PMID(sorted descending)
studies in carotenogenesis. 9. general cultural conditions controlling carotenoid (spirilloxanthin) synthesis in the photosynthetic bacterium rhodospirillum rubrum. 195313032107
biosynthesis of c14-labeled protein and amino acids with rhodosprillum rubrum. 195212997241
tryptophan phosphorescence spectroscopy reveals that a domain in the nad(h)-binding component (di) of transhydrogenase from rhodospirillum rubrum has an extremely rigid and conformationally homogeneous protein core.the characteristics of tryptophan phosphorescence from the nad(h)-binding component (di) component of rhodospirillum rubrum transhydrogenase are described. this enzyme couples hydride transfer between nad(h) and nadp(h) to proton translocation across a membrane and is only active as a dimer. tryptophan phosphorescence spectroscopy is a sensitive technique for the detection of protein conformational changes and was used here to characterize di under mechanistically relevant conditions. our result ...200312972415
photosynthesis and growth of tobacco with a substituted bacterial rubisco mirror the properties of the introduced enzyme.complete replacement, by biolistic plastid transformation, of the hexadecameric ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) of tobacco (nicotiana tabacum) with the dimeric version from the bacterium, rhodospirillum rubrum, resulted in fully autotrophic and reproductive tobacco plants that required high co(2) concentrations to grow (whitney sm, andrews tj [2001] proc natl acad sci usa 98: 14738-14743). growth and photosynthesis of these plants was compared with that of nontransforme ...200312970494
circular symmetry of the light-harvesting 1 complex from rhodospirillum rubrum is not perturbed by interaction with the reaction center.the effect of the interaction of the reaction center (rc) upon the geometrical arrangement of the bacteriochlorophyll a (bchla) pigments in the light-harvesting 1 complex (lh1) from rhodospirillum rubrum has been examined using single molecule spectroscopy. fluorescence excitation spectra at 1.8 k obtained from single detergent-solubilized as well as single membrane-reconstituted lh1-rc complexes showed predominantly (>70%) a single broad absorption maximum at 880-900 nm corresponding to the q(y ...200312950162
inter- and intraspecific variation in excited-state triplet energy transfer rates in reaction centers of photosynthetic protein-cofactor reaction center (rc) complexes of purple photosynthetic bacteria, the major role of the bound carotenoid (c) is to quench the triplet state formed on the primary electron donor (p) before its sensitization of the excited singlet state of molecular oxygen from its ground triplet state. this triplet energy is transferred from p to c via the bacteriochlorophyll monomer b(b). using time-resolved electron paramagnetic resonance (trepr), we have examined the temperature dependence ...200312945578
modeling stability of photoheterotrophic continuous cultures in photobioreactors.continuous cultures of the purple non-sulfur bacterium rhodospirillum rubrum were grown in a cylindrical photobioreactor in photoheterotrophic conditions, using acetate as carbon source. a new kinetic and stoichiometric knowledge model was developed, and its ability to simulate experimental results obtained under varying incident light fluxes and residence times is discussed. the model accurately predicts the stable, unstable, or oscillating behavior observed for the reactor productivity. in par ...200312892484
modelling continuous culture of rhodospirillum rubrum in photobioreactor under light limited conditions.rhodospirillum rubrum was grown continuously and photoheterotrophically under light limitation using a cylindrical photobioreactor in which the steady state biomass concentration was varied between 0.4 to 4 kg m(-3) at a constant radiant incident flux of 100 w m(-2). kinetic and stoichiometric models for the growth are proposed. the biomass productivities, acetate consumption rate and the co2 production rate can be quantitatively predicted to a high level of accuracy by the proposed model calcul ...200312882553
the influence of detergents and amphiphiles on the solubility of the light-harvesting i complex.the effect of detergents and amphiphiles on protein solubility and their use in crystallization solutions was examined for an integral membrane protein, the light-harvesting i complex from rhodospirillum centenum. measurement by a centrifugation assay of the solubility of the protein in different detergents and amphiphiles showed high protein-solubility values when either octyl glucoside or lauryldimethylamine-n-oxide was present with heptanetriol or when deoxycholate was present with spermine. ...200312876344
activation mechanism of the co sensor cooa. mutational and resonance raman spectroscopic studies.cooa is a co-dependent heme protein transcription factor of the bacterium rhodospirillum rubrum. co binding to its heme causes cooa to bind dna and activate expression of genes for co metabolism. to understand the nature of co activation, several cooa mutational variants have been studied by resonance raman spectroscopy, in vivo activity measurements, and dna binding assays. analysis of the fe-c and c-o stretching raman spectroscopy bands permits the conclusion that when co displaces the pro2 he ...200312796503
a reaction center-light-harvesting 1 complex (rc-lh1) from a rhodospirillum rubrum mutant with altered esterifying pigments: characterization by optical spectroscopy and cryo-electron microscopy.introduction of the bchp gene from rhodobacter sphaeroides encoding geranylgeranyl reductase into rhodospirillum rubrum alters the esterification of the bacteriochlorophylls so that phytol is used instead of geranylgeraniol. the resulting transconjugant strain of rs. rubrum grows photosynthetically, showing that phytolated bchla can substitute for the native pigment in both the reaction center (rc) and the light-harvesting 1 (lh1) complexes. this genetic manipulation perturbs the native caroteno ...200312719425
pulsed high-frequency epr study on the location of carotenoid and chlorophyll cation radicals in photosystem ii.when the primary electron-donation pathway from the water-oxidation complex in photosystem ii (ps ii) is inhibited, chlorophyll (chl(z) and chl(d)), beta-carotene (car) and cytochrome b(559) are alternate electron donors that are believed to function in a photoprotection mechanism. previous studies have demonstrated that high-frequency epr spectroscopy (at 130 ghz), together with deuteration of ps ii, yields resolved car(+) and chl(+) epr signals (lakshmi et al. j. phys. chem. b 2000, 104, 10 44 ...200312708850
electron transport dynamics at the quinone acceptor site of bacterial photosynthetic reaction centers as probed using fast temperature changes.methods of laser-induced temperature jumps and fast freezing were used for testing the rates of thermoinduced conformational transitions of reaction center (rc) complexes in chromatophores and isolated rc preparations of various photosynthesizing purple bacteria. an electron transfer reaction from primary to secondary quinone acceptors was used as a probe of electron transport efficiency. the thermoinduced transition of the acceptor complex to the conformational state facilitating electron trans ...200312679860
rhodobacter sphaeroides has a family ii pyrophosphatase: comparison with other species of photosynthetic bacteria.the cytoplasmic pyrophosphatase from rhodobacter sphaeroides was purified and characterized. the enzyme is a homodimer of 64 kda. the n-terminus was sequenced and used to obtain the complete pyrophosphatase sequence from the preliminary genome sequence of rba. sphaeroides, showing extensive sequence similarity to family ii or class c pyrophosphatases. the enzyme hydrolyzes only mg-pp(i) and mn-pp(i) with a k(m) of 0.35 mm for both substrates. it is not activated by free mg (2+), in contrast to t ...200312669192
ni and co: more surprises. 200312660715
rhodospirillum rubrum has a family i pyrophosphatase: purification, cloning, and sequencing.the cytoplasmic pyrophosphatase of the photosynthetic bacterium rhodospirillum rubrum was purified to electrophoretic homogeneity. the enzyme is a homohexamer of 20-kda monomers. the gene was cloned and sequenced. alignment of the deduced 179-amino-acid protein with known bacterial pyrophosphatases revealed conservation of all residues in the active site. attempts to obtain an insertion mutant of the cytoplasmic pyrophosphatase gene did not yield any cell completely devoid of cytoplasmic pyropho ...200312658333
cd bioaccumulation by a freshwater bacterium, rhodospirillum bioaccumulation by rhodospirillum rubrum, a gram-negative freshwater bacterium, was studied in a synthetic medium. the free ion (cd2+) was the best predictor of the cd internalization fluxes. representation of the short-term uptake fluxes as a function of [cd2+] in the medium demonstrated a linear relationship, as would be expected for a rate-limiting, first-order internalization with a single transporter. nonetheless, several different accumulation profiles were observed, depending on the cd ...200312636267
[two-level heterogenous energy migration. modeling and application to purple bacteria].the dynamics of migration of electronic excitations and the efficiency of their trapping in two-dimensional ensembles of molecules were analyzed. molecules were characterized using the following parameters: the width of long-wavelength bands, the values of extinction and rate constant of deactivation of electronic excitations, critical distances of migration close to those of dye molecules, in particular, bacteriochlorophyll a and purple bacteria. a comparative analysis of two-dimensional models ...200312630112
complete spectra of the far-red chemiluminescence of the oxygenase reaction of mn2+-activated ribulose-bisphosphate carboxylase/oxygenase establish excited mn2+ as the source.chemiluminescence emitted by mn(2+)-activated ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) while catalyzing oxygenation was analyzed to clarify the source of the emission. using dual detectors capturing radiation over a wide range of visible and infrared wavelengths, we tested for radiation from singlet o(2) decay and found it to be essentially absent (less than 0.1% of the total luminescence intensity). spectra were determined between 647 and 885 nm with a very sensitive, charge-co ...200312604603
isolation and molecular characterization of pmg160, a mobilizable cryptic plasmid from rhodobacter blasticus.a 3.4-kb cryptic plasmid was obtained from a new isolate of rhodobacter blasticus. this plasmid, designated pmg160, was mobilizable by the conjugative strain escherichia coli s17.1 into rhodobacter sphaeroides, rhodobacter capsulatus, and rhodopseudomonas palustris. it replicated in the latter strains but not in rhodospirillum rubrum, rhodocyclus gelatinosus, or bradyrhizobium species. plasmid pmg160 was stably maintained in r. sphaeroides for more than 100 generations in the absence of selectio ...200312570988
single-molecule study of the electronic couplings in a circular array of molecules: light-harvesting-2 complex from rhodospirillum molischianum.applying single-molecule spectroscopic techniques allowed us to determine the mutual angles between the transition-dipole moments associated with optical transitions of the eight bacteriochlorophyll a molecules which form the so-called b800 ring of the light-harvesting-2 complex from rhodospirillum molischianum. the orientation of the transition-dipole moment is a sensitive probe for the strength of the local intermolecular interactions because of the well-defined arrangement of the individual m ...200312570608
glutamine 132 in the nad(h)-binding component of proton-translocating transhydrogenase tethers the nucleotides before hydride transfer.transhydrogenase, found in bacterial membranes and inner mitochondrial membranes of animal cells, couples the redox reaction between nad(h) and nadp(h) to proton translocation. in this work, the invariant gln132 in the nad(h)-binding component (di) of the rhodospirillum rubrum transhydrogenase was substituted with asn (to give di.q132n). mixtures of the mutant protein and the nadp(h)-binding component (diii) of the enzyme readily produced an asymmetric complex, (di.q132n)(2)diii(1). the x-ray st ...200312564924
crystal structure of a photoactive yellow protein from a sensor histidine kinase: conformational variability and signal transduction.photoactive yellow protein (e-pyp) is a blue light photoreceptor, implicated in a negative phototactic response in ectothiorhodospira halophila, that also serves as a model for the per-arnt-sim superfamily of signaling molecules. because no biological signaling partner for e-pyp has been identified, it has not been possible to correlate any of its photocycle intermediates with a relevant signaling state. however, the pyp domain (ppr-pyp) from the sensor histidine kinase ppr in rhodospirillum cen ...200312563032
identification and preliminary characterization of acsf, a putative ni-insertase used in the biosynthesis of acetyl-coa synthase from clostridium thermoaceticum.the acsabcde genes in the clostridium thermoaceticum genome are used for autotrophic acetyl-coa synthesis using the wood-ljungdahl pathway. a 2.8-kb region between acsc and acsd was cloned and sequenced. two open reading frames, orf7 (approximately 1.9 kb) and acsf (approximately 0.7 kb) were identified. orf7 appears to encode an fe-s protein, in that it contains five conserved cysteine residues, three of which are present in a motif (cggxxxcgxc) commonly used to coordinate fe-s clusters. howeve ...200312538050
low-intensity pump-probe measurements on the b800 band of rhodospirillum molischianum.we have measured low-intensity, polarized one-color pump-probe traces in the b800 band of the light-harvesting complex lh2 of rhodospirillum molischianum at 77 k. the excitation/detection wavelength was tuned through the b800 band. a single-wavelength and a global target analysis of the data were performed with a model that accounts for excitation energy transfer among the b800 molecules and from b800 to b850. by including the anisotropy of the signals into the fitting procedure, both transfer p ...200312524297
repositioning about the dimer interface of the transcription regulator cooa: a major signal transduction pathway between the effector and dna-binding domains.activation of the homodimeric transcriptional regulator cooa depends on the coupling of co binding at an effector domain heme with the allosteric repositioning of the dna-binding domain f-helix that promotes specific dna interaction. by analogy to the homologous camp receptor protein (crp), it has been proposed that effector binding elicits subunit reorientation about their coiled-coil c-helix interface, and that this effector domain reorientation stabilizes the active position of the dna-bindin ...200312507482
phylogenetic relationships of the helical-shaped bacteria in the alpha proteobacteria inferred from 16s rdna sequences.16s ribosomal rna gene sequences from seven strains of aquaspirillum peregrinum, aqu. itersonii, aqu. polymorphum, and oceanospirillum pusillum were compared with homologous sequences from other members of helical-shaped bacteria. the bootstrapped neighbor-joining tree, inferred from 887 aligned sites, placed the spirillum taxa assigned to aquaspirillum, oceanospirillum, azospirillum, magnetospirillum, rhodospirillum, and rhodocista of the proteobacteria in seven clusters of alpha proteobacteria ...199712501339
time-resolved dissociation of the light-harvesting 1 complex of rhodospirillum rubrum, studied by infrared laser temperature jump.for the first time, data are presented on the time-resolved disassembly reaction of a highly organized membrane protein complex in vitro. the photosynthetic core light-harvesting complex of the bacterial strain rhodospirillum rubrum g9 consists of 12-16 dimeric subunits that in vivo are associated with the photosynthetic reaction center in a ringlike manner. isolated in a detergent solution, its appearance either as a ringlike complex (called b873 and absorbing at 873 nm), subunit dimer (called ...200212484747
the role of the hydrophobic distal heme pocket of cooa in ligand sensing and response.cooa from rhodospirillum rubrum is a heme-containing transcriptional activator that becomes activated only upon binding co. the basis for this specificity has been probed in a cooa variant, termed deltap3r4 cooa, lacking two residues adjacent to the pro(2) heme ligand, which weakens that ligand. deltap3r4 cooa can bind imidazole and cn(-), as well as co, and form a 6-coordinate low spin adduct with each. however, in contrast to the case with co, imidazole and cn(-) do not stimulate the dna bindi ...200312433917
inhibition of acetate and propionate assimilation by itaconate via propionyl-coa carboxylase in isocitrate lyase-negative purple bacterium rhodospirillum rubrum.itaconate is known as a potent inhibitor of isocitrate lyase. unexpectedly, itaconate was a strong inhibitor of acetate and propionate assimilation in isocitrate lyase-negative purple non-sulfur bacterium rhodospirillum rubrum. it was shown that in cell extracts of r. rubrum itaconate inhibited propionyl-coa carboxylase (pcc) activity. the participation of pcc in propionate assimilation in r. rubrum is well-documented, but the inhibition of acetate assimilation suggests that pcc is also involved ...200212423751
crystal structures of transhydrogenase domain i with and without bound nadh.transhydrogenase (th) is a dimeric integral membrane enzyme in mitochondria and prokaryotes that couples proton translocation across a membrane with hydride transfer between nad(h) and nadp(h) in soluble domains. crystal structures of the nad(h) binding alpha1 subunit (domain i) of rhodospirillum rubrum th have been determined at 1.8 a resolution in the absence of dinucleotide and at 1.9 a resolution with nadh bound. each structure contains two domain i dimers in the asymmetric unit (ab and cd); ...200212379117
characterization of three spiral-shaped purple nonsulfur bacteria isolated from coastal lagoon sediments, saline sulfur springs, and microbial mats: emended description of the genus roseospira and description of roseospira marina sp. nov., roseospira navarrensis sp. nov., and roseospira thiosulfatophila sp. nov.three new spirilloid phototrophic purple nonsulfur bacteria were isolated in pure culture from three different environments: strain ce2105 from a brackish lagoon in the arcachon bay (atlantic coast, france), strain se3104 from a saline sulfur spring in the pyrenees (navarra, spain), and strain at2115 a microbial mat (tetiaroa atoll, society islands). single cells of the three strains were spiral-shaped and highly motile. their intracellular photosynthetic membranes were of the vesicular type. ba ...200212375098
converting the nifes carbon monoxide dehydrogenase to a hydrogenase and a hydroxylamine reductase.substitution of one amino acid for another at the active site of an enzyme usually diminishes or eliminates the activity of the enzyme. in some cases, however, the specificity of the enzyme is changed. in this study, we report that the changing of a metal ligand at the active site of the nifes-containing carbon monoxide dehydrogenase (codh) converts the enzyme to a hydrogenase or a hydroxylamine reductase. codh with alanine substituted for cys(531) exhibits substantial uptake hydrogenase activit ...200212374822
spectroscopic characterisation of a tetrameric subunit form of the core antenna protein from rhodospirillum rubrum.the core light-harvesting complex (lh1) of rhodospirillum rubrum is constituted of multiple heterodimeric subunits, each containing two transmembrane polypeptides, alpha and beta. the detergent octylglucoside induces the stepwise dissociation of lh1 into b820 (an alphabeta dimer) and b777 (monomeric polypeptides), both of which still retain their bound bacteriochlorophyll molecules. we have investigated the absorption properties of b820 as a function of temperature, whereby a spectral population ...200212297309
biochemical characterization of the dissociated forms from the core antenna proteins from purple bacteria.the core light-harvesting protein from rhodospirillum rubrum is of particular interest for studying membrane polypeptide association, as it can be reversibly dissociated in the presence of n-octyl-beta-d-glucopyranoside (betaog) into smaller subunit forms, which exhibit dramatically blue-shifted absorption properties (miller et al. (1987) biochemistry 26, 5055-5062). during this dissociation/reassociation process, two main spectroscopic forms are observed, absorbing at 820 (b820) and 777 (b777) ...200212269824
cloning a gene encoding a light-harvesting i polypeptide from ectothiorhodospira sp.trying to detect the genes coding for light harvesting ii polypeptides of the purple bacteria ectothiorhodospira sp. a gene corresponding to a light harvesting i polypeptide was cloned. this paper discusses the probable reasons of this result. the sequence of this polypeptide underlines the strong similarity with light harvesting complexes from bacteria such as rhodospirillum molischianum and chromatium vinosum.200212240998
aminomethylenediphosphonate: a potent type-specific inhibitor of both plant and phototrophic bacterial h+-pyrophosphatases.the suitability of different pyrophosphate (ppi) analogs as inhibitors of the vacuolar h+-translocating inorganic pyrophosphatase (v-ppase; ec of tonoplast vesicles isolated from etiolated hypocotyls of vigna radiata was investigated. five 1,1-diphosphonates and imidodiphosphate were tested for their effects on substrate hydrolysis by the v-ppase at a substrate concentration corresponding to the km of the enzyme. the order of inhibitory potency (apparent inhibition constants, kiapp valu ...199412232069
photosynthetic fractionation of the stable isotopes of oxygen and carbon.isotope discrimination during photosynthetic exchange of o2 and co2 was measured using enzyme, thylakoid, and whole cell preparations. evolved oxygen from isolated spinach thylakoids was isotopically identical (within analytical error) to its source water. similar results were obtained with anacystis nidulans richter and phaeodactylum tricornutum bohlin cultures purged with helium. for consumptive reactions, discrimination ([delta], where 1 + [delta]/1000 equals the isotope effect, k16/k18 or k1 ...199312231663
supramolecular organisation of the photosynthetic chain in anoxygenic bacteria.this minireview summarizes our present view of the supramolecular organization of the photosynthetic apparatus of rhodobacter sphaeroides and rhodobacter capsulatus. these two species present a close association between two reaction centers (rcs), one cytochrome (cyt) bc(1) and one cyt c. in r. sphaeroides, the rcs are only partially surrounded by lh1 complexes. this open ring of lh1 complexes is required for an efficient photoinduced cyclic electron transfer only under conditions where the quin ...200212206892
a conformational change in the isolated nadp(h)-binding component (diii) of transhydrogenase induced by low ph: a reflection of events during proton translocation by the complete enzyme?transhydrogenase couples the reduction of nadp(+) by nadh to inward proton translocation across the bacterial (or mitochondrial) membrane. conformational changes in the nadp(h)-binding component of the enzyme (diii) are central to the coupling mechanism. in the "open" state, nadp(h) bound to diii can readily exchange with nucleotides in the solvent but hydride transfer [to/from nad(h) bound to di] is prevented. in the "occluded" state, bound nadp(h) cannot exchange with solvent nucleotides but t ...200212206884
carbon monoxide dehydrogenase from rhodospirillum rubrum produces formate.carbon monoxide dehydrogenase (codh) from rhodospirillum rubrum reversibly catalyzes the oxidation of co to co(2) at the active site c-cluster. in this article, the reduction of co(2) to formate is reported as a slow side reaction catalyzed by both ni-containing codh and ni-deficient codh. recently, the structures of r. rubrum codh and its active site nifes cluster (the c-cluster) have been solved. the data in this manuscript describe the formate-producing capability of codh with or without ni i ...200212203017
spectroscopy on individual light-harvesting 1 complexes of rhodopseudomonas this paper the fluorescence-excitation spectra of individual lh1-rc complexes (rhodopseudomonas acidophila) at 1.2 k are presented. all spectra show a limited number of broad bands with a characteristic polarization behavior, indicating that the excitations are delocalized over a large number of pigments. a significant variation in the number of bands, their bandwidths, and polarization behavior is observed. only 30% of the spectra carry a clear signature of delocalized excited states of a ci ...200212202393
thalassospira lucentensis gen. nov., sp. nov., a new marine member of the alpha-proteobacteria.a novel bacterium from the mediterranean sea was isolated under oligotrophic conditions at in situ temperature after prolonged continuous culture. the isolates were initially characterized by partial 16s rrna gene sequencing. similarity searches of one of the isolates, qmt2t, indicated high sequence identity to the well-characterized rhodospirillum rubrum, [aquaspirillum] itersonii and [oceanospirillum] pusillum micro-organisms, which are representatives of the alpha-subclass of the proteobacter ...200212148640
projection structure of the photosynthetic reaction centre-antenna complex of rhodospirillum rubrum at 8.5 a resolution.two-dimensional crystals of the reaction-centre-light-harvesting complex i (rc-lh1) of the purple non- sulfur bacterium rhodospirillum rubrum have been formed from detergent-solubilized and purified protein complexes. unstained samples of this intrinsic membrane protein complex have been analysed by electron cryomicroscopy (cryo em). projection maps were calculated to 8.5 a from two different crystal forms, and show a single reaction centre surrounded by 16 lh1 subunits in a ring of approximatel ...200212145194
analysis of the l116k variant of cooa, the heme-containing co sensor, suggests the presence of an unusual heme ligand resulting in novel activity.cooa is the co-sensing transcriptional activator from rhodospirillum rubrum, in which co binding to its heme prosthetic group triggers a conformational change of cooa that allows the protein to bind its cognate target dna sequence. by a powerful in vivo screening method following the simultaneous randomization of the codons for two c-helix residues, 113 and 116, near the distal heme pocket of cooa, we have isolated a series of novel cooa variants. in vivo, these show very high co-independent act ...200212121986
a quantum chemistry study of binding carotenoids in the bacterial light-harvesting complexes.carotenoids play the dual function of light harvesting and photoprotection in photosynthetic organisms. despite their functional importance, the molecular basis for binding of carotenoids in the photosynthetic proteins is poorly understood. we have discovered that all carotenoids are surrounded either by aromatic residues or by chlorophylls in all known crystal structures of the photosynthetic pigment-protein complexes. the intermolecular pi-pi stacking interactions between carotenoids and the s ...200212105926
evidence for a wide occurrence of proton-translocating pyrophosphatase genes in parasitic and free-living protozoa.proton-translocating inorganic pyrophosphatases (h(+)-ppase, ec are integral membrane proteins that have been extensively studied in higher plants, the photosynthetic bacterium rhodospirillum rubrum and, more recently, in some human pathogenic protozoa. by using a pcr-based approach, fragments of genes coding for h(+)-ppases in a number of protists, both free-living and parasites of animals and plants, that belong to diverse taxonomic groups (trypanosomatids, ciliates, apicomplexans, eu ...200212056804
n-terminal methylation of the core light-harvesting complex in purple photosynthetic bacteria.several core light-harvesting complexes from both sulfur and non-sulfur purple photosynthetic bacteria have been identified to be methylated at the n-terminal alpha-amino group of beta-polypeptides by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and nuclear magnetic resonance. monomethylation has been confirmed for the n-terminal alanine residues of the beta-polypeptides from rhodospirillum rubrum, thermochromatium tepidum and chromatium vinosum, but not for ...200212023037
bioreactor design studies for a hydrogen-producing bacterium.carbon monoxide (co) can be metabolized by a number of microorganisms along with water to produce hydrogen (h2) and carbon dioxide. national renewable energy laboratory researchers have isolated a number of bacteria that perform this so-called water-gas shift reaction at ambient temperatures. we performed experiments to measure the rate of co conversion and h2 production in a trickle-bed reactor (tbr). the liquid recirculation rate and the reactor support material both affected the mass transfer ...200212018287
bacteriophytochrome controls photosystem synthesis in anoxygenic bacteria.plants use a set of light sensors to control their growth and development in response to changes in ambient light. in particular, phytochromes exert their regulatory activity by switching between a biologically inactive red-light-absorbing form (pr) and an active far-red-light absorbing form (pfr). recently, biochemical and genetic studies have demonstrated the occurrence of phytochrome-like proteins in photosynthetic and non-photosynthetic bacteria--but little is known about their functions. he ...200212000965
photosynthetic apparatus of purple bacteria. 200211997980
an alternative carotenoid-to-bacteriochlorophyll energy transfer pathway in photosynthetic light and green sunlight become available for photosynthetic energy conversion through the light-harvesting (lh) function of carotenoids, which involves transfer of carotenoid singlet excited states to nearby (bacterio)chlorophylls (bchls). the excited-state manifold of carotenoids usually is described in terms of two singlet states, s(1) and s(2), of which only the latter can be populated from the ground state by the absorption of one photon. both states are capable of energy transfer to (b)chl. ...200211972067
[modeling of energy migration and trapping in purple bacteria. analysis of extreme formulae].homogeneous pigment ensembles similar to those of purple bacteria rhodospirillum rubrum were studied. two formulae were advanced for the limiting values of excitation lifetime and quantum yield of excitation trapping in these ensembles, provided all reaction centers are in an active state. it was demonstrated by mathematical modeling that these limiting values strictly depend on three parameters of molecular ensembles: the numbers of core-bacteriochlorophyll molecules per reaction center, the va ...200211969165
the reaction order of the dissociation reaction of the b820 subunit of rhodospirillum rubrum light-harvesting i complex.we have studied the equilibrium between the dissociated b777 form (absorbing at 777 nm) of the light-harvesting complex of rhodospirillum rubrum and the oligomeric b820 form. analysis of the reaction order for the b820 dissociation reaction to form b777 shows that this reaction depends on the concentration of octylglucoside detergent (n-octyl-beta-d-glucopyranoside (betaog)) present in the sample. at low betaog concentrations (less than 1.2%) this reaction requires two components, presumably one ...200211959099
h+-pyrophosphatase of rhodospirillum rubrum. high yield expression in escherichia coli and identification of the cys residues responsible for inactivation my mersalyl.h(+)-translocating pyrophosphatase (h(+)-ppase) of the photosynthetic bacterium rhodospirillum rubrum was expressed in escherichia coli c43(de3) cells. recombinant h(+)-ppase was observed in inner membrane vesicles, where it catalyzed both pp(i) hydrolysis coupled with h(+) transport into the vesicles and pp(i) synthesis. the hydrolytic activity of h(+)-ppase in e. coli vesicles was eight times greater than that in r. rubrum chromatophores but exhibited similar sensitivity to the h(+)-ppase inhi ...200211956221
rhodospirillum centenum utilizes separate motor and switch components to control lateral and polar flagellum rotation.rhodospirillum centenum is a purple photosynthetic bacterium that is capable of differentiating from vibrioid swimming cells that contain a single polar flagellum into rod-shaped swarming cells that have a polar flagellum plus numerous lateral flagella. microscopic studies have demonstrated that the polar flagellum is constitutively present and that the lateral flagella are found only when the cells are grown on solidified or viscous medium. in this study, we demonstrated that r. centenum contai ...200211948156
formation of glyoxylate from alpha-hydroxyglutarate by rhodospirillum rubrum. 197011947489
the occurrence of hydroxy-derivatives of phytoene and phytofluene in diphenylamine-inhibited cultures of rhodospirillum rubrum. 197011947408
on the nature of the light-induced bacteriochlorophyll absorbance changes in chromatophores of rhodospirillum rubrum. 197311947102
dissociation-produced loss of regulatory control of homoserine dehydrogenase of rhodospirillum rubrum. 196911946964
partial resolution of energy-linked reactions in rhodospirillum rubrum chromatophores. 196911946959
a coupling factor from rhodospirillum rubrum chromatophores. 197211946452
energy-linked changes of the membrane of rhodospirillum rubrum chromatophores detected by the fluorescent probe 8-anilinonaphthalene-1-sulfonic acid. 197111945994
relationship between light-induced quenching of atebrin fluorescence and atp formation in rhodospirillum rubrum chromatophores. 197111945647
isolation of a "basic membrane" fraction enriched in an ornithine-containing lipid, from a blue-green mutant of rhodospirillum rubrum. 197011945444
bacterial photosynthesis begins with quantum-mechanical the antenna system of photosynthetic bacteria, pigments form circular aggregates whose excitations are excitons with quantum-mechanical coherence extending over many pigments. these excitons play crucial roles in light harvesting, storage, and excitation-energy transfer (eet). eet takes place rapidly to and/or from optically forbidden exciton states, without total transition dipole, within the antenna system and to the reaction center. such eets cannot be rationalized by förster's formula, th ...200111933253
absorption and cd spectroscopy and modeling of various lh2 complexes from purple bacteria.the absorption (od) and circular dichroism (cd) spectra of lh2 complexes from various purple bacteria have been measured and modeled. based on the lineshapes of the spectra we can sort the lh2 complexes into two distinguishable groups: "acidophila"-like (type 1) and "molischianum"-like (type 2). starting from the known geometric structures of rhodopseudomonas (rps.) acidophila and rhodospirillum (rsp.) molischianum we can model the od and cd spectra of all species by just slightly varying some k ...200211916874
photosynthetic apparatus in roseateles depolymerans 61a is transcriptionally induced by carbon limitation.production of a photosynthetic apparatus in roseateles depolymerans 61a, a recently discovered freshwater beta-proteobacterium showing characteristics of aerobic phototrophic bacteria, was observed when the cells were subjected to a sudden decrease in carbon sources (e.g., when cells grown with 0.1 to 0.4% casamino acids were diluted or transferred into medium containing <or=0.04% casamino acids). accumulation of bacteriochlorophyll (bchl) a was observed in the presence of oxygen and was enhance ...200211916683
excitons in a photosynthetic light-harvesting system: a combined molecular dynamics, quantum chemistry, and polaron model study.the dynamics of pigment-pigment and pigment-protein interactions in light-harvesting complexes is studied with an approach that combines molecular dynamics simulations with quantum chemistry calculations and a polaron model analysis. the molecular dynamics simulation of light-harvesting (lh) complexes was performed on an 87 055 atom system comprised of a lh-ii complex of rhodospirillum molischianum embedded in a lipid bilayer and surrounded with appropriate water layers. for each of the 16 b850 ...200211909121
general random matrix approach to account for the effect of static disorder on the spectral properties of light harvesting systems.we develop a random matrix model approach to study static disorder in pigment-protein complexes in photosynthetic organisms. as a case study, we examine the ring of b850 bacteriochlorophylls in the peripheral light-harvesting complex of rhodospirillum molischianum, formulated in terms of an effective hamiltonian describing the collective electronic excitations of the system. we numerically examine and compare various models of disorder and observe that both the density of states and the absorpti ...200211909118
rhodospirillum rubrum possesses a variant of the bchp gene, encoding geranylgeranyl-bacteriopheophytin reductase.the bchp gene product of rhodobacter sphaeroides is responsible for the reduction of the isoprenoid moiety of bacteriochlorophyll (bchl) from geranylgeraniol (gg) to phytol; here, we show that this enzyme also catalyzes the reduction of the isoprenoid moiety of bacteriopheophytin (bphe). in contrast, we demonstrate that a newly identified homolog of this gene in rhodospirillum rubrum encodes an enzyme, gg-bphe reductase, capable of reducing the isoprenoid moiety of bphe only. we propose that rho ...200211872709
calculability analysis in underdetermined metabolic networks illustrated by a model of the central metabolism in purple nonsulfur bacteria.metabolite balancing has turned out to be a powerful computational tool in metabolic engineering. however, the linear equation systems occurring in this analysis are often underdetermined. if it is difficult or impossible to find the missing constraints, it is nevertheless feasible in some cases to determine the values of a subset of the unknown rates. here, a procedure for finding out which reaction rates can be uniquely calculated in underdetermined metabolic networks and computing these rates ...200211835134
unsuspected diversity among marine aerobic anoxygenic phototrophs.aerobic, anoxygenic, phototrophic bacteria containing bacteriochlorophyll a (bchla) require oxygen for both growth and bchla synthesis. recent reports suggest that these bacteria are widely distributed in marine plankton, and that they may account for up to 5% of surface ocean photosynthetic electron transport and 11% of the total microbial community. known planktonic anoxygenic phototrophs belong to only a few restricted groups within the proteobacteria alpha-subclass. here we report genomic an ...200211832943
spectroscopic studies of nickel-deficient carbon monoxide dehydrogenase from rhodospirillum rubrum: nature of the iron-sulfur clusters.carbon monoxide dehydrogenase (codh) from rhodospirillum rubrum utilizes three types of fe-s clusters to catalyze the reversible oxidation of co to co(2): a novel [ni4fe5s] active site (c cluster) and two distinct [4fe4s] electron-transfer sites (b and d clusters). while recent x-ray data show the geometric arrangement of the five metal centers at the c cluster, electronic structures of the various [ni4fe5s] oxidation states remain ambiguous. these studies report magnetic circular dichroism (mcd ...200211814363
effect of carotenoids on the interaction between pigment-protein complexes in membranes of the sulfur photosynthetic bacterium chromatium minutissimum. 200111813560
the 7.5-a electron density and spectroscopic properties of a novel low-light b800 lh2 from rhodopseudomonas palustris.a novel low-light (ll) adapted light-harvesting complex ii has been isolated from rhodopseudomonas palustris. previous work has identified a ll b800-850 complex with a heterogeneous peptide composition and reduced absorption at 850 nm. the work presented here shows the 850 nm absorption to be contamination from a high-light b800-850 complex and that the true ll light-harvesting complex ii is a novel b800 complex composed of eight alpha beta(d) peptide pairs that exhibits unique absorption and ci ...200211806936
evidence for three distinct hydrogenase activities in rhodospirillum rubrum.inducer, inhibitor, and mutant studies on three hydrogenase activities of rhodospirillum rubrum indicate that they are mediated by three distinct hydrogenase enzymes. uptake hydrogenase mediates h2 uptake to an unknown physiological acceptor or methylene blue and is maximally synthesized during autotrophic growth in light. formate-linked hydrogenase is synthesized primarily during growth in darkness or when light becomes limiting, and links formate oxidation to h2 production. carbon-monoxide-lin ...200111778889
structure of the rhodobacter sphaeroides light-harvesting 1 beta subunit in detergent micelles.the light harvesting 1 antenna (lh1) complex from rhodobacter sphaeroides funnels excitation energy to the photosynthetic reaction center. our ultimate goal is to build up the structure of lh1 from structures of its individual subunits, much as the antenna can self-assemble from its components in membrane-mimicking detergent micelles. the beta subunit adopts a nativelike conformation in zwittergent 3:12 micelles as demonstrated by its ability to take the first step of assembly, binding bchl a. m ...200211772000
plastome-encoded bacterial ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) supports photosynthesis and growth in tobacco.the efficiency with which crop plants use their resources of light, water, and fertilizer nitrogen could be enhanced by replacing their co(2)-fixing enzyme, d-ribulose-1,5-bisphosphate carboxylase-oxygenase (rubisco), with more efficient forms, such as those found in some algae, for example. this important challenge has been frustrated by failure of all previous attempts to substitute a fully functional, foreign rubisco (efficient or inefficient) into higher plants. this failure could be caused ...200111724961
hydrophobicity and prediction of the secondary structure of membrane proteins and peptides.reliability of the hydropathy method to predict the formation of membrane-spanning alpha-helices by integral membrane proteins and peptides whose structure is known from x-ray crystallography is analysed. it is shown that kyte-doolittle hydropathy plots do not predict accurately 22 transmembrane alpha-helices in the reaction centres (rc) of the photosynthetic bacteria rhodopseudomonas viridis and rhodobacter sphaeroides (r-26). the accuracy of prediction for these proteins was improved using an ...200111699870
photophysical characterization of natural means of steady-state fluorescence spectroscopy we explore the photophysics of two lowest lying singlet excited states in two natural 15-cis-carotenoids, namely phytoene and phytofluene, possessing three and five conjugated double bonds (n), respectively. the results are interpreted in relation to the photophysics of all-transcarotenoids with varying n. the fluorescence of phytofluene is more stokes-shifted relative to that of phytoene, and is ascribed to the forbidden s1-->s0 transition, wit ...200111683034
structure of cytochrome c2 from rhodospirillum centenum.cytochrome c(2) from the purple photosynthetic bacterium rhodospirillum centenum has been crystallized by the sitting-drop vapour-diffusion method. the crystals belong to the orthorhombic space group p2(1)2(1)2(1), with unit-cell parameters a = 29.7, b = 59.9, c = 65.4 a, and diffract to a resolution limit of 1.7 a. the fe-atom position was determined from its anomalous scattering contribution and a molecular-replacement solution was calculated. the correctness of the solution was confirmed by p ...200111679712
oligomerization of light-harvesting i antenna peptides of rhodospirillum rubrum.we investigated the oligomerization of the core light-harvesting complex (lh1) of rhodospirillum rubrum from the separated alpha beta bchl(2) subunits (b820) and the oligomerization of the b820 subunit from its monomeric peptides. the full lh1 complex was reversibly associated from b820 subunits by either varying the temperature in the range 277-300 k or by varying the detergent concentration in the buffer from 0.36 to 0.52% n-octyl-beta-d-glucopyranoside. temperature-induced transition measurem ...200111669628
supramolecular arrangement of rhodospirillum rubrum b880 holochrome as studied by radiation inactivation and electron paramagnetic resonance.oxidation of the b880 antenna holochrome gives rise to a 3.8-g linewidth electron paramagnetic resonance (epr) signal that is considerably narrower than the 13-g signal of monomeric bacteriochlorophyll (bchl) cation. radiation inactivation was used to verify a model according to which this linewidth narrowing is due to delocalization over several bchl molecules. chromatophores of the photoreaction centerless mutant f24 of rhodospirillum rubrum were subjected to different doses of gamma-radiation ...199011607076
time-dependent changes in the carotenoid composition and preferential binding of spirilloxanthin to the reaction center and anhydrorhodovibrin to the lh1 antenna complex in rhodobium marinum.carotenoids were isolated from the cells of rhodobium marinum, and their structures were determined by mass spectrometry and 1h nuclear magnetic resonance spectroscopy; the carotenoids include lycopene, rhodopin, anhydrorhodovibrin, rhodovibrin and spirilloxanthin. time-dependent changes in the carotenoid composition in the reaction center (rc) and the light-harvesting complex 1 (lh1) were traced by high-performance liquid chromatography analysis of the extracts. the carotenoid composition chang ...200111594059
life on carbon monoxide: x-ray structure of rhodospirillum rubrum ni-fe-s carbon monoxide dehydrogenase.a crystal structure of the anaerobic ni-fe-s carbon monoxide dehydrogenase (codh) from rhodospirillum rubrum has been determined to 2.8-a resolution. the codh family, for which the r. rubrum enzyme is the prototype, catalyzes the biological oxidation of co at an unusual ni-fe-s cluster called the c-cluster. the ni-fe-s c-cluster contains a mononuclear site and a four-metal cubane. surprisingly, anomalous dispersion data suggest that the mononuclear site contains fe and not ni, and the four-metal ...200111593006
conformational dynamics of the transcriptional regulator cooa protein studied by subpicosecond mid-infrared vibrational spectroscopy.cooa, which is a transcriptional regulator heme protein allosterically triggered by co, is studied by femtosecond visible-pump mid-ir-probe spectroscopy. transient bleaching upon excitation of the heme in the soret band is detected at approximately 1979 cm(-1), which is the absorption region of the co bound to the heme. the bleach signal shows a nonexponential decay with time constants of 56 and 290 ps, caused by the rebinding of the co to the heme. about 98% of dissociated co recombines geminat ...200111592884
functional characterization of three glnb homologs in the photosynthetic bacterium rhodospirillum rubrum: roles in sensing ammonium and energy status.the glnb (p(ii)) protein, the product of glnb, has been characterized previously in the photosynthetic bacterium rhodospirillum rubrum. here we describe identification of two other p(ii) homologs in this organism, glnk and glnj. although the sequences of these three homologs are very similar, the molecules have both distinct and overlapping functions in the cell. while glnb is required for activation of nifa activity in r. rubrum, glnk and glnj do not appear to be involved in this process. in co ...200111591658
fast hydride transfer in proton-translocating transhydrogenase revealed in a rapid mixing continuous flow device.transhydrogenase couples the redox reaction between nad(h) and nadp(h) to proton translocation across a membrane. coupling is achieved through changes in protein conformation. upon mixing, the isolated nucleotide-binding components of transhydrogenase (di, which binds nad(h), and diii, which binds nadp(h)) form a catalytic di(2).diii(1) complex, the structure of which was recently solved by x-ray crystallography. the fluorescence from an engineered trp in diii changes when bound nadp(+) is reduc ...200111577115
detection of bacteria in environmental samples by direct pcr without dna extraction.cultured cells and environmental samples were used directly in pcrs without the isolation of dna. serial dilution was used to eliminate the inhibitory effect of materials in natural samples. primers specific for pmoa, which encodes a subunit of the particulate methane monooxygenase, were used to detect and quantify methanotrophic bacteria by direct most probable number pcr. phototrophic bacteria were detected in environmental samples by direct pcr with primers specific for pufm, and members of t ...200111570503
the heme pocket afforded by gly117 is crucial for proper heme ligation and activity of cooa.cooa, a co-sensing homodimeric transcription activator from rhodospirillum rubrum, undergoes a conformational change in response to co binding to its heme prosthetic group that allows it to bind specific dna sequences. in a recent structural study (lanzilotta, w. n., schuller, d. j., thorsteinsson, m. v., kerby, r. l., roberts, g. p., and poulos, t. l. (2000) nat. struct. biol. 7, 876-880), it was suggested that co binding to cooa results in a modest repositioning of the c-helices that serve as ...200111551932
effects of specific amino acid substitutions on activities of dinitrogenase reductase-activating glycohydrolase from rhodospirillum mutagenesis of the drag gene was used to generate altered forms of dinitrogenase reductase-activating glycohydrolase (drag) with d123a, h142l, h158n, d243g, and e279r substitutions. the amino acid residues h142 and e279 are not required either for the coordination to the metal center or for catalysis since the variants h142l and e279r retained both catalytic and electron paramagnetic resonance spectral properties similar to those of the wild-type enzyme. since drag-h158n and drag-d ...200111544238
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 ...199611543311
the evolution of glutathione metabolism in phototrophic microorganisms.of the many roles ascribed to glutathione (gsh) the one most clearly established is its role in the protection of higher eucaryotes against oxygen toxicity through destruction of thiol-reactive oxygen byproducts. if this is the primary function of gsh then gsh metabolism should have evolved during or after the evolution of oxygenic photosynthesis. that many bacteria do not produce gsh is consistent with this view. in the present study we have examined the low-molecular-weight thiol compositio ...198711542078
phylogenetic origins of the plant mitochondrion based on a comparative analysis of 5s ribosomal rna sequences.the complete nucleotide sequences of 5s ribosomal rnas from rhodocyclus gelatinosa, rhodobacter sphaeroides, and pseudomonas cepacia were determined. comparisons of these 5s rna sequences show that rather than being phylogenetically related to one another, the two photosynthetic bacterial 5s rna sequences show that rather than being phylogenetically related to one another, the two photosynthetic bacterial 5s rnas share more sequence and signature homology with the rnas of two nonphotosynthetic ...198511542018
the phylogeny of purple bacteria: the alpha subdivision.the technique of oligonucleotide cataloging shows the purple photosynthetic eubacteria to comprise three major subdivisions, temporarily called alpha, beta, and gamma--previously designated groups i-iii by gibson et al. (1979). each subdivision contains a number of non-photosynthetic genera in addition to the photosynthetic ones. the alpha subdivision, the subject of the present report, contains most but not all of the species that fall into the classically defined genera rhodospirillum, rhodo ...198411541974
cooa: a heme-containing regulatory protein that serves as a specific sensor of both carbon monoxide and redox state.cooa, the heme-containing carbon monoxide (co) sensor from the bacterium rhodospirillum rubrum, is a transcriptional factor that activates expression of certain genes in response to co. as with other heme proteins, cooa is unable to bind co when the fe heme is oxidized, consistent with the fact that some of the regulated gene products are oxygen-labile. upon reduction, there is an unusual switch of protein ligands to the six-coordinate heme and the reduced heme is able to bind co. co binding sta ...200111525385
mapping cooa.rna polymerase interactions. identification of activating regions 2 and 3 in cooa, the co-sensing transcriptional activator.cooa is a co-sensing protein that activates the transcription of genes encoding the co-oxidation (coo) regulon, whose polypeptide products are required for utilizing co as an energy source in rhodospirillum rubrum. cooa binds to a position overlapping the -35 element of the p(coof) promoter, similar to the arrangement of class ii crp (camp receptor protein)- and fnr (fumarate and nitrate reductase activator protein)-dependent promoters when expressed in escherichia coli. gain-of-function cooa va ...200111522788
purification and characterization of membrane-associated cooc protein and its functional role in the insertion of nickel into carbon monoxide dehydrogenase from rhodospirillum rubrum.the accessory protein cooc, which contains a nucleotide-binding domain (p-loop) near the n terminus, participates in the maturation of the nickel center of carbon monoxide dehydrogenase (codh). in this study, cooc was purified from the chromatophore membranes of rhodospirillum rubrum with a 3,464-fold purification and a 0.8% recovery, and its biochemical properties were characterized. cooc is a homodimer with a molecular mass of 61-63 kda, contains less than 0.1 atom of ni(2+) or fe(2+) per dime ...200111507093
ligand-switching intermediates for the co-sensing transcriptional activator cooa measured by pulse radiolysis.cooa is a heme-containing and co-sensing transcriptional activator whose activity is regulated by co. the protoheme that acts as a co sensor in cooa shows unique properties for its coordination structure. the cys75 axial ligand of the ferric heme is replaced by his77 upon the reduction of the heme iron and vice versa. in this work, the ligand-switching process induced by the reduction of the heme was investigated by the technique of pulse radiolysis. hydrated electron reduced the heme iron in fe ...200111487580
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