological consequences of segmental alterations in mrna stability: effects of deletion of the intercistronic hairpin loop region of the rhodobacter capsulatus puf operon. | it has been proposed that intercistronic stem and loop structures located in the puf operon of the photosynthetic bacterium rhodobacter capsulatus account for segmental differences in transcript stability and consequently, the differential expression of the b870 and reaction center (rc) proteins encoded by puf. we report here that deletion of these structures leads to a failure to detect as discrete fragments the b870-encoding 0.49 kb and 0.50 kb mrna segments located upstream from the site of t ... | 1987 | 3428264 |
| red blood cell rhodanese: its possible role in modulating delta-aminolaevulinate synthetase activity in mammals. | the optimum conditions for measuring rhodanese activity in human erythrocytes were established. the mean control values for males (112 nmol scn/30 min/mg protein) and females (127 nmol scn/30 min/mg protein) were determined. rhodanese activity was measured in different porphyric patients. the activity was diminished in porphyria cutanea tarda (pct), acute intermittent porphyria (aip), variegate porphyria (vp) and lead intoxication (pb), remaining normal in erythropoietic protoporphyria (epp). de ... | 1987 | 3471602 |
| ferrochelatase from rhodopseudomonas sphaeroides: substrate specificity and role of sulfhydryl and arginyl residues. | purified ferrochelatase (protoheme ferrolyase; ec 4.99.1.1) from the bacterium rhodopseudomonas sphaeroides was examined to determine the roles of cationic and sulfhydryl residues in substrate binding. reaction of the enzyme sulfhydryl residues with n-ethylmaleimide or monobromobimane resulted in a rapid loss of enzyme activity. ferrous iron, but not porphyrin substrate, had a protective effect against inactivation by these two reagents. quantitation with 3h-labeled n-ethylmaleimide revealed tha ... | 1986 | 3484475 |
| the phosphoenolpyruvate-dependent fructose-specific phosphotransferase system in rhodopseudomonas sphaeroides. energetics of the phosphoryl group transfer from phosphoenolpyruvate to fructose. | energy coupling to fructose transport in rhodopseudomonas sphaeroides is achieved by phosphorylation of the membrane-spanning fructose-specific carrier protein, efruii. the phosphoryl group of phosphoenolpyruvate is transferred to efruii via the cytoplasmic component sf (soluble factor). the standard free enthalpy of hydrolysis of the two phosphorylated proteins has been estimated from isotope exchange measurements in chemical equilibrium. the delta g degrees for sf-p is -60.5 kj/mol. the standa ... | 1986 | 3484702 |
| labelling of chlorophylls and precursors by [2-14c]glycine and 2-[1-14c]oxoglutarate in rhodopseudomonas spheroides and zea mays. resolution of the c5 and shemin pathways of 5-aminolaevulinate biosynthesis by thin-layer radiochromatography. | the c-5 of 5-aminolaevulinate, a tetrapyrrole precursor which accumulates when inhibitory laevulinate is present, is derived from either the c-2 of glycine by the 5-aminolaevulinate-synthase-mediated shemin pathway or the c-1 of 2-oxoglutarate by the c5 pathway. thin-layer-radiochromatographic procedures are described for determining whether [2-14c]glycine or 2-[1-14c]oxoglutarate labelled the macrocycle of bacteriochlorophyll a, in addition to or rather than the methyl ester or phytyl ester moi ... | 1986 | 3485524 |
| a new membrane-bound b-type cytochrome, cytochrome b-558, from photosynthetically grown rhodopseudomonas sphaeroides. | a new membrane-bound b-type cytochrome, cytochrome b-558, was removed from chromatophore membranes of photosynthetically grown rhodopseudomonas sphaeroides strain r-26 by deoxycholate-cholate extraction. the cytochrome was purified by ammonium sulfate fractionation and ion-exchange chromatography. cytochrome b-558 had absorption maxima at 280 and 405 nm in the oxidized form, and at 558, 528, and 420 nm in the reduced form. it had a midpoint potential of--130 mv at ph 7.0. the minimal molecular w ... | 1986 | 3485957 |
| the role of c-type cytochromes in the photosynthetic electron transport pathway of rhodobacter capsulatus. | (1) short flash excitation of membrane vesicles of a cytochrome-c2-deficient mutant of rhodobacter capsulatus (strain mt-g4/s4) led to rapid oxidation of a c-type cytochrome. in redox titrations, the photooxidation of c-type cytochrome was attenuated with a midpoint of approx. +360 mv. vesicles from a control strain, mt1131, gave similar results. these findings are consistent with those of prince et al. (prince, r.c., davidson, e., haith, l.e. and daldal, f. (1986) biochemistry 25, 5208-5214). ( ... | 1990 | 2168749 |
| the phosphoenolpyruvate-dependent fructose-specific phosphotransferase system in rhodopseudomonas sphaeroides. evidence for a shift in the midpoint potential of the dithiol redox center during turnover of the carrier. | redox titrations of the fructose-specific carrier protein, efruii, in rhodopseudomonas sphaeroides show that only the reduced form of the enzyme is active. the oxidized form of the enzyme can still be phosphorylated but is unable to transfer the phosphoryl group to fructose. the redox properties of the enzyme change upon phosphorylation. the reduction rate of efruii is slower than that of efruii-p, whereas the opposite is true for the oxidation rate. consequently the midpoint potential of the re ... | 1986 | 3488904 |
| [rhodopseudomonas sphaeroides mutants defective in nitrogen fixation]. | mutants of phototrophic bacterium rhodopseudomonas sphaeroides deficient in nitrogen fixation and unable to utilize alanine, proline, arganine and glutamic acid as nitrogen sources have been obtained as a result of nitrosomethylurea mutagenesis. the majority of the nif-mutants have no nitrogenase activity and aminotransferase activity of glutamine synthetase during their growth in glutamine containing medium is sharply lowered. the specific activity of glutamate synthase and alanine dehydrogenas ... | 1986 | 3489487 |
| statistical distribution of hydrophobic residues along the length of protein chains. implications for protein folding and evolution. | we consider in this paper the statistical distribution of hydrophobic residues along the length of protein chains. for this purpose we used a binary hydrophobicity scale which assigns hydrophobic residues a value of one and non-hydrophobes a value of zero. the resulting binary sequences are tested for randomness using the standard run test. for the majority of the 5,247 proteins examined, the distribution of hydrophobic residues along a sequence cannot be distinguished from that expected for a r ... | 1990 | 2188687 |
| preliminary characterization by x-ray diffraction of crystals of photochemical reaction centres from wild-type rhodopseudomonas spheroides. | reaction centres from wild-type rhodopseudomonas spheroides (strain y) in a solution of octylglucoside have been crystallized with polyethylene glycol as precipitant, either by vapour diffusion or dialysis. orthorhombic crystals (space group p2(1)2(1)2(1)) diffract to 3.5 a resolution. the unit cell parameters are a = 142.5 a, b = 141.5 a, c = 80 a; they are compatible with the presence of one reaction centre per asymmetric unit. | 1987 | 3496461 |
| observations concerning topology and locations of helix ends of membrane proteins of known structure. | hydropathy plots of amino acid sequences reveal the approximate locations of the transbilayer helices of membrane proteins of known structure and are thus used to predict the helices of proteins of unknown structure. because the three-dimensional structures of membrane proteins are difficult to obtain, it is important to be able to extract as much information as possible from hydropathy plots. we describe an "augmented" hydropathy plot analysis of the three membrane proteins of known structure, ... | 1990 | 2192066 |
| in vitro biosynthesis and membrane association of photosynthetic reaction center subunits from rhodopseudomonas sphaeroides. | the reaction center of rhodopseudomonas sphaeroides is an integral membrane protein complex responsible for primary photochemical charge separation in photosynthesis. we report the synthesis of two of the three subunits of the photosynthetic reaction center using a dna-directed in vitro transcription-translation system prepared from r. sphaeroides. the in vitro-synthesized polypeptides, as resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, had apparent mrs of 24,000 and 21,00 ... | 1986 | 3512531 |
| isolation and characterization of a subunit form of the b875 light-harvesting complex from rhodobacter capsulatus. | a structural subunit (called b816) has been isolated from the b875 light-harvesting complex of rhodobacter capsulatus using a detergent-mediated dissociation of chromatophores. rb. capsulatus mw442 (b800-850- b875+ car+) chromatophores were extracted with benzene and titrated with octyl glucoside (og) to shift the near-infrared absorption maximum from 873 to 816 nm. gel filtration chromatography was then used to separate b816 from reaction centers. b816 could be quantitatively shifted back to a ... | 1990 | 2195560 |
| rhodobacter capsulatus genes involved in early steps of the bacteriochlorophyll biosynthetic pathway. | three open reading frames in the rhodobacter capsulatus photosynthesis gene cluster, designated f0, f108, and f1025, were disrupted by site-directed mutagenesis. mutants bearing insertions in these reading frames were defective in converting protoporphyrin ix to magnesium-protoporphyrin monomethyl ester, protochlorophyllide to chlorophyllide a, and magnesium-protoporphyrin monomethyl ester to protochlorophyllide, respectively. these results demonstrate that the genes examined most likely encode ... | 1990 | 2203738 |
| lipid a with 2,3-diamino-2,3-dideoxy-glucose in lipopolysaccharides from slow-growing members of rhizobiaceae and from "pseudomonas carboxydovorans". | lipid a's from two bradyrhizobium species and from the phylogenetically closely related species "pseudomonas carboxydovorans" were found to contain 2,3-diamino-2,3-dideoxy-glucose as lipid a backbone sugar. in contrast, three representatives of the genus rhizobium, as well as the phylogenetically related species agrobacterium tumefaciens, contain solely glucosamine as lipid a backbone sugar. these findings support independent studies on the phylogenetical relatedness based on 16s rrna-data of th ... | 1989 | 2719525 |
| transposon mutagenesis and physiological analysis of strains containing inactivated form i and form ii ribulose bisphosphate carboxylase/oxygenase genes in rhodobacter sphaeroides. | strains of rhodobacter sphaeroides (rhodopseudomonas sphaeroides) were constructed such that either the gene encoding form i ribulose 1,5-bisphosphate carboxylase/oxygenase (rubpc-o) or the gene encoding form ii rubpc-o was inactivated. both strains were capable of photoheterotrophic growth with malate as the electron donor, with only slight differences in growth rate and overall carboxylase specific activity compared with the wild-type strain. photolithotrophic growth with 1.5% co2 in hydrogen ... | 1988 | 2826406 |
| light-driven amino acid uptake in streptococcus cremoris or clostridium acetobutylicum membrane vesicles fused with liposomes containing bacterial reaction centers. | reaction centers of the phototrophic bacterium rhodopseudomonas palustris were introduced as proton motive force-generating systems in membrane vesicles of two anaerobic bacteria. liposomes containing reaction center-light-harvesting complex i pigment protein complexes were fused with membrane vesicles of streptococcus cremoris or clostridium acetobutylicum by freeze-thawing and sonication. illumination of these fused membranes resulted in the generation of a proton motive force of approximately ... | 1988 | 2832381 |
| cytochrome c2-independent respiratory growth of rhodobacter capsulatus. | to assess the role of cytochrome c2 as a respiratory electron carrier, we obtained a double mutant of rhodobacter capsulatus defective in cytochrome c2 and in the quinol oxidase260. this mutant was able to grow chemoheterotrophically, indicating that an electron pathway independent of cytochrome c2 was functional between the ubiquinol:cytochrome c2 oxidoreductase and the cytochrome oxidase410. | 1988 | 2834343 |
| cloning of the rhodobacter capsulatus hema gene. | portions of the rhodobacter capsulatus hema gene have been cloned from a hema::tn5 insertion strain into the lambda bacteriophage derivative embl3. a cosmid containing the wild-type r. capsulatus hema gene was isolated by complementation of the hema::tn5 mutant. the cosmid contains a 1.4-kilobase ecori fragment that spans the hema::tn5 insertion site. the entire hema gene is contained in this fragment and the adjacent 0.6-kilobase ecori fragment. | 1988 | 2842318 |
| porphobilinogenase from rhodopseudomonas palustris. | 1. porphobilinogenase (pbgase) from rp. palustris has been isolated and some properties of a partially purified fraction were studied. 2. pbgase has an optimum ph of 7.4 when activity was expressed in terms of porphyrins formed and two ph maxima at 7.4 and 8.5 when activity was based on the amount of pbg consumed. 3. cyclotetramerization rate and distribution of reaction products were not affected either by the presence or absence of oxygen. 4. two pbgase active species of mol. wt 115,000 and 50 ... | 1989 | 2924537 |
| differential expression of photosynthesis genes in r. capsulata results from segmental differences in stability within the polycistronic rxca transcript. | we report that the light-harvesting and reaction center genes in the rxca locus of r. capsulata are contained within a single operon and that their differential expression results predominantly from marked segmental differences in stability within the polycistronic rxca transcript. the 3' portion of this transcript is rapidly degraded to give rise to either of two slowly decaying mrna remnants, both of which encode only the light-harvesting polypeptides. the greater stability of these remnants a ... | 1985 | 2981627 |
| nitrous oxide reduction by members of the family rhodospirillaceae and the nitrous oxide reductase of rhodopseudomonas capsulata. | after growth in the absence of nitrogenous oxides under anaerobic phototrophic conditions, several strains of rhodopseudomonas capsulata were shown to possess a nitrous oxide reductase activity. the enzyme responsible for this activity had a periplasmic location and resembled a nitrous oxide reductase purified from pseudomonas perfectomarinus. electron flow to nitrous oxide reductase was coupled to generation of a membrane potential and inhibited by rotenone but not antimycin. it is suggested th ... | 1985 | 2997133 |
| iron-depleted reaction centers from rhodopseudomonas sphaeroides r-26.1: characterization and reconstitution with fe2+, mn2+, co2+, ni2+, cu2+, and zn2+. | reaction centers (rcs) from the photosynthetic bacterium rhodopseudomonas sphaeroides r-26.1 were depleted of fe by a simple procedure involving reversible dissociation of the h subunit. the resulting intact fe-depleted rcs contained 0.1-0.2 fe per rc as determined from atomic absorption and electron paramagnetic resonance (epr) spectroscopy. fe-depleted rcs that have no metal ion occupying the fe site differed from native rcs in the following respects: (1) the rate of electron transfer from qa- ... | 1986 | 3011083 |
| isolation of the rhodopseudomonas sphaeroides form i ribulose 1,5-bisphosphate carboxylase/oxygenase large and small subunit genes and expression of the active hexadecameric enzyme in escherichia coli. | a library of cloned rhodopseudomonas sphaeroides dna was screened by colony hybridization for form i ribulose 1,5-bisphosphate carboxylase/oxygenase (rubpc/o) sequences using heterologous rubpc/o probes. a recombinant plasmid was identified that hybridized to both the anacystis nidulans and the r. sphaeroides form ii rubpc/o genes. subcloning of a hybridizing 4-kb smai fragment allowed expression of active enzyme in escherichia coli that was identical to form i rubpc/o based on polyacrylamide ge ... | 1986 | 3023189 |
| homology between bacterial dna and bovine mitochondrial dna encoding cytochrome c oxidase subunit iii. | a segment of mitochondrial dna encoding the bovine cytochrome c oxidase subunit iii gene was isolated and inserted into an escherichia coli plasmid vector. a 556 base pair fragment of the insert dna representing about 70% of the 3'-end of the subunit iii gene was used to search for homology with bacterial dna from strains that contain heme aa3-type cytochrome c oxidases. bacillus subtilis, thermus thermophilus, and ps3 dnas all showed strong hybridization to the probe, whereas paracoccus denitri ... | 1987 | 3032681 |
| characterization by epr spectroscopy of cytochrome b-562 isolated from the cytochrome b-c1 complex of rhodopseudomonas sphaeroides r-26. | the epr spectra of cytochrome b-562 isolated from the cytochrome b-c1 complex of rhodopseudomonas sphaeroides were measured at liquid helium temperature. the purified cytochrome b-562 gives a high spin signal at g = 6.0. anaerobic titration of this signal confirmed the presence of two redox components with em = 40 and -110 mv at ph 7.5. these values are consistent with the published ones, em = 55 and -100 mv at ph 7.0, that were optically estimated for the same type of preparation (iba et al. (1 ... | 1986 | 3032916 |
| spectral properties of cytochrome c' from rhodopseudomonas capsulata b100 and its co complex. | the spectral properties of cytochrome c' from photosynthetic bacterium rhodopseudomonas capsulata (= rhodobacter capsulatus) b100 and its co complex are reported. the electronic absorption, mcd, and epr spectra have been compared with those of the other cytochromes c' and horse heart cytochrome c. epr and electronic spectral results for the ferric cytochrome c' suggest that the ground state of heme-iron(iii) at neutral ph consists of a quantum mechanical admixture of an intermediate-spin and a h ... | 1987 | 3034243 |
| spectral properties of nitric oxide complex of cytochrome c' from rhodopseudomonas capsulata b100. | the spectral properties for no complexes of ferric and ferrous cytochrome c' from photosynthetic bacterium rhodopseudomonas capsulata b100 are reported. the electronic absorption, mcd, and epr spectra have been compared with those of the no complexes of the other cytochromes c' and horse heart cytochrome c. the no-ferrous cytochrome c' would be a mixture of no complexes with six- and five-coordinate nitrosylheme, suggesting that the heme-iron to histidine bond in the ferrous cytochrome c' is mor ... | 1987 | 3036144 |
| independent regulation of synthesis of form i and form ii ribulose bisphosphate carboxylase-oxygenase in rhodopseudomonas sphaeroides. | ribulose 1,5-bisphosphate carboxylase-oxygenase (rubpc-o) activity was greatly enhanced when rhodopseudomonas sphaeroides was grown in a mineral salts medium supplied with 1.5% co2 in hydrogen. analysis of cell extracts by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that cells growing on 1.5% co2 in h2 specifically accumulated rubpc-o polypeptides. quantitative immunological determinations revealed that accumulation of form i and form ii rubpc-o closely correlates with th ... | 1986 | 3080410 |
| physiological and 15n-nmr analysis of molecular nitrogen fixation by methanococcus thermolithotrophicus, methanobacterium bryantii and methanospirillum hungatei. | two mesophilic methanogenic bacteria, methanobacterium bryantii strain moh and methanospirillum hungatei strain gp1 were demonstrated, using several different experimental approaches, to fix dinitrogen. evidence includes (1) growth with n2 as the sole nitrogen source; (2) incorporation of 15n2 into cellular material (both soluble amino acid pools and insoluble cell protein and other macromolecules) detected by 15n-nmr spectroscopy; (3) acetylene reduction to ethylene by the cells, and inhibition ... | 1988 | 3167101 |
| spectroscopic evidence for a porphobilinogen deaminase-tetrapyrrole complex that is an intermediate in the biosynthesis of uroporphyrinogen iii. | incubation of porphobilinogen (pbg) with pbg deaminase from rhodopseudomonas sphaeroides in carbonate buffer (ph 9.2) to total pbg consumption resulted in low yields of uroporphyrinogen i (uro'gen i). in the reaction mixture a pyrrylmethane accumulated, which at longer incubation periods was transformed into uro'gen i. the accumulated pyrrylmethane gave an ehrlich reaction which was different from that of a 2-(aminomethyl)dipyrrylmethane or 2-(aminomethyl)tripyrrane. it resembled that of a bilan ... | 1988 | 3262369 |
| anaerobic and aerobic metabolism of diverse aromatic compounds by the photosynthetic bacterium rhodopseudomonas palustris. | the purple nonsulfur photosynthetic bacterium rhodopseudomonas palustris used diverse aromatic compounds for growth under anaerobic and aerobic conditions. many phenolic, dihydroxylated, and methoxylated aromatic acids, as well as aromatic aldehydes and hydroaromatic acids, supported growth of strain cga001 in both the presence and absence of oxygen. some compounds were metabolized under only aerobic or under only anaerobic conditions. two other strains, cgc023 and cgd052, had similar anaerobic ... | 1988 | 3377491 |
| the dna sequence of the rhodobacter capsulatus nifh gene. | | 1988 | 3419937 |
| multiple-phase equilibration headspace analysis for the determination of n2o and n2 during bacterial denitrification. | a gas-handling manifold for the preparation, introduction and analysis by gas chromatography (gc) system of the gaseous products of denitrification is described. a procedure of multiple-phase equilibration is adopted which allows the quantitative determination of the total gas present in sample vials. assumptions of solubility coefficients are not required as these are determined during the analysis. the method is particularly suited to gases of appreciable solubilities as a significant proporti ... | 1986 | 3487992 |
| 3-hydroxyisobutyrate dehydrogenase, an impurity in commercial 3-hydroxybutyrate dehydrogenase. | the enzymic determination of d-3-hydroxybutyrate and acetoacetate normally involves the use of 3-hydroxybutyrate dehydrogenase (hbdh, ec 1.1.1.30) of bacterial origin. we show that hbdh from rhodopseudomonas spheroides (bcl, grade ii) contains a 3-hydroxyisobutyrate dehydrogenase (hibdh) activity: activity with 3-hydroxyisobutyrate as substrate was greater than 10% of that with 3-hydroxybutyrate. however, hbdh could be prepared essentially free of hibdh activity by incubation at 37 degrees c in ... | 1987 | 3494445 |
| structural gene of cytochrome b-562 from the cytochrome b-c1 complex of rhodobacter sphaeroides. | the structural gene coding for cytochrome b-562 isolated from the cytochrome b-c1 complex of rhodobacter (rhodopseudomonas) sphaeroides has been cloned. its nucleotide sequence has been determined and the amino acid sequence was deduced therefrom. it consists of 157 amino acids (mr 17,237) and contains four hydrophobic segments. the first 30 residues in the predicted amino acid sequence are the same as those determined for the nh2-terminal portion of purified cytochrome b-562. the amino acid com ... | 1987 | 3502345 |
| role of apparent membrane growth initiation sites during photosynthetic membrane development in synchronously dividing rhodopseudomonas sphaeroides. | sites of intracytoplasmic membrane growth and temporal relations in the assembly of photosynthetic units were examined in synchronously dividing rhodopseudomonas sphaeroides cells. after rate-zone sedimentation of cell-free extracts, apparent sites of initiation of intracytoplasmic membrane growth formed an upper pigmented band that sedimented more slowly than the intracytoplasmic membrane-derived chromatophore fraction. throughout the cell cycle, the levels of the peripheral b800-850 light-harv ... | 1986 | 3522542 |
| localization of the exposed n-terminal region of the b800-850 alpha and beta light-harvesting polypeptides on the cytoplasmic surface of rhodopseudomonas capsulata chromatophores. | proteinase k and trypsin were used to determine the orientation of the light-harvesting b800-850 alpha and beta polypeptides within the chromatophores (inside-out membrane vesicles) of the mutant strain y5 of rhodopseudomonas capsulata. with proteinase k 7 amino acid residues of the b800-850 alpha polypeptide were cleaved off up to position trp-7--thr-8 of the n terminus, and 11 residues were cleaved off up to position leu-11-ser-12 of the beta chain n terminus. the c termini of the b800-850 alp ... | 1986 | 3522557 |
| mapping of the triazine binding site to a highly conserved region of the qb-protein. | a number of herbicide classes, including the s-triazines and ureas (atrazine, diuron) inhibit photosynthetic electron transport via a direct interaction with the qb-protein. this protein, also known as the 32-kda protein or herbicide binding protein, is believed to bind the plastoquinone qb, which functions as the second stable electron acceptor at the reducing side of photosystem ii. the site of covalent attachment of the photoaffinity herbicide analog azido-[14c]atrazine to the qb-protein of s ... | 1986 | 3524461 |
| radical-pair energetics and decay mechanisms in reaction centers containing anthraquinones, naphthoquinones or benzoquinones in place of ubiquinone. | in reaction centers from rhodobacter sphaeroides (formerly called rhodopseudomonas sphaeroides), light causes an electron-transfer reaction that forms the radical pair state (p+i-, or pf) from the initial excited singlet state (p) of a bacteriochlorophyll dimer (p). subsequent electron transfer to a quinone (q) produces the state p+q-. back electron transfer can regenerate p from p+q-, giving rise to 'delayed' fluorescence that decays with approximately the same lifetime as p+q-. the free-energy ... | 1986 | 3524681 |
| methods for the determination of membrane potential in bioenergetic systems. | | 1986 | 3526088 |
| structure of rhodopseudomonas sphaeroides r-26 reaction center. | the molecular replacement method has been successfully used to provide a structure for the photosynthetic reaction center of rhodopseudomonas sphaeroides at 3.7 a resolution. atomic coordinates derived from the r. viridis reaction center were used in the search structure. the crystallographic r-factor is 0.39 for reflections between 8 and 3.7 a. validity of the resulting model is further suggested by the visualization of amino acid side chains not included in the r. viridis search structure, and ... | 1986 | 3527749 |
| [selective method of isolating mutants sensitive to ultraviolet radiation from a culture of rhodopseudomonas sphaeroides]. | the method of penicillin selection used after uv-irradiation (lambda = 254 nm) allows one to select uv-sensitive mutants (uvs-mutants) of the phototrophous bacterium rhodopseudomonas sphaeroides induced by nitrosomethylurea with an effectiveness greater by an order of magnitude. over 30% of the uvs-mutants obtained using this method had an elevated sensitivity not only to far-uv (f-uv, lambda = 254 nm) but also to near-uv (n-uv, lambda greater than 280 nm) uv-irradiation. no correlation was foun ... | 1986 | 3528771 |
| effect of uncoupler on assembly pathway for pigment-binding protein of bacterial photosynthetic membranes. | the uncoupler carbonylcyanide m-chlorophenylhydrazone (cccp) was used to investigate membrane protein assembly in the phototrophic bacterium rhodobacter capsulatus. as found for escherichia coli (t. date, g. zwizinsky, s. ludmerer, and w. wickner, proc. natl. acad. sci. 77:827-831, 1980) and mitochondrial proteins (n. nelson and g. schatz, proc. natl. acad. sci. usa 76:4365-4369, 1979), assembly across the bacterial photosynthetic membranes was sensitive to cccp. at uncoupler concentrations whic ... | 1986 | 3531166 |
| regulation of expression of genes for light-harvesting antenna proteins lh-i and lh-ii; reaction center polypeptides rc-l, rc-m, and rc-h; and enzymes of bacteriochlorophyll and carotenoid biosynthesis in rhodobacter capsulatus by light and oxygen. | rna levels were measured by blot hybridization to study the coordinate and differential expression of rhodobacter capsulatus genes for light-harvesting i antenna proteins lh-i and lh-ii; reaction center (rc) polypeptides l, m, and h; and bacteriochlorophyll and carotenoid biosynthesis in response to light and o2. the genes for lh-ii alpha and beta subunits only have one transcript, 0.5 kilobase (kb) long, whereas the genes for lh-i have two transcripts (0.5 and 2.6 kb). the small transcript (0.5 ... | 1986 | 3532117 |
| mechanism of nitrogenase switch-off by oxygen. | oxygen caused a reversible inhibition (switch-off) of nitrogenase activity in whole cells of four strains of diazotrophs, the facultative anaerobe klebsiella pneumoniae and three strains of photosynthetic bacteria (rhodopseudomonas sphaeroides f. sp. denitrificans and rhodopseudomonas capsulata strains ad2 and bk5). in k. pneumoniae 50% inhibition of acetylene reduction was attained at an o2 concentration of 0.37 microm. cyanide (90 microm), which did not affect acetylene reduction but inhibited ... | 1987 | 3542974 |