Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| temperature dependence of the reorganization energy for charge recombination in the reaction center from rhodobacter sphaeroides. | the rate of charge recombination from the primary quinone to the bacteriochlorophyll dimer of the reaction center from the photosynthetic purple bacterium rhodobacter sphaeroides has been investigated using time-resolved optical spectroscopy. measurements were performed at temperatures from 293 to 10 k on reaction centers that have specific mutations that result in a range of 425-780 mev for the free energy difference of charge recombination compared to 520 mev for wild type [lin, x., murchison, ... | 1996 | 8639484 |
| the gene for a subunit of an abc-type heme transporter is transcribed together with the gene for subunit 6 of nadh dehydrogenase in rice mitochondria. | we previously identified a chloroplast-derived (ct-derived) sequence of 32 base pairs (bp) in rice mitochondrial dna that includes a part (30 bp; psitrni) of a gene for isoleucine trna (cau) of the chloroplast. analyzing the ct-derived psitrni, we found that an open reading frame (orf240), which was homologous to the gene for a subunit of an atp-binding cassette-type (abc-type) heme transporter, namely helc, of rhodobacter capsulatus, and a gene for subunit 6 of nadh dehydrogenase (nad6) were lo ... | 1996 | 8625418 |
| in vitro reconstitution and characterization of the rhodobacter capsulatus ntrb and ntrc two-component system. | enhancer-dependent transcription in enteric bacteria depends upon an activator protein that binds dna far upstream from the promoter and an alternative sigma factor (sigma 54) that binds with the core rna polymerase at the promoter. in the photosynthetic bacterium rhodobacter capsulatus, the ntrb and ntrc proteins (rcntrb and rcntrc) are putative members of a two-component system that is novel because the enhancer-binding rcntrc protein activates transcription of sigma 54-independent promoters. ... | 1996 | 8626457 |
| structure and expression of the chlorobium vibrioforme hemb gene and characterization of its encoded enzyme, porphobilinogen synthase. | plasmids containing dna from the green photosynthetic bacterium chlorobium vibrioforme complement a heme-requiring escherichia coli hemb mutant that is deficient in porphobilinogen (pbg) synthase activity. pbg synthase activity was detected in extract of complemented cells but not in that of cells transformed with control plasmid. the sequence of the c. vibrioforme hemb gene predicts a hemb protein that contains 328 amino acids, has a molecular weight of 36,407, and is 53% identical to the homol ... | 1996 | 8626508 |
| expression of the thioredoxin gene (trxa) in rhodobacter sphaeroides y is regulated by oxygen. | the structural gene (trxa) coding for thioredoxin in the photosynthetic bacterium rhodobacter sphaeroides has been cloned and sequenced previously. in the present study, the role of oxygen in trxa expression in r. sphaeroides y was investigated using mrna analyses and plasmid-borne trxa'-lacz+ translational and transcriptional fusions. northern analysis revealed a trxa-specific transcript of approximately 420-460 nucleotides, indicating that trxa is transcribed as a single gene. by studying the ... | 1996 | 8628218 |
| sequence and characterisation of a ribosomal rna operon from agrobacterium vitis. | one of the four ribosomal rna operons (rrna) from the agrobacterium vitis vitopine strain s4 was sequenced, rrna is most closely related to the rrn operons of bradyrhizobium japonicum and rhodobacter sphaeroides and carries an fmet-trna gene downstream of its 5s gene, as in the case of r. sphaeroides. the 16s rrna sequence of s4 differs from the a. vitis k309 type strain sequence by only one nucleotide, in spite of the fact that s4 and k309 have very different ti plasmids. the predicted secondar ... | 1996 | 8628253 |
| three separate proteins constitute the magnesium chelatase of rhodobacter sphaeroides. | the insertion of magnesium into protoporphyrin ix is the first step unique to chlorophyll production and is catalyzed by magnesium chelatase. the rhodobacter sphaeroides genes, bchi and bchd together, and bchh alone, were cloned and expressed with the pet3a vector in escherichia coli strain bl21 (de3). the 40-kda bchi protein was synthesized in greater abundance compared to the 70-kda bchd protein when both were expressed together from the same plasmid. the production of large amounts of the 140 ... | 1996 | 8631364 |
| characterization of a glutathione-dependent formaldehyde dehydrogenase from rhodobacter sphaeroides. | glutathione-dependent formaldehyde dehydrogenases (gsh-fdh) represent a ubiquitous class of enzymes, found in both prokaryotes and eukaryotes. during the course of studying energy-generating pathways in the photosynthetic bacterium rhodobacter sphaeroides, a gene (adhi) encoding a gsh-fdh homolog has been identified as part of an operon (adhi-cyci) that also encodes an isoform of the cytochrome c2 family of electron transport proteins (isocytochrome c2). enzyme assays with crude escherichia coli ... | 1996 | 8631716 |
| a null mutant of synechococcus sp. pcc7942 deficient in the sulfolipid sulfoquinovosyl diacylglycerol. | the sulfolipid 6-sulfo-alpha-d-quinovosyldiacylglycerol is associated with the thylakoid membranes of many photosynthetic organisms. previously, genes involved in sulfolipid biosynthesis have been characterized only in the purple bacterium rhodobacter sphaeroides. unlike plants and cyanobacteria, photosynthesis in this bacterium is anoxygenic due to the lack of a water splitting photosystem ii. to test the function of sulfolipid in an organism with oxygenic photosynthesis, we isolated and inacti ... | 1996 | 8631780 |
| stereoselectivity of pigment exchange with 13(2)-hydroxylated tetrapyrroles in reaction centers of rhodobacter sphaeroides r26. | bacteriochlorophyll a and bacteriopheophytin a carry a stereochemically labile asymmetric carbon at position c13(2). the steric requirements of photosynthetic reaction centers from rhodobacter sphaeroides r26 have been probed by exchange experiments with the respective epimeric 13(2)-hydroxylated pigments, in which epimerisation is blocked. (13(2)s)-13(2)-hydroxy-bacteriochlorophyll a is accepted at both monomeric binding sites, ba,b, (13(2)s)-13(2)-hydroxy-bacteriopheophytin a exclusively at th ... | 1996 | 8665948 |
| the xanthopsins: a new family of eubacterial blue-light photoreceptors. | photoactive yellow protein (pyp) is a photoreceptor that has been isolated from three halophilic phototrophic purple bacteria. the pyp from ectothiorhodospira halophila bn9626 is the only member for which the sequence has been reported at the dna level. here we describe the cloning and sequencing of the genes encoding the pyps from e.halophila sl-1 (type strain) and rhodospirillum salexigens. the latter protein contains, like the e.halophila pyp, the chromophore trans p-coumaric acid, as we show ... | 1996 | 8670821 |
| regulation of the expression of the photosynthetic apparatus of rhodobacter capsulatus grown in nitrogen-limited chemostat cultures | rhodobacter capsulatus was grown in chemostat cultures under different dilution rates and with ammonium ions as the limiting nutrient. the maximal growth rate (μmax) and the monod cell growth saturation coefficient (ks), were calculated from batch cultures grown at different concentrations of nh4+. the experiments in chemostat were carried out at 0.25 mm (nh4)2so4, and the dilution rates were varied between 38% and 75% of μmax. the results indicated that under continuous culture conditions the c ... | 1996 | 8672094 |
| the bradyrhizobium japonicum fixghis genes are required for the formation of the high-affinity cbb3-type cytochrome oxidase. | we report structural and functional analyses of the bradyrhizobium japonicum fixghis genes, which map immediately downstream of the fixnoqp operon for the symbiotically essential cbb3-type heme-copper oxidase complex. expression of fixghis, like that of fixnoqp, is strongly induced in cells grown microaerobically or anaerobically. a fixghi deletion led to the same prominent phenotypes as those known from a fixnoqp deletion: defective symbiotic nitrogen fixation (fix-) and decreased cytochrome ox ... | 1996 | 8661920 |
| complete assimilation of cysteine by a newly isolated non-sulfur purple bacterium resembling rhodovulum sulfidophilum (rhodobacter sulfidophilus). | a rod-shaped, motile, phototrophic bacterium, strain sicys, was enriched and isolated from a marine microbial mat, with cysteine as sole substrate. during phototrophic anaerobic growth with cysteine, sulfide was produced as an intermediate, which was subsequently oxidized to sulfate. the molar growth yield with cysteine was 103 g mol-1, in accordance with complete assimilation of electrons from the carbon and the sulfur moiety into cell material. growth yields with alanine and serine were propor ... | 1996 | 8661933 |
| the distance between bacterial species in sequence space. | despite the revolution caused by information from macromolecular sequences, the basis of bacterial classification remains the genus and the species. how do these terms relate to the variety of bacteria that exist on earth? in this paper, the inter- and intraspecies differences in amino acid sequence of several bacterial electron transport proteins, cytochromes c, and blue copper proteins are compared. for the soil and water organisms studied, bacterial species can be classed as "tight" when ther ... | 1996 | 8662021 |
| sequence of the bchg gene from chloroflexus aurantiacus: relationship between chlorophyll synthase and other polyprenyltransferases. | the sequence of the chloroflexus aurantiacus open reading frame thought to be the c. aurantiacus homolog of the rhodobacter capsulatus bchg gene is reported. the bchg gene product catalyzes esterification of bacteriochlorophyllide a by geranylgeraniol-ppi during bacteriochlorophyll a biosynthesis. homologs from arabidopsis thaliana, synechocystis sp. strain pcc6803, and c. aurantiacus were identified in database searches. profile analysis identified three related polyprenyltransferase enzymes wh ... | 1996 | 8655525 |
| bacterium genome sequence. | 1996 | 8649508 | |
| carotenoids 2: genetics and molecular biology of carotenoid pigment biosynthesis. | the crucial roles of carotenoids and their metabolites in photooxidative protection and photosynthesis, not to mention nutrition, vision, and cellular differentiation, make them an important and complex class of biological pigments. significant advances within the last few years have enhanced our understanding of the genetics and molecular biology of carotenoid biosynthesis in bacteria, fungi, algae, and plants. all of the genes involved in carotenoid biosynthesis from rhodobacter capsulatus, an ... | 1996 | 8641556 |
| paclitaxel (taxol)-induced nf-kappab translocation in murine macrophages. | interaction of bacterial lipopolysaccharide (lps) with macrophages results in the induction of a cascade of cytokines that mediate the varied effects of lps. an early intracellular signaling event that follows receptor engagement is the activation of transcription factor nf-kappab. nf-kappab has been shown to be important for the induction of many lps-inducible cytokine genes, including tumor necrosis factor alpha, interleukin-1beta, and interleukin-6. previously, we and others have shown that t ... | 1996 | 8641795 |
| stability study of rhodobacter capsulatus ferrocytochrome c2 wild-type and site-directed mutants using hydrogen/deuterium exchange monitored by electrospray ionization mass spectrometry. | to estimate the stability of rhodobacter capsulatus ferrocytochrome c2 wild-type and site-directed mutants, charge state distributions and hydrogen/deuterium exchange rates were monitored by electrospray ionization mass spectrometry. the relative stability of the mutants was observed with the order: v11 insert > y75f > wild-type = k32e > k12d = k14e > or = k52e > k14e/k32e > w67y > p35a > i57n > g34s. (a preliminary account has been presented for mutants g34s and p35a [jaquinod et al. (1995) rap ... | 1996 | 8603744 |
| on the formation of the mixed pyrrole catalysed by porphobilinogen synthase from rhodobacter spheroides. | this enzyme porphobilinogen synthase (pbgs) catalyses the formation of porphobilinogen (pbg) from two molecules of 5-amino-levulinic acid (ala). it has been claimed that the pbgs from rhodobacter spheroides is able to form a mixed pyrrole, from one molecule of 5-aminolevulinic acid and one molecule of levulinic acid. the chemical synthesis of this mixed pyrrole allowed us to show that the compound formed from 5-aminolevulinic acid and levulinic acid with pbgs from r. spheroides has not the propo ... | 1996 | 8605237 |
| the rhodobacter sphaeroides 2.4.1 rho gene: expression and genetic analysis of structure and function. | the gene which encodes transcription termination factor rho from rhodobacter sphaeroides 2.4.1, the gram-negative facultative photosynthetic bacterium, has been cloned and sequenced. the deduced protein shows a high level of sequence similarity to other bacterial rho factors, especially those from proteobacteria. however, several amino acid substitutions in the conserved atp-binding site have been identified. when expressed in escherichia coli, the r. sphaeroides rho gene relieves rho-dependent ... | 1996 | 8606169 |
| promoters controlling expression of the alternative nitrogenase and the molybdenum uptake system in rhodobacter capsulatus are activated by ntrc, independent of sigma54, and repressed by molybdenum. | the alternative nitrogenase of rhodobacter capsulatus is expressed only under conditions of nitrogen and molybdenum depletion. the analysis of anfa-lacz fusions demonstrated that this dual control occurred at the level of transcription of anfa, which encodes a transcriptional activator specific for the alternative nitrogenase. the anfa promoter was found to be activated under nitrogen-limiting conditions by ntrc in a sigma54-independent manner. in addition, anfa transcription was repressed by tr ... | 1996 | 8606177 |
| identification and analysis of the rnc gene for rnase iii in rhodobacter capsulatus. | the large subunit ribosomal rna of the purple bacterium rhodobacter capsulatus shows fragmentation into pieces of 14 and 16s, both fragments forming the functional equivalent of intact 23s rrna. an rna-processing step removes an extra stem-loop structure from the 23s rrna [kordes, e., jock, s., fritsch, j., bosch, f. and klug, g. (1994) j. bacteriol., 176, 1121-1127]. taking advantage of the fragmentation deficient mutant strain fm65, we used genetic complementation to find the mutated gene resp ... | 1996 | 8614626 |
| cloning, sequencing and transcriptional regulation of the drat and drag genes of azospirillum lipoferum fs. | from azospirillum lipoferum (al) fs, a nitrogen-fixing bacterium isolated from the rhizosphere of rice, we cloned and sequenced drat, encoding dinitrogenase reductase adp-ribosyltransferase, and drag, encoding dinitrogenase reductase-activating glycohydrolase. the nucleotide sequences of dratg showed extensive similarity to the same genes from azospirillum brasilense, rhodospirillum rubrum and rhodobacter capsulatus, and they are assumed to be co-transcribed as a single operon. when this dratg o ... | 1996 | 8621068 |
| nucleotide sequence of the rhodobacter capsulatus hemh gene. | the last step in heme synthesis is the insertion of iron into the ring of protoporphyrin ix. the enzyme which catalyzes this reaction, ferrochelatase (fc), is encoded by the hemh gene. a clone containing this gene from rhodobacter capsulatus, a purple non-sulfur photosynthetic bacterium, has been sequenced. a single open reading frame was found which could encode a protein of 351 amino acids. this putative protein is very similar to other fc and contains the fc signature sequence. | 1996 | 8621079 |
| flagellar genes from rhodobacter sphaeroides are homologous to genes of the flif operon of salmonella typhimurium and to the type-iii secretion system. | a flagellar region of the genome of rhodobacter sphaeroides was cloned and sequenced. three orfs were identified and arranged in the same order as flih, flii and flij of salmonella typhimurium (st). orf2 is highly similar to flii from st (49% similarity) showing walker's a and b motifs. similar scores were found with proteins of the type-iii secretion system of virulence factors. orf3 shows 16.4 and 11.1% similarity to flij from st and bacillus subtilis, respectively. this work also shows that o ... | 1996 | 8621091 |
| characterisation of the mcpa and mcpb genes capable of encoding methyl-accepting type chemoreceptors in rhodobacter capsulatus. | two contiguous mcp genes, mcpa and mcpb, transcribed from the same dna strand and capable of encoding methyl-accepting chemotaxis proteins (mcp) have been isolated from rhodobacter capsulatus (rc), sequences and overexpressed in escherichia coli (ec). the deduced proteins (mcpa, 69 171 da; mcpb, 81 629 da) show a structure similar to that of ec mcp. the products of mcpa and mcpb, overproduced in ec, were recognized by anti-ec mcp (trg) antibodies. | 1996 | 8621092 |
| the membrane-bound cytochrome cy of rhodobacter capsulatus can serve as an electron donor to the photosynthetic reaction of rhodobacter sphaeroides. | rhodobacter capsulatus has two different pathways for reduction of the photo-oxidized reaction center, one using water-soluble cytochrome c2, the other via membrane-associated cytochrome cy. rhodobacter sphaeroides differs in that it lacks a cytochrome cy homologue capable of functioning in photosynthetic electron transfer; cytochrome c2 is thus the sole electron carrier, and is required for photosynthetic (ps+) growth. genetic evidence indicates that cytochrome cy of r. capsulatus can complemen ... | 1996 | 8611589 |
| isolation and expression of the rhodobacter sphaeroides gene (pgsa) encoding phosphatidylglycerophosphate synthase. | the rhodobacter sphaeroides pgsa gene (pgsars), encoding phosphatidylglycerophosphate synthase (pgsars), was cloned, sequenced, and expressed in both r. sphaeroides and escherichia coli. as in e. coli, pgsars is located immediately downstream of the uvrc gene. comparison of the deduced amino acid sequences revealed 41% identity and 69% similarity to the pgsa gene of e. coli, with similar homology to the products of the putative pgsa genes of several other bacteria. comparison of the amino acid s ... | 1996 | 8576035 |
| genetic evidence for an activator required for induction of colicin-like bacteriocin 28b production in serratia marcescens by dna-damaging agents. | bacteriocin 28b production is induced by mitomycin in wild-type serratia marcescens 2170 but not in escherichia coli harboring the bacteriocin 28b structural gene (bss). studies with a bss-lacz transcriptional fusion showed that mitomycin increased the level of bss gene transcription in s. marcescens but not in the e. coli background. a s. marcescens tn5 insertion mutant was obtained (s. marcescens 2170 reg::tn5) whose bacteriocin 28b production and bss gene transcription were not increased by m ... | 1996 | 8576068 |
| identification of the molybdenum cofactor of dimethyl sulfoxide reductase from rhodobacter sphaeroides f. sp. denitrificans as bis(molybdopterin guanine dinucleotide)molybdenum. | chemical analysis of dimethyl sulfoxide reductase from rhodobacter sphaeroides f. sp. denitrificans has shown that its molybdenum center contains two molybdopterin guanine dinucleotide molecules and a single atom of molybdenum. the enzyme, which exists as a monomer of 86 kda, was shown to contain 1 mol of molybdenum, 4 mol of organic phosphate, and 2 mol of guanine per mole of protein. in addition, the relative yield of form a, a fluorescent derivative of molybdopterin, was twice that obtained f ... | 1996 | 8554338 |
| occurrence of polyhydroxyalkanoic acid granule-associated proteins related to the alcaligenes eutrophus h16 ga24 protein in other bacteria. | fifty different polyhydroxyalkanoic acid (pha)-accumulating bacterial strains were investigated for the occurrence of phasin proteins bound to pha granules and related to the ga24 protein of alcaligenes eutrophus h16, by isolating pha granules and western blot analysis of granule-associated proteins employing antibodies raised against the ga24 protein. it could be demonstrated that th pha granules of many poly(3-hydroxybutyrate)-accumulating bacteria exhibited a similar protein pattern, and a pr ... | 1996 | 8598273 |
| functional expression of subunit iv of rhodobacter sphaeroides cytochrome b-c1 complex and reconstitution of recombinant protein with three-subunit core complex. | subunit iv of rhodobacter sphaeroides cytochrome b-c1 complex was over-expressed in escherichia coli jm109 cells as a glutathione s-transferase fusion protein (gst-rsiv) using the expression vector, pgex/rsiv. maximum yield of soluble active recombinant fusion protein was obtained from cells harvested 3 h after induction of growth at 37 degrees c in lb medium. subunit iv was released from the fusion protein by proteolytic cleavage with thrombin. when subjected to sds-polyacrylamide gel electroph ... | 1996 | 8567659 |
| spectroscopic characterization of nitrosylheme in nitric oxide complexes of ferric and ferrous cytochrome c' from photosynthetic bacteria. | reactions of ferric and ferrous cytochromes c' from four photosynthetic bacteria (rhodobacter capsulatus atcc 11166, rhodopseudomonas palustris atcc 17001, rhodospirillum rubrum atcc 11170, and chromatium vinosum atcc 17899) with nitric oxide have been investigated by electronic absorption and electron paramagnetic resonance spectroscopies. the heme iron(iii) of these ferric cytochromes c' has been recently reported to be in a quantum mechanically admixed (s = 5/2, 3/2) state [fujii, s., yoshimu ... | 1996 | 8547347 |
| a global signal transduction system regulates aerobic and anaerobic co2 fixation in rhodobacter sphaeroides. | complementation of a mutant of rhodobacter sphaeroides defective in photosynthetic co2 reduction led to the identification of a gene which encodes a protein that is related to a class of sensor kinases involved in bacterial signal transduction. the nucleotide sequence and deduced amino acid sequence led to the finding that the gene which complemented the mutant is the regb (prrb) gene, previously isolated from both r. sphaeroides and rhodobacter capsulatus and shown to regulate the anaerobic exp ... | 1996 | 8550404 |
| mgps, a complex regulatory locus involved in the transcriptional control of the puc and puf operons in rhodobacter sphaeroides 2.4.1. | a new method has been developed in order to select mutants showing decreased puc operon transcription in rhodobacter sphaeroides 2.4.1. a transcriptional fusion of a promoterless fragment derived from the sacb gene, encoding the levansucrase from bacillus subtilis, to the upstream regulatory region of the puc operon has been constructed. with appropriate levels of exogenous sucrose, survivors of a sucrose killing challenge have been isolated. subsequent analysis revealed the presence of both cis ... | 1996 | 8550440 |
| deduced amino acid sequence, functional expression, and unique enzymatic properties of the form i and form ii ribulose bisphosphate carboxylase/oxygenase from the chemoautotrophic bacterium thiobacillus denitrificans. | the cbbl cbbs and cbbm genes of thiobacillus denitrificans, encoding form i and form ii ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco), respectively, were found to complement a rubisco-negative mutant of rhodobacter sphaeroides to autotrophic growth. endogenous t. denitrificans promoters were shown to function in r. sphaeroides, resulting in high levels of cbbl cbbs and cbbm expression in the r. sphaeroides host. this expression system provided high levels of both t. denitrificans enz ... | 1996 | 8550452 |
| open reading frame 176 in the photosynthesis gene cluster of rhodobacter capsulatus encodes idi, a gene for isopentenyl diphosphate isomerase. | isopentenyl diphosphate (ipp) isomerase catalyzes an essential activation step in the isoprenoid biosynthetic pathway. a database search based on probes from the highly conserved regions in three eukaryotic ipp isomerases revealed substantial similarity with orf176 in the photosynthesis gene cluster in rhodobacter capsulatus. the open reading frame was cloned into an escherichia coli expression vector. the encoded 20-kda protein, which was purified in two steps by ion exchange and hydrophobic in ... | 1996 | 8550491 |
| repression of the escherichia coli modabcd (molybdate transport) operon by mode. | the modabc gene products constitute the molybdate-specific transport system in escherichia coli. another operon coding for two proteins which diverges from the modabcd operon has been identified. the first gene of this operon codes for a 262-amino-acid protein, designated mode (28 kda), and the second genes codes for a 490-amino-acid protein. modf (54 kda). the role of modf has not yet been determined; however, mutations in mode depressed modabcd transcription even in the presence of molybdate, ... | 1996 | 8550508 |
| primary structure and phylogeny of the calvin cycle enzymes transketolase and fructosebisphosphate aldolase of xanthobacter flavus. | xanthobacter flavus, a gram-negative facultatively autotrophic bacterium, employs the calvin cycle for the fixation of carbon dioxide. cells grown under autotrophic growth conditions possess an fe(2+)-dependent fructosebisphosphate (fbp) aldolase (class ii) in addition to a class i fbp aldolase. by nucleotide sequencing and heterologous expression in escherichia coli, genes encoding transketolase (ec 2.2.1.1.; cbbt) and class ii fbp aldolase (ec 4.1.2.13; cbba) were identified. a partial open re ... | 1996 | 8550527 |
| kinetic mechanism of folding and unfolding of rhodobacter capsulatus cytochrome c2. | in spite of marginal sequence homology, cytochrome c2 from photosynthetic bacteria and the mitochondrial cytochromes c exhibit some striking structural similarities, including the tertiary arrangement of the three main helices. to compare the folding mechanisms for these two distantly related groups of proteins, equilibrium and kinetic measurements of the folding/unfolding reaction of cytochrome c2 from rhodobacter capsulatus were performed as a function of guanidine hydrochloride (guhcl) concen ... | 1996 | 8988024 |
| ftir study of conformational substates in the co adduct of cytochrome c oxidase from rhodobacter sphaeroides. | fourier transform infrared (ftir) spectroscopy of cytochrome c oxidase from rhodobacter sphaeroides reveals multiple co stretch bands that are associated with different conformational substates of the enzyme. here we report the temperature dependence of the infrared bands for the co bound to the fea3 heme iron and to cub. we have also studied the kinetics of ligand return from fea3 to cub using temperature derivative spectroscopy (tds). two classes of substates (alpha/beta) can be distinguished ... | 1996 | 8988016 |
| natural abundance solid-state carbon nmr studies of photosynthetic reaction centers with photoinduced polarization. | solid-state nmr spectra of natural abundance 13c in reaction centers from photosynthetic bacteria rhodobacter sphaeroides r-26 was measured. when the quinone acceptors were removed and continuous visible illumination of the sample was provided, exceptionally strong nuclear spin polarization was observed in nmr lines with chemical shifts resembling those of the aromatic carbons in bacteriochlorophyll and bacteriopheophytin. the observation of spin polarized 15n nuclei in bacteriochlorophyll and b ... | 1996 | 11607689 |
| melissa: a potential experiment for a precursor mission to the moon. | melissa (micro-ecological life support system alternative) has been conceived as a micro-organism based ecosystem intended as a tool for developing the technology for a future artificial ecosystem for long term space missions, as for example a lunar base. the driving element of melissa is the recovering of edible biomass from waste, co2, and minerals with the use of sun light as energy source. in this publication, we focus our attention on the potential applications of melissa for a precursor mi ... | 1996 | 11543311 |
| preliminary crystallographic studies of dimethylsulfoxide reductase from rhodobacter capsulatus. | dimethylsulfoxide reductase from the photosynthetic bacterium rhodobacter capsulatus has been crystallized in two similar forms which are suitable for x-ray structure determination. both crystals forms belong to space group p4(1)22 or p4(3)22, with cell dimensions a = b = 80.81, c = 229.75 a (type i crystals) or a = b = 89.30, c = 230.05 a (type ii crystals) and one molecule in the asymmetric unit. diffraction has been observed to at least 2.0 a in type i crystals and to 2.6 a in type ii crystal ... | 1996 | 15299743 |
| crystallization and preliminary x-ray study of a new crystal form of cytochrome c' from rhodobacter capsulatus. | a new crystal form of diheme cytochrome c' from rhodobacter capsulatus has been obtained and preliminary crystallographic experiments have been performed. the crystals belong to the space group p2(1)2(1)2 with unit-cell dimensions of a = 47.82, b = 72.59, c = 34.32 a. the assumption that an asymmetric unit of the crystal contains one half of the homodimer molecule indicates that the monomers in the dimeric molecule may be related by a crystallographic twofold axis. crystals diffract up to 1.7 a ... | 1996 | 15299745 |
| influence of the degree and mode of light limitation on growth characteristics of the rhodobacter capsulatus continuous cultures. | the influence of the degree and mode of light limitation on growth characteristics of turbidostat cultures of rhodobacter capsulatus was investigated using mass and energy balance regularities. light limitation was achieved by increasing the steady-state biomass concentration at constant incident light intensity ( approximately 100 w/m(2)) or by decreasing the incident light intensity at constant steady-state biomass concentration ( approximately 500 mg of dry biomass/l). it was shown that under ... | 1996 | 18629825 |
| spiral tubular bioreactors for hydrogen production by photosynthetic microorganisms : design and operation. | spiral tubular bioreactors were constructed out of transparent pvc tubing for h2 production applications. both a cyanobacterial anabaena variabilis mutant that lacks uptake hydrogenase activity and the photosynthetic bacterium rhodobacter sp. cbs were tested in the bioreactors. continuous h2 photoproduction at an average rate of 19 ml min-2.h-1 was observed using the a. variabilis mutant under an air atmosphere (without argon sparging or application of a partial vacuum). the cyanobacterial photo ... | 1997 | 18576112 |
| structure of cytochrome c' from rhodobacter capsulatus strain st louis: an unusual molecular association induced by bridging zn ions. | rhodobacter capsulatus strain st louis cytochrome c' (rccp-sl) has been crystallized and the structure solved by molecular replacement. it was refined at 2.1 a resolution to an r value of 18.4%, and compared with rhodobacter capsulatus strain m110 cytochrome c' (rccp-m110). although these two proteins are very similar in sequence and structure, the intermolecular interaction is largely different. in rccp-m110, the molecules dimerize through interaction of helix b to form an antiparallel arrangem ... | 1997 | 15299853 |
| the nucleotide sequence of gltd gene encoding the small subunit of rhodobacter sphaeroides glutamate synthase. | we have determined the complete nucleotide sequence of a 2 387 bp chromosomal sali-ecori fragment, which contains the structural gene (gltd) for the small subunit of rhodobacter sphaeroides glutamate synthase, as well as the 5'- and 3'-flanking regions. an open reading frame of 1 242 base pairs was identified as the r. sphaeroides gltd gene. the mw of the small subunit, as deduced from the nucleotide sequence, was estimated to be 44 kd. a comparison of the nucleotide sequence revealed a high sim ... | 1997 | 12219208 |
| characterization of the chemotaxis protein chew from rhodobacter sphaeroides and its effect on the behaviour of escherichia coli. | in contrast to the situation in enteric bacteria, chemotaxis in rhodobacter sphaeroides requires transport and partial metabolism of chemoattractants. a chemotaxis operon has been identified containing homologues of the enteric chea, chew, cher genes and two homologues of the chey gene. however, mutations in these genes have only minor effects on chemotaxis. in enteric species, chew transmits sensory information from the chemoreceptors to the histidine protein kinase, chea. expression of r. spha ... | 1997 | 9140964 |
| temperature dependence of the qy resonance raman spectra of bacteriochlorophylls, the primary electron donor, and bacteriopheophytins in the bacterial photosynthetic reaction center. | qy-excited resonance raman spectra of the accessory bacteriochlorophylls (b), the bacteriopheophytins (h), and the primary electron donor (p) in the bacterial photosynthetic reaction center (rc) of rhodobacter sphaeroides have been obtained at 95 and 278 k. frequency and intensity differences are observed in the low-frequency region of the p vibrational spectrum when the sample is cooled from 278 to 95 k. the b and h spectra exhibit minimal changes of frequencies and relative intensities as a fu ... | 1997 | 9214301 |
| synthesis of atypical cyclic and acyclic hydroxy carotenoids in escherichia coli transformants. | a total of eight different hydroxy carotenoids were produced in transformants of the non-carotenogenic bacterium escherichia coli. they include the acyclic 1-hydroxyneurosporene, 1-hydroxylycopene, 1,1'-dihydroxylycopene and demethylspheroidene as well as the cyclic 3-hydroxy-beta-zeacarotene, 7,8-dihydrozeaxanthin, 3 or 3'-7,8-dihydro-beta-carotene and 1'-hydroxy-gamma-carotene. most of these uncommon carotenoids are found only in trace amounts in natural sources. for the synthesis of all the c ... | 1997 | 9470222 |
| the rhodobacter capsulatus hupslc promoter: identification of cis-regulatory elements and of trans-activating factors involved in h2 activation of hupslc transcription. | the [nife]hydrogenase of the photosynthetic bacterium rhodobacter capsulatus is encoded by the structural hupslc operon, the expression of which is induced by h2. h2 activation was no longer observable in chromosomal hupr mutants, an indication that hupr is implicated directly in the activation by h2 of hups gene expression. the transcriptional start site of the hups promoter, determined by primer extension mapping, was located 55 nucleotides upstream from the translational start codon of the hu ... | 1997 | 9426130 |
| evidence for two chemosensory pathways in rhodobacter sphaeroides. | in contrast to enteric bacteria, chemotaxis in rhodobacter sphaeroides requires transport and partial metabolism of chemoattractants. although a chemotaxis operon has been identified containing homologues of the enteric chea, chew, cher genes and two homologues of the chey gene, deletion of the entire chemotaxis operon had only minor effects on chemotactic behaviour under the conditions tested. responses to sugars were enhanced in tethered cells but in all other chemotaxis assays behaviour of th ... | 1997 | 9426144 |
| the nuoi subunit of the rhodobacter capsulatus respiratory complex i (equivalent to the bovine tyky subunit) is required for proper assembly of the membraneous and peripheral domains of the enzyme. | the nuoi gene that encodes a ferredoxin-like subunit of the rhodobacter capsulatus complex i (a subunit equivalent to the bovine tyky subunit) was mutated by homologous recombination. both a nuoi-deleted mutant (delta nuoi mutant) and a point mutant in which cys74 was replaced by a serine (c74s mutant) proved to be completely deficient in complex i activity. these strains were unable to grow under anaerobic photosynthetic conditions. their cytoplasmic membranes were also characterized by the abs ... | 1997 | 9428698 |
| characterisation of the pterin molybdenum cofactor in dimethylsulfoxide reductase of rhodobacter capsulatus. | analysis of dimethylsulfoxide reductase from rhodobacter capsulatus showed that it contained 1 mol mo and 2 mol gmp. this indicates that the molybdenum cofactor in dimethylsulfoxide reductase is bis(molybdopterin guanine dinucleotide) molybdenum. the absorption spectrum of the molybdopterin guanine dinucleotide released from dimethylsulfoxide reductase after denaturation of the holoenzyme was compared with those of pterin standards of known redox state. the spectra were most similar to pterin st ... | 1997 | 9210484 |
| genetic analysis of chlorophyll biosynthesis. | during this decade, there have been major advancements in the understanding of genetic loci involved in synthesis of the family of mg-tetrapyrroles known as chlorophylls and bacteriochlorophylls. molecular genetic analysis of mg-tetrapyrrole biosynthesis was initiated by the performance of detailed sequence and mutational analysis of the photosynthesis gene cluster from rhodobacter capsulatus. these studies provided the first detailed understanding of genes involved in bacteriochlorophyll a bios ... | 1997 | 9442890 |
| influence of iron-removal procedures on sequential electron transfer in photosynthetic bacterial reaction centers studied by transient epr spectroscopy. | electron spin polarized electron paramagentic resonance (esp epr) spectra were obtained with deuterated iron-removed photosynthetic bacterial reaction centers (rcs) to specifically investigate the effect of the rate of primary charge separation, metal-site occupancy, and h-subunit content on the observed p865+qa- charge-separated state. fe-removed and zn-substituted rcs from rb. sphaeroides r-26 were prepared by refined procedures, and specific electron transfer rates (kq) from the intermediate ... | 1997 | 9214300 |
| mixed lipid-protein films of bacterial photosynthetic reaction centres. ii. mixed multilayers on solid supports. | mixed lipid-protein multilayers composed of the reaction centre (rc) proteins from the chloroflexus aurantiacus and rhodobacter sphaeroides (wild type) photosynthetic bacteria and synthetic lipids were investigated. the optimal conditions for forming thin films on solid plates (approximately 100% transfer) were 30 mn/m surface pressure and transfer of the interfacial monolayers from the buffer/air interface onto the plates by the langmuir-schaefer method. the films transferred onto quartz and op ... | 1997 | 9225257 |
| triplet energy transfer between the primary donor and carotenoids in rhodobacter sphaeroides r-26.1 reaction centers incorporated with spheroidene analogs having different extents of pi-electron conjugation. | three carotenoids, spheroidene, 3,4-dihydrospheroidene and 3,4,5,6-tetrahydrospheroidene, having 8, 9 and 10 conjugated carbon-carbon double bonds, respectively, were incorporated into rhodobacter (rb.) sphaeroides r-26.1 reaction centers. the extents of binding were found to be 95 +/- 5% for spheroidene, 65 +/- 5% for 3,4-dihydrospheroidene and 60 +/- 10% for 3,4,5,6-tetrahydrospheroidene. the dynamics of the triplet states of the primary donor and carotenoid were measured at room temperature b ... | 1997 | 9230708 |
| polyhydroxyalkanoate production in rhodobacter capsulatus: genes, mutants, expression, and physiology. | like many other prokaryotes, the photosynthetic bacterium rhodobacter capsulatus produces high levels of polyhydroxyalkanoates (phas) when a suitable carbon source is available. the three genes that are traditionally considered to be necessary in the pha biosynthetic pathway, phaa (beta-ketothiolase), phab (acetoacetylcoenzyme a reductase), and phac (pha synthase), were cloned from rhodobacter capsulatus. in r. capsulatus, the phaab genes are not linked to the phac gene. translational beta-galac ... | 1997 | 9251189 |
| positive selection systems for discovery of novel polyester biosynthesis genes based on fatty acid detoxification. | the photosynthetic bacterium rhodobacter capsulatus can grow with short- to long-chain fatty acids as the sole carbon source (r. g. kranz, k. k. gabbert, t. a. locke, and m. t. madigan, appl. environ. microbiol. 63:3003-3009, 1997). concomitant with growth on fatty acids is the production to high levels of the polyester storage compounds called polyhydroxyalkanoates (phas). here, we describe colony screening and selection systems to analyze the production of phas in r. capsulatus. a screen with ... | 1997 | 9251190 |
| coupling of cytochrome and quinone turnovers in the photocycle of reaction centers from the photosynthetic bacterium rhodobacter sphaeroides. | a minimal kinetic model of the photocycle, including both quinone (q-6) reduction at the secondary quinone-binding site and (mammalian) cytochrome c oxidation at the cytochrome docking site of isolated reaction centers from photosynthetic purple bacteria rhodobacter sphaeroides, was elaborated and tested by cytochrome photooxidation under strong continuous illumination. the typical rate of photochemical excitation by a laser diode at 810 nm was 2.200 s-1, and the rates of stationary turnover of ... | 1997 | 9251814 |
| temperature dependence of the electrogenic reaction in the qb site of the rhodobacter sphaeroides photosynthetic reaction center: the qa-qb --> qaqb- transition. | the temperature dependencies for the kinetics and relative amplitudes of electrogenic reaction(s) coupled with the first reduction of the secondary quinone acceptor qb were measured with dark-adapted chromatophores of rhodobacter sphaeroides. the kinetics, while acceptably fitted by a single exponent at room temperature, clearly split into two components below 15 degrees c (rise times, 25 micros and 300 micros at ph 7.0 and 10 degrees c) with the slow phase ousting the fast one at ph > 9.0. the ... | 1997 | 9276452 |
| differential levels of specific cytochrome c biogenesis proteins in response to oxygen: analysis of the ccl operon in rhodobacter capsulatus. | the photosynthetic bacterium rhodobacter capsulatus synthesizes c-type cytochromes under a variety of growth conditions. for example, under aerobic growth, c-type cytochromes are synthesized as part of an electron transport pathway, using oxygen as the terminal electron acceptor. anaerobically in the light, r. capsulatus requires cytochrome bc1 and other c-type cytochromes for the photosynthetic electron transport pathway. it is shown here that the ccl1 and ccl2 genes of r. capsulatus are requir ... | 1997 | 9286996 |
| antenna excited state decay kinetics establish primary electron transfer in reaction centers as heterogeneous. | the decay of the excited primary electron donor p* in bacterial photosynthetic reaction centers (both membrane-bound and detergent-isolated) has been observed to be nonexponential on a time scale of some tens of picoseconds. although the multipicosecond nonexponentiality of p* has been ascribed to heterogeneity in teh rate of primary electron transfer (pet), the decay kinetics can be interpreted equally well using homogeneous models. to address this ambiguity, we studied the decay of excited bac ... | 1997 | 9289013 |
| in bacterial reaction centers rapid delivery of the second proton to qb can be achieved in the absence of l212glu. | in the reaction center (rc) of rhodobacter capsulatus, residue l212glu is a component of the pathway for proton transfer to the reduced secondary quinone, qb. we isolated phenotypic revertants of the photosynthetically incompetent (ps-) l212glu-->gln mutant; all of them retain the l212glu-->gln substitution and carry a second-site mutation: l227leu-->phe, l228gly-->asp, l231arg-->cys, or m231arg-->cys. we also characterized the l212ala strain, which is a phenotypic revertant of the ps- l212glu-l ... | 1997 | 9315859 |
| the amino-terminal portion of the rieske iron-sulfur protein contributes to the ubihydroquinone oxidation site catalysis of the rhodobacter capsulatus bc1 complex. | the rieske iron-sulfur (fe-s) protein subunit of bc1 complexes contains in its carboxyl-terminal part two highly conserved hexapeptide motifs (box i and box ii) that include the four amino acid ligands of its [2fe-2s] cluster. in the preceding paper [liebl, u., sled, v., brasseur, g., ohnishi, t., & daldal, f. (1997) biochemistry 36, 11675-11684], the effects of mutations at two of the nonliganding residues [threonine (t) 134 and leucine (l) 136 in the rhodobactercapsulatus rieske fe-s protein] ... | 1997 | 9305958 |
| factors determining electron-transfer rates in cytochrome c oxidase: studies of the fq(i-391) mutant of the rhodobacter sphaeroides enzyme. | the mechanisms of internal electron transfer and oxygen reduction were investigated in cytochrome c oxidase from rhodobacter sphaeroides (cytochrome aa3) using site-directed mutagenesis in combination with time-resolved optical absorption spectroscopy. electron-transfer reactions in the absence of o2 were studied after flash photolysis of co from the partly-reduced enzyme and the reaction of the fully-reduced enzyme with o2 was studied using the so-called flow-flash technique. results from studi ... | 1997 | 9305969 |
| extracellular reduction of selenite by a novel marine photosynthetic bacterium. | a novel purple nonsulfur bacterium strain nkpb030619, which has resistance to over 5 mm selenite, was isolated from a marine environment. an initial concentration of 1.1 mm selenite, added to the medium, was decreased to under 0.05 mm within 5 days. the color of the cell suspension turned red within 2 days. the red coloration gradually decreased and black precipitates appeared during 2 weeks of cultivation. under these conditions, two main types of deposit were formed extracellularly. these depo ... | 1997 | 9352678 |
| relationship between the oxidation potential and electron spin density of the primary electron donor in reaction centers from rhodobacter sphaeroides. | the primary electron donor in bacterial reaction centers is a dimer of bacteriochlorophyll a molecules, labeled l or m based on their proximity to the symmetry-related protein subunits. the electronic structure of the bacteriochlorophyll dimer was probed by introducing small systematic variations in the bacteriochlorophyll-protein interactions by a series of site-directed mutations that replaced residue leu m160 with histidine, tyrosine, glutamic acid, glutamine, aspartic acid, asparagine, lysin ... | 1997 | 9391069 |
| analysis of the fnrl gene and its function in rhodobacter capsulatus. | the fnr gene encodes a regulatory protein involved in the response to oxygen in a variety of bacterial genera. for example, it was previously shown that the anoxygenic, photosynthetic bacterium rhodobacter sphaeroides requires the fnrl gene for growth under anaerobic, photosynthetic conditions. additionally, the fnrl protein in r. sphaeroides is required for anaerobic growth in the dark with an alternative electron acceptor, but it is not essential for aerobic growth. in this study, the fnrl loc ... | 1997 | 9393689 |
| resonance raman characterization of reaction centers in which bacteriochlorophyll replaces the photoactive bacteriopheophytin. | qy-excitation resonance raman (rr) spectra are reported for two mutant reactions centers (rcs) from rhodobacter sphaeroides in which the photoactive bacteriopheophytin (bphl) is replaced by a bacteriochlorophyll (bchl) molecule, designated by beta l. one mutation, (m)l214h, yields the pigment change via introduction of a histidine residue at position m214. the other mutation, (m)l214h/(l)-e104v, removes the putative hydrogen bond between beta l and the native glutamic acid residue at position l1 ... | 1997 | 9398189 |
| glutamate 286 in cytochrome aa3 from rhodobacter sphaeroides is involved in proton uptake during the reaction of the fully-reduced enzyme with dioxygen. | the reaction with dioxygen of solubilized fully-reduced wild-type and eq(i-286) (exchange of glutamate 286 of subunit i for glutamine) mutant cytochrome c oxidase from rhodobacter sphaeroides has been studied using the flow-flash technique in combination with optical absorption spectroscopy. proton uptake was measured using a ph-indicator dye. in addition, internal electron-transfer reactions were studied in the absence of oxygen. glutamate 286 is found in a proton pathway proposed to be used fo ... | 1997 | 9374859 |
| conformation-activated protonation in reaction centers of the photosynthetic bacterium rhodobacter sphaeroides. | kinetics and stoichiometry of proton binding/unbinding induced by intense (1 w cm-2) and continuous illumination were measured in the isolated reaction center (rc) protein from photosynthetic purple bacterium rhodobacter sphaeroides in the absence of an external electron donor. at high ionic strength (100 mm), large proton release (approximately 6 h+ per rc) was observed at ph 6 and substoichiometric h+-ion binding (approximately 0.3 h+ per rc) at ph 8. these observations together with optical s ... | 1997 | 9398255 |
| formation of a long-lived p+ba- state in plant pheophytin-exchanged reaction centers of rhodobacter sphaeroides r26 at low temperature. | femtosecond transient absorption spectroscopy in the range of 500-1040 nm was used to study electron transfer at 5 k in reaction centers of rhodobacter sphaeroides r26 in which the bacteriopheophytins (bphe) were replaced by plant pheophytin a (phe). primary charge separation took place with a time constant of 1.6 ps, similar to that found in native rcs. spectral changes around 1020 nm indicated the formation of reduced bacteriochlorophyll (bchl) with the same time constant, and its subsequent d ... | 1997 | 9405057 |
| influence of the protein binding site on the absorption properties of the monomeric bacteriochlorophyll in rhodobacter sphaeroides lh2 complex. | resonance raman spectroscopy was performed on peripheral light-harvesting proteins from rhodobacter sphaeroides in which the residue betaarg-10 has been modified by site-selected mutagenesis. we show that this residue is indeed involved (as proposed by x-ray crystallographic studies on the lh2 complex from rhodopseudomonas acidophila), in an h-bond with the acetyl carbonyl of the 800 nm-absorbing bchl in these proteins (b800), and that the presence of such an h-bond induces a ca. 10 nm red shift ... | 1997 | 9405063 |
| nucleotide sequences of genes coding for photosynthetic reaction centers and light-harvesting proteins of acidiphilium rubrum and related aerobic acidophilic bacteria. | the nucleotide sequences of the puf operons of the zn-bacteriochlorophyll a (zn-bchl a)-containing photosynthetic aerobic bacteria, acidiphilium rubrum and acidiphilium angustum, were determined. the nucleotide sequences of the pufl and -m of acidiphilium cryptum, acidiphilium multivorum, and acidiphilium organovorum were also determined. the puf operons of a. rubrum and a. angustum contained pufb, -a, -l, -m, and -c as seen in other purple bacteria with an unknown gene directly upstream of pufb ... | 1997 | 9435141 |
| the use of a long-lifetime component of tryptophan to detect slow orientational fluctuations of proteins. | the membrane protein porin and a synthetic polypeptide of 21 hydrophobic residues were inserted into detergent micelles or lipid membranes, and the fluorescence of their single tryptophan residue was measured in the time-resolved and polarized mode. in all cases, the tryptophan fluorescence exhibits a long-lifetime component of about 20 ns. this long-lifetime component was exploited to detect slow orientational motions in the range of tens of nanoseconds via the anisotropy decay. for this purpos ... | 1997 | 8994617 |
| a mammalian mitochondrial drug receptor functions as a bacterial "oxygen" sensor. | the rat mitochondrial outer membrane-localized benzodiazepine receptor (mbr) was expressed in wild-type and tspo- (tryptophan-rich sensory protein) strains of the facultative photoheterotroph, rhodobacter sphaeroides 2.4.1, and was shown to retain its structure within the bacterial outer membrane as assayed by its binding properties with a variety of mbr ligands. functionally, it was able to substitute for tspo by negatively regulating the expression of photosynthesis genes in response to oxygen ... | 1997 | 9144197 |
| association of lhialpha(b870) polypeptide with phospholipids during insertion in the photosynthetic membrane of an lhii- mutant of rhodobacter capsulatus. | membranes from in vivo labeled cells of rhodobacter capsulatus u43[ptx35] grown photosynthetically carried 60% of the [32p]-pi in the "heavy" fraction (hm) after sucrose gradient sedimentation. metal-chelating chromatography of either"heavy" or "light" (lm) membrane fractions rendered similar bchl-protein complex profiles after octyl-glucoside treatment,including most of the radioactivity in the same corresponding elution fraction (f ii). similar labeling distribution of pigment-protein complexe ... | 1997 | 9009068 |
| molecular cloning and functional characterization of the paracoccus denitrificans porin. | bacterial porins facilitate the passive uptake of small solutes across the outer membrane of the cell. the channel properties and the primary structure of the porin from paracoccus denitrificans were investigated. as judged from single-channel conductance experiments, this porin forms trimeric pores that show no ion selectivity in potassium chloride solution, which indicates that the charges within or near the channel are balanced. based on peptide fragment sequence, the gene porg, which codes f ... | 1997 | 9151957 |
| expression and epitope tagging of the membrane anchor subunit (dmsc) of escherichia coli dimethyl sulfoxide reductase. | escherichia coli dimethyl sulfoxide reductase is a heterotrimer comprising a catalytic subunit (dmsa), an electron transfer subunit (dmsb) and an integral membrane anchor subunit (dmsc). dmsc is not antigenic and the production of antibodies to this subunit has not been successful. we have tagged dmsc at the c-terminus with a dystrophin-specific amino acid sequence (dysp) to which antibodies are readily available. we were able to use this tagging technique to monitor expression and localization ... | 1997 | 9153079 |
| reactions of isocytochrome c2 in the photosynthetic electron transfer chain of rhodobacter sphaeroides. | rhodobacter sphaeroides strains lacking cytochrome c2 (cyt c2), the normal electron donor to p870+ in light-oxidized reaction center (rc) complexes, are unable to grow photosynthetically. however, spd mutations that suppress the photosynthetic deficiency of cyt c2 mutants elevate levels of the cyt c2 isoform, isocyt c2. we monitored photosynthetic electron transfer in whole cells, in chromatophores, and with purified components to ascertain if and how isocyt c2 reduced light-oxidized rc complexe ... | 1997 | 9020790 |
| membrane localization, topology, and mutual stabilization of the rnfabc gene products in rhodobacter capsulatus and implications for a new family of energy-coupling nadh oxidoreductases. | the rnf genes in rhodobacter capsulatus are unique nitrogen fixation genes that encode potential membrane proteins (rnfa, rnfd, and rnfe) and potential iron-sulfur proteins (rnfb and rnfc). in this study, we first analyzed the localization and topology of the rnfa, rnfb, and rnfc proteins. by activity and immunoblot analysis of expression of translational fusions to escherichia coli alkaline phosphatase, rnfa protein was shown to span the chromatophore membrane with its odd-numbered hydrophilic ... | 1997 | 9154934 |
| isolation, cloning, sequence analysis and x-ray structure of dimethyl sulfoxide/trimethylamine n-oxide reductase from rhodobacter capsulatus. | the periplasmic enzyme dimethyl sulfoxide/trimethylamine n-oxide reductase (dmsor/tmaor) from the photosynthetic purple bacterium rhodobacter capsulatus functions as the terminal electron acceptor in its respiratory chain. the enzyme catalyzes the reduction of highly oxidized substrates like dimethyl sulfoxide (dmso) or trimethylamine n-oxide (tmao). at a molybdenum redox centre, two single electrons are transferred from cytochrome c556 to the substrate, e.g. dmso, generating dimethyl sulfide (d ... | 1997 | 9165084 |
| organization of the dmso respiratory operon of rhodobacter capsulatus and its consequences for homologous expression of dmsor/tmaor. | in this report we describe the organization of the respiratory operon from the non-sulfur photosynthetic bacterium rhodobacter capsulatus and its consequences for homologous expression of recombinant dimethylsulfoxide/trimethylamine n-oxide reductase (dmsor/tmaor). this enzyme is of special interest since molybdopterin dinucleotide is its only cofactor. overexpression of the dmsa gene and production of active enzyme is not possible in e. coli because this bacterium is unable to supply the requir ... | 1997 | 9165085 |
| a native electrostatic environment near q(b) is not sufficient to ensure rapid proton delivery in photosynthetic reaction centers. | flash-induced absorption spectroscopy has been used to characterize rhodobacter capsulatus reaction centers mutated in the secondary quinone acceptor site (q(b). we compared the wild-type, the l212glu-l213asp --> ala-ala photosynthetically incompetent double mutant (dm), and two photocompetent revertants, the dm+l217arg --> cys and the dm+m5asn- --> asp strains. the electrostatic environment for q(b)- is different in the two revertant strains. only the l217arg --> cys mutation nearly restores th ... | 1997 | 9166891 |
| cloning, sequencing and expressing the carotenoid biosynthesis genes, lycopene cyclase and phytoene desaturase, from the aerobic photosynthetic bacterium erythrobacter longus sp. strain och101 in escherichia coli. | two genes which encode the enzymes lycopene cyclase and phytoene desaturase in the aerobic photosynthetic bacterium erythrobacter longus sp. strain och101 have been cloned and sequenced. the gene for lycopene cyclase, designated crty, was expressed in a strain of escherichia coli which contained the crte, b, i and z genes encoding geranylgeranyl pyrophosphate synthase, phytoene synthase, phytoene desaturase, and beta-carotene hydroxylase, respectively. as a result, zeaxanthin production was obse ... | 1997 | 9168123 |
| characterization and regulation of the gene encoding nitrite reductase in rhodobacter sphaeroides 2.4.3. | nitrite reductase catalyzes the reduction of nitrite to nitric oxide, the first step in denitrification to produce a gaseous product. we have cloned the gene nirk, which encodes the copper-type nitrite reductase from a denitrifying variant of rhodobacter sphaeroides, strain 2.4.3. the deduced open reading frame has significant identity with other copper-type nitrite reductases. analysis of the promoter region shows that transcription initiates 31 bases upstream of the translation start codon. th ... | 1997 | 9023188 |
| [photochemical reaction centers]. | 1997 | 9028167 | |
| demonstration that the bchh protein of rhodobacter capsulatus activates s-adenosyl-l-methionine:magnesium protoporphyrin ix methyltransferase. | the bchh gene of rhodobacter capsulatus has been cloned into an expression strain of escherichia coli. following induction of expression of the bchh protein, it was found that the e. coli strain also accumulated porphyrins with the fluorescence properties of protoporphyrin and zinc protoporphyrin. it was also found that the soluble bchh protein increased the activity of s-adenosyl-l-methionine:magnesium protoporphyrin ix methyltransferase, when mixed with membranes of an expression strain of e. ... | 1997 | 9175880 |
| resonance raman spectroscopy of 2h-labelled spheroidenes in petroleum ether and in the rhodobacter sphaeroides reaction centre. | as a step towards the structural analysis of the carotenoid spheroidene in the rhodobacter sphaeroides reaction centre, we present the resonance raman spectra of 14-2h, 15-2h, 15'-2h, 14'-2h, 14,15'-2h2 and 15-15'-2h2 spheroidenes in petroleum ether and, except for 14,15'-2h2 spheroidene, in the rb. sphaeroides r26 reaction center (rc). analysis of the spectral changes upon isotopic substitution allows a qualitative assignment of most of the vibrational bands to be made. for the all-trans sphero ... | 1997 | 9177038 |
| a new pathway for transmembrane electron transfer in photosynthetic reaction centers of rhodobacter sphaeroides not involving the excited special pair. | it is generally accepted that electron transfer in bacterial photosynthesis is driven by the first singlet excited state of a special pair of bacteriochlorophylls (p*). we have examined the first steps of electron transfer in a mutant of the rhodobacter sphaeroides reaction center in which charge separation from p* is dramatically slowed down. the results provide for the first time clear evidence that excitation of the monomeric bacteriochlorophyll in the active branch of the reaction center (b( ... | 1997 | 9188680 |
| comparative characterization of seca from the alpha-subclass purple bacterium rhodobacter capsulatus and escherichia coli reveals differences in membrane and precursor specificity. | we have cloned the seca gene of the alpha-subclass purple bacterium rhodobacter capsulatus, a close relative to the mitochondrial ancestor, and purified the protein after expression in escherichia coli. r. capsulatus seca contains 904 amino acids with 53% identity to e. coli and 54% identity to caulobacter crescentus seca. in contrast to the nearly equal partitioning of e. coli seca between the cytosol and plasma membrane, r. capsulatus seca is recovered predominantly from the membrane fraction. ... | 1997 | 9190818 |
| 6-ketocholestanol is a recoupler for mitochondria, chromatophores and cytochrome oxidase proteoliposomes. | the effect of 6-ketocholestanol (kch) on various natural and reconstituted membrane systems has been studied. 6-ketocholestanol (5 alpha-cholestan-3 beta-ol-6-one), a compound increasing the membrane dipole potential, completely prevents or reverses the uncoupling action of low concentrations of the most potent artificial protonophore sf6847. this effect can be shown in the rat liver and heart muscle mitochondria, in the intact lymphocytes, in the rhodobacter sphaeroides chromatophores, and in p ... | 1997 | 9030261 |
| anaerobic carotenoid biosynthesis in rhodobacter sphaeroides 2.4.1: h2o is a source of oxygen for the 1-methoxy group of spheroidene but not for the 2-oxo group of spheroidenone. | anaerobic biosynthesis of carotenoids in the purple facultative photosynthetic bacterium rhodobacter sphaeroides was studied using mass spectrometry. we have demonstrated that (18)o from h2(18)o was incorporated into the 1-methoxy group of spheroidene and spheroidenone, the two major carotenoids produced by this bacterium during photosynthetic growth. neither water nor co2 was shown to provide an oxygen atom for the 2-oxo group of spheroidenone in r. sphaeroides 2.4.1 grown photosynthetically in ... | 1997 | 9038350 |
| regulation of synthesis of pyruvate carboxylase in the photosynthetic bacterium rhodobacter capsulatus. | the synthesis of pyruvate carboxylase (pc) was studied by using quantitative immunoblot analysis with an antibody raised against pc purified from rhodobacter capsulatus and was found to vary 20-fold depending on the growth conditions. the pc content was high in cells grown on pyruvate or on carbon substrates metabolized via pyruvate (lactate, d-malate, glucose, or fructose) and low in cells grown on tricarboxylic acid (tca) cycle intermediates or substrates metabolized without intermediate forma ... | 1997 | 9045800 |