PMID(sorted descending)
the lhialpha and lhiialpha complexes in association with phospholipids are able to be inserted in heavy membranes of rhodobacter capsulatus b10.we show in this paper that a complex constituted by phospholipids and lhi and lhii alpha polypeptides was inserted in a heavy membrane fraction in a nonextractable form, indicating a transmembrane localization. the best accepting membranes originated from aerobically grown cells. addition of atp during the insertion inhibited this reaction 25 to 30% in heavy membranes isolated from aerobically grown cells (hmaer) and a higher inhibition (60 to 65%) was detected when using heavy membranes isolate ...199910387115
h+-proton-pumping inorganic pyrophosphatase: a tightly membrane-bound family.the earliest known h+-proton-pumping inorganic pyrophosphatase, the integrally membrane-bound h+-proton-pumping inorganic pyrophosphate synthase from rhodospirillum rubrum, is still the only alternative to h+-atp synthase in biological electron transport phosphorylation. cloning of several higher plant vacuolar h+-proton-pumping inorganic pyrophosphatase genes has led to the recognition that the corresponding proteins form a family of extremely similar proton-pumping enzymes. the bacterial h+-pr ...199910386575
identification of critical, conserved vicinal aspartate residues in mammalian and bacterial adp-ribosylarginine hydrolases.nad:arginine adp-ribosyltransferases and adp-ribosylarginine hydrolases catalyze opposing arms of a putative adp-ribosylation cycle. adp-ribosylarginine hydrolases from mammalian tissues and rhodospirillum rubrum exhibit three regions of similarity in deduced amino acid sequence. we postulated that amino acids in these consensus regions could be critical for hydrolase function. to test this hypothesis, hydrolase, cloned from rat brain, was expressed as a glutathione s-transferase fusion protein ...199910358013
kinetic behavior of some polyphosphate-accumulating bacteria isolates in the presence of nitrate and oxygen.this paper studies the phosphate uptake by pure cultures of aeromonas hydrophila, klebsiella oxytoca, agrobacterium tumefaciens, and aquaspirillum dispar in the presence of both nitrate and oxygen. it is shown that species were able to respire both electron acceptors for phosphate accumulation. a. tumefaciens and a. dispar accumulated overall phosphate both in oxic and anoxic culture conditions, whereas a. hydrophila and k. oxytoca eliminated overall phosphate only in oxic conditions. a. dispar ...199910355118
the reaction center-lh1 antenna complex of rhodobacter sphaeroides contains one pufx molecule which is involved in dimerization of this complex.the pufx membrane protein is essential for photosynthetic growth of rhodobacter sphaeroides wild-type cells. pufx is associated with the reaction center-light harvesting 1 (rc-lh1) core complex and plays a key role in lateral ubiquinone/ubiquinol transfer. we have determined the pufx/rc stoichiometry by quantitative western blot analysis and rc photobleaching. independent of copy number effects and growth conditions, one pufx molecule per rc was observed in native membranes as well as in deterge ...199910346905
groel-groes cycling: atp and nonnative polypeptide direct alternation of folding-active rings.the double-ring chaperonin groel mediates protein folding in the central cavity of a ring bound by atp and groes, but it is unclear how groel cycles from one folding-active complex to the next. we observe that hydrolysis of atp within the cis ring must occur before either nonnative polypeptide or groes can bind to the trans ring, and this is associated with reorientation of the trans ring apical domains. subsequently, formation of a new cis-ternary complex proceeds on the open trans ring with po ...199910319813
a catalytically active complex formed from the recombinant di protein of rhodospirillum rubrum transhydrogenase, and the recombinant diii protein of the human enzyme.transhydrogenase is a proton pump. it has three components: di and diii protrude from the membrane and contain the binding sites for nad(h) and nadp(h), respectively, and dii spans the membrane. we have expressed diii from homo sapiens transhydrogenase (hsdiii) in escherichia coli. the purified protein was associated with stoichiometric amounts of nadp(h) bound to the catalytic site. the nadp+ and nadph were released only slowly from the protein, supporting the suggestion that nucleotide-binding ...199910216162
transcription activation by cooa, the co-sensing factor from rhodospirillum rubrum. the interaction between cooa and the c-terminal domain of the alpha subunit of rna polymerase.cooa, a member of the camp receptor protein (crp) family, is a co-sensing transcription activator from rhodospirillum rubrum that binds specific dna sequences in response to co. the location of the cooa-binding sites relative to the start sites of transcription suggested that the cooa-dependent promoters are analogous to class ii crp-dependent promoters. in this study, we developed an in vivo cooa reporter system in escherichia coli and an in vitro transcription assay using rna polymerases (rnap ...199910196160
a light-harvesting antenna protein retains its folded conformation in the absence of protein-lipid and protein-pigment interactions.the first study by nmr of the integral membrane protein, the bacterial light-harvesting (lh) antenna protein lh1 beta, is reported. the photosynthetic apparatus of purple bacteria contains two different kinds of antenna complexes (lh1 and lh2), which consist of two small integral membrane proteins alpha and beta, each of approximately 6 kda, and bacteriochlorophyll and carotenoid pigments. we have purified the antenna polypeptide lh1 beta from rhodobacter sphaeroides, and have recorded cd spectr ...199910101971
the development of microfabricated biocatalytic fuel cells.the production of electricity by biocatalytic fuel cells has been feasible for almost two decades and can produce electric power at a practical level. these fuel cells use immobilized microorganisms or enzymes as catalysts, and glucose as a fuel. a microfabricated enzyme battery has recently been made that is designed to function as a power supply for microsurgery robots or artificial organs.199910087603
on the role of high-potential iron-sulfur proteins and cytochromes in the respiratory chain of two facultative phototrophsthe capability of high potential iron-sulfur proteins (hipips) and soluble cytochromes to shuttle electrons between the bc1 complex and the terminal oxidase in aerobically grown cells of rhodoferax fermentans and rhodospirillum salinarum, two facultative phototrophs, was evaluated. in rs. salinarum, hipip and a c-type cytochrome (alpha-band at 550 nm, em,7=+290 mv) are both involved in the electron transfer step from the bc1 complex to the terminal oxidase. kinetic studies indicate that cytochro ...199910076014
resonance raman evidence for a novel charge relay activation mechanism of the co-dependent heme protein transcription factor cooa.resonance raman spectra of the co-responsive transcription factor cooa from rhodospirillum rubrum provides evidence on the nature of heme ligation and its co activation mechanism. the fe(iii) form gives standard low-spin heme spectrum, while the fe(ii) form is low spin for wild-type (wt) cooa and mixed spin for a cooa variant, h77y, with an his77tyr substitution. the fe(ii) porphyrin skeletal mode nu11 is at a value (1541 cm-1) indicative of a neutral donor ligand for the h77y variant but is at ...199910052938
identification of two important heme site residues (cysteine 75 and histidine 77) in cooa, the co-sensing transcription factor of rhodospirillum rubrum.the co-sensing mechanism of the transcription factor cooa from rhodospirillum rubrum was studied through a systematic mutational analysis of potential heme ligands. previous electron paramagnetic resonance (epr) spectroscopic studies on wild-type cooa suggested that oxidized (feiii) cooa contains a low-spin heme with a thiolate ligand, presumably a cysteine, bound to its heme iron. in the present report, electronic absorption and epr analysis of various substitutions at cys residues establish th ...199910052937
correlation of activity regulation and substrate recognition of the adp-ribosyltransferase that regulates nitrogenase activity in rhodospirillum rhodospirillum rubrum, nitrogenase activity is regulated posttranslationally through the adp-ribosylation of dinitrogenase reductase by dinitrogenase reductase adp-ribosyltransferase (drat). several drat variants that are altered both in the posttranslational regulation of drat activity and in the ability to recognize variants of dinitrogenase reductase have been found. this correlation suggests that these two properties are biochemically connected.199910049407
presence of a structurally novel type ribulose-bisphosphate carboxylase/oxygenase in the hyperthermophilic archaeon, pyrococcus kodakaraensis kod1.we have characterized the gene encoding ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) of the hyperthermophilic archaeon, pyrococcus kodakaraensis kod1. the gene encoded a protein consisting of 444 amino acid residues, corresponding in size to the large subunit of previously reported rubiscos. rubisco of p. kodakaraensis kod1 (pk-rubisco) showed only 51.4% similarity with the large subunit of type i rubisco from spinach and 47.3% with that of type ii rubisco from rhodospirillum rubrum ...19999988755
distinct structures and environments for the three hemes of the cytochrome bc1 complex from rhodospirillum rubrum. a resonance raman study using b-band excitations.the b-band excited resonance raman (rr) spectra (100-1700 cm-1) of the bacterial cytochrome bc1 complex purified from rhodospirillum rubrum are reported. four redox states, i.e., the persulfate-oxidized, "as prepared", and ascorbate- and dithionite-reduced states of the complex, were investigated with the laser excitations at 406.7, 413.1, and 441.6 nm. following the different absorption properties of the b- and c-type hemes and the different resonance enhancements of the vibrational modes of ox ...19999894003
catalytic properties of hybrid complexes of the nad(h)-binding and nadp(h)-binding domains of the proton-translocating transhydrogenases from escherichia coli and rhodospirillum rubrum.transhydrogenase couples reversible hydride transfer from nadh to nadp+ to proton translocation across the inner membrane in mitochondria and the cytoplasmic membrane in bacteria. the enzyme is composed of three parts. domain i (di) and domain iii (diii) are water soluble and contain the binding sites for nad(h) and nadp(h), respectively; domain ii (dii) spans the membrane. in the present investigation, di from rhodospirillum rubrum (rri) and escherichia coli (eci), and diii from r. rubrum (rrii ...19999890924
the transcriptional regulator gene phrr in sinorhizobium meliloti wsm419 is regulated by low ph and other stresses.the phrr gene in sinorhizobium meliloti (previously known as rhizobium meliloti) wsm419, directly downstream from acta, is induced by low ph or certain stresses (e.g. high concentrations of zn2+, cu2+, h2o2 or ethanol), but not in stationary phase or by other stresses (e.g. phosphate limitation, elevated temperature, high concentrations of sucrose or iron). a dna fragment containing the wild-type phrr gene could not be cloned and inverse pcr was therefore used to amplify a 3.5 kb bamhi fragment ...19989884225
thioredoxin is involved in oxygen-regulated formation of the photosynthetic apparatus of rhodobacter sphaeroides.thioredoxin, a redox active protein, has been previously demonstrated to be essential for growth of the anoxygenic photosynthetic bacterium rhodobacter sphaeroides. in the present study, the involvement of thioredoxin in the formation of the photosynthetic apparatus of r. sphaeroides ws8 was investigated by construction and analysis of a mutant strain disrupted for the chromosomal trxa copy and carrying a plasmid-borne copy of trxa under the control of the hybrid ptrc promoter inducible by iptg ...19999864318
generation of triplet and cation-radical bacteriochlorophyll a in carotenoidless lh1 and lh2 antenna complexes from rhodobacter sphaeroides.the lh1 antenna complex and a native form of the lh2 complex were isolated from the carotenoidless r26 and r26.1 mutants of rhodobacter sphaeroides by the use of a new detergent, sucrose monocholate. one-color, pump-and-probe transient raman spectroscopy of these complexes using 351 nm, approximately 50 ps pulses showed the generation of the triplet state of bacteriochlorophyll a (bchl a), whereas measurements using 355 nm, approximately 12 ns pulses showed the generation of bchl a cation radica ...19989860862
in vitro reconstitution of the core and peripheral light-harvesting complexes of rhodospirillum molischianum from separately isolated most purple bacteria, the core light-harvesting complex (lh1) differs from the peripheral light-harvesting complex (lh2) in spectral properties and amino acid sequences. in rhodospirillum (rs. )molischianum, however, the lh2 closely resembles the lh1 of many species in amino acid sequence identity and in some spectral properties (e.g., circular dichroism and resonance raman). despite these similarities to lh1, the lh2 of rs. molischianum displays an absorption spectrum similar to the lh2 comp ...19989860861
basis for monomer stabilization in rhodopseudomonas palustris cytochrome c' derived from the crystal structure.the crystal structure of an unusual monomeric cytochrome c' from rhodopseudomonas palustris (rpcp) has been determined at 2.3 a resolution. rpcp has the four-helix (helices a, b, c and d) bundle structure similar to dimeric cytochromes c'. however the amino acid composition of the surface of helices a and b in rpcp is remarkably different from that of the dimeric cytochromes c'. this surface forms the dimer interface in the latter proteins. rpcp has seven charged residues on this surface contrar ...19989826513
the lh1-rc core complex of rhodobacter sphaeroides: interaction between components, time-dependent assembly, and topology of the pufx protein.mutant strains of the photosynthetic bacterium rhodobacter sphaeroides, lacking either lh1, the rc or pufx, were analysed by mild detergent fractionation of the cores. this reveals a hierarchy of binding of pufx in the order rc:lh1 > lh1 > rc. the assembly of photosynthetic membranes was studied by switching highly aerated cells to conditions of low aeration in the dark. the rc-h subunit appears before other components, followed by the pufbalmx then pufba transcripts. synthesis of the pufx polyp ...19989814844
mutation of amino acid residues in the mobile loop region of the nad(h)-binding domain of proton-translocating transhydrogenase.the effects of single amino acid substitutions in the mobile loop region of the recombinant nad(h)-binding domain (di) of transhydrogenase have been examined. the mutations lead to clear assignments of well-defined resonances in one-dimensional 1h-nmr spectra. as with the wild-type protein, addition of nadh, or higher concentrations of nad+, led to broadening and some shifting of the well-defined resonances. with many of the mutant di proteins more nucleotide was required for these effects than ...19989804876
in situ detection of bacteria in continuous-flow cultures of seawater sediment suspensions with fluorescently labelled rrna-directed oligonucleotide probes.rrna-targeted and fluorescently labelled oligonucleotide probes were used to study the composition of natural bacterial populations in continuous-flow cultures of seawater sediment suspensions. the cultures were run as enrichment cultures with increasing dilution rates, and hexadecane as the sole carbon source. total cell numbers were analysed by counting dapi (4',6-diamidino-2-phenylindole)-stained cells. to differentiate the population composition, oligonucleotide probes for eubacteria, for cy ...19989802019
quenching of chlorophyll fluorescence by quinones.quinones caused quenching of chl a fluorescence in native and model systems. menadione quenched twofold the fluorescence of chl a and bchl a in pea chloroplasts, chromatophores of purple bacteria, and liposomes at concentrations of 50-80 microm. to obtain twofold quenching in triton x-100 micelles and in ethanol, the addition of 1.3 mm and 11 mm menadione was required, respectively. a proportional decrease in the lifetime and yield of chl a fluorescence in chloroplasts, observed as the menadione ...19989801801
the respiratory chain of the halophilic anoxygenic purple bacterium rhodospirillum sodomense.the halophilic purple nonsulfur bacterium rhodospirillum sodomense has been previously described as an obligate phototroph that requires yeast extract and a limited number of organic compounds for photoheterotrophic growth. in this work, we report on chemoheterotrophic growth of r. sodomense in media containing either acetate or succinate supplemented with 0.3-0.5% yeast extract. plasma membranes isolated from cells grown aerobically in the dark contained three b-type and three c-type membrane-b ...19989799287
stopped-flow kinetics of hydride transfer between nucleotides by recombinant domains of proton-translocating transhydrogenase.transhydrogenase catalyses the transfer of reducing equivalents between nad(h) and nadp(h) coupled to proton translocation across the membranes of bacteria and mitochondria. the protein has a tridomain structure. domains i and iii protrude from the membrane (e.g. on the cytoplasmic side in bacteria) and domain ii spans the membrane. domain i has the binding site for nad+/nadh, and domain iii for nadp+/nadph. we have separately purified recombinant forms of domains i and iii from rhodospirillum r ...19989799120
the effect of pressure on the bacteriochlorophyll a binding sites of the core antenna complex from rhodospirillum this paper we examine the effect of pressure on the absorption spectrum and binding site of the core antenna complex from the photosynthetic bacterium rhodospirillum rubrum. absorption spectra and raman spectra in preresonance with the qy transition of the bacteriochlorophyll a were studied at pressures up to 625 mpa. in agreement with previous work we observe a pressure-induced red shift and broadening of the absorption spectrum. we show that at these pressures the pigments within the protei ...19989778363
triphenyltin as an inhibitor of membrane-bound pyrophosphatase of rhodospirillum rubrum.the effect of triphenyltin on the activity of membrane-bound pyrophosphatase of rhodospirillum rubrum was investigated. triphenyltin inhibits the hydrolysis of chromatophore membrane-bound pyrophosphatase in a ph-dependent pattern, being maximal at ph 9-10. at basic ph values, the inhibition produced by this organotin on membrane-bound pyrophosphatase is very similar to that produced on the chromatophore h+atpase (i50 = 14.4 and 10 microm, respectively). detergent-solubilized membrane-bound pyro ...19989750176
redox-controlled ligand exchange of the heme in the co-sensing transcriptional activator cooa.the transcriptional activator cooa from rhodospirillum rubrum contains a b-type heme that acts as a co sensor in vivo. cooa is the first example of a transcriptional regulator containing a heme as a prosthetic group and of a hemeprotein in which co plays a physiological role. in this study, we constructed an in vivo reporter system to measure the transcriptional activator activity of cooa and prepared some cooa mutants in which a mutation was introduced at cys, his, met, lys, or tyr. only the mu ...19989748246
projection structures of three photosynthetic complexes from rhodobacter sphaeroides: lh2 at 6 a, lh1 and rc-lh1 at 25 a.three photosynthetic complexes, light-harvesting complex 2 (lh2), light-harvesting complex 1 (lh1), and the reaction centre-light-harvesting complex 1 photounit (rc-lh1), were purified from a single species of a purple bacterium, rhodobacter sphaeroides, and reconstituted into two-dimensional (2-d) crystals. vesicular 2-d crystals of lh1 and rc-lh1 were imaged in negative stain and projection maps at 25 a resolution were produced. the rings formed by lh1 have approximately the same mean diameter ...19989743630
are the light-harvesting i complexes from rhodospirillum rubrum arranged around the reaction centre in a square geometry?the basic photosynthetic unit containing the reaction centre and the light-harvesting i complex (rc-lhi) of the purple non-sulphur bacterium rhodospirillum rubrum was purified and reconstituted into two-dimensional (2d) membrane crystals. transmission electron microscopy using conventional techniques and cryoelectron microscopy of the purified single particles and of 2d crystals yielded a projection of the rc-lhi complex at a resolution of at least 1.6 nm. in this projection the lhi ring appears ...19989743629
reclassification of species of the spiral-shaped phototrophic purple non-sulfur bacteria of the alpha-proteobacteria: description of the new genera phaeospirillum gen. nov., rhodovibrio gen. nov., rhodothalassium gen. nov. and roseospira gen. nov. as well as transfer of rhodospirillum fulvum to phaeospirillum fulvum comb. nov., of rhodospirillum molischianum to phaeospirillum molischianum comb. nov., of rhodospirillum salinarum to rhodovibrio salexigens.the 165 rdna sequence of rhodospirillum mediosalinum was determined and compared with corresponding sequences from other spiral-shaped purple non-sulfur bacteria classified as or related to the genus rhodospirillum in the alpha subclass of the proteobacteria. sequence similarities separate the currently recognized rhodospirillum species into five different groups with no more than 91% sequence similarity, clearly indicating the necessity to recognize these groups as different genera. major diagn ...19989734033
the effect of chemical oxidation on the fluorescence of the lh1 (b880) complex from the purple bacterium rhodobium marinum.the effect of chemical oxidation on the absorption and fluorescence emission spectra of the lh1 complex from rhodobium marinum was investigated. mild chemical oxidation of the lh1 complex, by addition of 10 mm potassium ferricyanide, caused a 2-3% bleaching of the 880-nm qy absorption band. in contrast, at the same ferricyanide concentration, fluorescence emission intensity of the lh1 complex was quenched by about 50%. this result demonstrates that oxidation of very few bacteriochlorophyll (bchl ...19989710244
correlation between protein flexibility and electron transfer from qa-* to qb in psii membrane fragments from analyze a possible correlation between the extent of qa-* reoxidation and protein dynamics, fluorometric and mössbauer spectroscopic measurements were performed in photosystem ii membrane fragments from spinach. numerical evaluation of the flash-induced change of the normalized fluorescence quantum yield revealed that the extent of reoxidation starts to decrease below 275 k and is almost completely suppressed at 230 k. detailed analyses of mössbauer spectra measured at different temperatures ...19989708974
[effect of serotonin (5-hydroxytryptamine) on the growth and differentiation of microorganisms].serotonin (5-hydroxytryptamine), a neurotransmitter and social behavior factor in higher animals, accelerates culture growth and induces cell aggregation in escherichia coli and rhodospirillum rubrum at concentrations of 2 x 10(-7)-2 x 10(-5)m. in the myxobacterium polyangium sp., 10(-6)-10(-5)m serotonin stimulates cell aggregation and myxospore formation. at concentrations over 20 microm, serotonin induces the opposite effect: it inhibits cell aggregation and microbial culture growth. serotoni ...19989702725
domains, specific residues and conformational states involved in hydride ion transfer and proton pumping by nicotinamide nucleotide transhydrogenase from escherichia coli.nicotinamide nucleotide transhydrogenase constitutes a proton pump which links the nad(h) and nadp(h) pools in the cell by catalyzing a reversible reduction of nadp+ by nadh. the recent cloning and characterization of several proton-pumping transhydrogenases show that they share a number of features. they are composed of three domains, i.e., the hydrophilic domains i and iii containing the nad(h)- and nadp(h)-binding sites, respectively, and domain ii containing the transmembrane and proton-cond ...19989693716
isolation of the pufx protein from rhodobacter capsulatus and rhodobacter sphaeroides: evidence for its interaction with the alpha-polypeptide of the core light-harvesting complex.using mutant strains of rhodobacter capsulatus and rhodobacter sphaeroides in which the pufx gene had been deleted, it was possible to identify by hplc membrane protein components present in pufx+ cells but absent in pufx- cells. in parallel preparations, membrane proteins soluble in chloroform/methanol containing ammonium acetate were first extracted from lyophilized membrane fractions of the pufx+ cells and separated from pigments and larger protein material by gel-filtration chromatography. p ...19989693001
occurrence, overexpression and partial purification of the protein (majastridin) corresponding to the urf6 gene of the rhodobacter blasticus atp operon.antibodies were produced against two antigenic peptides of a protein, which was named majastridin, corresponding to the urf6 gene of the rhodobacter blasticus atp operon [tybulewicz, v. l. j., falk, g. & walker, j. e. (1984) j. mol. biol. 179, 185-214]. a protein band of the expected size is labelled by immunoblotting in western blots containing the cytosolic fractions from rb. blasticus and paracoccus denitrificans but not from escherichia coli or rhodospirillum rubrum. although the protein is ...19989692905
nitrogen-fixing aerobic bacteria have higher genomic gc content than non-fixing species within the same genus.the genomic gc contents of both nitrogen-fixing and non-fixing members of eight genera of bacteria are investigated. analysis by t-tests showed that in the two aerobic general investigated (aquaspirillum and vibrio) there is a significantly higher gc content in the nitrogen-fixing members of the genus than in those unable to fix nitrogen, whilst in aerobic genera there is either no gc bias, or in the case of two genera (rhodospirillum and clostridium) there is a significantly higher gc content i ...19989687237
heme environmental structure of cooa is modulated by the target dna binding. evidence from resonance raman spectroscopy and co rebinding order to investigate the gene activation mechanism triggered by the co binding to cooa, a heme-containing transcriptional activator, the heme environmental structure and the dynamics of the co rebinding and dissociation have been examined in the absence and presence of its target dna. in the absence of dna, the fe-co and c=o stretching raman lines of the co-bound cooa were observed at 487 and 1969 cm-1, respectively, suggesting that a neutral histidine is an axial ligand trans to co. the freq ...19989685335
model for the light-harvesting complex i (b875) of rhodobacter sphaeroides.the light-harvesting complex i (lh-i) of rhodobacter sphaeroides has been modeled computationally as a hexadecamer of alphabeta-heterodimers, based on a close homology of the heterodimer to that of light-harvesting complex ii (lh-ii) of rhodospirillum molischianum. the resulting lh-i structure yields an electron density projection map that is in agreement with an 8.5-a resolution electron microscopic projection map for the highly homologous lh-i of rs. rubrum. a complex of the modeled lh-i with ...19989675170
purification and primary structure analysis of two cytochrome c2 isozymes from the purple phototrophic bacterium rhodospirillum centenum.the isolation and amino acid sequences of two cytochromes c-552 from the thermotolerant bacterium rhodospirillum (r.) centenum have been determined. they are very similar to one another with 85% identity. they are homologous to the cytochromes c2 from purple bacteria with approximately 67% identity to that from rhodopseudomonas (rps.) palustris compared to only 42% identity with others of the c2 subclass. in addition, they share an unusual six-residue insertion with rps. palustris cytochrome c2 ...19989659396
a null lesion in the rhodopin 3,4-desaturase of rhodospirillum rubrum unmasks a cryptic branch of the carotenoid biosynthetic pathway.the carotenoids accumulated by a mutant rhodospirillum rubrum st4, containing a single tn5 lesion in the pathway for carotenoid biosynthesis, were analyzed by hplc, 1h nmr spectroscopy, and field desorption mass spectrometry. the main carotenoid was identified as 3,4,3',4'-tetrahydrospirilloxanthin, and the four minor carotenoids were identified as rhodopin, 3,4-dihydroanhydrorhodovibrin, 3', 4'-dihydrorhodovibrin, and 1,1'-dihydroxylycopene. the c-3,4 and c-3',4' bonds of all 5 carotenoids are ...19989636041
action of the allelochemical, fischerellin a, on photosystem ii.the cyanobacterium, fischerella muscicola, produces a secondary metabolite named fischerellin a (fs) that strongly inhibits the growth of cyanobacteria and other photosynthetic organisms. the compound exhibits a unique structure and is composed of two cyclic amines and a c15 substituent that contains a double bond in the (z) configuration and two triple bonds [l. hagmann, f. jüttner, tetrahedron lett., 37 (1996) 6539-6542]. the site of fs action is located in photosystem ii (psii). the chlorophy ...19989630706
a pyrophosphate synthase gene: molecular cloning and sequencing of the cdna encoding the inorganic pyrophosphate synthase from rhodospirillum rubrum.the integrally membrane-bound, proton-pumping inorganic pyrophosphate (ppi) synthase in phototrophic bacteria is hitherto the only described alternative to the atp synthase in biological electron transport phosphorylation. we have identified and sequenced the first gene coding for a pyrophosphate synthase. the deduced protein contains 660 amino acid residues and 15 putative membrane-spanning segments. it is homologous to the vacuolar pyrophosphatases from plants.19989630689
microbial production of hydrogen: an overview.production of hydrogen by anaerobes, facultative anaerobes, aerobes, methylotrophs, and photosynthetic bacteria is possible. anaerobic clostridia are potential producers and immobilized c. butyricum produces 2 mol h2/mol glucose at 50% efficiency. spontaneous production of h2 from formate and glucose by immobilized escherichia coli showed 100% and 60% efficiencies, respectively. enterobactericiae produces h2 at similar efficiency from different monosaccharides during growth. among methylotrophs, ...19989561824
mutagenesis of beta-glu-195 of the rhodospirillum rubrum f1-atpase and its role in divalent cation-dependent catalysis.we introduced mutations at the fully conserved residue glu-195 in subunit beta of rhodospirillum rubrum f1-atpase. the activities of the expressed wild type (wt) and mutant beta subunits were assayed by following their capacity to assemble into the earlier prepared beta-depleted, membrane-bound r. rubrum enzyme (philosoph, s., binder, a., and gromet-elhanan, z. (1977) j. biol. chem. 252, 8742-8747) and to restore atp synthesis and/or hydrolysis activity. all three mutations, beta-e195k, beta-e19 ...19989556571
characterization of the dominant and rare members of a young hawaiian soil bacterial community with small-subunit ribosomal dna amplified from dna fractionated on the basis of its guanine and cytosine composition.the small-subunit ribosomal dna (rdna) diversity was found to be very high in a hawaiian soil community that might be expected to have lower diversity than the communities in continental soils because the hawaiian soil is geographically isolated and only 200 years old, is subjected to a constant climate, and harbors low plant diversity. since an underlying community structure could not be revealed by analyzing the total eubacterial rdna, we first fractionated the dna on the basis of guanine-plus ...19989546163
the identification, purification, and characterization of cooj. a nickel-binding protein that is co-regulated with the ni-containing co dehydrogenase from rhodospirillum rubrum.cooj, a nickel-binding protein from the co dehydrogenase system of rhodospirillum rubrum, was purified by immobilized metal affinity chromatography. cooj is a co-induced protein predicted to contain a nickel binding motif composed of 16 histidine residues in the final 34 amino acids of the 12.5-kda protein. when cells grown in the presence of co were fractionated on an immobilized metal affinity chromatography column and analyzed by sds-polyacrylamide gel electrophoresis, the major protein obser ...19989545348
multiple catalytic roles of his 287 of rhodospirillum rubrum ribulose 1,5-bisphosphate carboxylase/ his 287 of rhodospirillum rubrum ribulose 1,5-bisphosphate (rubp) carboxylase/oxygenase interacts with the c3-hydroxyl of bound substrate or reaction-intermediate analogue (cabp), water molecules, and ligands for the activator metal-ion (andersson i, 1996, j mol biol 259:160-174; taylor tc, andersson i, 1997, j mol biol 265:432-444). to test structure-based postulates of catalytic functionality, his 287 was replaced with asn or gln. the mutants are not affected adversely in subunit a ...19989541405
genetic complementation and kinetic analyses of rhodobacter capsulatus orf1696 mutants indicate that the orf1696 protein enhances assembly of the light-harvesting i complex.rhodobacter capsulatus orf1696 mutant strains were created by insertion of antibiotic resistance cartridges at different sites within the orf1696 gene in a strain that lacks the light-harvesting ii (lhii) complex. steady-state absorption spectroscopy profiles and the kinetics of the light-harvesting i (lhi) complex assembly and decay were used to evaluate the function of the orf1696 protein in various strains. all of the mutant strains were found to be deficient in the lhi complex, including one ...19989537372
transmembrane helix stability: the effect of helix-helix interactions studied by fourier transform infrared spectroscopy.we have measured, using infrared spectroscopy, the hydrogen/deuterium exchange rates of the amide protons in the photosynthetic antenna of rhodospirillum rubrum. these measurements were made not only on the intact protein in detergent solution but also on two dissociated forms (b820 and b777). we have, on the basis of our knowledge of the structure of this protein, been able to assign the various groups of amide protons that exchange with different time constants to distinct regions of the prote ...19989533710
the rieske protein from purple sulfur bacteria is an extrinsic protein.the mode of membrane attachment of the rieske iron-sulfur protein from cytochrome bc1 complex of rhodospirillum rubrum has been studied using biochemical approaches. in contrast to cytochrome c1 the bacterial rieske protein was extracted from chromatophores using chaotropic agents (nascn, urea, guanidine), an alkaline ph and relatively low concentration of triton x-100. the results presented here lead to the conclusion, that the rieske protein from chromatophores is extrinsic and that their asso ...19989528121
unisite atp hydrolysis by soluble rhodospirillum rubrum f1-atpase is accelerated by ca2+at saturating concentrations of atp, soluble f1 from the rhodospirillum rubrum (rf1) exhibits a higher rate of hydrolysis with ca2+ than with mg2+. the mechanisms involved in the expression of a higher catalytic activity with ca2+ were explored by measuring the atpase activity of rf1 at substiochiometric concentrations of atp (unisite conditions). at a ratio of 0.25 [gamma-32p]atp per rf1, the enzyme exhibited a 50 times higher hydrolytic rate with ca2+ than with mg2+. the rate of [gamma-32p]atp ...19989526049
reconstitution of core light-harvesting complexes of photosynthetic bacteria using chemically synthesized polypeptides. 2. determination of structural features that stabilize complex formation and their implications for the structure of the subunit complex.chemically synthesized polypeptides have been utilized with a reconstitution assay to determine the role of specific amino acid side chains in stabilizing the core light-harvesting complex (lh1) of photosynthetic bacteria and its subunit complex. in the preceding paper [meadows, k. a., parkes-loach, p. s., kehoe, j. w., and loach, p. a. (1998) biochemistry 37, 3411-3417], it was demonstrated that 31-residue polypeptides (compared to 48 and 54 amino acids in the native polypeptides) having the sa ...19989521663
reconstitution of core light-harvesting complexes of photosynthetic bacteria using chemically synthesized polypeptides. 1. minimal requirements for subunit formation.described are the chemical synthesis, isolation and characterization of each of three polypeptides whose amino acid sequences reproduce portions of the amino acid sequence of the beta-polypeptides of the core light-harvesting complex (lh1) of rhodobacter sphaeroides or rhodospirillum rubrum. the native beta-polypeptides of lh1 of these organisms contain 48 and 54 amino acids, respectively. the smallest synthetic polypeptide had an amino acid sequence identical to that of the last 16 amino acids ...19989521662
cloning and sequencing of a form ii ribulose-1,5-biphosphate carboxylase/oxygenase from the bacterial symbiont of the hydrothermal vent tubeworm riftia pachyptila.the bacterial symbiont of the hydrothermal vent tubeworm fixes carbon via the calvin-benson cycle and has been shown previously to express a form ii ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco). the gene cbbm, which encodes this enzyme, has been cloned and sequenced. the gene has the highest identity with the cbbm gene from rhodospirillum rubrum, and analysis of the inferred amino acid sequence reveals that all active-site residues are conserved. this is the first form ii rubisco cl ...19989515935
isolation of rhodospirillum centenum mutants defective in phototactic colony motility by transposon mutagenesis.the purple photosynthetic bacterium rhodospirillum centenum is capable of forming swarm colonies that rapidly migrate toward or away from light, depending on the wavelength of excitation. to identify components specific for photoperception, we conducted mini-tn5-mediated mutagenesis and screened approximately 23,000 transposition events for mutants that failed to respond to either continuous illumination or to a step down in light intensity. a majority of the ca. 250 mutants identified lost the ...19989495765
substitution of valine for histidine 265 in carbon monoxide dehydrogenase from rhodospirillum rubrum affects activity and spectroscopic carbon monoxide dehydrogenase (codh) from rhodospirillum rubrum, histidine 265 was replaced with valine by site-directed mutagenesis of the coos gene. the altered form of codh (h265v) had a low nickel content and a dramatically reduced level of catalytic activity. although treatment with nicl2 and cocl2 increased the activity of h265v codh by severalfold, activity levels remained more than 1000-fold lower than that of wild-type codh. histidine 265 was not essential for the formation and stabi ...19989461598
demonstration of the key role played by the pufx protein in the functional and structural organization of native and hybrid bacterial photosynthetic core complexes.the role of a component of the bacterial photosystem, the pufx protein, was examined by heterologous expression of the pufx gene from rhodobacter capsulatus in a strain of r. sphaeroides that lacks the native pufx gene. the strain of r. sphaeroides containing the r. capsulatus pufx protein was capable of efficient transduction of light energy despite a low degree of sequence conservation between the pufx proteins from the two species. the organization of the hybrid reaction center/lh1 photosyste ...19989457869
cloning and sequencing of dratg genes and their downstream region of azospirillum brasilense 8-kb fragment was cloned by probing the gene library of azospirillum brasilense yu62 with the 4.0-kb dratg fragment of a. brasilense sp7. dna hybridization of this fragment demonstrated that dratg genes were located in a 3.0-kb ecor i-kpn i fragment, and were contiguous to the nifh gene. this 3.0-kb fragment was completely sequenced on both strands. sequence analysis of the fragment revealed that it included the full-length dratg genes and two orfs downstream of drag (orf3 and incomplete orf4 ...19979429775
dinitrogenase reductase-activating glycohydrolase can be released from chromatophores of rhodospirillum rubrum by treatment with mggdp.dinitrogenase reductase-activating glycohydrolase (drag), involved in the regulation of nitrogenase activity in rhodospirillum rubrum, is associated with chromatophore membranes in cell extracts. we show that drag can be specifically released by treatment with mggdp; other nucleotides studied had no effect. the drag activity released corresponds to the release of drag protein.19979401050
single transduction in the transcriptional activator cooa containing a heme-based co sensor: isolation of a dominant positive mutant which is active as the transcriptional activator even in the absence of co.we constructed an in vivo reporter system to measure the activity of cooa as the transcriptional activator and showed that the recombinant cooa was active as the transcriptional activator in the presence of co even in e. coli cells. a dominant positive mutant of cooa, in which met131 was replaced by leu, was isolated by a random mutagenesis with this reporter system. the electronic absorption spectra of m131l mutant were identical to those of wild type cooa in oxidized (fe3+), reduced (fe2+), an ...19979398645
role of methionine-239, an amino acid residue in the mobile-loop region of the nadh-binding domain (domain i) of proton-translocating transhydrogenase.transhydrogenase couples the transfer of hydride equivalents between nad(h) and nadp(h) to proton translocation across a membrane. the one-dimensional proton nmr spectrum of the recombinant nad(h)-binding domain (domain i) of transhydrogenase from rhodospirillum rubrum reveals well-defined resonances, several of which arise from a mobile loop at the protein surface. four have been assigned to met residues (meta-metd). substitution of met239 with either ile (di.m239i) or phe (di.m239f) resulted i ...19979398196
the ph dependences of reactions catalyzed by the complete proton-translocating transhydrogenase from rhodospirillum rubrum, and by the complex formed from its recombinant nucleotide-binding domains.transhydrogenase couples the translocation of protons across a membrane to the transfer of reducing equivalents between nad(h) and nadp(h). using transhydrogenase from rhodospirillum rubrum we have examined the ph dependences of the 'forward' and 'reverse' reactions, and of the 'cyclic' reaction (nadp(h)-dependent reduction of the analogue, acetyl pyridine adenine dinucleotide, by nadh). in the case of the membrane-bound protein in chromatophores, the imposition of a protonmotive force through t ...19979398076
site-directed modification of the ligands to the bacteriochlorophylls of the light-harvesting lh1 and lh2 complexes of rhodobacter sphaeroides.the core light-harvesting lh1 complex of rhodobactersphaeroides consists of an assembly of membrane-spanning alpha and beta polypeptides, each of which binds one bacteriochlorophyll molecule. in this study we have used site-directed mutagenesis to demonstrate that the b880 bacteriochlorophyll binding site of lh1 shows a high degree of specificity for the residue that provides the ligand to the bchl mg2+ ion. alpha his0 (alphah0) was changed to asn, leu, and tyr, and beta his0 (betah0) to asn, gl ...19979376369
photoresponses of the purple nonsulfur bacteria rhodospirillum centenum and rhodobacter sphaeroides.we have measured the photoresponse of two purple nonsulfur bacteria, rhodobacter sphaeroides and rhodospirillum centenum, under defined conditions in a light beam propagating at 90 degrees to the optical axis of the microscope. this beam presented cells with a steep gradient of intensity perpendicular to the direction of propagation and a shallow gradient in the direction of light propagation. r. centenum, a species that reverses to change direction, accumulated in the light beam, as expected fo ...19979352928
evidence that the transfer of hydride ion equivalents between nucleotides by proton-translocating transhydrogenase is direct.the molecular masses of the purified, recombinant nucleotide-binding domains (domains i and iii) of transhydrogenase from rhodospirillum rubrum were determined by electrospray mass spectrometry. the values obtained, 40,273 and 21,469 da, for domains i and iii, respectively, are similar to those estimated from the amino acid sequences of the proteins. evidently, there are no prosthetic groups or metal centers that can serve as reducible intermediates in hydride transfer between nucleotides bound ...19979346886
autofluorescence of live purple bacteria in the near infrared.we have developed a novel microscope with which to study the fluorescence of cells in the near-infrared region (lambda = 750-2500 nm). for one of its first applications we report on the autofluorescence of live purple bacteria, rhodospirillum rubrum, and suggest that the autofluorescent component is bacteriochlorophyll. the rapid fading of the autofluorescence of fixed bacteria and of purified bacteriochlorophyll suggests that the live bacteria are able to regenerate their pigment with a time co ...19979344583
cooa, a co-sensing transcription factor from rhodospirillum rubrum, is a co-binding heme protein.biological sensing of small molecules such as no, o2, and co is an important area of research; however, little is know about how co is sensed biologically. the photosynthetic bacterium rhodospirillum rubrum responds to co by activating transcription of two operons that encode a co-oxidizing system. a protein, cooa, has been identified as necessary for this response. cooa is a member of a family of transcriptional regulators similar to the camp receptor protein and fumavate nitrate reduction from ...19979326589
the electron transport system of the halophilic purple nonsulfur bacterium rhodospirillum salinarum. 1. a functional and thermodynamic analysis of the respiratory chain in aerobically and photosynthetically grown cells.plasma membranes isolated from cells of the halophilic purple nonsulfur bacterium rhodospirillum salinarum grown in light or in the dark were examined. membranes isolated from cells grown aerobically in the dark contained three b-type and two c-type membrane-bound cytochromes with em,7 of +180, +72 and -5 mv (561-575 nm), and +244 and +27 mv (551-540 nm), respectively. conversely, membranes isolated from cells grown anaerobically in the light contained two b-type and five c-type haems with em,7 ...19979297468
chemosensory and photosensory perception in purple photosynthetic bacteria utilize common signal transduction components.the chemotaxis gene cluster from the photosynthetic bacterium rhodospirillum centenum contains five open reading frames (orfs) that have significant sequence homology to chemotaxis genes from other bacteria. to elucidate the functions of each orf, we have made various mutations in the gene cluster and analyzed their phenotypic defects. deletion of the entire che operon (delta che), as well as nonpolar disruptions of cheay, chew, and cher, resulted in a smooth-swimming phenotype, whereas disrupti ...19979294427
analysis of a chemotaxis operon from rhodospirillum centenum.a chemotaxis gene cluster from the photosynthetic bacterium rhodospirillum centenum has been cloned, sequenced, and analyzed for the control of transcription during swimmer-to-swarm cell differentiation. the first gene of the operon (cheay) codes for a large 108-kda polypeptide with an amino-terminal domain that is homologous to chea and a carboxyl terminus that is homologous to chey. cheay is followed by chew, an additional homolog of chey, cheb, and cher. sequence analysis indicated that all o ...19979294426
antenna excited state decay kinetics establish primary electron transfer in reaction centers as heterogeneous.the decay of the excited primary electron donor p* in bacterial photosynthetic reaction centers (both membrane-bound and detergent-isolated) has been observed to be nonexponential on a time scale of some tens of picoseconds. although the multipicosecond nonexponentiality of p* has been ascribed to heterogeneity in teh rate of primary electron transfer (pet), the decay kinetics can be interpreted equally well using homogeneous models. to address this ambiguity, we studied the decay of excited bac ...19979289013
structure of the puf operon of the obligately aerobic, bacteriochlorophyll alpha-containing bacterium roseobacter denitrificans och114 and its expression in a rhodobacter capsulatus puf puc deletion mutant.roseobacter denitrificans (erythrobacter species strain och114) synthesizes bacteriochlorophyll a (bchl) and the photosynthetic apparatus only in the presence of oxygen and is unable to carry out primary photosynthetic reactions and to grow photosynthetically under anoxic conditions. the puf operon of r. denitrificans has the same five genes in the same order as in many photosynthetic bacteria, i.e., pufbalmc. pufc, the tetraheme subunit of the reaction center (rc), consists of 352 amino acids ( ...19979286973
distinct actions of cis and trans atp within the double ring of the chaperonin groel.the chaperonin groel is a double-ring structure with a central cavity in each ring that provides an environment for the efficient folding of proteins when capped by the co-chaperone groes in the presence of adenine nucleotides. productive folding of the substrate rhodanese has been observed in cis ternary complexes, where groes and polypeptide are bound to the same ring, formed with either atp, adp or non-hydrolysable atp analogues, suggesting that the specific requirement for atp is confined to ...19979285593
effect of hydration on the structure, dynamics and function of photosynthetic membranes of purple bacteria.nmr spectra and relaxation times t1 and t2 for 31p in membranes of rhodobacter sphaeroides were investigated at different relative humidity levels. the results are compared to the hydration curves, fatty acid composition and the structure-dynamic and functional characteristics of the membranes of photosynthetic bacteria rb. sphaeroides, rhodospirillum rubrum and ectothiorhodospira shaposhnikovii. the differences in the state of lipid phase of these membranes are revealed under low humidity, and ...19979257278
the effect of ring currents on carbon chemical shifts in cytochromes.calculations suggest that some carbon chemical shifts in proteins should have large ring current shifts (> 1 ppm). we present 13c, 15n and 1h assignments for cytochrome c2 from rhodospirillum rubrum, compare these with shifts for other cytochromes c, and show that the calculated ring current shifts are similar to experimentally observed shifts, but that there remain substantial conformation-dependent shifts of side-chain carbons. ring current shifts as large as 6 ppm are observed. we show that t ...19979255943
reductive dehalogenation of halocarboxylic acids by the phototrophic genera rhodospirillum and rhodopseudomonas.type strains of the purple nonsulfur species rhodospirillum rubrum, rhodospirillum photometricum, and rhodopseudomonas palustris grew phototrophically on a number of two- and three-carbon halocarboxylic acids in the presence of co2, by reductive dehalogenation and assimilation of the resulting acid. strains of each of these species were able to grow on chloroacetic, 2-bromopropionic, 2-chloropropionic, and 3-chloropropionic acids at a concentration of 2 mm. only r. palustris dsm 123 was able to ...19979251226
regulation of nitrogen fixation in azospirillum brasilense.the regulation of nitrogen fixation in azospirillum brasilense is very complicated, and it responds to exogenous fixed nitrogen or a change of oxygen concentration. this regulation occurs at both transcriptional and posttranslational levels. unlike regulation seen in klebsiella pneumoniae, transcription of nifa does not require ntrb/ntrc in a. brasilense and the expression of nifhdk is controlled by posttranslational regulation of nifa activity. addition of nh4+ or a shift from microaerobic to a ...19979231412
mutations at tyrosine-235 in the mobile loop region of domain i protein of transhydrogenase from rhodospirillum rubrum strongly inhibit hydride transfer.transhydrogenase from mitochondrial and bacterial membranes couples proton translocation to hydride transfer between nad(h) and nadp(h). the enzyme has three domains, of which domains i and iii protrude from the membrane. these possess the nad(h)- and nadp(h)-binding sites, respectively, whereas domain ii spans the membrane. in domain i there is a mobile loop which emanates from the surface of the protein, but which closes down upon nad(h) binding. in this report we show that the nadp(h)-depende ...19979230921
a single mutation in the m-subunit of rhodospirillum rubrum confers herbicide resistance.cells of the photosynthetic bacterium rhodospirillum rubrum were rendered resistant against the inhibitor 2-(1-phenyl)ethylamino-3-propionylamino-4-cyano-thiazole (ppcth). electron transport in reaction centers prepared from one of the mutants (m6) was neither inhibited by ppcth and other nh-thiazoles nor terbutryn. these inhibitors are known to bind at the q(b) site of the l-subunit. compared to the wild type, chromatophores from m6 exhibited strongly altered q(b)- fe2+ and q(a)- fe2+ epr signa ...19979224686
rhodospira trueperi gen. nov., spec. nov., a new phototrophic proteobacterium of the alpha group.a new phototrophic purple bacterium was isolated from a flat, laminated microbial mat in a salt marsh near woods hole, mass., usa. the spiral-shaped bacterium was highly motile and had bipolar tufts of flagella and intracytoplasmic membranes of the vesicular type. the major photosynthetic pigments were identified as the carotenoid tetrahydrospirilloxanthin and bacteriochlorophyll b. the long wavelength in vivo absorption maximum of the bacteriochlorophyll was at 986 nm. the marine bacterium show ...19979211712
uridylylation of the p(ii) protein in the photosynthetic bacterium rhodospirillum rubrum.the regulatory protein p(ii) has been studied in great detail in enteric bacteria; however, its function in photosynthetic bacteria has not been clearly established. as a number of these bacteria have been shown to regulate nitrogenase activity by a metabolic control system, it is of special interest to establish the role of p(ii) in these diazotrophs. in this study, we show that p(ii) in rhodospirillum rubrum is modified in response to the n status in the cell and that addition of ammonium or g ...19979209032
adp-ribosylarginine hydrolases and adp-ribosyltransferases. partners in adp-ribosylation cycles.mono-adp-ribosylation is a reversible modification of arginine residues in proteins, with nad:arginine adp-ribosyltransferases and adp-ribosylarginine hydrolases constituting opposing arms of a putative adp-ribosylation cycle. the enzymatic components of an adp-ribosylation cycle have been identified in both prokaryotic and eukaryotic systems. the regulatory significance of the cycle has been best documented in prokaryotes. as shown by ludden and coworkers, adp-ribosylation controls the activity ...19979193633
the reduction of acetylpyridine adenine dinucleotide by nadh: is it a significant reaction of proton-translocating transhydrogenase, or an artefact?transhydrogenase is a proton pump. it has separate binding sites for nad+/nadh (on domain i of the protein) and for nadp+/nadph (on domain iii). purified, detergent-dispersed transhydrogenase from escherichia coli catalyses the reduction of the nad+ analogue, acetylpyridine adenine dinucleotide (acpdad+), by nadh at a slow rate in the absence of added nadp+ or nadph. although it is slow, this reaction is surprising, since transhydrogenase is generally thought to catalyse hydride transfer between ...19979186780
energy migration in the light-harvesting antenna of the photosynthetic bacterium rhodospirillum rubrum studied by time-resolved excitation annihilation at 77 k.the intensity dependence of picosecond kinetics in the light-harvesting antenna of the photosynthetic bacterium rhodospirillum rubrum is studied at 77 k. by changing either the average excitation intensity or the pulse intensity we have been able to discriminate singlet-singlet and singlet-triplet annihilation. it is shown that the kinetics of both annihilation types are well characterized by the concept of percolative excitation dynamics leading to the time-dependent annihilation rates. the tim ...19969172762
composition and primary structure of the f1f0 atp synthase from the obligately anaerobic bacterium clostridium thermoaceticum.the subunit composition and primary structure of the proton-translocating f1f0 atp synthase have been determined in clostridium thermoaceticum. the isolated enzyme has a subunit composition identical to that of the f1f0 atp synthase purified from clostridium thermoautotrophicum (a. das, d. m. ivey, and l. g. ljungdahl, j. bacteriol. 179:1714-1720, 1997), both having six different polypeptides. the molecular masses of the six subunits were 60, 50, 32, 17, 19, and 8 kda, and they were identified a ...19979171425
nad-dependent cross-linking of dinitrogenase reductase and dinitrogenase reductase adp-ribosyltransferase from rhodospirillum rubrum.chemical cross-linking of dinitrogenase reductase and dinitrogenase reductase adp-ribosyltransferase (drat) from rhodospirillum rubrum has been investigated with a cross-linking system utilizing two reagents, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide and sulfo-n-hydroxysuccinimide. cross-linking between dinitrogenase reductase and drat requires the presence of nad, the cellular adp-ribose donor, or a nad analog containing an unmodified nicotinamide group, such as nicotinamide hypoxanthine d ...19979150224
the role of nad+ as a signal during nitrogenase switch-off in rhodospirillum rubrum.the role of nad+ in the metabolic regulation of nitrogenase, the 'switch-off' effect, in rhodospirillum rubrum has been studied. we now show that the decrease in nitrogenase activity upon addition of nad+ to r. rubrum is due to modification of dinitrogenase reductase. there was no effect when nad+ was added to a mutant of r. rubrum devoid of dinitrogenase reductase adp-ribosyltransferase, indicating that nad+ 'switch-off' is an effect of the same regulatory system as ammonium 'switch-off'. we al ...19979148756
the effect of respiration on the phototactic behavior of the purple nonsulfur bacterium rhodospirillum centenum.the effect of respiration on the positive phototactic movement of swarming agar colonies of the facultative phototroph rhodospirillum centenum was studied. when the electron flow was blocked at the bc1 complex level by myxothiazol, the oriented movement of the colonies was totally blocked. conversely, inhibition of respiration via the cytochrome c oxidase stimulated the phototactic response. no phototaxis was observed in a photosynthesis deficient mutant (yb707) lacking bacteriochlorophylls. ana ...19979133331
evaluation of structure-function relationships in the core light-harvesting complex of photosynthetic bacteria by reconstitution with mutant mutant lh1 polypeptides of rhodobactor sphaeroides have been isolated, and their behaviors in in vitro reconstitution of lh1 and its subunit complex have been characterized. two mutants were selected to address the increased stability of the subunit complex of rb. sphaeroides compared with that of rhodobacter capsulatus. we found that this difference can be largely ascribed to the existence of tyr at position +4 in the beta-polypeptide (the numbering system used assigns position 0 to the h ...19979132020
role of isoleucine-164 at the active site of rubisco from rhodospirillum rubrum.isoleucine-164 is in van der waals contact with two ligands (lysine-191 and aspartate-193) of the activator magnesium ion at the active site of ribulose-1,5-bisphosphate carboxylase/oxygenase from rhodospirillum rubrum. to observe the effect of mutations in the second sphere of coordination of the metal ion, isoleucine-164 was replaced by threonine, asparagine, and aspartate. all the mutant enzymes obtained exhibit a low carboxylase activity. ile164asp has less than 0.1% of the wild-type carboxy ...19979125206
spectroscopy and structure of bacteriochlorophyll dimers. i. structural consequences of nonconservative circular dichroism spectra.the origin of the nonconservative nature of the circular dichroism (cd) spectrum of bacteriochlorophyll dimers is investigated. it is shown that coupling between the qy and qx transitions can, under rather restricting circumstances, lead to an asymmetrical cd spectrum: only for a limited set of relative orientations of the monomers within the dimer is the spectrum found to be asymmetrical. the relation between intensity and asymmetry of the cd spectrum is elucidated. the results are applied to t ...19979083687
in vivo nickel insertion into the carbon monoxide dehydrogenase of rhodospirillum rubrum: molecular and physiological characterization of cooctj.the products of cooctj are involved in normal in vivo ni insertion into the carbon monoxide dehydrogenase (codh) of rhodospirillum rubrum. located on a 1.5-kb dna segment immediately downstream of the codh structural gene (coos), two of the genes encode proteins that bear motifs reminiscent of other (urease and hydrogenase) ni-insertion systems: a nucleoside triphosphate-binding motif near the n terminus of cooc and a run of 15 histidine residues regularly spaced over the last 30 amino acids of ...19979079911
influence of asn/his l166 on the hydrogen-bonding pattern and redox potential of the primary donor of purple bacterial reaction centers.the primary electron donor (p) of the photosynthetic reaction center (rc) from the purple bacterium rhodobacter (rb.) sphaeroides is constituted of two bacteriochlorophyll molecules in excitonic interaction. the c2 acetyl carbonyl group of one of the two bacteriochlorophyll molecules (pl), the one more closely associated with the l polypeptide subunit, is engaged in a hydrogen bond with histidine l168, while the other pi-conjugated carbonyl groups of p are free from such hydrogen-bonding interac ...19979062134
functions of conserved tryptophan residues of the core light-harvesting complex of rhodobacter sphaeroides.we have examined mutants in the core light-harvesting complex of rhodobacter sphaeroides in which the tryptophan residues located at positions alpha+11, beta+6, and beta+9 have been mutated to each of the three other aromatic amino acids, namely tyrosine, phenylalanine, and histidine. we confirm that the alpha+11 residue and show that the beta+9 residue each form a hydrogen bond to a c2-acetyl group of a bchl molecule. mutation of either of these residues to a phenylalanine results in a breakage ...19979062104
the effect of respiration on the phototactic behavior of the purple nonsulfur bacterium rhodospirillum centenumthe effect of respiration on the positive phototactic movement of swarming agar colonies of the facultative phototroph rhodospirillum centenum was studied. when the electron flow was blocked at the bc1 complex level by myxothiazol, the oriented movement of the colonies was totally blocked. conversely, inhibition of respiration via the cytochrome c oxidase stimulated the phototactic response. no phototaxis was observed in a photosynthesis deficient mutant (yb707) lacking bacteriochlorophylls. ana ...19979042748
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