Publications

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 ...	1998	9546163
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, ...	1998	9561824
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 ...	1998	9659396
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 ...	1998	9675170
heme environmental structure of cooa is modulated by the target dna binding. evidence from resonance raman spectroscopy and co rebinding kinetics.	in 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 ...	1998	9685335
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 ...	1998	9734033
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 ...	1998	9687237
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 ...	1998	9750176
the effect of pressure on the bacteriochlorophyll a binding sites of the core antenna complex from rhodospirillum rubrum.	in 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 ...	1998	9778363
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 ...	1998	9799120
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 ...	1998	9693001
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 ...	1998	9693716
[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 ...	1998	9702725
correlation between protein flexibility and electron transfer from qa-* to qb in psii membrane fragments from spinach.	to 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 ...	1998	9708974
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 ...	1998	9710244
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 ...	1998	9743629
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.	1997	9401050
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 ...	1997	9398076
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 ...	1997	9376369
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 ...	1997	9352928
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 ...	1997	9398196
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 ...	1997	9398645
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 ...	1997	9346886
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 ...	1997	9125206
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 ...	1997	9230921
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 ...	1997	9326589
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 ...	1997	9294427
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 ...	1997	9297468
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 ...	1997	9344583
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 ...	1997	9294426
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 ...	1997	9257278
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 ...	1997	9285593
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 ...	1997	9251226
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 ...	1997	9255943
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 ( ...	1997	9286973
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 ...	1997	9289013
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 ...	1997	9193633
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 ...	1997	9211712
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 ...	1997	9224686
a 3-hydroxy-3-methylglutaryl-coa lyase gene in the photosynthetic bacterium rhodospirillum rubrum.	a 1.2 kb long dna segment from rhodospirillum rubrum has been sequenced (embl/genbank accession number: u41280). this dna segment includes the first sequenced gene for a putative 3-hydroxy-3-methylglutaryl-coa (hmg-coa) lyase, termed hmgl, from a photosynthetic organism. the sequenced segment also contains a ribosome-binding site and two clusters of possible-35 and -10 promotor sequences preceding the hmgl gene. translation of the gene would yield a 303 amino-acid-long protein with a calculated ...	1997	9003443
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 ...	1997	9079911
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 ...	1997	9150224
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 ...	1997	9209032
two-dimensional crystallization of the light-harvesting i-reaction centre photounit from rhodospirillum rubrum.	a stoichiometric unit of the light-harvesting complex i and the reaction centre (lhi-rc complex) has been isolated from a carotenoid-less mutant of the purple non-sulphur bacterium rhodospirillum rubrum by mild solubilization of photosynthetic membranes with the phospholipid detergent diheptylphosphatidylcholine. dialysis of the isolated lhi-rc complexes in the presence of added dioleoyl-sn-phosphatidylcholine produced ordered two-dimensional crystals. digital image processing revealed that the ...	1997	9020974
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 ...	1997	9231412
high cyclic transhydrogenase activity catalyzed by expressed and reconstituted nucleotide-binding domains of rhodospirillum rubrum transhydrogenase.	the hydrophilic, extramembranous domains i (alpha 1 subunit) and iii of the rhodospirillum rubrum nicotinamide nucleotide transhydrogenase were expressed in escherichia coli and purified therefrom as soluble proteins. these domains bind nad(h) and nadp(h). respectively, and together they form the enzyme's catalytic site. we have demonstrated recently that the isolated domains i and iii of the bovine transhydrogenase (or domain i of r. rubrum plus domain iii of the bovine enzyme) reconstitute to ...	1997	9030266
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 ...	1997	9062104
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 ...	1997	9062134
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 ...	1997	9083687
evaluation of structure-function relationships in the core light-harvesting complex of photosynthetic bacteria by reconstitution with mutant polypeptides.	seven 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 ...	1997	9132020
quinolones and their n-oxides as inhibitors of mitochondrial complexes i and iii.	4(1h)-quinolones (2-alkyl- (1), 2-alkyl-3-methyl- (2), 2-methyl-3-alkyl- (3), 1-hydroxy-2-methyl-3-alkyl- (4) and 1-hydroxy-2-alkyl- (5)) with n-alkyl side chains varying from c5 to c17 have been synthesized and tested for biological activity in mitochondrial complexes. whereas all quinolones were efficient inhibitors of electron transport in the cytochrome b/c1-complex from either beef heart or rhodospirillum rubrum, in complex i from beef heart quinolones 1 and 2 only were highly active. in a ...	1997	9030270
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 ...	1997	9042748
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 ...	1997	9133331
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 ...	1997	9148756
cloning and sequencing of dratg genes and their downstream region of azospirillum brasilense yu62.	an 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 ...	1997	9429775
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 ...	1997	9171425
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 ...	1997	9186780
phylogenetic relationships of the helical-shaped bacteria in the alpha proteobacteria inferred from 16s rdna sequences.	16s ribosomal rna gene sequences from seven strains of aquaspirillum peregrinum, aqu. itersonii, aqu. polymorphum, and oceanospirillum pusillum were compared with homologous sequences from other members of helical-shaped bacteria. the bootstrapped neighbor-joining tree, inferred from 887 aligned sites, placed the spirillum taxa assigned to aquaspirillum, oceanospirillum, azospirillum, magnetospirillum, rhodospirillum, and rhodocista of the proteobacteria in seven clusters of alpha proteobacteria ...	1997	12501339
melissa: a potential experiment for a precursor mission to the moon.	melissa (micro-ecological life support system alternative) has been conceived as a micro-organism based ecosystem intended as a tool for developing the technology for a future artificial ecosystem for long term space missions, as for example a lunar base. the driving element of melissa is the recovering of edible biomass from waste, co2, and minerals with the use of sun light as energy source. in this publication, we focus our attention on the potential applications of melissa for a precursor mi ...	1996	11543311
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 ...	1996	9172762
rubisco in marine symbiotic dinoflagellates: form ii enzymes in eukaryotic oxygenic phototrophs encoded by a nuclear multigene family.	genes encoding ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) were cloned from dinoflagellate symbionts (symbiodinium spp) of the giant clam tridacna gigas and characterized. strikingly, symbiodinium rubisco is completely different from other eukaryotic (form i) rubiscos: it is a form ii enzyme that is approximately 65% identical to rubisco from rhodospirillum rubrum (rubisco forms i and ii are approximately 25 to 30% identical); it is nuclear encoded by a multigene family; and the pr ...	1996	8721755
the crystal structure of the light-harvesting complex ii (b800-850) from rhodospirillum molischianum.	the light-harvesting complexes ii (lh-2s) are integral membrane proteins that form ring-like structures, oligomers of alpha beta-heterodimers, in the photosynthetic membranes of purple bacteria. they contain a large number of chromophores organized optimally for light absorption and rapid light energy migration. recently, the structure of the nonameric lh-2 of rhodopseudomonas acidophila has been determined; we report here the crystal structure of the octameric lh-2 from rhodospirillum molischia ...	1996	8736556
a peptidoglycan binding domain in the porin-associated protein (pap) of rhodospirillum rubrum fr1.	the porin-associated protein of rhodospirillum rubrum fr1 was found to contain a peptidoglycan binding motif. a partial fragment of 179 amino acids, obtained by cleavage of pap with trypsin, asp-n protease, and cnbr, was sequenced. substantial sequence homology was found of the c-terminal part (residues 126-179) of porin-associated protein with ompa, the peptidoglycan-associated lipoprotein of several bacteria, protein f of pseudomonas aeruginosa, and piii of neisseria gonorrhoeae, the latter be ...	1996	8674970
high-resolution crystal structures of two polymorphs of cytochrome c' from the purple phototrophic bacterium rhodobacter capsulatus.	the structures of two polymorphs of cytochrome c' from rhodobacter capsulatus (rccp) strain m110 have been determined by the molecular replacement method. iron anomalous scattering data were used to confirm the molecular replacement solution. the structures were refined at 1.72 angstrom and 2.0 angstrom resolution to r-values of 15.0% and 16.3%, respectively. the rccp molecule is a dimer and each of the identical 129 residue subunits folds as a four-helical bundle with a covalently bound heme gr ...	1996	8676382
the binding of nucleotides to domain i proteins of the proton-translocating transhydrogenases from rhodospirillum rubrum and escherichia coli as measured by equilibrium dialysis.	transhydrogenase catalyses the transfer of reducing equivalents between nad(h) and nadp(h) coupled to the translocation of protons across a membrane. the nad(h)-binding domain of transhydrogenase (domain i protein) from rhodospirillum rubrum and from escherichia coli were overexpressed and purified. nucleotide binding to the domain i proteins was determined by equilibrium dialysis. nadh and its analogue, acetylpyridine adenine dinucleotide (reduced form), bound with relatively high affinity (kd ...	1996	8774721
posttranslational regulation of nitrogenase activity by fixed nitrogen in azotobacter chroococcum.	using anti-(fe protein) antibody raised against the fe protein of the photosynthetic bacterium rhodospirillum rubrum, it was found that the fe protein component of nitrogenase (ec 1.18.2.1) from azotobacter chroococcum cells subjected to an ammonium shock, and hence with an inactive nitrogenase, appeared as a doublet in western blot analysis of cell extracts. the fe protein incorporated [32p]phosphate and [3h]adenine in response to ammonium treatment, and l-methionine-dl-sulfoximine, an inhibito ...	1996	8781527
a perturbed two-level model for exciton trapping in small photosynthetic systems.	the study of exciton trapping in photosynthetic systems provides significant information about migration kinetics within the light harvesting antenna (lha) and the reaction center (rc). we discuss two random walk models for systems with weakly coupled pigments, with a focus on the application to small systems (10-40 pigments/rc). details of the exciton transfer to and from the rc are taken into consideration, as well as migration within the lha and quenching in the rc. the first model is obtaine ...	1996	8789084
effect of the pufq-pufb intercistronic region on puf mrna stability in rhodobacter capsulatus.	differential expression of genes localized within the polycistronic puf operon of rhodobacter capsulatus is partly due to altered stabilities of individual mrna segments. we show that the 5' untranslated region (utr) of pufb contributes to the unusual longevity of the 0.5 kb light-harvesting (lh) i specific pufba mrna and of the 2.7 kb pufbalmx mrna. three stem-loop structures have been identified within the pufq-pufb intercistronic region by means of rna secondary-structure analysis in vitro an ...	1996	8809769
formation of the light-harvesting complex i (b870) of anoxygenic phototrophic purple bacteria.	the light-harvesting (lh) complex i (b870) of anoxygenic photosynthetic purple bacteria is the oligomeric form of its subunit b820 consisting of the low-molecular-weight polypeptides alpha, beta, bacteriochlorophyll (bchl), and carotenoids in the stoichiometric ratio [alpha1 beta1 (bchl2) crt1-2]n. lhi surrounds the photochemical reaction center (rc). the major absorption band of the lhi complex is species-specific and is found at 870-890 nm; those of the subunit and the monomeric bchl a (dissol ...	1996	8703191
evidence for a proximal histidine interaction in the structure of cytochromes c in solution: a resonance raman study.	soret-excited resonance raman (rr) spectra of oxidized and reduced cytochromes ć from rhodospirillum molischianum and rhodobacter sphaeroides, in solution, are reported. the spectra of the type i ferricytochromes ć in both species contain different extents of two forms. one of these is readily assignable to a "normal" five-coordinated high-spin heme. the second species with v3 and v10 modes at 1502 and 1635 cm-1, respectively, is attributed to a five-coordinated intermediate-spin heme. the rr da ...	1996	8703928
transcription of the glnb and glna genes in the photosynthetic bacterium rhodospirillum rubrum.	the pii protein, encoded by glnb, has a central role in the control of nitrogen metabolism in nitrogen-fixing prokaryotes. the glnb gene of rhodospirillum rubrum was isolated and sequenced. the deduced amino acid sequence had very high sequence identity to other pii proteins. the glna gene, encoding glutamine synthetase, was located 135 bp downstream of glnb and was partially sequenced. glnb is cotranscribed with glna from a promoter with high similarity to the sigma 54-dependent promoter consen ...	1996	8704966
a global two component signal transduction system that integrates the control of photosynthesis, carbon dioxide assimilation, and nitrogen fixation.	photosynthesis, biological nitrogen fixation, and carbon dioxide assimilation are three fundamental biological processes catalyzed by photosynthetic bacteria. in the present study, it is shown that mutant strains of the nonsulfur purple photosynthetic bacteria rhodospirillum rubrum and rhodobacter sphaeroides, containing a blockage in the primary co2 assimilatory pathway, derepress the synthesis of components of the nitrogen fixation enzyme complex and abrogate normal control mechanisms. the abs ...	1996	8962083
characterization of the region encoding the co-induced hydrogenase of rhodospirillum rubrum.	in the photosynthetic bacterium rhodospirillum rubrum, the presence of carbon monoxide (co) induces expression of several proteins. these include carbon monoxide dehydrogenase (codh) and a co-tolerant hydrogenase. together these enzymes catalyze the following conversion: co + h2o --> co2 + h2. this system enables r. rubrum to grow in the dark on co as the sole energy source. expression of this system has been shown previously to be regulated at the transcriptional level by co. we have now identi ...	1996	8892819
properties of the purified, recombinant, nadp(h)-binding domain iii of the proton-translocating nicotinamide nucleotide transhydrogenase from rhodospirillum rubrum.	transhydrogenase comprises three domains. domains i and iii are peripheral to the membrane and possess the nad(h)- and nadp(h)-binding sites, respectively, and domain ii spans the membrane. domain iii of transhydrogenase from rhodospirillum rubrum was expressed at high levels in escherichia coli, and purified. the purified protein was associated with substoichiometric quantities of tightly bound nadp+ and nadph. fluorescence spectra of the domain iii protein revealed emissions due to tyr residue ...	1996	8898902
a novel heme protein that acts as a carbon monoxide-dependent transcriptional activator in rhodospirillum rubrum.	the gene coding for a carbon monoxide-dependent transcriptional activator (cooa) in rhodospirillum rubrum has been expressed in e. coli, and the recombinant cooa has been purified. cooa contains b-type heme which may act as a co sensor in vivo. co-bound cooa was formed when reduced cooa was reacted with co, but not in the case of oxidized cooa. cooa is the first example of the heme protein acting as a dna-binding transcriptional activator.	1996	8941349
unleashing hydrogenase activity in carbon monoxide dehydrogenase/acetyl-coa synthase and pyruvate:ferredoxin oxidoreductase.	these results demonstrate that two well-studied metalloenzymes, carbon monoxide dehydrogenase/acetyl-coa synthase (codh/acs) and pyruvate:ferredoxin oxidoreductase (pfor), can reduce protons to h2 and, at much lower rates, oxidize h2 to protons and electrons. to our knowledge, this if the first time that pfor has been shown to have hydrogenase activity. codh/acs and pfor evolved h2 at maximum rates when co and pyruvate were the electron donors, respectively, and when electron acceptors are absen ...	1996	8961945
the effects of decyl aurachins c and d on the respiratory electron flow of facultative phototrophic bacteria.	decyl aurachins c and d are two synthetic compounds related to the natural products aurachins c and d extracted from stigmatella aurantiaca. titrations of a range of partial respiratory activities in membranes from facultative phototrophs indicate that decyl aurachin c is more effective than aurachin d in inhibiting the quinol oxidase. decyl aurachin c also affects the nadh-ubiquinone oxidoreductase of rhodobacter capsulatus and the cytochrome bc1 complexes of rb.capsulatus and rhodospirillum ce ...	1996	8843334
control of nitrogen fixation by oxygen in purple nonsulfur bacteria	some members of the facultatively phototrophic bacteria are able to grow diazotrophically in the presence of oxygen. as in other diazotrophs, the nitrogenase of the phototrophic bacteria is highly sensitive to oxygen; therefore, both the function and the expression of nitrogenase are strictly controlled by oxygen. this review focuses on the different levels of oxygen control in the two most extensively studied facultatively phototrophic bacteria, rhodospirillum rubrum and rhodobacter capsulatus. ...	1996	8952942
mutants that show increased sensitivity to hydrogen peroxide reveal an important role for the pentose phosphate pathway in protection of yeast against oxidative stress.	we have isolated several mutants of saccharomyces cerevisiae that are sensitive to oxidative stress in a screen for elevated sensitivity to hydrogen peroxide. two of the sixteen complementation groups obtained correspond to structural genes encoding enzymes of the pentose phosphate pathway. allelism of the pos10 mutation (pos for peroxide sensitivity) to the zwf1/met1 mutants in the structural gene for glucose 6-phosphate dehydrogenase was reported previously. the second mutation, pos18, was com ...	1996	8879247
presence of a second mechanism for the posttranslational regulation of nitrogenase activity in azospirillum brasilense in response to ammonium.	although adp-ribosylation of dinitrogenase reductase plays a significant role in the regulation of nitrogenase activity in azospirillum brasilense, it is not the only mechanism of that regulation. the replacement of an arginine residue at position 101 in the dinitrogenase reductase eliminated this adp-ribosylation and revealed another regulatory system. while the constructed mutants had a low nitrogenase activity, nh4+ still partially inhibited their nitrogenase activity, independent of the dini ...	1996	8631686
directed mutagenesis of the rhodobacter capsulatus puha gene and orf 214: pleiotropic effects on photosynthetic reaction center and light-harvesting 1 complexes.	rhodobacter capsulatus puha mutant strains containing either a nonpolar, translationally in-frame deletion or a polar insertion of an antibiotic resistance cartridge were constructed and evaluated for their photosynthetic growth properties, absorption spectroscopy profiles, and chromatophore protein compositions. both types of mutants were found to be incapable of photosynthetic growth and deficient in the reaction center (rc) and light-harvesting 1 (lh1) complexes. the translationally in-frame ...	1996	8636035
axial heme ligation in the cytochrome bc1 complexes of mitochondrial and photosynthetic membranes. a near-infrared magnetic circular dichroism and electron paramagnetic resonance study.	the combination of epr and low-temperature near-ir magnetic circular dichroism spectroscopies have been used to investigate the axial ligation of the cytochromes in the cytochrome bc1 complexes from bovine heart mitochondria, rhodobacter capsulatus, rhodobacter sphaeroides, and rhodospirillum rubrum, and the purified cytochromes c1 from bovine heart mitochondria, rb. capsulatus and rb. sphaeroides. the possibility of axial ligation of cytochrome c1 by the amino terminus of the polypeptide was al ...	1996	8645697
rubisco, an old challenge with new perspectives.		1996	8663895
molecular cloning, dna sequence and transcriptional analysis of the rhodospirillum molischianum b800/850 light-harvesting genes.	the amino acid sequences of the b800/850 light-harvesting proteins from rhodospirillum molischianum were determined by edman degradation. on the basis of these amino acid sequences, two degenerated oligonucleotides were synthesized and used for pcr of genomic dna. the resulting 150 bp dna fragment was cloned, sequenced and used for subsequent southern blot analysis of digested genomic dna. a 2.3 kbp ecori fragment strongly hybridized to the probe and a size selected genomic library from genomic ...	1996	8695630
identification and sequence of a nifj-like gene in rhodospirillum rubrum: partial characterization of a mutant unaffected in nitrogen fixation.	a nifj-like gene was identified in the photosynthetic purple non-sulphur bacterium rhodospirillum rubrum. a dna segment hybridizing to klebsiella pneumoniae nifj was isolated, the gene was inactivated, and a mutant strain, snj-1, was constructed by allele replacement. the mutation was confirmed by dna sequencing. northern blotting and by the lack of pyruvate oxidoreductase activity. this is the first report of a nifj-like gene in photosynthetic bacteria. unexpectedly, snj-1 was capable of nitrog ...	1996	8736535
spectroscopic characterization of nitrosylheme in nitric oxide complexes of ferric and ferrous cytochrome c' from photosynthetic bacteria.	reactions of ferric and ferrous cytochromes c' from four photosynthetic bacteria (rhodobacter capsulatus atcc 11166, rhodopseudomonas palustris atcc 17001, rhodospirillum rubrum atcc 11170, and chromatium vinosum atcc 17899) with nitric oxide have been investigated by electronic absorption and electron paramagnetic resonance spectroscopies. the heme iron(iii) of these ferric cytochromes c' has been recently reported to be in a quantum mechanically admixed (s = 5/2, 3/2) state [fujii, s., yoshimu ...	1996	8547347
characterization of a co-responsive transcriptional activator from rhodospirillum rubrum.	in rhodospirillum rubrum, co induces the expression of at least two transcripts that encode an enzyme system for co oxidation. this regulon is positively regulated by cooa, which is a member of the camp receptor protein family of transcriptional regulators. the transcriptional start site of one of the transcripts (coofsctj) has been identified by primer extension. the ability of cooa to bind to this promoter in vitro was characterized with dnase i footprinting experiments using extracts of a coo ...	1996	8550545
estimation of the h+/h- ratio of the reaction catalysed by the nicotinamide nucleotide transhydrogenase in chromatophores from over-expressing strains of rhodospirillum rubrum and in liposomes inlaid with the purified bovine enzyme.	two strains of rhodospirillum rubrum were constructed in which, by a gene dosage effect, the transhydrogenase activity of isolated chromatophores was increased 7-10-fold and 15-20-fold, respectively. the h+/h- ratio (the ratio of protons translocated per hydride ion equivalent transferred from nadph to an nad+ analogue, acetyl pyridine adenine dinucleotide), determined by a spectroscopic technique, was approximately 1.0 for chromatophores from the over-expressing strains, but was only approximat ...	1996	8573594
two-dimensional structure of light harvesting complex ii (lhii) from the purple bacterium rhodovulum sulfidophilum and comparison with lhii from rhodopseudomonas acidophila.	within the membranes of photosynthetic bacteria, up to three types of light harvesting complexes (lhi, lhii, lhiii) are found. these complexes absorb photons and transfer the excitation energy to the photosynthetic reaction centre. the lh complexes comprise units that contain alpha and beta polypeptides with associated pigment molecules.	1996	8805531
sequence evidence for strong conservation of the photoactive yellow proteins from the halophilic phototrophic bacteria chromatium salexigens and rhodospirillum salexigens.	the photoactive yellow proteins (pyp) have been found to date only in three species of halophilic purple phototrophic bacteria. they have photochemical activity remarkably similar to that of the bacteria rhodopsins. in contrast to rhodopsins, however, the pyps are small water-soluble proteins. we now report the complete amino acid sequences of rhodospirillum salexigens and chromatium salexigens pyp which allow comparison with the known sequence and three-dimensional structure of the prototypic p ...	1996	8611556
kinetic characterization of the hydrolytic activity of the h+-pyrophosphatase of rhodospirillum rubrum in membrane-bound and isolated states.	substrate hydrolysis by the h+-pyrophosphatase (pyrophosphate phosphohydrolase, h+-ppase) of the photosynthetic bacterium rhodospirillum rubrum follows a two-pathway reaction scheme in which preformed 1:1 and 1:2 . enzyme . mg2+ complexes (emg and emg2) convert dimagnesium pyrophosphate (the substrate). this scheme is applicable to isolated enzyme, uncoupled chromatophores and chromatophores energized by a k+/valinomycin diffusion potential. tris and other amine buffers exert a specific effect o ...	1996	8617255
cloning, sequencing and transcriptional regulation of the drat and drag genes of azospirillum lipoferum fs.	from azospirillum lipoferum (al) fs, a nitrogen-fixing bacterium isolated from the rhizosphere of rice, we cloned and sequenced drat, encoding dinitrogenase reductase adp-ribosyltransferase, and drag, encoding dinitrogenase reductase-activating glycohydrolase. the nucleotide sequences of dratg showed extensive similarity to the same genes from azospirillum brasilense, rhodospirillum rubrum and rhodobacter capsulatus, and they are assumed to be co-transcribed as a single operon. when this dratg o ...	1996	8621068
characterization of the co-induced, co-tolerant hydrogenase from rhodospirillum rubrum and the gene encoding the large subunit of the enzyme.	in the presence of carbon monoxide, the photosynthetic bacterium rhodospirillum rubrum induces expression of proteins which allow the organism to metabolize carbon monoxide in the net reaction co + h2o --> co2 + h2. these proteins include the enzymes carbon monoxide dehydrogenase (codh) and a co-tolerant hydrogenase. in this paper, we present the complete amino acid sequence for the large subunit of this hydrogenase and describe the properties of the crude enzyme in relation to other known hydro ...	1996	8626276
development of gene transfer methods for rubrivivax gelatinosus s1: construction, characterization and complementation of a puf operon deletion strain.	gene transfer systems were developed in rubrivivax (rx.) gelatinosus s1. first, a system for conjugative transfer of mobilizable plasmids from escherichia coli to rx. gelatinosus s1 was established. secondly, optimal conditions for the transformation of rx. gelatinosus s1 by electroporation were determined. a delta puf strain was constructed. complementation with the puf operon from a wild-type strain cloned in a replicative plasmid restored photosynthetic growth. two insertion strains were also ...	1996	8879238
spectroelectrochemical characterization of the metal centers in carbon monoxide dehydrogenase (codh) and nickel-deficient codh from rhodospirillum rubrum.	carbon-monoxide dehydrogenase (codh) from rhodospirillum rubrum contains two metal centers: a ni-x-[fe4s4]2+/1+ cluster (c-center) that serves as the cooxidation site and a standard [fe4s4]2+/1+ cluster (b-center) that mediates electron flow from the c-center to external electron acceptors. four states of the c-center were previously identified in electron paramagnetic resonance (epr) and mössbauer studies. in this report, epr-redox titrations demonstrate that the fully oxidized, diamagnetic for ...	1996	8626477
mutation of tyr235 in the nad(h)-binding subunit of the proton-translocating nicotinamide nucleotide transhydrogenase of rhodospirillum rubrum affects the conformational dynamics of a mobile loop and lowers the catalytic activity of the enzyme.	the tyr residue in the mobile loop region of the soluble, domain i polypeptide (called ths) of the proton-translocating transhydrogenase from rhodospirillum rubrum has been substituted by asn and by phe. the recombinant proteins were expressed at high levels in escherichia coli and purified to homogeneity. the two well defined resonances at 6.82 and 7.12ppm, observed in the one-dimensional proton nmr spectrum of wild-type protein, and previously attributed to the tyr residue, were absent in both ...	1996	8626569
purification and characterization of the alternative nitrogenase from the photosynthetic bacterium rhodospirillum rubrum.	the alternative nitrogenase from a nifh mutant of the photosynthetic bacterium rhodospirillum rubrum has been purified and characterized. the dinitrogenase protein (anf1) contains three subunits in an apparent alpha2beta2gamma2 structure and contains fe but no mo or v. a factor capable of activating apo-dinitrogenase (lacking the femo cofactor) from azotobacter vinelandii was extracted from the alternative dinitrogenase protein with n-methylformamide. the electron paramagnetic resonance (epr) si ...	1996	8631723
facilitation of the terminal proton transfer reaction of ribulose 1,5-bisphosphate carboxylase/oxygenase by active-site lys166.	the terminal step in the carboxylation pathway catalyzed by ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) is stereospecific protonation of the c-2 aci-acid of 3-phosphoglycerate (pga). x-ray crystallographic results favor the epsilon-amino group of lys166 as the proton donor in this step [knight et al. (1990) j. mol. biol. 215, 113]. nonetheless, position-166 mutants are able to catalyze forward processing of isolated 2-carboxy-3-ketoarabinitol 1,5-bisphosphate (ckabp), the carboxyla ...	1996	8909282
consequences for the organization of reaction center-light harvesting antenna 1 (lh1) core complexes of rhodobacter sphaeroides arising from deletion of amino acid residues from the c terminus of the lh1 alpha polypeptide.	the light harvesting antenna 1 (lh1) complex of rhodobacter sphaeroides is intimately associated with the reaction center (rc) as part of the reaction center rc-lh1 core complex. the pufa gene has been modified such that between 5 and 16 amino acid residues were progressively deleted from the c terminus of the lh1 alpha polypeptide. the two largest deletions produced strains which were deficient in lh1. the remaining four deletion mutants exhibited significant reductions in the average level of ...	1996	8621732
deletion of a b800-850 light-harvesting complex in rhodospirillum molischianum dsm119 leads to "revertants" expressing a b800-820 complex: insights into pigment binding.	a b800-850 light-harvesting complex (also called lh2) deficient strain of rhodospirillum molischianum was constructed by replacing a portion of the lh2 gene cluster by a kanamycin resistance gene cartridge. the lh2 deficient strain was characterized spectroscopically and by southern blot analysis. surprisingly, pseudorevertants were obtained which express a b800-820 complex which could not be observed in the wild type. this b800-820 complex was isolated and characterized. it consists of an alpha ...	1996	8639597