| multiple catalytic roles of his 287 of rhodospirillum rubrum ribulose 1,5-bisphosphate carboxylase/oxygenase. | active-site 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 ... | 1998 | 9541405 |
| 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 ... | 1998 | 9545348 |
| 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 |
| 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 ... | 1998 | 9556571 |
| 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 |
| 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. | 1998 | 9630689 |
| 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 ... | 1998 | 9630706 |
| 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 ... | 1998 | 9636041 |
| 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 |
| 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 |
| 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 ... | 1998 | 9692905 |
| 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 |
| 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 |
| 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 |
| 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 ... | 1998 | 9743630 |
| 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 ... | 1998 | 9748246 |
| 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 |
| 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 ... | 1998 | 9799287 |
| 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 ... | 1998 | 9801801 |
| 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 ... | 1998 | 9802019 |
| 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 ... | 1998 | 9804876 |
| 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 ... | 1998 | 9814844 |
| 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 ... | 1998 | 9826513 |
| in vitro reconstitution of the core and peripheral light-harvesting complexes of rhodospirillum molischianum from separately isolated components. | in 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 ... | 1998 | 9860861 |
| 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 ... | 1998 | 9860862 |
| 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 ... | 1999 | 9864318 |
| 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 ... | 1998 | 9884225 |
| 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 ... | 1999 | 9890924 |
| 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 ... | 1999 | 9894003 |
| 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 ... | 1999 | 9988755 |
| correlation of activity regulation and substrate recognition of the adp-ribosyltransferase that regulates nitrogenase activity in rhodospirillum rubrum. | in 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. | 1999 | 10049407 |
| 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 ... | 1999 | 10052937 |
| 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 ... | 1999 | 10052938 |
| on the role of high-potential iron-sulfur proteins and cytochromes in the respiratory chain of two facultative phototrophs | the 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 ... | 1999 | 10076014 |
| 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. | 1999 | 10087603 |
| 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 ... | 1999 | 10101971 |
| 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 ... | 1999 | 10196160 |
| 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 ... | 1999 | 10216162 |
| 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 ... | 1999 | 10319813 |
| 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 ... | 1999 | 10346905 |
| 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 ... | 1999 | 10355118 |
| 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 ... | 1999 | 10358013 |
| 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 ... | 1999 | 10386575 |
| 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 ... | 1999 | 10387115 |
| a shift in the equilibrium constant at the catalytic site of proton-translocating transhydrogenase: significance for a 'binding-change' mechanism. | in mitochondria and bacteria, transhydrogenase uses the transmembrane proton gradient (deltap) to drive reduction of nadp+ by nadh. we have investigated the pre-steady-state kinetics of nadp+ reduction by acetylpyridine adenine dinucleotide (acpdadh, an analogue of nadh) in complexes formed from the two, separately prepared, recombinant, peripheral subunits of the enzyme: the di component, which binds nad+ and nadh, and the diii component, which binds nadp+ and nadph. in the stopped-flow spectro ... | 1999 | 10393090 |
| the mobile loop region of the nad(h) binding component (di) of proton-translocating nicotinamide nucleotide transhydrogenase from rhodospirillum rubrum: complete nmr assignment and effects of bound nucleotides. | the di component of transhydrogenase binds nad+ and nadh. a mobile loop region of di plays an important role in the nucleotide binding process, and mutations in this region result in impaired hydride transfer in the complete enzyme. we have previously employed one-dimensional 1h-nmr spectroscopy to study wild-type and mutant di proteins of rhodospirillum rubrum and the effects of nucleotide binding. here, we utilise two- and three-dimensional nmr experiments to assign the signals from virtually ... | 1999 | 10393257 |
| uphill energy transfer in lh2-containing purple bacteria at room temperature | uphill energy transfer in the lh2-containing purple bacteria rhodopseudomonas acidophila, rhodopseudomonas palustris, rhodobacter sphaeroides, chromatium vinosum and chromatium purpuratum was studied by stationary fluorescence spectroscopy at room temperature upon selective excitation of the b800 pigments of lh2 and the b880 pigments of lh1 at 803 nm and 900 nm, respectively. the resulting fluorescence spectra differed significantly at wavelengths shorter than the fluorescence maximum but agreed ... | 1999 | 10393258 |
| characterization of the interaction of dinitrogenase reductase-activating glycohydrolase from rhodospirillum rubrum with bacterial membranes. | the interaction of dinitrogenase reductase-activating glycohydrolase (drag) with bacterial membranes and the solubilization of drag in response to nucleotides were characterized. purified drag from rhodospirillum rubrum reversibly bound bacterial pellet fractions from rsp. rubrum and other nitrogen-fixing bacteria. drag saturated the membrane fraction of rsp. rubrum at a concentration of 0.2 mol drag/mol bacteriochlorophyll, suggesting that the drag-binding species is prevalent in the membrane. ... | 1999 | 10398752 |
| refolding of recombinant alpha and beta subunits of the rhodospirillum rubrum f(0)f(1) atp synthase into functional monomers that reconstitute an active alpha(1)beta(1)-dimer. | the alpha subunit from the rhodospirillum rubrum f(0)f(1) atp synthase (rrf(1)alpha) was over-expressed in unc operon-deleted escherichia coli strains under various growth conditions only in insoluble inclusion bodies. the functional refolding of urea-solubilized rrf(1)alpha was followed by measuring its ability to stimulate the restoration of atp synthesis and hydrolysis in beta-less r. rubrum chromatophores reconstituted with pure native or recombinant rrf(1)beta [nathanson, l. & gromet-elhana ... | 1999 | 10406951 |
| bacterial photoreceptor with similarity to photoactive yellow protein and plant phytochromes. | a phytochrome-like protein called ppr was discovered in the purple photosynthetic bacterium rhodospirillum centenum. ppr has a photoactive yellow protein (pyp) amino-terminal domain, a central domain with similarity to phytochrome, and a carboxyl-terminal histidine kinase domain. reconstitution experiments demonstrate that ppr covalently attaches the blue light-absorbing chromophore p-hydroxycinnamic acid and that it has a photocycle that is spectrally similar to, but kinetically slower than, th ... | 1999 | 10411503 |
| hydrolysis of native poly(hydroxybutyrate) granules (phb), crystalline phb, and artificial amorphous phb granules by intracellular and extracellular depolymerases. | native poly(hydroxybutyrate) (phb) granules, purified phb and artificial amorphous phb granules were examined as putative substrates for hydrolysis by the intracellular depolymerase system of rhodospirillum rubrum and the extracellular depolymerase of pseudomonas lemoignei. the r. rubrum depolymerizing system requires pretreatment of granules with a heat stable 'activator' fraction; the activator can be replaced by mild trypsin treatment. artificial granules were prepared with a cationic deterge ... | 1999 | 10416659 |
| ni(2+) transport and accumulation in rhodospirillum rubrum. | the cooctj gene products are coexpressed with co-dehydrogenase (codh) and facilitate in vivo nickel insertion into codh. a ni(2+) transport assay was used to monitor uptake and accumulation of (63)ni(2+) into r. rubrum and to observe the effect of mutations in the cooc, coot, and cooj genes on (63)ni(2+) transport and accumulation. cells grown either in the presence or absence of co transported ni(2+) with a k(m) of 19 +/- 4 microm and a v(max) of 310 +/- 22 pmol of ni/min/mg of total protein. i ... | 1999 | 10419953 |
| identification of genes unique to mo-independent nitrogenase systems in diverse diazotrophs. | a number of nitrogen-fixing bacteria were screened using pcr for genes (vnfg and anfg) unique to the v-containing nitrogenase (vnf) and the fe-only nitrogenase (anf) systems. products with sequences similar to that of vnfg were obtained from azotobacter paspali and azotobacter salinestris genomic dnas, and products with sequences similar to that of anfg were obtained from azomonas macrocytogenes, rhodospirillum rubrum, and azotobacter paspali dnas. phylogenetic analysis of the deduced amino acid ... | 1999 | 10420583 |
| disordered exciton model for the core light-harvesting antenna of rhodopseudomonas viridis. | in this work we explain the spectral heterogeneity of the absorption band (. biochim. biophys. acta. 1229:373-380), as well as the spectral evolution of pump-probe spectra for membranes of rhodopseudomonas (rps.) viridis. we propose an exciton model for the lh1 antenna of rps. viridis and assume that lh1 consists of 24-32 strongly coupled bchl b molecules that form a ring-like structure with a 12- or 16-fold symmetry. the orientations and pigment-pigment distances of the bchls were taken to be t ... | 1999 | 10423416 |
| recognition of target dna and transcription activation by the co-sensing transcriptional activator cooa. | cooa from rhodospirillum rubrum is a heme-based co-sensing transcriptional activator, in which co acts as a physiological effector. in this study, we examined the mechanism of site-specific recognition and transcriptional activation by cooa by elucidating the transcriptional activator activity of the mutant cooa proteins and the chimeric proteins derived from crp and cooa and the promoter activity of the mutant promoters. site-directed mutagenesis has revealed that arg(177), gln(178), and ser(18 ... | 1999 | 10425177 |
| conformation of bacteriochlorophyll molecules in photosynthetic proteins from purple bacteria. | fourier transform near-infrared resonance raman spectroscopy can be used to obtain information on the bacteriochlorophyll a (bchl a) molecules responsible for the redmost absorption band in photosynthetic complexes from purple bacteria. this technique is able to distinguish distortions of the bacteriochlorin macrocycle as small as 0.02 a, and a systematic analysis of those vibrational modes sensitive to bchl a macrocycle conformational changes was recently published [näveke et al. (1997) j. rama ... | 1999 | 10460167 |
| amino acid sequences of two high-potential iron-sulfur proteins (hipips) from the moderately halophilic purple phototrophic bacterium, rhodospirillum salinarum. | the amino acid sequences of two very different high-potential iron-sulfur protein (hipip) isozymes have been determined from the moderately halophilic purple phototrophic bacterium, rhodospirillum salinarum. iso-1 hipip, which is monomeric and contains 57 amino acid residues, is most similar to the thiobacillus ferrooxidans iron-oxidizing enzyme (45% identity and a 6-residue deletion). on the other hand, iso-2 hipip, which is isolated as an oligomer, contains a peptide chain with 54 amino acid r ... | 1999 | 10462450 |
| nmr characterization of the nadp(h)-binding domain of escherichia coli transhydrogenase: sequential assignment and global fold. | the soluble nadp(h)-binding domain of escherichia coli transhydrogenase (186 amino acids, 20.4 kda, rotational correlation time 14 ns) was characterized using nmr techniques. the global fold is similar to that of a classical dinucleotide-binding fold with six parallel beta-strands in a central sheet surrounded by helices and irregular structures, but is lacking both alphad and alphae. the substrate is bound in an extended conformation at the c-terminal end of the parallel beta-sheet and our data ... | 1999 | 10481061 |
| methanobacterium thermoautotrophicum encodes two multisubunit membrane-bound [nife] hydrogenases. transcription of the operons and sequence analysis of the deduced proteins. | two gene groups, designated energy converting hydrogenase a (eha) and energy converting hydrogenase b (ehb), each encoding a putative multisubunit membrane-bound [nife] hydrogenase, were identified in the genome of methanobacterium thermoautotrophicum. the length of the transcription units was determined using reverse transcription (rt)-pcr. the eha operon (12.5 kb) and the ehb operon (9.6 kb) were found to be composed of 20 and 17 open reading frames, respectively. competitive rt-pcr was used t ... | 1999 | 10491142 |
| probing the heme axial ligation in the co-sensing cooa protein with magnetic circular dichroism spectroscopy. | the combination of uv/visible/near-ir variable-temperature magnetic circular dichroism (vtmcd) and epr spectroscopies has been used to investigate the spin states and axial ligation of the heme group in oxidized, reduced, and co-bound reduced forms of the rhodospirillum rubrum co oxidation transcriptional activator protein (cooa) and its h77y and c75s variants. the energy of the porphyrin(pi)-to-fe(iii) charge-transfer band (8930 cm(-)(1)) and the presence of cysteinate s-to-fe(iii) charge-trans ... | 1999 | 10504250 |
| evidence for the stabilization of nadph relative to nadp(+) on the diii components of proton-translocating transhydrogenases from homo sapiens and from rhodospirillum rubrum by measurement of tryptophan fluorescence. | a unique trp residue in the recombinant diii component of transhydrogenase from human heart mitochondria (hsdiii), and an equivalent trp engineered into the diii component of rhodospirillum rubrum transhydrogenase (rrdiii.d155w), are more fluorescent when nadp(+) is bound to the proteins, than when nadph is bound. we have used this to determine the occupancy of the binding site during transhydrogenation reactions catalysed by mixtures of recombinant di from the r. rubrum enzyme and either hsdiii ... | 1999 | 10514549 |
| purification of p(ii) and p(ii)-ump and in vitro studies of regulation of glutamine synthetase in rhodospirillum rubrum. | the p(ii) protein from rhodospirillum rubrum was fused with a histidine tag, overexpressed in escherichia coli, and purified by ni(2+)-chelating chromatography. the uridylylated form of the p(ii) protein could be generated in e. coli. the effects on the regulation of glutamine synthetase by p(ii), p(ii)-ump, glutamine, and alpha-ketoglutarate were studied in extracts from r. rubrum grown under different conditions. p(ii) and glutamine were shown to stimulate the atp-dependent inactivation (adeny ... | 1999 | 10515945 |
| expression of p(ii) and glutamine synthetase is regulated by p(ii), the ntrbc products, and processing of the glnba mrna in rhodospirillum rubrum. | we have studied the transcription of the glnb and glna genes in rhodospirillum rubrum with firefly luciferase as a reporter enzyme. under nh(4)(+) and n(2) conditions, glnba was cotranscribed from a weak and a strong promoter. in nitrogen-fixing cultures, activity of the latter was highly enhanced by ntrc, but transcription from both promoters occurred under both conditions. there is no promoter controlling transcription of glna alone, supporting our proposal that the glna mrna is produced by pr ... | 1999 | 10515946 |
| characterization by mass spectrometry of poly(3-hydroxyalkanoates) produced by rhodospirillum rubrum from 3-hydroxyacids. | the sequence distributions of two microbial copolyesters obtained by fermentation of rhodospirillum rubrum, grown with 3-hydroxyhexanoic or 3-hydroxyheptanoic acids, were determined by analyzing the oligomers prepared by partial pyrolysis or partial methanolysis of these copolyesters using fast atom bombardment mass spectrometry (fab-ms). oligomers up to pentamers were identified in the case of partial pyrolysis and up to tetradecamers in the case of partial methanolysis. the comparison between ... | 1999 | 10517530 |
| h+ -ppases: a tightly membrane-bound family. | the earliest known h+-ppase (proton-pumping inorganic pyrophosphatase), the integrally membrane-bound h+-ppi synthase (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+-ppase genes has led to the recognition that the corresponding proteins form a family of extremely similar proton-pumping enzymes. the bacterial h+-ppi synthase a ... | 1999 | 10523139 |
| reduction of selenite and detoxification of elemental selenium by the phototrophic bacterium rhodospirillum rubrum. | the effect of selenite on growth kinetics, the ability of cultures to reduce selenite, and the mechanism of detoxification of selenium were investigated by using rhodospirillum rubrum. anoxic photosynthetic cultures were able to completely reduce as much as 1. 5 mm selenite, whereas in aerobic cultures a 0.5 mm selenite concentration was only reduced to about 0.375 mm. the presence of selenite in the culture medium strongly affected cell division. in the presence of a selenite concentration of 1 ... | 1999 | 10543779 |
| a thermostable vacuolar-type membrane pyrophosphatase from the archaeon pyrobaculum aerophilum: implications for the origins of pyrophosphate-energized pumps. | vacuolar-type h(+)-translocating pyrophosphatases (v-ppases) have been considered to be restricted to plants, a few species of phototrophic proteobacteria and protists. here, we describe pvp, a thermostable, sequence-divergent v-ppase from the facultatively aerobic hyperthermophilic archaeon pyrobaculum aerophilum. pvp shares only 38% sequence identity with both the prototypical v-ppase from arabidopsis thaliana and the h(+)-ppi synthase from rhodospirillum rubrum, yet possesses most of the stru ... | 1999 | 10556526 |
| certain species of the proteobacteria possess unusual bacteriochlorophyll a environments in their light-harvesting proteins. | in this work, we have examined, using fourier-transform raman (ft-r) spectroscopy, the bacteriochlorophyll a (bchl a) binding sites in light-harvesting (lh) antennae from different species of the proteobacteria that exhibit unusal absorption properties. while the lh1 complexes from erythromicrobium (e.) ramosum (rc-b871) and rhodospirillum centenum (b875) present classic ft-r spectra in the carbonyl high-frequency region, we show that in the blue-shifted lh1 complex, absorbing at 856 nm, from ro ... | 1999 | 10604286 |
| mutations in the beta-subunit thr(159) and glu(184) of the rhodospirillum rubrum f(0)f(1) atp synthase reveal differences in ligands for the coupled mg(2+)- and decoupled ca(2+)-dependent f(0)f(1) activities. | in the crystal structure of the mitochondrial f(1)-atpase, the beta-thr(163) residue was identified as a ligand to mg(2+) and the beta-glu(188) as directly involved in catalysis. we replaced the equivalent beta-thr(159) of the chromatophore f(0)f(1) atp synthase of rhodospirillum rubrum with ser, ala, or val and the glu(184) with gln or lys. the mutant beta subunits were isolated and tested for their capacity to assemble into a beta-less chromatophore f(0)f(1) and restore its lost activities. al ... | 2000 | 10625625 |
| hybrid rhodospirillum rubrum f(0)f(1) atp synthases containing spinach chloroplast f(1) beta or alpha and beta subunits reveal the essential role of the alpha subunit in atp synthesis and tentoxin sensitivity. | trace amounts ( approximately 5%) of the chloroplast alpha subunit were found to be absolutely required for effective restoration of catalytic function to licl-treated chromatophores of rhodospirillum rubrum with the chloroplast beta subunit (avital, s., and gromet-elhanan, z. (1991) j. biol. chem. 266, 7067-7072). to clarify the role of the alpha subunit in the rebinding of beta, restoration of catalytic function, and conferral of sensitivity to the chloroplast-specific inhibitor tentoxin, licl ... | 2000 | 10625626 |
| electronic absorption, epr, and resonance raman spectroscopy of cooa, a co-sensing transcription activator from r. rubrum, reveals a five-coordinate no-heme. | electronic absorption, epr, and resonance raman spectroscopies revealed that cooa, the co-sensing transcriptional regulator from rhodospirillum rubrum, reacts with no to form a five-coordinate no-heme. no must therefore displace both of the heme ligands from six-coordinate, low-spin fe(ii)cooa in forming five-coordinate fe(ii)cooa(no). co, in contrast, displaces a single heme ligand from fe(ii)cooa to form six-coordinate fe(ii)cooa(co). of a series of common heme-binding ligands, only co and no ... | 2000 | 10631000 |
| mutagenesis and functional characterization of the glnb, glna, and nifa genes from the photosynthetic bacterium rhodospirillum rubrum. | nitrogen fixation is tightly regulated in rhodospirillum rubrum at two different levels: transcriptional regulation of nif expression and posttranslational regulation of dinitrogenase reductase by reversible adp-ribosylation catalyzed by the drat-drag (dinitrogenase reductase adp-ribosyltransferase-dinitrogenase reductase-activating glycohydrolase) system. we report here the characterization of glnb, glna, and nifa mutants and studies of their relationship to the regulation of nitrogen fixation. ... | 2000 | 10648524 |
| regulation of dinitrogenase reductase adp-ribosyltransferase and dinitrogenase reductase-activating glycohydrolase by a redox-dependent conformational change of nitrogenase fe protein. | the nitrogenase-regulating enzymes dinitrogenase reductase adp-ribosyltransferase (drat) and dinitrogenase reductase-activating glycohydrolase (drag), from rhodospirillum rubrum, were shown to be sensitive to the redox status of the [fe(4)s(4)](1+/2+) cluster of nitrogenase fe protein from r. rubrum or azotobacter vinelandii. drag had <2% activity with oxidized r. rubrum fe protein relative to activity with reduced fe protein. the activity of drag with oxygen-denatured fe protein or a low molecu ... | 2000 | 10652344 |
| exchanging cofactors in the core antennae from purple bacteria: structure and properties of zn-bacteriopheophytin-containing lh1. | the core light-harvesting lh1 complex of rhodospirillum rubrum consists of an assembly of membrane-spanning alpha and beta polypeptides, each of which binds one bacteriochlorophyll (bchl) a molecule. in this work, we describe a technique that allows the replacement of the natural, mg bchl a cofactors present in this protein by zn-bacteriopheophytin (zn-bpheo). this technique makes use of the well-characterized, reversible dissociation of lh1 induced by the detergent beta-octylglucoside. incubati ... | 2000 | 10653655 |
| role of the h protein in assembly of the photochemical reaction center and intracytoplasmic membrane in rhodospirillum rubrum. | rhodospirillum rubrum is a model for the study of membrane formation. under conditions of oxygen limitation, this facultatively phototrophic bacterium forms an intracytoplasmic membrane that houses the photochemical apparatus. this apparatus consists of two pigment-protein complexes, the light-harvesting antenna (lh) and photochemical reaction center (rc). the proteins of the photochemical components are encoded by the puf operon (lhalpha, lhbeta, rc-l, and rc-m) and by puha (rc-h). r. rubrum pu ... | 2000 | 10671438 |
| relative orientation of the hemes of the cytochrome bc(1) complexes from rhodobacter sphaeroides, rhodospirillum rubrum, and beef heart mitochondria. a linear dichroism study. | the orientation of the chromophores in the cytochrome bc(1) of rhodospirillum rubrum, rhodobacter sphaeroides, and beef heart mitochondria is reported. the combination of redox-resolved absorption spectrophotometry and linear dichroism experiments at low temperature allows the determination of the orientation of the three hemes with respect to the membrane plane. the orientations of the b(h)-and b(l)-hemes of the r. sphaeroides and beef heart mitochondrial complexes are similar to those determin ... | 2000 | 10681500 |
| escape probability and trapping mechanism in purple bacteria: revisited. | despite intensive research for decades, the trapping mechanism in the core complex of purple bacteria is still under discussion. in this article, it is attempted to derive a conceptionally simple model that is consistent with all basic experimental observations and that allows definite conclusions on the trapping mechanism. some experimental data reported in the literature are conflicting or incomplete. therefore we repeated two already published experiments like the time-resolved fluorescence d ... | 2000 | 10692545 |
| a novel covalent modification of nitrogenase in a cyanobacterium. | in extracts of the unicellular cyanobacterium gloeothece, the fe-protein of nitrogenase can be separated by sds-page into two antigenically identifiable components. unlike the situation in photosynthetic bacteria such as rhodospirillum rubrum, these two forms do not arise from covalent modification of the protein by adp-ribosylation. rather, the fe-protein of gloeothece nitrogenase is subjected to modification by palmitoylation. | 2000 | 10692592 |
| dos, a heme-binding pas protein from escherichia coli, is a direct oxygen sensor. | a direct sensor of o(2), the dos protein, has been found in escherichia coli. previously, the only biological sensors known to respond to o(2) by direct and reversible binding were the fixl proteins of rhizobia. a heme-binding region in dos is 60% homologous to the o(2)-sensing pas domain of the fixl protein, but the remainder of dos does not resemble fixl. specifically, the c-terminal domain of dos, presumed to be a regulatory partner that couples to its heme-binding domain, is not a histidine ... | 2000 | 10704219 |
| characterization and cloning of an (r)-specific trans-2,3-enoylacyl-coa hydratase from rhodospirillum rubrum and use of this enzyme for pha production in escherichia coli. | an (r)-trans-2,3-enoylacyl-coa hydratase was purified to near-homogeneity from rhodospirillum rubrum. protein sequencing of enriched protein fractions allowed the construction of a degenerate oligonucleotide. the gene encoding the (r)-specific hydratase activity was cloned following three rounds of colony hybridization using the oligonucleotide, and overexpression of the gene in e. coli led to the purification of the enzyme to homogeneity. the purified enzyme used crotonyl-coa, trans-2,3-penteno ... | 2000 | 10709984 |
| control of cooa activity by the mutation at the c-terminal end of the heme-binding domain. | a constitutively active mutant of a cooa, in which met131 was replaced by leu, was isolated by random mutagenesis. site-directed mutagenesis at position 131 revealed that m131r-cooa was also constitutively active even in the absence of co and that m131p-, m131d-, and m131e-cooa were constitutively inactive regardless of the presence or absence of co. while m131l- and m131e-cooa showed almost the same electronic absorption spectra as those of the wild type in the ferric, ferrous, and co-bound for ... | 2000 | 10714706 |
| stopped-flow reaction kinetics of recombinant components of proton-translocating transhydrogenase with physiological nucleotides. | new information on the high resolution structure of the membrane proton pump, transhydrogenase, now provides a framework for understanding kinetic descriptions of the enzyme. here, we have studied redox reactions catalyzed by mixtures of the recombinant nad(h)-binding component (di) of rhodospirillum rubrum transhydrogenase, and the recombinant nadp(h)-binding component (diii) of either the r. rubrum enzyme or the human enzyme. by recording changes in the fluorescence emission of native and engi ... | 2000 | 10747934 |
| modeling photoheterotrophic growth kinetics of rhodospirillum rubrum inrectangular photobioreactors. | based on a previously established model for radiant light transfer in photobioreactors (pbr), taking into account absorption and scattering of light, a new knowledge model for coupling radiant light energy available and local growth kinetics in pbrs for the photoheterotrophic bacteria rhodospirillum rubrum is discussed. a revised method is presented for the calculation of the absorption and scattering coefficients. the specific characteristics of the electron-transfer chains in such microorganis ... | 2000 | 10753444 |
| the solution structure of rhodobacter sphaeroides lh1beta reveals two helical domains separated by a more flexible region: structural consequences for the lh1 complex. | here, the solution structure of the rhodobacter sphaeroides core light-harvesting complex beta polypeptide solubilised in chloroform:methanol is presented. the structure, determined by homonuclear nmr spectroscopy and distance geometry, comprises two alpha helical regions (residue -34 to -15 and -11 to +6, using the numbering system in which the conserved histidine residue is numbered zero) joined by a more flexible four amino acid residue linker. the c-terminal helix forms the membrane spanning ... | 2000 | 10756106 |
| adp-ribosylation of variants of azotobacter vinelandii dinitrogenase reductase by rhodospirillum rubrum dinitrogenase reductase adp-ribosyltransferase. | in a number of nitrogen-fixing bacteria, nitrogenase is posttranslationally regulated by reversible adp-ribosylation of dinitrogenase reductase. the structure of the dinitrogenase reductase from azotobacter vinelandii is known. in this study, mutant forms of dinitrogenase reductase from a. vinelandii that are affected in various protein activities were tested for their ability to be adp-ribosylated or to form a complex with dinitrogenase reductase adp-ribosyltransferase (drat) from rhodospirillu ... | 2000 | 10762264 |
| induction of carbon monoxide dehydrogenase to facilitate redox balancing in a ribulose bisphosphate carboxylase/oxygenase-deficient mutant strain of rhodospirillum rubrum. | a ribulose-1,5-bisphosphate carboxylase/oxygenase-deficient mutant strain (strain i-19) of rhodospirillum rubrum was capable of growth under photoheterotrophic conditions in the absence of exogenous electron acceptors. these results suggested that alternative means of removing reducing equivalents have been acquired that allow this strain to remove reducing equivalents in the absence of a functional calvin-benson-bassham reductive pentose phosphate pathway. previously, the proton-reducing activi ... | 2000 | 10763751 |
| interaction of photosynthetic pigments with various organic solvents 2. application of magnetic circular dichroism to bacteriochlorophyll a and light-harvesting complex 1. | magnetic circular dichroism (mcd) and absorption spectra of metal bacteriochlorin complexes have been measured on bacteriochlorophyll (bchl) a in various solvents and different forms of light-harvesting complexes 1 (lh1 complexes). in hydrophilic organic solvents, the mcd intensity of the q(y)(0-0) transition of bchl a was sensitive to the wavelength of absorption maximum of q(x)(0-0), and the ratio of mcd q(y)(0-0) intensity to the dipole strength (b/d) was inversely proportional to the differe ... | 2000 | 10773156 |
| organization of the pigment molecules in the chlorophyll a/b/c containing alga mantoniella squamata (prasinophyceae) studied by means of absorption, circular and linear dichroism spectroscopy. | in order to obtain information on the organization of the pigment molecules in chlorophyll (chl) a/b/c-containing organisms, we have carried out circular dichroism (cd), linear dichroism (ld) and absorption spectroscopic measurements on intact cells, isolated thylakoids and purified light-harvesting complexes (lhcs) of the prasinophycean alga mantoniella squamata. the cd spectra of the intact cells and isolated thylakoids were predominated by the excitonic bands of the chl a/b/c lhc. however, so ... | 2000 | 10773164 |
| axenic cultivation of anoxygenic phototrophic bacteria, cyanobacteria, and microalgae in a new closed tubular glass photobioreactor. | a low-cost closed tubular glass photobioreactor allowing axenic cultivation of phototrophic microorganisms was constructed. standard glass tubes were arranged in a helical array providing a working volume of 80 1. the glass tubes were connected with a degassing chamber, which also provided ports for measuring and regulating oxygen supply, ph, foam, and optical density and for adding substrates and antifoam agents as well as disposing of vent gas. a pump module allowed agitation of the medium in ... | 2000 | 10803892 |
| sequence of pha synthase gene from two strains of rhodospirillum rubrum and in vivo substrate specificity of four pha synthases across two heterologous expression systems. | a 3.0-kb genomic fragment has been isolated from rhodospirillum rubrum (atcc 25903) that contains an open reading frame (orf) with strong homology to other known polyhydroxyalkanoate (pha) synthase genes. this orf has lower homology to the r. rubrum strain ha pha synthase than would be expected within the same species. we have conducted a series of heterologous expression studies evaluating the in vivo substrate specificity of pha synthase genes from rhodobacter sphaeroides, ralstonia eutropha ( ... | 2000 | 10803898 |
| [dark metabolism of acetate in rhodospirillum rubrum cells, grown under photoheterotropic conditions]. | the mechanism of the dark assimilation of acetate in the photoheterotrophically grown nonsulfur bacterium rhodospirillum rubrum was studied. both in the light and in the dark, acetate assimilation in rsp. rubrum cells, which lack the glyoxylate pathway, was accompanied by the excretion of glyoxylate into the growth medium. the assimilation of propionate was accompanied by the excretion of pyruvate. acetate assimilation was found to be stimulated by bicarbonate, pyruvate, the c4-dicarboxylic acid ... | 2000 | 10808482 |
| interactions between the soluble domain i of nicotinamide nucleotide transhydrogenase from rhodospirillum rubrum and transhydrogenase from escherichia coli. effects on catalytic and h+-pumping activities. | nicotinamide nucleotide transhydrogenase from escherichia coli is composed of two subunits, the alpha and the beta subunits, each of which contains a hydrophilic domain, domain i and iii, respectively, as well as several transmembrane helices, collectively denoted domain ii. the interactions between domain i from rhodospirillum rubrum (rri) and the intact or the protease-treated enzyme from e. coli was investigated using the separately expressed and purified domain i from r. rubrum, and his-tagg ... | 2000 | 10824114 |