naphxhylmercaptobenzoquinone, a new inhibitor of photophosphorylation in rhodospirillum rubrum chromatophores at the level of ubiquinone. 1976826250
[regulation of citrate synthese in bacteria: comparison of the action of various effectors on the enzymes of rhodospirillum rurbum and bacillus stearothermophilus].a comparative study of the citrate synthases purified from the facultatively photosynthetic bacterium rhodospirillum rubrum (gram negative) and the thermophile bacillus stearothermophilus (gram positive) was made. the citrate synthase from r. rubrum was activated by kcl (6-fold at 0.1 m kcl) and, less effectively, by nacl and nh4cl. its molecular weight was about 300,000. the enzyme was strongly inhibited by nadh, and this inhibition was counteracted by amp. the citrate synthase from b. stearoth ...1976826987
interrelationships among excited states in bacterial reaction centers. 1976830043
base competition of dna isolated from thiobacillus ferrooxidans grown on different substrates.the present study indicates some anomalies with respect to the dna base composition of thiobacillus ferrooxidans when it is cultured on different substrates. the % gc of the dna of this bacterium has been calculated by three different methods (melting temperature, cscl density gradient centrifugation and ultra-violet absorbancy ratios) using escherichia coli and rhodospirillum rubrum as references. the main values for t. ferrooxidans grown on ferrous iron, chalcopyrite and lead sulfide concentra ...1976981743
[bacteriochlorophyll fluorescence changes related to the bacteriopheophytin photoreduction in the chromatophores of purple sulfur bacteria].it is shown that illumination of chromatophores of sulfur bacterium chromatium minutissimum at eh of the medium --200 mv divided by --620 mv (when the photooxidation of pigment p890 is completely inhibited) induces a decrease in bacteriochlorophyll fluorescence yield, reversible in the dark. under these conditions a reversible photoreduction of bacteriopheophytin is detected (bleaching of absorption bands at 543 and 760 nm and development of a band at 650 nm), which is accompanied by a blue shif ...19761024595
absolute configuration of 3-hydroxy fatty acids present in lipopolysaccharides from various bacterial groups.the absolute configuration of 3-hydroxy fatty acids has been studied, which are present in the lipopolysaccharides of the following bacteria: phodopseudomonas gelatinosa, rh. viridis, rhodospirillum tenue, chromobacterium violaceum, pseudomonas aeruginosa, bordetella pertussis, vibrio metchnikovii, vibrio cholerae, salmonella spp., escherichia coli, shigella flexneri, proteus mirabilis, yersinia enterocolitica and fusobacterium nucleatum. the 3-hydroxy acids were liberated by strong alkaline hyd ...19761278168
mg2+ is an essential activator of hydrolytic activity of membrane-bound pyrophosphatase of rhodospirillum rubrum.the substrate for the hydrolytic activity of membrane-bound pyrophosphatase is the pp(i)-mg2+ complex. the enzyme has no activity when the free mg2+ concentration is lower than 10 microm (at 0.5 mm-pp(i)-mg2+), and therefore free mg2+ is an essential activator of the hydrolytic activity. the km for the substrate changes in response to variation in free mg2+ concentration, from 10.25 to 0.6 mm when free mg2+ is increased from 0.03 to 1.0 mm respectively. the km for mg2+ depends on the substrate c ...19921315519
three-dimensional structure of ferricytochrome c' from rhodospirillum rubrum at 2.8 a resolution.the structure of ferricytochrome c' extracted from rhodospirillum rubrum has been determined by the x-ray crystallographic method. crystals in hexagonal space group p6(1), with unit-cell dimensions a = b = 51.72 a and c = 155.49 a, contain one dimer molecule composed of chemically identical polypeptide chains (monomer i and monomer ii) per asymmetric unit. an electron density map has been calculated at a resolution of 2.8 a by the multiple isomorphous replacement method using four-circle diffrac ...19921316891
isolation and characterisation of a functional alpha beta heterodimer from the atp synthase of rhodospirillum alpha beta heterodimer of the f1-atpase of rhodospirillum rubrum was isolated by extraction of chromatophores with licl. each alpha beta heterodimer contains one tightly bound adp, which is released upon removal of medium mg2+. the dimer can be reversibly dissociated by removal of mg(2+)-ions. the alpha beta heterodimer restores both atp-synthetic and -hydrolytic activities to licl-treated chromatophores, saturation being achieved at approximately 2 mmol alpha beta.mol bchl-1. the heterodimer ...19921327870
evidence of an essential carboxyl residue in membrane-bound pyrophosphatase of rhodospirillum rubrum.chemical modifications with water-soluble carbodiimides (edc and cmc) were performed to elucidate whether some carboxyl residues are involved in the catalytic activity of membrane-bound pyrophosphatase of rhodospirillum rubrum. edc and cmc cause a loss of hydrolytic activity following pseudo-first-order kinetics up to 10 min of reaction. the enzyme was completely protected against edc inhibition by ppi or mg2+, whereas ppi or mg2+ gave partial protection against cmc inactivation. mg-ppi protecte ...19921334073
conformational states of ribulosebisphosphate carboxylase and their interaction with chaperonin 60.conformational states of ribulosebisphosphate carboxylase (rubisco) from rhodospirillum rubrum were examined by far-uv circular dichroism (cd), tryptophan fluorescence, and 1-anilino-naphthalenesulfonate (ans) binding. at ph 2 and low ionic strength (i = 0.01), rubisco adopts an unfolded, monomeric conformation (ua1 state) as judged by far-uv cd and tryptophan fluorescence. as with other acid-unfolded proteins [goto, y., calciano, l. j., & fink, a. l. (1990) proc. natl. acad. sci. u.s.a. 87, 573 ...19921348956
purified chaperonin 60 (groel) interacts with the nonnative states of a multitude of escherichia coli vitro experiments employing the soluble proteins from escherichia coli reveal that about half of them, in their unfolded or partially folded states, but not in their native states, can form stable binary complexes with chaperonin 60 (groel). these complexes can be isolated by gel filtration chromatography and are efficiently discharged upon the addition of mg.atp. binary complex formation is substantially reduced if chaperonin 60 is presaturated with rubisco-i, the folding intermediate of rub ...19921363913
nucleotide sequence of cdna clones encoding the beta subunit of mitochondrial atp synthase from the green alga chlamydomonas reinhardtii: the precursor protein encoded by the cdna contains both an n-terminal presequence and a c-terminal extension.cdna and genomic clones encoding the beta subunit of mitochondrial atp synthase from chlamydomonas reinhardtii have been isolated using heterologous dna probes from the photosynthetic bacterium rhodospirillum rubrum. the protein encoded by the cdna is 79-83% identical to corresponding proteins from higher-plant and mammalian mitochondria, and 75% identical to the r. rubrum protein. it contains both an n-terminal presequence and a unique c-terminal extension. the presequence, which is the first m ...19921386535
tentoxin sensitivity of chloroplasts determined by codon 83 of beta subunit of proton-atpase.tentoxin is a naturally occurring phytotoxic peptide that causes seedling chlorosis and arrests growth in sensitive plants and algae. in vitro, it inhibits activity of the beta subunit of the plastid proton-adenosine triphosphatase (atpase) from sensitive species. plastid atpb genes from six closely related, tentoxin-sensitive or -resistant nicotiana species differ at codon 83, according to their response to the toxin: glutamate correlated with resistance and aspartate correlated with sensitivit ...19921387730
in vitro activation of dinitrogenase reductase from the cyanobacterium anabaena variabilis (atcc 29413).nitrogenase of the heterocystous cyanobacterium anabaena variabilis was inactivated in vivo (s. reich, h. almon, and p. böger, fems microbiol. lett. 34:53-56, 1986). partially purified and modified (inactivated) dinitrogenase reductase (fe-protein) of such cells was reactivated by isolated membrane fractions of a. variabilis or of rhodospirillum rubrum, and acetylene reduction was measured. reactivation requires atp, mg2+, and mn2+. the activating principle is localized in the heterocyst and was ...19921400166
prokaryotic triterpenoids: o-alpha-d-glucuronopyranosyl bacteriohopanetetrol, a novel hopanoid from the bacterium rhodospirillum rubrum.a novel hopanoid bearing a glucuronopyranosyl residue linked via an alpha-glycosidic bond to the hydroxyl group of c-35 in bacteriohopanetetrol was isolated, from the type strain of rhodospirillum rubrum as well as from a mutant lacking blue carotenoid.19921417769
surface-enhanced raman scattering spectroscopy of photosynthetic membranes and complexes. 19921435308
[the evolutionary changes in the amino acid sequences and properties of the atp-synthase in chloroplasts, mitochondria and bacteria].studies have been made on atpase from chloroplasts, cyanobacteria and mitochondria of higher plants and animals. no intraspecies and interspecies variability of chloroplast and mitochondrial atpase was found with respect to ph optimum of the activity, to specificity to cations as substrate components, to sensitivity to stimulating and inhibiting anions and ethanol, to optimal stimulating ethanol concentration. intergenus variation of these properties of atpase from chloroplasts, plant mitochondr ...19921441793
conservation of the photosynthesis gene cluster in rhodospirillum centenum.intraspecies and intergenus complementation analysis were utilized to demonstrate that photosynthesis genes are clustered in distantly related purple photosynthetic bacteria. specifically, we show that the linkage order for genes involved in bacteriochlorophyll and carotenoid biosynthesis in rhodospirillum centenum are arranged essentially as in rhodobacter capsulatus and rhodobacter sphaeroides. in addition, the location and relative distance observed between the puf and puh operons which encod ...19921447976
restoration of the wild-type locus in an rubp carboxylase/oxygenase mutant of synechocystis pcc 6803 via targeted gene recombination.the interaction between homologous dna sequences, distant from each other in the chromosome, was examined in the cyanobacterium synechocystis pcc 6803. most of the rbcl gene encoding the large subunit of ribulose bisphosphate carboxylase/oxygenase (rubisco) was duplicated in the genome by a targeted insertion of a 3'-truncated gene copy into the psb a-i locus. both rbcl genes, in the psb a-i region and at the rbc locus, were non-functional; the former due to the 3' truncation, and the latter due ...19921465099
molecular basis for biosynthesis and accumulation of polyhydroxyalkanoic acids in bacteria.the current knowledge on the structure and on the organization of polyhydroxyalkanoic acid (pha)-biosynthetic genes from a wide range of different bacteria, which rely on different pathways for biosynthesis of this storage polyesters, is provided. molecular data will be shown for genes of alcaligenes eutrophus, purple non-sulfur bacteria, such as rhodospirillum rubrum, purple sulfur bacteria, such as chromatium vinosum, pseudomonads belonging to rrna homology group i, such as pseudomonas aerugin ...19921476773
cloning of poly(3-hydroxybutyric acid) synthase genes of rhodobacter sphaeroides and rhodospirillum rubrum and heterologous expression in alcaligenes eutrophus.from genomic libraries of the purple non-sulfur bacteria rhodospirillum rubrum ha and rhodobacter sphaeroides atcc 17023 in the broad-host range cosmid pvk100, we cloned a 15- and a 14-kbp hindiii restriction fragment, respectively. each of these fragments restored the ability to accumulate poly(3-hydroxybutyrate) (phb), in the phb-negative mutant alcaligenes eutrophus phb-4. these hybrid cosmids also complemented phb-negative mutants derived from wild-type r. rubrum or r. sphaeroides. both frag ...19921499989
dynamics of energy transfer and trapping in the light-harvesting antenna of rhodopseudomonas low intensity picosecond absorption spectroscopy it is shown that the exciton lifetime in the light-harvesting antenna of rhodopseudomonas (rps.) viridis membranes with photochemically active reaction centers at room temperature is 60 +/- 10 ps. this lifetime reflects the overall trapping rate of the excitation energy by the reaction center. with photochemically inactive reaction centers, in the presence of p+, the exciton lifetime increases to 150 +/- 15 ps. prereducing the secondary electro ...19921504241
studies on the effect of nad(h) on nitrogenase activity in rhodospirillum rubrum.the effect of nad(p) and analogs of this nucleotide on nitrogenase activity in rhodospirillum rubrum has been studied. addition of nad+ to nitrogen fixing rsp. rubrum leads to inhibition of nitrogenase. nadp+ has the same effect but nadh or analogs modified in the nicotinamide portion do not cause inhibition. in contrast to ammonium ions, addition of nad+ leads to inhibition of nitrogenase in cells that have been n-starved under argon. the inhibitory effect of nad+ is more pronounced at lower li ...19921510568
purification and characterization of glutathione reductase from rhodospirillum rubrum.glutathione reductase (nad(p)h:gssg oxidoreductase ec was purified 1160-fold to homogeneity from the nonsulfurous purple bacteria rhodospirillum rubrum (wild type). specific activity of the pure preparation was 102 u/mg. the enzyme displayed a typical flavoprotein absorption spectrum with maxima at 274,365, and 459 nm and an absorbance ratio a280/a459 of 7.6. the amino acid analysis revealed an unusually high content of glycine and arginine residues. titration of the enzyme with 5,5'-d ...19921524433
enhanced co2/o2 specificity of a site-directed mutant of ribulose-bisphosphate carboxylase/oxygenase.the co2/o2 specificity factor of ribulose-bisphosphate carboxylase/oxygenase partially determines the efficiency of photosynthetic carbon assimilation. heretofore, engineered alterations of the enzyme have only decreased the selectivity for co2 utilization. we show that alanyl replacement of active-site ser-368 of the rhodospirillum rubrum carboxylase enhances the carboxylation selectivity approximately 1.6-fold over the wild-type level. this enhancement reflects a greater relative decline in ox ...19921551863
characterization of lhi- and lhi+ rhodobacter capsulatus pufa mutants.the nh2 termini of light-harvesting complex i (lhi) polypeptides alpha and beta of rhodobacter capsulatus are thought to be involved in the assembly of the lhi complex. for a more detailed study of the role of the nh2-terminal segment of the lhi alpha protein in insertion into the intracytoplasmic membrane (icm) of r. capsulatus, amino acids 6 to 8, 9 to 11, 12 and 13, or 14 and 15 of the lhi alpha protein were deleted. additionally, the hydrophobic stretch of the amino acids 7 to 11 was lengthe ...19921569029
role of asparagine-111 at the active site of ribulose-1,5-bisphosphate carboxylase/oxygenase from rhodospirillum rubrum as explored by site-directed mutagenesis.crystallographic studies of ribulose-1,5-bisphosphate carboxylase/oxygenase from rhodospirillum rubrum suggest that active-site asn111 interacts with mg2+ and/or substrate (lundqvist, t., and schneider, g. (1991) j. biol. chem. 266, 12604-12611). to examine possible catalytic roles of asn111, we have used site-directed mutagenesis to replace it with a glutaminyl, aspartyl, seryl, or lysyl residue. although the mutant proteins are devoid of detectable carboxylase activity, their ability to form a ...19921569095
cloning, sequencing, mutagenesis, and functional characterization of drat and drag genes from azospirillum brasilense.the azospirillum brasilense drat gene, encoding dinitrogenase reductase atp-ribosyltransferase, and drag gene, encoding dinitrogenase reductase activating glycohydrolase, were cloned and sequenced. two genes were contiguous on the a. brasilense chromosome and showed extensive similarity to the same genes from rhodospirillum rubrum. analysis of mutations introduced into the dra region on the a. brasilense chromosome showed that mutants affected in drat were incapable of regulating nitrogenase act ...19921577701
on the structure of the nickel/iron/sulfur center of the carbon monoxide dehydrogenase from rhodospirillum rubrum: an x-ray absorption spectroscopy study.the nickel/iron/sulfur center of the carbon monoxide dehydrogenase (carbon monoxide:(acceptor)oxidoreductase; ec enzyme from rhodospirillum rubrum (rr-codh) was studied by x-ray absorption spectroscopy at the ni k edge. extended x-ray absorption fine structure data show that the first ni coordination shell consists of 2 s atoms at 2.23 a and 2-3 n/o atoms at 1.87 a. the edge structure indicates a distorted tetrahedral or five-coordinate ni environment in both oxidized and reduced rr-co ...19921584775
mutation of asparagine 111 of rubisco from rhodospirillum rubrum alters the carboxylase/oxygenase specificity.the conserved asparagine 111 of ribulose-1,5-bisphosphate carboxylase/oxygenase from the photosynthetic bacteria rhodospirillum rubrum was identified as a candidate for a side-chain that might be involved in the carboxylase/oxygenase specificity. it was replaced by site-directed mutagenesis with aspartic acid, leucine, glutamine or glycine residues. the mutant enzymes exhibit a very low carboxylase activity compared with the wild-type enzyme. the values of km(rubp) and kcat for asn111----gly, th ...19921602488
electrostatic fields at the active site of ribulose-1,5-bisphosphate carboxylase.a macroscopic approach has been employed to calculate the electrostatic potential field of nonactivated ribulose-1,5-bisphosphate carboxylase and of some complexes of the enzyme with activator and substrate. the overall electrostatic field of the l2-type enzyme from the photosynthetic bacterium rhodospirillum rubrum shows that the core of the dimer, consisting of the two c-terminal domains, has a predominantly positive potential. these domains provide the binding sites for the negatively charged ...19921603801
substitution of asp193 to asn at the active site of ribulose-1,5-bisphosphate carboxylase results in conformational changes.the crystal structure of a mutant of ribulose bisphosphate carboxylase/oxygenase from rhodospirillium rubrum, where asp193, one of the ligands of the magnesium ion at the activator site, is replaced by asn, has been determined to a nominal resolution of 0.26 nm. the mutation of asp to asn induces both local and global conformation changes as follows. the side chain of asn193 moves away from the active site and interacts with main-chain oxygen of residue 165, located in the neighbouring strand be ...19921606957
the relation between the soluble factor associated with h(+)-transhydrogenase of rhodospirillum rubrum and the enzyme from mitochondria and escherichia coli.although in mitochondria, escherichia coli and rhodobacter capsulatus the h(+)-transhydrogenases are intrinsic membrane proteins, in rhodospirillum rubrum a water-soluble component (ths) and a membrane-bound component are together required for activity. ths was selectively removed from chromatophore membranes of rhs. rubrum and was purified to homogeneity by precipitation with (nh4)2so4 and ion-exchange, affinity dye and gel exclusion chromatography. the latter indicated an mr of approx. 74,000 ...19921610876
enhancement of carotenoid-to-chlorophyll singlet energy transfer by carotenoid-carotenoid interaction.the apparent quantum yield of singlet-singlet spirilloxanthin-to-bacteriochlorophyll a energy transfer increases linearly with the residual spirilloxanthin content in rhodospirillum rubrum membrane vesicles from which this carotenoid has been partially removed. since it has been previously shown that carotenoid-carotenoid interaction is a linear function of the residual spirilloxanthin level in the major pigment-protein complex of those vesicles (zurdo, j., r. m. lozano, c. fernandez-cabrera, an ...19921617133
direct electrochemical studies of hydrogenase and co dehydrogenase.the reduction potentials of two relatively high-molecular-mass enzymes were determined directly at an edge pyrolytic graphite electrode by using square-wave voltammetry. the equilibrium reduction potential versus standard hydrogen electrode was determined for clostridium pasteurianum hydrogenase i (e'0 = -377 +/- 10 mv; molecular mass 60 kda) and rhodospirillum rubrum carbon monoxide dehydrogenase (e'0 = -418 +/- 7 mv; molecular mass 62 kda). the reduction potential of each enzyme was ph-indepen ...19921637298
genetic and physiological characterization of the rhodospirillum rubrum carbon monoxide dehydrogenase system.a 3.7-kb dna region encoding part of the rhodospirillum rubrum co oxidation (coo) system was identified by using oligonucleotide probes. sequence analysis of the cloned region indicated four complete or partial open reading frames (orfs) with acceptable codon usage. the complete orfs, the 573-bp coof and the 1,920-bp coos, encode an fe/s protein and the ni-containing carbon monoxide dehydrogenase (codh), respectively. the four 4-cysteine motifs encoded by coof are typical of a class of proteins ...19921644755
functional size analysis of pyrophosphatase from rhodospirillum rubrum determined by radiation inactivation.a radiation inactivation technique was employed to determine the functional size of pyrophosphatase (ppase) from the chromatophores of rhodospirillum rubrum. the activities of hydrolysis and synthesis reactions of pyrophosphatase and its coupled proton translocation decayed in a simple exponential function with the increase of radiation dosages. d37 values of 5.2 +/- 0.7 and 5.8 +/- 0.8 mrads were obtained for pyrophosphate hydrolysis and its associated proton translocation yielding molecular ma ...19911645297
sequence variability in bacterial cytochromes c.cytochromes c are proteins that can be defined both phenotypically and by their possession of a characteristic sequence motif. many sequences from bacterial sources are known, and new ones are being reported every year. an analysis can be made as to what fraction of new sequences are members of already known classes or subclasses, and how many map into previously uninhabited regions of sequence space.19911646017
high-resolution 1h- and 15n-nmr studies of rhodospirillum rubrum cytochrome c2.rhodospirillum rubrum cytochrome c2 was uniformly enriched in 15n and studied by 1h- and 15n-nmr spectroscopy. relaxation and noe data allowed determination of the rotational correlation time and indicated more rapid side-chain motion in the native protein and increased segmental motion in the base-denatured protein. the pi nitrogen of the ligand histidine and the indolic nitrogen of the invariant tryptophan both remain protonated and act as proton-donors in hydrogen bonds over a wide ph range a ...19911646025
ligand binding properties of cytochromes c'.the cytochromes c' bind co, alkylisocyanides and cn- with rate and equilibrium constants which are 10(2)- to 10(6)-fold smaller than other high-spin hemoproteins. the decreased affinity for exogenous ligands is largely associated with steric interactions at the heme coordination site. while co and alkylisocyanides bind noncooperatively to the dimeric rhodospirillum molischianum cytochrome c', co, alkylisocyanides and cn- appear to bind cooperatively to the dimeric chromatium vinosum cytochrome c ...19911646027
the rhodospirillum rubrum cytochrome bc1 complex: redox properties, inhibitor sensitivity and proton pumping.a detergent-solubilized, three-subunit-containing cytochrome bc1 complex, isolated from the photosynthetic bacterium r. rubrum, has been shown to be highly sensitive to stigmatellin, myxothiazol, antimycin a and uhdbt, four specific inhibitors of these complexes. oxidation-reduction titrations have allowed the determination of em values for all the electron-carrying prosthetic groups in the complex. antimycin a has been shown to produce a red shift in the alpha-band absorbance maximum of one of ...19911646633
genetic analysis of photosynthesis in rhodospirillum centenum.a genetic system has been developed for studying bacterial photosynthesis in the recently described nonsulfur purple photosynthetic bacterium rhodospirillum centenum. nonphotosynthetic mutants of r. centenum were obtained by enrichment for spontaneous mutations, by ethyl methanesulfonate mutagenesis coupled to penicillin selection on solid medium, and by tn5 transposition mutagenesis with an incp plasmid vector containing a temperature-sensitive origin of replication. in vivo and in vitro charac ...19911648078
molecular structure of cytochrome c2 isolated from rhodobacter capsulatus determined at 2.5 a resolution.the molecular structure of the cytochrome c2, isolated from the purple photosynthetic bacterium rhodobacter capsulatus, has been solved to a nominal resolution of 2.5 a and refined to a crystallographic r-factor of 16.8% for all observed x-ray data. crystals used for this investigation belong to the space group r32 with two molecules in the asymmetric unit and unit cell dimensions of a = b = 100.03 a, c = 162.10 a as expressed in the hexagonal setting. an interpretable electron density map calcu ...19911651396
cytochrome c' of paracoccus denitrificans.cytochrome c' was identified in periplasmic extracts of the paracoccus denitrificans strains lmd 22.21 and lmd 52.44. the cytochrome c' was purified from the latter using the device of sequential molecular exclusion chromatography in the dimeric and monomeric states. although showing the overall spectroscopic features of the cytochrome c' family, the paracoccus cytochrome c' is unusual in having a red-shifted oxidised soret band at 407 nm. also unusual is the midpoint potential of 202 mv, well a ...19911653018
electrostatic effects on the kinetics of electron transfer reactions of cytochrome c caused by binding to negatively charged lipid bilayer vesicles.the effect of binding reduced tuna mitochondrial cytochrome c to negatively charged lipid bilayer vesicles at low ionic strength on the kinetics of electron transfer to various oxidants was studied by stopped-flow spectrophotometry. binding strongly stimulated (up to 100-fold) the rate of reaction with the positively charged cobalt phenanthroline ion, whereas the rate of reaction with the negatively charged ferricyanide ion was greatly inhibited (up to 60-fold), as compared with the same systems ...19911654779
electron transfer proteins of the purple phototrophic bacterium, rhodopseudomonas rutila.the soluble electron transfer protein content of rhodopseudomonas rutila was found to consist of two basic cytochromes and a (4fe-4s) ferredoxin. cytochrome c' was easily identified by its characteristic high spin absorption spectra. the native molecular weight is 29,000 and the subunit is 14,000. cytochrome c-550 has low spin absorption spectra and a high redox potential (376 mv) typical of cytochromes c2. the molecular weight is about 14,000. the ferredoxin is apparently a dimer (43,000) of ap ...19911654788
structural and functional features of pseudomonas cytochrome c peroxidase.the secondary structure of pseudomonas cytochrome c peroxidase (ferrocytochrome c: hydrogen-peroxide oxidoreductase, ec has been predicted from the established amino acid sequence of the enzyme using a chou-fasman-type algorithm. the amount of alpha-helicity thus obtained is in agreement with previously obtained results based on circular dichroic measurements at far uv. the two heme c moieties of the enzyme have earlier been shown to have widely different characteristics, e.g., the red ...19911657179
an improved tn7-based system for the single-copy insertion of cloned genes into chromosomes of gram-negative bacteria.a system is described for the single-copy, stable insertion of cloned dna sequences into the chromosomes of gram- bacteria. two narrow-host-range plasmids form the basis of this system: the 'carrier' plasmid contains the mini tn7-km transposon, into which foreign dna can be cloned; the 'helper' plasmid provides the tn7 transposition functions in trans. both plasmids are readily transferred into gram- bacteria by conjugation. the functionality of this system has been demonstrated in rhodospirillu ...19911661697
immunological cross-reactivity between proton-pumping inorganic pyrophosphatases of widely phylogenic separated species.immunological cross-reactivity among three types of inorganic pyrophosphatases, that is, the proton pumping inorganic pyrophosphate synthase (h(+)-ppi synthase) and the soluble inorganic pyrophosphatase, both from rhodospirillum rubrum, and the vacuolar membrane inorganic pyrophosphatase (h(+)-ppase) from mung bean (vigna radiata), were examined by means of immunoblot analyses. antibodies raised against the mung bean h(+)-ppase cross-reacted with the h(+)-ppi synthase from r. rubrum but not with ...19911662506
an electrochemical assay for the characterization of redox proteins from biological electron transfer chains.a sensitive and quick assay for redox proteins based on electrochemical titrations in a thin-layer electrochemical cell is described. using a combination of modified-electrode and "mediator-enhanced" electrochemistry, equilibration of the cell volume (4 microliters) with the applied potential allows series of spectra as a function of the potential to be recorded rapidly. a complete redox titration between +500 and -600 mv (vs ag/agcl/3 m kcl) in 30-mv intervals takes approximately 2 h. the detec ...19911667456
reactivation of the chloroplast cf1-atpase beta subunit by trace amounts of the cf1 alpha subunit suggests a chaperonin-like activity for cf1 alpha.incubation of tobacco and lettuce thylakoids with 2 m licl in the presence of mgatp removes the beta subunit from their cf1-atpase (cf1 beta) together with varying amounts of the cf1 alpha subunit (cf1 alpha). these 2 m licl extracts, as with the one obtained from spinach thylakoids (avital, s., and gromet-elhanan, z. (1991) j. biol. chem. 266, 7067-7072), could form active hybrid atpases when reconstituted into inactive beta-less rhodospirillum rubrum chromatophores. pure cf1 beta fractions tha ...19911673460
low- and high-activity forms of glutamine synthetase from rhodospirillum rubrum: sensitivity to feed-back effectors and activation of the low-activity form.glutamine synthetase from rhodospirillum rubrum can be isolated in two forms, with low and high activity, respectively, depending on the concentration of combined nitrogen in the medium before harvest. the two forms have been studied with respect to their dependence on mn2+ and mg2+ in both the transferase and the biosynthetic assay. there is no difference in ph optimum between the forms in the biosynthetic assay. in addition the ph-optima for the two cations studied are very close, 7.4 (mg2+) a ...19911683256
antigenic sites on cytochrome c2 from rhodospirillum rubrum.the antigenic determinants for three monoclonal antibodies against cytochrome c2 from rhodospirillum rubrum were partially characterized by differential chemical modification of free and antibody-bound cytochrome c2 and by cross-reactivity analysis with different antigens. circular dichroism spectroscopy was used to probe the effect of antibody binding on the conformation of cytochrome c2. the binding of two antibodies was strongly dependent on the native folding of the antigen. the first antibo ...19901688799
phylogenetic analysis and evolution of rnase p rna in proteobacteria.the secondary structures of the eubacterial rnase p rnas are being elucidated by a phylogenetic comparative approach. sequences of genes encoding rnase p rna from each of the recognized subgroups (alpha, beta, gamma, and delta) of the proteobacteria have now been determined. these sequences allow the refinement, to nearly the base pair level, of the phylogenetic model for rnase p rna secondary structure. evolutionary change among the rnase p rnas was found to occur primarily in four discrete str ...19911711030
construction, characterization, and complementation of rhodospirillum rubrum puf region mutants.rhodospirillum rubrum is a facultatively phototrophic bacterium that, under certain growth conditions, forms an intracytoplasmic chromatophore membrane (icm) housing the photochemical apparatus. the puf operon of r. rubrum encodes protein subunits of the photochemical reaction center and the b880 light-harvesting antenna complex. mutant strains of r. rubrum were constructed by interposon mutagenesis through which a kanamycin resistance gene cartridge was inserted into restriction sites and in pl ...19911715861
mutations affecting nitrogenase switch-off in rhodobacter vivo 'switch-off' and subsequent reactivation of nitrogenase activity in rhodobacter capsulatus or rhodospirillum rubrum in response to a variety of environmental stimuli, including the addition of fixed nitrogen, is thought to be due to the action of two nitrogenase fe protein modifying activities; drat (dinitrogenase reductase adp-ribosyl transferase) and drag (dinitrogenase reductase-activating glycohydrolase). here it is demonstrated that strains, including one mutated in glnb, that const ...19921730034
functional analysis of the putative catalytic bases his-321 and ser-368 of rhodospirillum rubrum ribulose bisphosphate carboxylase/oxygenase by site-directed mutagenesis.numerous candidates have been suggested according to chemical and structural criteria for the active site base of ribulose bisphosphate carboxylase/oxygenase that catalyzes substrate enolization. we evaluate the functional significance of two such candidates, his-321 and ser-368 of the rhodospirillum rubrum enzyme, by site-directed mutagenesis. position 321 mutants retain 3-12% of wild-type rates of both overall carboxylation and the initial enolization, with little effect on km for co2 or ribul ...19911761567
protein engineering of rubisco.modification of the kinetic parameters of enzymes by protein engineering requires extensive knowledge of the structural details of the enzyme and its complexes with different reaction intermediate analogues. such structural studies are described here for rubisco, ribulose-1,5-bisphosphate carboxylase/oxygenase, which catalyzes the initial reactions of two important but competing physiological events in green plants; carbon dioxide fixation and photorespiration. observed functional changes in mut ...19911772628
dna sequencing and complementation/deletion analysis of the bcha-puf operon region of rhodobacter sphaeroides: in vivo mapping of the oxygen-regulated puf promoter.within the photosynthetic gene cluster of rhodobacter sphaeroides the genes encoding light-harvesting lhi and reaction-centre complexes are transcriptionally linked in the order pufbalmx. the region stretching 1.6 kb upstream of pufb has been examined by dna sequencing and by complementation/deletion analysis. these studies demonstrate that three open reading frames are located upstream of pufb. one open reading frame, designated bcha, terminates just inside pufq, which is located proximal to pu ...19911779756
extraction and purification of the beta subunit and an active alpha beta-core complex from the spinach chloroplast cfof1-atp synthase.incubation of rhodospirillum rubrum chromatophores with 2 m licl in the presence of mgatp has been shown to remove their f1 beta subunit leaving inactive but fully reconstitutable beta-less chromatophores (gromet-elhanan, z., and khanashvili, d., (1986) methods enzymol, 126, 528-538). a similar treatment of thoroughly washed spinach thylakoids has now been shown to release the cf1 beta subunit (cf1 beta) together with a complex containing equal amounts of cf1 alpha and cf1 beta (cf1 (alpha beta] ...19911826683
proton-translocating transhydrogenase from photosynthetic bacteria. 19911838340
electron spin echo envelope modulation spectroscopy supports the suggested coordination of two histidine ligands to the rieske fe-s centers of the cytochrome b6f complex of spinach and the cytochrome bc1 complexes of rhodospirillum rubrum, rhodobacter sphaeroides r-26, and bovine heart mitochondria.electron spin echo envelope modulation (eseem) experiments performed on the rieske fe-s clusters of the cytochrome b6f complex of spinach chloroplasts and of the cytochrome bc1 complexes of rhodospirillum rubrum, rhodobacter sphaeroides r-26, and bovine heart mitochondria show modulation components resulting from two distinct classes of 14n ligands. at the g = 1.92 region of the rieske epr spectrum of the cytochrome b6f complex, the measured hyperfine couplings for the two classes of coupled nit ...19911847076
proton-pumping n,n'-dicyclohexylcarbodiimide-sensitive inorganic pyrophosphate synthase from rhodospirillum rubrum: purification, characterization, and reconstitution.a new method has been developed for the isolation of the proton-pumping n,n'-dicyclohexylcarbodiimide-sensitive ppi synthase (h(+)-ppi synthase) from chromatophores of rhodospirillum rubrum. the h(+)-ppi synthase was purified by extraction of chromatophores with a mixture of nonanoyl-n-methylglucamide and cholate, by fractionation with poly(ethylene glycol) 4000, hydroxyapatite chromatography, and affinity chromatography. the purified enzyme is homogeneous and has a specific activity of 20.4 mum ...19911848779
purification and properties of the h(+)-nicotinamide nucleotide transhydrogenase from rhodobacter capsulatus.1. h(+)-transhydrogenase from rhodobacter capsulatus is an integral membrane protein which, unlike the enzyme from rhodospirillum rubrum, does not require the presence of a water-soluble component for activity. 2. the enzyme from rb. capsulatus was solubilised in triton x-100 and subjected to ion-exchange, hydroxyapatite and then gel-exclusion column chromatography. sds/page of the purified enzyme revealed the presence of two polypeptides with apparent mr 53,000 and 48,000. other minor component ...19911849819
attenuated effect of oxygen on photopigment synthesis in rhodospirillum centenum.rhodospirillum centenum resembles typical nonsulfur photosynthetic bacteria in a number of respects, including its ability to grow either anaerobically as a phototroph or aerobically as a heterotroph. we demonstrate, however, that r. centenum is unusual in its ability to synthesize a functional photosynthetic apparatus regardless of the presence of molecular oxygen. aerobically expressed photopigments were shown to be functionally active, as demonstrated by the ability of heterotrophically grown ...19911885527
[the role of propionyl-coa carboxylase in the biosynthesis of antibiotics]. 19911892432
rapid purification and characterization of homoserine dehydrogenase from saccharomyces cerevisiae.homoserine dehydrogenase of saccharomyces cerevisiae has been rapidly purified to homogeneity by heat and acid treatments, ammonium sulfate fractionation, and chromatography on matrex gel red a and q-sepharose columns. the final preparation migrated as a single entity upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a mr of 40,000. the mr of the native enzyme was 81,000 as determined by gel filtration, suggesting that the enzyme is composed of two identical subunits. this feat ...19911897932
crystal structure of the ternary complex of ribulose-1,5-bisphosphate carboxylase, mg(ii), and activator co2 at 2.3-a resolution.the activated ternary complex, enzyme-co2-mg(ii), of the dimeric ribulose-1,5-bisphosphate carboxylase/oxygenase from rhodospirillum rubrum can be prepared in the same crystal form that was used for the crystallographic structure determination of the native nonactivated enzyme (schneider, g., bränden, c.-i., & lorimer, g. (1986) j. mol. biol. 187, 141-143). the three-dimensional structure of the activated enzyme has been determined to a nominal resolution of 2.3 a by protein crystallographic met ...19911899197
probing the primary quinone environment in photosynthetic bacterial reaction centers by light-induced ftir difference spectroscopy.the photoreduction of the primary electron acceptor, qa, has been characterized by light-induced fourier transform infrared difference spectroscopy for rb. sphaeroides reaction centers and for rsp. rubrum and rp. viridis chromatophores. the samples were treated both with redox compounds, which rapidly reduce the photooxidized primary electron p+, and with inhibitors of electron transfer from qa- to the secondary quinone qb. this approach yields spectra free from p and p+ contributions which make ...19911899390
expression of endogenous and foreign ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) genes in a rubisco deletion mutant of rhodobacter sphaeroides.a rhodobacter sphaeroides ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) deletion strain was constructed that was complemented by plasmids containing either the form i or form ii co2 fixation gene cluster. this strain was also complemented by genes encoding foreign rubisco enzymes expressed from a rhodospirillum rubrum rubisco promoter. in r. sphaeroides, the r. rubrum promoter was regulated, resulting in variable levels of disparate rubisco molecules under different growth conditions ...19911900508
dimeric carotenoid interaction in the light-harvesting antenna of purple phototrophic bacteria.the carotenoid content of intracytoplasmic membrane vesicles isolated from purple phototrophic bacteria was reduced to a variable extent by mild extraction with light petroleum. using preparations obtained from rhodobacter capsulatus strains that contained the light harvesting system i (lhi) complex as the only major photosynthetic holochrome, it was shown that the visible circular dichroism of the carotenoids increased with the square of the membrane carotenoid content, as expected from being c ...19911901490
the puh structural gene coding for the h subunit of the rhodospirillum rubrum photoreaction center.the rhodospirillum rubrum structural gene puh, coding for the photoreaction center h polypeptide, and three other putative genes that surround puh were cloned and sequenced. the deduced 257 amino acid h polypeptide has a molecular weight of 27,909, in close agreement with polyacrylamide gel electrophoresis determination. hydropathy plots predict a single hydrophobic alpha helix. the h polypeptide of rhodospirillum rubrum shares only 23% of its residues with all three of the h polypeptides from r ...19911903263
pyruvate is a by-product of catalysis by ribulosebisphosphate carboxylase/oxygenase.pyruvate is a minor product of the reaction catalyzed by ribulosebisphosphate carboxylase/oxygenase from spinach leaves. labeled pyruvate was detected, in addition to the major labeled product, 3-phosphoglycerate, when 14co2 was the substrate. pyruvate production was also measured spectrophotometrically in the presence of lactate dehydrogenase and nadh. the km for co2 of the pyruvate-producing activity was 12.5 microm, similar to the co2 affinity of the 3-phosphoglycerate-producing activity. no ...19911903385
demonstration of a functional requirement for the carbamate nitrogen of ribulosebisphosphate carboxylase/oxygenase by chemical rescue.ribulosebisphosphate carboxylase/oxygenase is reversibly activated by the reaction of co2 with a specific lysyl residue (lys191 of the rhodospirillum rubrum enzyme) to form a carbamate that coordinates an essential mg2+ cation. surprisingly, the lys191----cys mutant protein, in the presence of co2 and mg2+, exhibits tight binding of the reaction intermediate analogue 2-carboxyarabinitol bisphosphate [smith, h. b., larimer, f. w., & hartman, f. c. (1988) biochem. biophys. res. commun. 152, 579-58 ...19911903652
fluorescence polarization and low-temperature absorption spectroscopy of a subunit form of light-harvesting complex i from purple photosynthetic bacteria.measurements of polarized fluorescence and cd were made on light-harvesting complex 1 and a subunit form of this complex from rhodospirillum rubrum, rhodobacter sphaeroides, and rhodobacter capsulatus. the subunit form of lh1, characterized by a near-infrared absorbance band at approximately 820 nm, was obtained by titration of carotenoid-depleted lh1 complexes with the detergent n-octyl beta-d-glucopyranoside as reported by miller et al. (1987) [miller j. f., hinchigeri, s. b., parkes-loach, p. ...19911904275
crystal structure of activated ribulose-1,5-bisphosphate carboxylase complexed with its substrate, ribulose-1,5-bisphosphate.the three-dimensional structure of the complex of ribulose-1,5-bisphosphate carboxylase from rhodospirillum rubrum, co2, mg2+, and ribulose bisphosphate has been determined with x-ray crystallographic methods to 2.6-a resolution. ribulose-1,5-bisphosphate binds across the active site with the two phosphate groups in the two phosphate binding sites of the beta/alpha barrel. the oxygen atoms of the carbamate and the side chain of asp-193 provide the protein ligands to the bound mg2+ ion. the c2 an ...19911905726
identification of an alternative nitrogenase system in rhodospirillum rubrum.a second nitrogenase activity has been demonstrated in rhodospirillum rubrum. this nitrogenase is expressed whenever a strain lacks an active mo nitrogenase because of physiological or genetic inactivation. the alternative nitrogenase is able to support growth on n2 in the absence of fixed n. v does not stimulate, nor does mo or w inhibit, growth or activity under the conditions tested. the proteins responsible for this activity were identified by electrophoretic and immunological properties. th ...19911909322
glycine 100 in the dinitrogenase reductase of rhodospirillum rubrum is required for nitrogen fixation but not for adp-ribosylation.dinitrogenase reductase (rr2) is required for reduction of the molybdenum dinitrogenase in the nitrogen fixation reaction and is the target of posttranslational regulation in rhodospirillum rubrum. this posttranslational regulation involves the adp-ribosylation of rr2. to study the structural requirements for these two functions of rr2, i.e., activity and regulation, two site-directed mutations in nifh, the gene encoding rr2, were constructed and analyzed. the mutations both affected a region of ...19911917849
characterization of the co oxidation/h2 evolution system of rhodospirillum rubrum. role of a 22-kda iron-sulfur protein in mediating electron transfer between carbon monoxide dehydrogenase and hydrogenase.the response of the membrane-associated carbon monoxide dehydrogenase (codh) from rhodospirillum rubrum to solubilization by detergents and organic solvents, the properties of solubilized codh, and the mechanism for coupling co oxidation to hydrogen evolution via a co-induced hydrogenase activity have been investigated. the release of codh by a variety of ionic and nonionic detergents occurs in a redox-dependent fashion: codh is solubilized in the presence of low-potential reductants (dithionite ...19911917963
performance of trickle-bed bioreactors for converting synthesis gas to methane.carbon monoxide, h2, and co2 in synthesis gas can be converted to ch4 by employing a triculture of rhodospirillum rubrum, methanosarcina barkeri, and methanobacterium formicicum. trickle-bed reactors have been found to be effective for this conversion because of their high mass-transfer coefficients. this paper compares results obtained for the conversion of synthesis gas to ch4 in 5-cm- and 16.5-cm-diameter trickle-bed reactors. mass-transfer and scale-up parameters are defined, and light requi ...19911929378
cos degradation by selected co-utilizing bacteria. scientific note. 19911929384
purification and partial characterization of glutamate synthase from rhodospirillum rubrum grown under nitrogen-fixing conditions.glutamate synthase, a key enzyme in ammonia assimilation, has been purified from the photosynthetic bacterium rhodospirillum rubrum. the purification procedure involves ion-exchange chromatography, affinity chromatography and gel filtration. the recovery in the procedure is high (62%) and the specific activity is 21 mumol of nadph oxidized/min per mg. the enzyme is specific for its substrates, and no activity was demonstrated with nadh or nh4+ ions substituting for nadph and glutamine respective ...19911930133
purification and partial characterization of a pyruvate oxidoreductase from the photosynthetic bacterium rhodospirillum rubrum grown under nitrogen-fixing conditions.a pyruvate oxidoreductase with the capacity to support pyruvate-dependent nitrogenase activity in vitro has been purified from the photosynthetic bacterium rhodospirillum rubrum. the enzyme requires coa for activity and is irreversibly inactivated by oxygen. the molecular properties and km values for the substrates have been studied. in supporting nitrogenase activity addition of ferredoxin is required. overall the enzyme is similar to the nif-specific pyruvate: flavodoxin oxidoreductase purifie ...19911930134
mutations in the drat and drag genes of rhodospirillum rubrum result in loss of regulation of nitrogenase by reversible adp-ribosylation.reversible adp-ribosylation of dinitrogenase reductase forms the basis of posttranslational regulation of nitrogenase activity in rhodospirillum rubrum. this report describes the physiological effects of mutations in the genes encoding the enzymes that add and remove the adp-ribosyl moiety. mutants lacking a functional drat gene had no dinitrogenase reductase adp-ribosyltransferase (drat, the drat gene product) activity in vitro and were incapable of modifying dinitrogenase reductase with adp-ri ...19911938894
examination of the intersubunit interaction between glutamate-48 and lysine-168 of ribulose-bisphosphate carboxylase/oxygenase by site-directed mutagenesis.the active site of ribulose-bisphosphate carboxylase/oxygenase is constituted from domains of adjacent subunits and includes an intersubunit electrostatic interaction between lys 168 and glu48, which has been recently identified by x-ray crystallography (andersson, i., knight, s., schneider, g., lindqvist, y., lundqvist, t., brändén, c.-i., and lorimer, g.h. (1989) nature 337, 229-234; lundqvist, t., and schneider, g. (1989) j. biol. chem. 264, 7078-7083). to examine the structural and functiona ...19901969412
atp-dependent and nad-dependent modification of glutamine synthetase from rhodospirillum rubrum in vitro.glutamine synthetase from the photosynthetic bacterium rhodospirillum rubrum is the target of both atp- and nad-dependent modification. incubation of r. rubrum cell supernatant with [alpha-32p]nad results in the labeling of glutamine synthetase and two other unidentified proteins. dinitrogenase reductase adp-ribosyltransferase does not appear to be responsible for the modification of glutamine synthetase or the unidentified proteins. the [alpha-32p]atp- and [alpha-32p] nad-dependent modification ...19901974253
identification of a groes-like chaperonin in mitochondria that facilitates protein folding.mitochondria contain a polypeptide that is functionally equivalent to escherichia coli chaperonin 10 (cpn10; also known as groes). this mitochondrial cpn10 has been identified in beef and rat liver and is able to replace bacterial cpn10 in the chaperonin-dependent reconstitution of chemically denatured ribulose-1,5-bisphosphate carboxylase. thus, like the bacterial homologue, mitochondrial cpn10 facilitates a k(+)- and mg.atp-dependent discharge of unfolded (or partially folded) ribulose bisphos ...19901977163
the cloning and functional characterization of the nifh gene of rhodospirillum rubrum.dinitrogenase reductase (the nifh product) from rhodospirillum rubrum is regulated by a post-translational modification system encoded by dratg. as demonstrated in this report, the cloning, sequencing, and functional characterization of the nifh gene provides a basis for further analysis as well as revealing interesting features of gene organization. the coding regions of nifh and drat are separated by only 400 bp, though the genes are divergently transcribed and differentially regulated. the co ...19901979299
complementation of a pleiotropic nif-gln regulatory mutant of rhodospirillum rubrum by a previously unrecognized azotobacter vinelandii regulatory locus.a spontaneous pleiotropic nif- mutation in rhodospirillum rubrum has been partially characterized biochemically and by complementation analysis with recombinant plasmids carrying azotobacter vinelandii dna in the vicinity of orf12 [jacobson et al. (1989) j. bacteriol 171: 1017-1027]. in addition to being unable to grow on n2 as a nitrogen source the phenotypic characterization of this and other metronidazole enriched spontaneous mutants showed (a) no nitrogenase activity, (b) the absence of nifh ...19901980582
possible role of the highly conserved amino acids trp-8 and pro-13 in the n-terminal segment of the pigment-binding polypeptide lhi alpha of rhodobacter capsulatus.trp-8 and pro-13 of the rhodobacter capsulatus light-harvesting (lh) i alpha polypeptide are highly conserved among lhi and lhii alpha proteins of several species of the rhodospirillaceae. exchange of trp-8 and pro-13 to other amino acyl residues similar in structure and/or hydrophobicity indicates that trp-8 is involved in the insertion of the lhi alpha polypeptide into the intracytoplasmic membrane (icm). pro-13, however, seems not to participate in the integration process of the lhi alpha pro ...19912065784
isolation and characterization of a structural subunit from the core light-harvesting complex of rhodobacter sphaeroides 2.4.1 and puc705-ba.a method for isolating a structural subunit, b825, from the b875 core light-harvesting complex (lhc) of rhodobacter sphaeroides 2.4.1 (wild-type) and a b800-b850(-) mutant, puc705-ba, is presented. this method, based on one developed to prepare a similar subunit, b820, from the core lhc of rhodospirillum rubrum [miller et al., biochemistry 26, 5055-5062 (1987)], requires the dissociation of treated chromatophores with the detergent, octyl-glucoside. a subsequent gel filtration step separates b80 ...19902089436
cellular differentiation in the process of generation of the eukaryotic cell.primitive atmosphere of the earth did not contain oxygen gas (o2) when the proto-cells were generated successfully as the result of chemical evolution and then evolved. therefore, they first had acquired anaerobic energy metabolism, fermentation. the cellular metabolisms have often been formed by reorganizing to combine or recombinate between pre-existing metabolisms and newly born bioreactions. photosynthetic metabolism in eukaryotic chloroplast consists of an electron-transfer photosystem and ...19902103939
an engineered change in substrate specificity of ribulosebisphosphate carboxylase/oxygenase.the potential for altering the specificity of ribulosebisphosphate carboxylase/oxygenase toward gaseous substrates is explored through a modest perturbation of the active site microenvironment. specifically, replacement of active site glu-48 with carboxy-methylcysteine is achieved in a two-step process in which the catalytically incompetent cys-48 mutant protein is first generated and then treated with iodoacetic acid. this regimen of concerted site-directed mutagenesis and chemical modification ...19902104836
spectroscopic characterization of the light-harvesting complex of rhodospirillum rubrum and its structural subunit.the spectroscopic properties of the light-harvesting complex of rhodospirillum rubrum, b873, and a detergent-isolated subunit form, b820, are presented. absorption and circular dichroism spectra suggest excitonically interacting bacteriochlorophyll alpha (bchl alpha) molecules give b820 its unique spectroscopic properties. resonance raman results indicate that bchl alpha is 5-coordinate in both b820 and b873 but that the interactions with the bchl c2 acetyl in b820 and b873 are different. the re ...19902105744
reversible adp-ribosylation is demonstrated to be a regulatory mechanism in prokaryotes by heterologous expression.the primary product of biological nitrogen fixation, ammonia, reversibly regulates nitrogenase activity in a variety of diazotrophs by a process called "nh4(+)-switch-off/on." strong correlative evidence from work in azospirillum lipoferum and rhodospirillum rubrum indicates that this regulation involves both the inactivation of dinitrogenase reductase by dinitrogenase reductase adp-ribosyltransferase and the reactivation by dinitrogenase reductase activating glycohydrolase. the genes encoding t ...19902106680
cloning and expression of dratg genes from azospirillum lipoferum.a genomic library of azospirillum lipoferum was constructed with phage lambda embl4 as vector. from this library, the genes encoding dinitrogenase reductase adp-ribosyltransferase (drat), drat, and dinitrogenase reductase-activating glycohydrolase (drag), drag, were cloned by hybridization with the heterologous probes of rhodospirillum rubrum. as in r. rubrum, drat is located between drag and nifh, the gene encoding dinitrogenase reductase (a substrate for the drag/drat system). in the crude ext ...19902107127
crystallographic refinement and structure of ribulose-1,5-bisphosphate carboxylase from rhodospirillum rubrum at 1.7 a resolution.the amino acid sequence of ribulose-1,5-bisphosphate carboxylase/oxygenase from rhodospirillum rubrum has been fitted to the electron density maps. the resulting protein model has been refined to a nominal resolution of 1.7 a using the constrained-restrained least-squares refinement program of sussman and the restrained least-squares refinement program of hendrickson & konnert. the crystallographic refinement, based on 76,452 reflections with f greater than sigma (f) in the resolution range 5.5 ...19902107319
determination of hopanoid levels in bacteria using high-performance liquid chromatography.a reverse-phase hplc method to detect and quantify levels of hopanoids in bacteria has been developed. chromophores have been introduced by derivatization and the levels of the c35 hopanoids and their conjugates can be measured in bacterial lipid extracts down to picomole levels. some structural variations of the complex lipids were detected after derivatization and were easily purified using the same hplc system. zymomonas mobilis and rhodospirillum rubrum extracts were examined using this syst ...19902109551
activation of the nickel-deficient carbon monoxide dehydrogenase from rhodospirillum rubrum: kinetic characterization and reductant requirement.the requirements for and kinetics of the activation of the nickel-deficient (apo) co dehydrogenase from rhodospirillum rubrum by exogenous nickel have been investigated. the activation is strictly dependent upon the presence of a low-potential one-electron reductant. sodium dithionite and reduced methylviologen (e degrees' = -440 mv) are suitable reductants, whereas reduced indigo carmine (e degrees' = -125 mv) and the two-electron reductants sodium borohydride, nadh, and dithiothreitol are inef ...19902109635
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