TitleAbstractYear(sorted ascending)
a hybrid of the transhydrogenases from rhodospirillum rubrum and mycobacterium tuberculosis catalyses rapid hydride transfer but not the complete, proton-translocating reaction.all transhydrogenases appear to have three components: di, which binds nad(h), and diii, which binds nadp(h), protrude from the membrane, and dii spans the membrane. however, the polypeptide composition of the enzymes varies amongst species. the transhydrogenases of mycobacterium tuberculosis and of rhodospirillum rubrum have three polypeptides. sequence analysis indicates that an ancestral three-polypeptide enzyme evolved into transhydrogenases with either two polypeptides (such as the escheric ...200616624251
the poor growth of rhodospirillum rubrum mutants lacking pii proteins is due to an excess of glutamine synthetase activity.the p(ii) family of proteins is found in all three domains of life and serves as a central regulator of the function of proteins involved in nitrogen metabolism, reflecting the nitrogen and carbon balance in the cell. the genetic elimination of the genes encoding these proteins typically leads to severe growth problems, but the basis of this effect has been unknown except with escherichia coli. we have analysed a number of the suppressor mutations that correct such growth problems in rhodospiril ...200616762025
two pathways of electron transport to nitrogenase in rhodospirillum rubrum: the major pathway is dependent on the fix gene the photosynthetic bacterium rhodospirillum rubrum, as in many other diazotrophs, electron transport to nitrogenase has not been characterized in great detail. in this study, we show that there are two pathways operating in r. rubrum. the products of the fix genes constitute the major pathway operating under heterotrophic conditions, whereas a pyruvate:ferredoxin oxidoreductase, encoded by the nifj gene, may play a central role under anaerobic conditions in the dark. in both systems, ferredox ...200616790015
effect of amtb homologues on the post-translational regulation of nitrogenase activity in response to ammonium and energy signals in rhodospirillum rubrum.the amtb protein transports uncharged nh(3) into the cell, but it also interacts with the nitrogen regulatory protein p(ii), which in turn regulates a variety of proteins involved in nitrogen fixation and utilization. three p(ii) homologues, glnb, glnk and glnj, have been identified in the photosynthetic bacterium rhodospirillum rubrum, and they have roles in at least four overlapping and distinct functions, one of which is the post-translational regulation of nitrogenase activity. in r. rubrum, ...200616804182
catalytic by-product formation and ligand binding by ribulose bisphosphate carboxylases from different phylogenies.during catalysis, all rubisco (d-ribulose-1,5-bisphosphate carboxylase/oxygenase) enzymes produce traces of several by-products. some of these by-products are released slowly from the active site of rubisco from higher plants, thus progressively inhibiting turnover. prompted by observations that form i rubisco enzymes from cyanobacteria and red algae, and the form ii rubisco enzyme from bacteria, do not show inhibition over time, the production and binding of catalytic by-products was measured t ...200616822231
mechanically driven proton conduction in single delta-free order to observe mechanically driven proton flux in f(0)f(1)-atpase coupled with artificial driven rotation on f(1) simultaneously, a double channel observation system was established. an artificial delta-free f(0)f(1)-atpase was constructed with alpha(3), beta(3), epsilon, gamma, and c(n) subunits as rotator and a, b(2) as stator. the chromatophore was immobilized on the glass surface through biotin-streptavidin-biotin system, and the magnetic bead was attached to the beta subunit of delta-f ...200616844089
theoretical prediction of spectral and optical properties of bacteriochlorophylls in thermally disordered lh2 antenna complexes.a general approach for calculating spectral and optical properties of pigment-protein complexes of known atomic structure is presented. the method, that combines molecular dynamics simulations, quantum chemistry calculations, and statistical mechanical modeling, is demonstrated by calculating the absorption and circular dichroism spectra of the b800-b850 bacteriochlorophylls of the lh2 antenna complex from rs. molischianum at room temperature. the calculated spectra are found to be in good agree ...200616863329
effect of mutation on the dissociation and recombination dynamics of co in transcriptional regulator cooa: a picosecond infrared transient absorption study.the co ligation process in a mutant (h77g) of cooa, the co-sensing transcriptional regulator in rhodospirillum rubrum, is studied with femtosecond time-resolved transient absorption spectroscopy in the mid-infrared region. following photolyzing excitation, a transient bleach in the vibrational region of bound co due to the co photodissociation is detected. in contrast to the spectra of the wild-type (wt) cooa, the transient bleach spectra of h77g cooa show a bimodal shape with peaks shifting to ...200616866371
heme displacement mechanism of cooa activation: mutational and raman spectroscopic evidence.the heme-containing protein cooa of rhodospirillum rubrum regulates the expression of genes involved in co oxidation. cooa binds its target dna sequence in response to co binding to its heme. activity measurements and resonance raman (rr) spectra are reported for cooa variants that bind dna even in the absence of co, those in which the wild-type residues at the 121-126 positions, tscmrt, are replaced by the residues ayllrl or ryllrl, and also for variants that bind dna poorly in the presence of ...200616873369
roles of the heme and heme ligands in the activation of cooa, the co-sensing transcriptional activator.cooa of rhodospirillum rubrum is a co-sensing, heme-containing transcriptional activator that regulates the expression of the genes responsible for co oxidation. we randomized the codons for residues 75-77 of cooa which include two proximal heme ligands, screened for both co-dependent and co-independent variants, and characterized in vivo and in vitro properties of selected cooa variants. the analysis showed that small residues at position 75 are critical and that, as previously suspected, his77 ...200616889751
dynamics and diffusion in photosynthetic membranes from rhodospirillum photometricum.photosynthetic organisms drive their metabolism by converting light energy into an electrochemical gradient with high efficiency. this conversion depends on the diffusion of quinones within the membrane. in purple photosynthetic bacteria, quinones reduced by the reaction center (rc) diffuse to the cytochrome bc(1) complex and then return once reoxidized to the rc. in rhodospirillum photometricum the rc-containing core complexes are found in a disordered molecular environment, with fixed light-ha ...200616950840
bacterial lateral flagella: an inducible flagella system.flagella are complex surface organelles that allow bacteria to move towards favourable environments and that contribute to the virulence of pathogenic bacteria through adhesion and biofilm formation on host surfaces. there are a few bacteria that possess functional dual flagella systems, such as vibrio parahaemolyticus, some mesophilic aeromonas spp., rhodospirillum centenum and azospirillum brasilense. these bacteria are able to express both a constitutive polar flagellum required for swimming ...200616978346
mori-zwanzig memory analysis in single-molecule spectroscopy.we study the dynamical behavior of the rhodospirillum molischianum lh2 complex based on intensity time series obtained from single-molecule spectroscopy experiments. this is achieved by reconstructing the memory function describing the time-dependent fluctuations of the excited states. we conclude that the apparent stochastic evolution of the dynamics is controlled by at least two different non-markovian main processes.200616986896
functions of carotenoids in xanthorhodopsin and archaerhodopsin, from action spectra of photoinhibition of cell respiration.the recent discovery of a carotenoid light-harvesting antenna in xanthorhodopsin, a retinal-based proton pump in salinibacter ruber, made use of photoinhibition of respiration in whole cells to obtain action spectra [balashov et al. science 309, (2005) 2061-2064]. here we provide further details of this phenomenon, and compare action spectra in three different systems where carotenoids have different functions or efficiencies of light-harvesting. the kinetics of light-induced inhibition of respi ...200617020745
self-assembled monolayer of light-harvesting core complexes of photosynthetic bacteria on an amino-terminated ito electrode.light-harvesting antenna core (lh1-rc) complexes isolated from rhodospirillum rubrum and rhodopseudomonas palustris were successfully self-assembled on an ito electrode modified with 3-aminopropyltriethoxysilane. near infra-red (nir) absorption, fluorescence, and ir spectra of these lh1-rc complexes indicated that these lh1-rc complexes on the electrode were stable on the electrode. an efficient energy transfer and photocurrent responses of these lh1-rc complexes on the electrode were observed u ...200617111238
co-dependent h2 evolution by rhodospirillum rubrum: role of codh:coof complex.upon exposure to co during anaerobic growth, the purple phototrophic bacterium rhodospirillum rubrum expresses a co-oxidizing h(2) evolving enzymatic system. the co-oxidizing enzyme, carbon monoxide dehydrogenase (codh), has been purified and extensively characterized. however the electron transfer pathway from codh to the co-induced hydrogenase that evolves h(2) is not well understood. coof is an fe-s protein that is the proposed mediator of electron transfer between codh and the co-induced hyd ...200617123462
molecular assembly of artificial photosynthetic antenna core complex on an amino-terminated ito electrode.bacterial photosynthetic membrane proteins, light-harvesting antenna complex (lh1), reaction center (rc), and their combined 'core' complex (lh1-rc) are functional elements in the primary photosynthetic events, i.e., capturing and transferring light energy and subsequent charge separation. these photosynthetic units (psus) isolated from rhodospirillum rubrum (rs. rubrum) were assembled onto an ito electrode modified with 3-aminopropyltriethoxysilane (aps-ito). the near ir absorption spectra of p ...200717142019
mutations within the c-terminus of the gamma subunit of the photosynthetic f1-atpase activate mgatp hydrolysis and attenuate the stimulatory oxyanion effect.two highly conserved amino acid residues near the c-terminus within the gamma subunit of the mitochondrial atp synthase form a "catch" with an anionic loop on one of the three beta subunits within the catalytic alphabeta hexamer of the f1 segment [abrahams, j. p., leslie, a. g. w., lutter, r., and walker, j. e. (1994) nature 370, 621-628]. forming the catch is considered to be an essential step in cooperative nucleotide binding leading to gamma subunit rotation. the analogous residues, arg304 an ...200717288458
crystal structure of co-sensing transcription activator cooa bound to exogenous ligand imidazole.cooa is a co-dependent transcriptional activator and transmits a co-sensing signal to a dna promoter that controls the expression of the genes responsible for co metabolism. cooa contains a b-type heme as the active site for sensing co. co binding to the heme induces a conformational change that switches cooa from an inactive to an active dna-binding form. here, we report the crystal structure of an imidazole-bound form of cooa from carboxydothermus hydrogenoformans (ch-cooa). in the resting for ...200717292914
single-enzyme conversion of fmnh2 to 5,6-dimethylbenzimidazole, the lower ligand of b12.the synthesis of 5,6-dimethylbenzimidazole (dmb), the lower ligand of coenzyme b(12), has remained elusive. we report in vitro and in vivo evidence that the blub protein of the photosynthetic bacterium rhodospirillum rubrum is necessary and sufficient for catalysis of the o(2)-dependent conversion of fmnh(2) to dmb. the product of the reaction (dmb) was isolated by using reverse-phase high-pressure liquid chromatography, and its identity was established by uv-visible spectroscopy and ms. no meta ...200717301238
structures of the di2diii1 complex of proton-translocating transhydrogenase with bound, inactive analogues of nadh and nadph reveal active site geometries.transhydrogenase couples the redox reaction between nadh and nadp+ to proton translocation across a membrane. the enzyme comprises three components; di binds nad(h), diii binds nadp(h), and dii spans the membrane. the 1,4,5,6-tetrahydro analogue of nadh (designated h2nadh) bound to isolated di from rhodospirillum rubrum transhydrogenase with similar affinity to the physiological nucleotide. binding of either nadh or h2nadh led to closure of the di mobile loop. the 1,4,5,6-tetrahydro analogue of ...200717323922
structure-based hypothesis on the activation of the co-sensing transcription factor cooa.the cooa family of proteins are prokaryotic co-sensing transcription factors that regulate the expression of genes involved in the utilization of co as an energy source. they are homodimeric proteins that contain two hemes. each monomer contains an n-terminal heme-binding domain and a c-terminal dna-binding domain. binding of co to the heme leads to activation by a large reorientation of the dna-binding domain such that the dna-binding domain is in position for specific dna recognition. the crys ...200717327664
solution structure of the rhodobacter sphaeroides pufx membrane protein: implications for the quinone exchange and protein-protein interactions.pufx membrane protein is found in rhodobacter species of purple photosynthetic bacteria and has been known to play an essential role in ubiquinone/ubiquinol exchange between the reaction center and cytochrome bc1 complex and also contribute to the dimerization of the reaction center-light-harvesting core complex. we have determined the solution structure of the rhodobacter sphaeroides pufx using multidimensional nmr spectroscopy. the pufx, functionally expressed in escherichia coli, forms a stab ...200717335288
in vitro studies of the uridylylation of the three pii protein paralogs from rhodospirillum rubrum: the transferase activity of r. rubrum glnd is regulated by alpha-ketoglutarate and divalent cations but not by glutamine.p(ii) proteins have been shown to be key players in the regulation of nitrogen fixation and ammonia assimilation in bacteria. the mode by which these proteins act as signals is by being in either a form modified by ump or the unmodified form. the modification, as well as demodification, is catalyzed by a bifunctional enzyme encoded by the glnd gene. the regulation of this enzyme is thus of central importance. in rhodospirillum rubrum, three p(ii) paralogs have been identified. in this study, we ...200717337583
[the structural diversity of lipid a from gram-negative bacteria].the majority of gram-negative bacteria are pathogenic to humans and animals. lipopolysaccharide (lps) is the most biologically active component of these microorganisms. this compound is also called endotoxin to emphasize its negative impact on a macroorganism. lipid a, one of the three structural components of the lps molecule, is responsible for the pathophysiological effects associated with gram-negative bacteria infections. although lipid a is considered the conservative component of endotoxi ...200717369779
the activity of adenylyltransferase in rhodospirillum rubrum is only affected by alpha-ketoglutarate and unmodified pii proteins, but not by glutamine, in vitro.ammonium assimilation is tightly regulated in nitrogen-fixing bacteria; the target of regulation is primarily the activity of the key enzyme glutamine synthetase that is regulated by reversible covalent modification by amp groups in reactions catalysed by the bifunctional adenylyltransferase (atase). the properties and regulation of atase from escherichia coli have been studied in great detail. we have investigated the regulation of atase from rhodospirillum rubrum, a photosynthetic nitrogen-fix ...200717419734
[screening and identification of a photosynthetic bacterium reducing selenite to red elemental selenium].selenium is essential element for humans and animals but is very toxic at higher concentrations. in four inorganic states of selenate [seo4 2- ( vi)], selenite [seo3 2- (iv)], elemental selenium [se (0)] and selenide [se2- (- ii )], selenite is well known to be more soluble and higher toxic than other three forms. many microorganisms have the capacity to reduce selenite to red elemental selenium, which provide the potential to cope with the detoxification of pollution and to use the biological a ...200717436622
h+-ppases: yesterday, today and tomorrow.suggestions by calvin about a role of inorganic pyrophosphate (ppi) in early photosynthesis and by lipmann that ppi may have been the original energy-rich phosphate donor in biological energy conversion, were followed in the mid-1960s by experimental results with isolated chromatophore membranes from the purple photosynthetic bacterium rhodospirillum rubrum. ppi was shown to be hydrolysed in an uncoupler stimulated reaction by a membrane-bound inorganic pyrophosphatase (ppase), to be formed at t ...200717454298
ferripyochelin uptake genes are involved in pyochelin-mediated signalling in pseudomonas response to iron starvation, pseudomonas aeruginosa produces the siderophore pyochelin. when secreted to the extracellular environment, pyochelin chelates iron and transports it to the bacterial cytoplasm via its specific outer-membrane receptor fpta and the inner-membrane permease fptx. exogenously added pyochelin also acts as a signal which induces the expression of the pyochelin biosynthesis and uptake genes by activating pchr, a cytoplasmic regulatory protein of the arac/xyls family. the ...200717464065
the emitting state of tryptophan in proteins with highly blue-shifted fluorescence. 200717539030
possible pathway for ubiquinone shuttling in rhodospirillum rubrum revealed by molecular dynamics the last decade, the structures of many components of the photosynthetic apparatus of purple bacteria, as well as the mutual organization of these components within the purple membrane, were resolved. one key question that emerged concerned the assembly of the core complex consisting of the reaction center (rc) and the light-harvesting 1 (lh1) complex. in some species, like rhodobacter sphaeroides, the ring-shaped lh1 complex was found to be open, whereas other species, like rhodospirillum ru ...200717028136
growth of rhodospirillum rubrum on synthesis gas: conversion of co to h2 and examine the potential use of synthesis gas as a carbon and energy source in fermentation processes, rhodospirillum rubrum was cultured on synthesis gas generated from discarded seed corn. the growth rates, growth and poly-beta-hydroxyalkanoates (pha) yields, and co oxidation/h(2) evolution rates were evaluated in comparison to the rates observed with an artificial synthesis gas mixture. depending on the gas conditioning system used, synthesis gas either stimulated or inhibited co-oxidation ra ...200717054121
overexpression and characterization of the rhodobacter sphaeroides pufx membrane protein in escherichia coli.heterologous expression of the pufx membrane protein from purple photosynthetic bacterium rhodobacter sphaeroides was attempted by using escherichia (e.) coli cells. the pufx was overexpressed as a recombinant protein with a histidine tag added to the carboxyl terminus, and can be extracted from the cell membrane by various detergents. circular dichroism measurements showed that the expressed pufx protein had alpha-helix contents of 29% in organic solvents and 22-26% in 0.8-2.0% (w/v) n-octyl be ...200716752956
dna binding by an imidazole-sensing cooa variant is dependent on the heme redox state.cooa is a transcription factor from rhodospirillum rubrum that is regulated by the binding of the small molecule effector, co, to a heme moiety in the protein. the heme in cooa is axially ligated by two endogenous donors in the fe(iii) and fe(ii) states of the protein, and co binding to the fe(ii) state results in replacement of the distal ligand. reduction of the heme in the absence of co results in a ligand switch on the proximal side, in which a cysteine thiolate in the fe(iii) state is repla ...200717082920
physiological versatility of the genus rhodocista.a new purple bacterium (strain t4), capable of heterotrophic aerobic and phototrophic anaerobic growth, was isolated from waste water of a noodle factory near hanoi, vietnam. a comparison of 16s rdna sequences revealed its association with the genus rhodocista. the isolate, tentatively named "rhodocista hanoiensis", forms cysts after growth on butyrate-containing plates at 42 degrees c. the vegetative cells form short (under aerobic conditions) or long curve-shaped rods. in contrast to other spe ...200717913074
on the effects of pufx on the absorption properties of the light-harvesting complexes of rhodobacter sphaeroides.some species of purple bacteria as, e.g., rhodobacter sphaeroides contain the protein pufx. concurrently, the light harvesting complexes 1 (lh1) form dimers of open rings. in mutants without pufx, the lh1s are closed rings and photosynthesis breaks down, because the ubiquinone exchange at the reaction center is blocked. however, the main purpose of the lh1 is light harvesting. we therefore investigate the effects that the pufx-induced dimerization has on the absorption properties of the core com ...200717766331
green and orange cdte quantum dots as effective ph-sensitive fluorescent probes for dual simultaneous and independent detection of of the most highlighted and fastest moving interfaces of nanotechnology is the application of quantum dots (qds) in biology. the unparalleled advantages of the size-tunable fluorescent emission and the simultaneous excitation at a single wavelength make qds the great possibility for use in optical encoding detection. in this paper, we report that green and orange cdte qds as convenient, cheap, reversible, and effective ph-sensitive fluorescent probes could monitor the proton (h+) flux driven ...200717887667
substitution of tyrosine 146 in the di component of proton-translocating transhydrogenase leads to reversible dissociation of the active dimer into inactive monomers.transhydrogenase couples the redox reaction between nadh and nadp+ to proton translocation across a membrane. the protein has three components: di binds nadh, diii binds nadp+, and dii spans the membrane. transhydrogenase is a "dimer" of two di-dii-diii "monomers"; x-ray structures suggested that the two catalytic sites alternate during turnover. invariant tyr146 in recombinant di of rhodospirillum rubrum transhydrogenase was substituted with phe and ala (proteins designated di.y146f and di.y146 ...200717911104
the photoactivated pyp domain of rhodospirillum centenum ppr accelerates the recovery of the bacteriophytochrome domain after white light illumination.ppr from the purple phototrophic bacterium, rhodospirillum centenum (also known as rhodocista centenaria), is a hybrid of photoactive yellow protein (pyp), bacteriophytochrome (bph), and histidine kinase (hk) domains. the holo-ppr (containing both chromophores) exhibits characteristic absorption maxima at 435 nm due to the pyp domain and at 400, 642, and 701 nm due to the bph domain. illumination of the ppr with white light causes a bleach of both pyp and bph absorbance; weak blue light primaril ...200717590020
purification and reconstitution of pyp-phytochrome with biliverdin and 4-hydroxycinnamic acid.pyp-phytochrome (ppr) is a unique photoreceptor that contains a blue light-absorbing photoactive yellow protein (pyp) domain, a red light-absorbing phytochrome domain, and a histidine kinase domain. this chapter describes overexpression of ppr in a strain of escherichia coli that allows covalent attachment of substoichiometric amounts of biliverdin in vivo. ppr is then fully reconstituted with biliverdin, followed by attachment of 4-hydroxycinnamic acid (p-coumaric acid), in vitro. holo-ppr with ...200717628140
specificity and regulation of interaction between the pii and amtb1 proteins in rhodospirillum rubrum.the nitrogen regulatory protein p(ii) and the ammonia gas channel amtb are both found in most prokaryotes. interaction between these two proteins has been observed in several organisms and may regulate the activities of both proteins. the regulation of their interaction is only partially understood, and we show that in rhodospirillum rubrum one p(ii) homolog, glnj, has higher affinity for an amtb(1)-containing membrane than the other two p(ii) homologs, glnb and glnk. this interaction strongly f ...200717644595
engineering of a type iii rubisco from a hyperthermophilic archaeon in order to enhance catalytic performance in mesophilic host cells.the hyperthermophilic archaeon thermococcus kodakaraensis harbors a type iii ribulose 1,5-bisphosphate carboxylase/oxygenase (rbc(tk)). it has previously been shown that rbc(tk) is capable of supporting photoautotrophic and photoheterotrophic growth in a mesophilic host cell, rhodopseudomonas palustris delta3, whose three native rubisco genes had been disrupted. here, we have examined the enzymatic properties of rbc(tk) at 25 degrees c and have constructed mutant proteins in order to enhance its ...200717675435
directed evolution of rubisco in escherichia coli reveals a specificity-determining hydrogen bond in the form ii enzyme.ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) occupies a critical position in photosynthetic co2-fixation and consequently has been the focus of intense study. crystal-structure-guided site-directed mutagenesis studies have met with limited success in engineering kinetic improvements to rubisco, highlighting our inadequate understanding of structural constraints at the atomic level that dictate the enzyme's catalytic chemistry. bioselection provides an alternative random mutagenic ap ...200718004873
phylogenomics and signature proteins for the alpha proteobacteria and its main groups.alpha proteobacteria are one of the largest and most extensively studied groups within bacteria. however, for these bacteria as a whole and for all of its major subgroups (viz. rhizobiales, rhodobacterales, rhodospirillales, rickettsiales, sphingomonadales and caulobacterales), very few or no distinctive molecular or biochemical characteristics are known.200718045498
cloning and characterization of monofunctional catalase from photosynthetic bacterium rhodospirillum rubrum this study, an approx. 2.5-kb gene fragment including the catalase gene from rhodospirillum rubrum s1 was cloned and characterized. the determination of the complete nucleotide sequence revealed that the cloned dna fragment was organized into three open reading frames, designated as orf1, catalase, and orf3 in that order. the catalase gene consisted of 1,455 nucleotides and 484 amino acids, including the initiation and stop codons, and was located 326 bp upstream in the opposite direction of ...200718062223
structures of various cytochromes c evaluated from the redox behaviors using the optically active co(iii) complex-modified au electrode.electrochemical studies of three c-type cytochromes (cyt c from horse heart, cyt c(2) from rhodospirillum rubrum, and cyt c(553) from alcaligenes xylosoxidans gifu 1051) were performed by using the optically active co(iii) complex-modified au electrode. three cytochromes gave different redox behaviors reflected from the respective structural information. from relationship between their redox behaviors and their structural characteristics, we evaluated the solution structure around heme center of ...200719356022
differences in carbon isotope discrimination of three variants of d-ribulose-1,5-bisphosphate carboxylase/oxygenase reflect differences in their catalytic mechanisms.the carboxylation kinetic (stable carbon) isotope effect was measured for purified d-ribulose-1,5-bisphosphate carboxylases/oxygenases (rubiscos) with aqueous co(2) as substrate by monitoring rayleigh fractionation using membrane inlet mass spectrometry. this resulted in discriminations (delta) of 27.4 +/- 0.9 per thousand for wild-type tobacco rubisco, 22.2 +/- 2.1 per thousand for rhodospirillum rubrum rubisco, and 11.2 +/- 1.6 per thousand for a large subunit mutant of tobacco rubisco in whic ...200717925403
factors affecting hydrogen production from cassava wastewater by a co-culture of anaerobic sludge and rhodospirillum rubrum.series of batch experiments were used to investigate the effects of environmental factors, i.e., total nitrogen and total phosphorus concentrations, initial ph, illumination pattern and stirring conditions on hydrogen production from cassava wastewater by a co-culture of anaerobic sludge and rhodospirillum rubrum. the maximum of the hydrogen yield of 150.46 and 340.19 ml g-cod(-1) was obtained at the total nitrogen and total phosphorus concentrations of 0.2 and 0.04 m, respectively. an effect of ...200719093464
a novel peroxiredoxin activity is located within the c-terminal end of rhodospirillum rubrum adenylyltransferase.adenylyltransferase (glne) catalyzes the reversible adenylylation of glutamine synthetase. in this report we present, for the first time, evidence for a peroxiredoxin activity of rhodospirillum rubrum glne, through the carboxyl-terminal ahpc/thiol-specific antioxidant (tsa) domain. the combination of glne and ahpc/tsa domains within the same polypeptide constitutes a unique domain architecture that has not previously been identified among proteobacteria.200817951375
rhodospirillum sulfurexigens sp. nov., a phototrophic alphaproteobacterium requiring a reduced sulfur source for growth.a gram-negative, spiral-shaped, phototrophic, purple non-sulfur bacterial strain, ja143(t), was isolated from a freshwater habitat. strain ja143(t) was motile by means of bipolar tufts of flagella. intracellular photosynthetic membranes are of the lamellar stacked type. bacteriochlorophyll a and carotenoids of the spirilloxanthin series with rhodovibrin are present as photosynthetic pigments. thiamine and a reduced sulfur source are required for growth. phylogenetic analysis on the basis of 16s ...200819060082
mesaconyl-coenzyme a hydratase, a new enzyme of two central carbon metabolic pathways in bacteria.the coenzyme a (coa)-activated c5-dicarboxylic acids mesaconyl-coa and beta-methylmalyl-coa play roles in two as yet not completely resolved central carbon metabolic pathways in bacteria. first, these compounds are intermediates in the 3-hydroxypropionate cycle for autotrophic co2 fixation in chloroflexus aurantiacus, a phototrophic green nonsulfur bacterium. second, mesaconyl-coa and beta-methylmalyl-coa are intermediates in the ethylmalonyl-coa pathway for acetate assimilation in various bacte ...200818065535
biosilicification of dual-fusion enzyme immobilized on magnetic nanoparticle.rapid recovery, immobilization, and silica encapsulation of a dual-fusion enzyme was achieved by using iminodiacetic acid (ida) modified magnetic nanoparticle as a carrier. d-amino acid oxidase (daao) of rhodosporidium toruloides was used as a model enzyme in which a silica-precipitating peptide r5 and a metal ion complexing peptide (his)(6) were fused to its n- and c-terminal, respectively. after charging the magnetic particle with cu(2+), the dual-fusion daao of 0.43 g could be directly recove ...200818078291
rhodospirillum rubrum: utilization of condensed corn solubles for poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) production.this study sought to develop a less expensive medium for growth of the polyhydroxyalkanoate-producing bacterium rhodospirillum rubrum from the ethanol production coproduct, condensed corn solubles (ccs).200818179537
intermolecular vibrational coherence in the bacteriochlorophyll proteins b777 and b820 from rhodospirillum rubrum.the low-frequency vibrational coherence in the bacteriochlorophyll (bchl)-containing subunit proteins b777 and b820 from the lh1 light-harvesting complex isolated from rhodospirillum rubrum g9 exhibits rapidly damped modulation components arising from intermolecular, formally nonbonding interactions between the bchl macrocycle and polar groups in the surrounding detergent or protein. the vibrational coherence observed in the monomeric b777 system resembles that observed previously with bchl in a ...200818181604
thermodynamics of the beta(2) association in light-harvesting complex i of rhodospirillum rubrum. implication of peptide identity in dimer stability.the core light-harvesting lh1 protein from rhodospirillum rubrum can dissociate reversibly in the presence of n-octyl-beta-d-glucopyranoside into smaller subunit forms, exhibiting a dramatic blue-shift in absorption. during this process, two main species are observed: a dimer that absorbs at 820 nm (b820) and a monomer absorbing at 777 nm (b777). in the presence of n-octyl-beta-d-glucopyranoside, we have previously shown that the b820 form is not only constituted by the alphabeta heterodimer alo ...200818266761
formation of a cross-linking complex of dinitrogenase reductase-activating glycohydrolase (drag) with membrane proteins from rhodospirillum rubrum chromatophores.association of dinitrogenase reductase-activating glycohydrolase (drag) with membrane proteins of chromatophores has been investigated. the formation of a multicomponent complex between drag and membrane proteins was demonstrated in the presence of glutaraldehyde and edc/nhs (n-(3-dimethylaminopropyl)-n -ethylcarbodiimide hydrochloride/hydroxy-2,5-dioxopyrrolidine-3-sulfonic acid sodium salt). complex formation was observed both in native chromatophore membrane and in chromatophores treated with ...200818298373
redox-state dynamics of ubiquinone-10 imply cooperative regulation of photosynthetic membrane expression in rhodospirillum is now well established that, for photosynthetic bacteria, the aerobic-to-microaerophilic transition activates the membrane-bound sensor kinase regb, which subsequently phosphorylates the transcriptional activator rega, thereby inducing elevated levels of intracellular photosynthetic membranes. the mechanism of regb activation--in particular, the role of ubiquinone-10--is controversial at present. one problem here is that very limited quantitative in vivo data for the response of the ubiquino ...200818487324
comparative proteomic studies in rhodospirillum rubrum grown under different nitrogen conditions.forty-four differentially expressed proteins have been identified in the photosynthetic diazotroph rhodospirillum rubrum grown anaerobic and photoheterotrophically, with different nitrogen sources, using 2d-page and maldi-tof, from gels containing an average of 679 +/- 52 (in n(+)) and 619 +/- 37 (in n(-)) protein spots for each gel. a higher level of expression was found under nitrogen-rich growth, for proteins involved in carbon metabolism (reductive tricarboxylic acid cycle, co(2) fixation, a ...200818570453
dynamic aspects and controllability of the melissa project: a bioregenerative system to provide life support in space.manmade ecosystems differ from their prototype biosphere by the principle of control. the earth biosphere is sustainable by stochastic control and very large time constants. by contrast, in a closed ecosystem such as the micro-ecological life support system alternative (melissa system) developed by the european space agency for space exploration, a deterministic control is a prerequisite of sustainable existence. melissa is an integrated sum of interconnected biological subsystems. on one hand, ...200818592407
mutations in transhydrogenase change the fluorescence emission state of trp72 from 1la to 1lb.the di component of rhodospirillum rubrum transhydrogenase has a single trp residue (trp(72)), which has distinctive optical properties, including short-wavelength fluorescence emission with clear vibrational fine structure, and long-lived, well-resolved phosphorescence emission. we have made a set of mutant di proteins in which residues contacting trp(72) are conservatively substituted. the room-temperature fluorescence-emission spectra of our three met(97) mutants are blue shifted by approxima ...200818599622
bacteriophytochromes in anoxygenic photosynthetic bacteria.since the first discovery of a bacteriophytochrome in rhodospirillum centenum, numerous bacteriophytochromes have been identified and characterized in other anoxygenic photosynthetic bacteria. this review is focused on the biochemical and biophysical properties of bacteriophytochromes with a special emphasis on their roles in the synthesis of the photosynthetic apparatus.200818612842
probing the effect of the binding site on the electrostatic behavior of a series of carotenoids reconstituted into the light-harvesting 1 complex from purple photosynthetic bacterium rhodospirillum rubrum detected by stark spectroscopy.reconstitutions of the lh1 complexes from the purple photosynthetic bacterium rhodospirillum rubrum s1 were performed with a range of carotenoid molecules having different numbers of c=c conjugated double bonds. since, as we showed previously, some of the added carotenoids tended to aggregate and then to remain with the reconstituted lh1 complexes (nakagawa, k.; suzuki, s.; fujii, r.; gardiner, a.t.; cogdell, r.j.; nango, m.; hashimoto, h. photosynth. res. 2008, 95, 339-344), a further purificat ...200818613723
[a new methodical approach to the determination of the quantum yield of the photoelectric conversion of electronic excitations in reaction centers of purple bacteria].a new methodical approach has been developed, which enables one to determine with a high precision (approximately 1.5%) the quantum yield of energy conversion in reaction centers isolated from purple bacterium. this parameter for reaction centers from rhodospirillum rubrum was estimated to be 93.5 +/- 1,5%. our methodical approach makes it possible to calculate quantum yield values for complete photosystems of purple bacteria.200818634316
interaction of the signal transduction protein glnj with the cellular targets amtb1, glne and glnd in rhodospirillum rubrum: dependence on manganese, 2-oxoglutarate and the adp/atp ratio.the pii family of signal transduction proteins is widespread amongst the three domains of life, and its members have fundamental roles in the general control of nitrogen metabolism. these proteins exert their regulatory role by direct protein-protein interaction with a multitude of cellular targets. the interactions are dependent on the binding of metabolites such as atp, adp and 2-oxoglutarate (2-og), and on whether or not the pii protein is modified. in the photosynthetic nitrogen-fixing bacte ...200818667566
identification and functional characterization of nifa variants that are independent of glnb activation in the photosynthetic bacterium rhodospirillum rubrum.the activity of nifa, the transcriptional activator of the nitrogen fixation (nif) gene, is tightly regulated in response to ammonium and oxygen. however, the mechanisms for the regulation of nifa activity are quite different among various nitrogen-fixing bacteria. unlike the well-studied nifl-nifa regulatory systems in klebsiella pneumoniae and azotobacter vinelandii, in rhodospirillum rubrum nifa is activated by a direct protein-protein interaction with the uridylylated form of glnb, which in ...200818757802
[effects of extremely low frequency magnetic fields on hydrolysis of f0f1-atpases and their relationship with turnover rates of f1].to study the effects of extremely low frequency sinusoidal magnetic fields on hydrolysis of f(0)f(1)-atpase and its mechanism.200818771613
burst analysis spectroscopy: a versatile single-particle approach for studying distributions of protein aggregates and fluorescent assemblies.many essential cellular functions depend on the assembly and disassembly of macromolecular complexes. the size, form, and distribution of these assemblies can be heterogeneous and complex, rendering their detailed characterization difficult. here we describe a simple non-correlation-based method capable of directly measuring population distributions at very low sample concentrations. specifically, we exploit the highest signal-to-noise light bursts from single fluorescent particles transiting a ...200818780782
mechanistic diversity in the rubisco superfamily: a novel isomerization reaction catalyzed by the rubisco-like protein from rhodospirillum rubrum.some homologues of d-ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) do not catalyze carboxylation and are designated rubisco-like proteins (rlps). the rlp from rhodospirillum rubrum (gi:83593333) catalyzes a novel isomerization reaction (overall 1,3-proton transfer reaction; likely, two 1,2-proton transfer reactions) that converts 5-methylthio-d-ribulose 1-phosphate to a 3:1 mixture of 1-methylthioxylulose 5-phosphate and 1-methylthioribulose 5-phosphate. disruption of the gene encodi ...200818826254
regulation of aerobic photosystem synthesis in the purple bacterium rhodospirillum centenum by crtj and aerr.genes coding for putative crtj and aerr homologs were identified and characterized in the purple photosynthetic bacterium rhodospirillum centenum (also known as rhodocista centenaria), an organism that synthesizes photopigments even under highly aerated conditions. mutational analysis indicated that in rsp. centenum, gene crtj codes for a repressor for photosynthesis gene expression as in rhodobacter capsulatus, which exhibits a high level of oxygen repression of photosystem synthesis. in contra ...200818846293
probing binding site of bacteriochlorophyll a and carotenoid in the reconstituted lh1 complex from rhodospirillum rubrum s1 by stark spectroscopy.stark spectroscopy is a powerful technique to investigate the electrostatic interactions between pigments as well as between the pigments and the proteins in photosynthetic pigment-protein complexes. in this study, stark spectroscopy has been used to determine two nonlinear optical parameters (polarizability change tr(deltaalpha) and static dipole-moment change |deltamu| upon photoexcitation) of isolated and of reconstituted lh1 complexes from the purple photosynthetic bacterium, rhodospirillum ...200817912603
electrostatic effect of surfactant molecules on bacteriochlorophyll a and carotenoid binding sites in the lh1 complex isolated from rhodospirillum rubrum s1 probed by stark spectroscopy.the lh1 complexes were isolated from the purple photosynthetic bacterium rhodospirillum rubrum strain s1. they were initially solubilized using ldao and then purified in the presence of triton x-100. the purified complexes were then either used directly or following an exchange into ldao. stark spectroscopy was applied to probe the electrostatic field around the bacteriochlorophyll a (bchl a) and carotenoid binding sites in the lh1 complexes surrounded by these two different surfactant molecules ...200817922213
biohydrogen production in a continuous stirred tank bioreactor from synthesis gas by anaerobic photosynthetic bacterium: rhodopirillum rubrum.hydrogen may be considered a potential fuel for the future since it is carbon-free and oxidized to water as a combustion product. bioconversion of synthesis gas (syngas) to hydrogen was demonstrated in continuous stirred tank bioreactor (cstbr) utilizing acetate as a carbon source. an anaerobic photosynthetic bacterium, rhodospirillum rubrum catalyzed water-gas shift reaction which was applied for the bioconversion of syngas to hydrogen. the continuous fermentation of syngas in the bioreactor wa ...200817582763
putative functional role for the invariant aspartate 263 residue of rhodospirillum rubrum rubisco.although aspartate residue d263 of rhodospirillum rubrum rubisco is close to the active site and invariant in all reported rubiscos, its possible functional and structural roles in rubisco activity have not been investigated. we have mutagenised d263 to several selected amino acids (asparagine, alanine, serine, glutamate, and glutamine) to probe possible roles in facilitating proton movements within the active site and maintaining structural positioning of key active-site groups. the mutants hav ...200919231887
shotgun proteome analysis of rhodospirillum rubrum s1h: integrating data from gel-free and gel-based peptides fractionation methods.beside bioreactor modeling studies, the molecular characterization of life-support organisms appeared to be essential to complete their global behavior picture, in particular, culture conditions. using a combination of lc-ms/ms approaches with gel-free and gel-based peptides fractionation steps, we identified 932 proteins from the alpha-proteobacterium rhodospirillum rubrum s1h. in addition, abundance data were retrieved using the recently developed empai approach which takes into account the nu ...200919243122
self-assembly of f0f1-atpase motors and ghost.f0f1-atpase motors have unique mechanical properties, making them attractive building blocks in the field of nanotechnology. however, their organization into well-defined structures with practical functions remains a critical challenge. here, we describe a self-assembling complex formed by f0f1-atpase and a ghost which is ordered. formation of the complex includes two steps: the molecular motors first self-assemble into filaments and then attach to the ghost. the ghost and attached filaments the ...200919374455
pigment organization and energy level structure in light-harvesting complex 4: insights from two-dimensional electronic spectroscopy.photosynthetic light-harvesting antennae direct energy collected from sunlight to reaction centers with remarkable efficiency and rapidity. despite their common function, the pigment-protein complexes that make up antenna systems in different types of photosynthetic organisms exhibit a wide variety of structural forms. some individual organisms express different types of complexes depending on growth conditions. for example, purple photosynthetic bacteria rp. palustris preferentially synthesize ...200919402730
atomic force microscopy studies of native photosynthetic addition to providing the earliest surface images of a native photosynthetic membrane at submolecular resolution, examination of the intracytoplasmic membrane (icm) of purple bacteria by atomic force microscopy (afm) has revealed a wide diversity of species-dependent arrangements of closely packed light-harvesting (lh) antennae, capable of fulfilling the basic requirements for efficient collection, transmission, and trapping of radiant energy. a highly organized architecture was observed with ...200919265434
structural and functional similarities between a ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco)-like protein from bacillus subtilis and photosynthetic rubisco.the sequences classified as genes for various ribulose-1,5-bisphosphate (rubp) carboxylase/oxygenase (rubisco)-like proteins (rlps) are widely distributed among bacteria, archaea, and eukaryota. in the phylogenic tree constructed with these sequences, rubiscos and rlps are grouped into four separate clades, forms i-iv. in rubisco enzymes encoded by form i, ii, and iii sequences, 19 conserved amino acid residues are essential for co(2) fixation; however, 1-11 of these 19 residues are substituted ...200919279009
[enzymes of the citramalate cycle in rhodospirillum rubrum].rhodospirillum rubrum is among the bacteria that can assimilate acetate in the absence of isocitrate lyase, the key enzyme of glyoxylate shunt. previously we have suggested the functioning of a new anaplerotic cycle of acetate assimilation in this bacterium: citramalate cycle, where acetyl-coa is oxidized to glyoxylate. this work has demonstrated the presence of all the key enzymes of this cycle in r. rubrum extracts: citramalate synthase catalyzing condensation of acetyl-coa and pyruvate with t ...200919334594
ungual and trans-ungual iontophoretic delivery of terbinafine for the treatment of onychomycosis.the application of iontophoresis was demonstrated in the nail drug delivery of terbinafine (th) recently. this study explored a systematic assessment of this approach to enhance the drug delivery using a novel topical formulation, and the subsequent release of th from the drug loaded nails. for the first time, a nail on-agar plate model was used to study the release of drug from the iontophoresis (0.5 ma/cm(2)) loaded nails. in addition, the activity of the drug released from the drug loaded nai ...200919340887
gut-associated denitrification and in vivo emission of nitrous oxide by the earthworm families megascolecidae and lumbricidae in new zealand.previous studies have documented the capacity of european earthworms belonging to the family lumbricidae to emit the greenhouse gas nitrous oxide (n(2)o), an activity attributed primarily to the activation of ingested soil denitrifiers. to extend the information base to earthworms in the southern hemisphere, four species of earthworms in new zealand were examined for gut-associated denitrification. lumbricus rubellus and aporrectodea rosea (introduced species of lumbricidae) emitted n(2)o, where ...200919346358
cooc1 from carboxydothermus hydrogenoformans is a nickel-binding atpase.the maturation of nickel-dependent enzymes requires the participation of several accessory proteins. typically the hydrolysis of nucleotides is necessary for the final metal transfer steps. the atpase cooc has been implicated in the insertion of nickel into the ni,fe cluster (c cluster) of the carbon monoxide dehydrogenase from rhodospirillum rubrum. analysis of the amino acid sequence of cooc suggests the presence of motifs typical for the mind family of simibi class ntpases, which contain a de ...200919883128
energy transfer in light-adapted photosynthetic membranes: from active to saturated bacterial photosynthesis light-harvesting complexes, lh2 and lh1 absorb sunlight energy and deliver it to reaction centers (rcs) with extraordinarily high efficiency. submolecular resolution images have revealed that both the lh2:lh1 ratio, and the architecture of the photosynthetic membrane itself, adapt to light intensity. we investigate the functional implications of structural adaptations in the energy transfer performance in natural in vivo low- and high-light-adapted membrane architectu ...200919883589
spectral diffusion and electron-phonon coupling of the b800 bchl a molecules in lh2 complexes from three different species of purple bacteria.we have investigated the spectral diffusion and the electron-phonon coupling of b800 bacteriochlorophyll a molecules in the peripheral light-harvesting complex lh2 for three different species of purple bacteria, rhodobacter sphaeroides, rhodospirillum molischianum, and rhodopseudomonas acidophila. we come to the conclusion that b800 binding pockets for rhodobacter sphaeroides and rhodopseudomonas acidophila are rather similar with respect to the polarity of the protein environment but that the p ...200919883604
effect of perturbation of atp level on the activity and regulation of nitrogenase in rhodospirillum rubrum.nitrogenase activity in rhodospirillum rubrum and in some other photosynthetic bacteria is regulated in part by the availability of light. this regulation is through a posttranslational modification system that is itself regulated by p(ii) homologs in the cell. p(ii) is one of the most broadly distributed regulatory proteins in nature and directly or indirectly senses nitrogen and carbon signals in the cell. however, its possible role in responding to light availability remains unclear. because ...200919542280
comparison of rhizobacterial community composition in soil suppressive or conducive to tobacco black root rot on soils suppressive to thielaviopsis basicola-mediated tobacco black root rot has focused on antagonistic pseudomonads to date. the role of non-pseudomonas rhizosphere populations has been neglected, and whether they differ in black root rot-suppressive versus -conducive soils is unknown. to assess this possibility, tobacco was grown in a suppressive and a conducive soil of similar physicochemical properties, and rhizobacterial community composition was compared using a 16s rrna taxonomic ...200919554036
experimental design and environmental parameters affect rhodospirillum rubrum s1h response to space view of long-haul space exploration missions, the european space agency initiated the micro-ecological life support system alternative (melissa) project targeting the total recycling of organic waste produced by the astronauts into oxygen, water and food using a loop of bacterial and higher plant bioreactors. in that purpose, the alpha-proteobacterium, rhodospirillum rubrum s1h, was sent twice to the international space station and was analyzed post-flight using a newly developed r. rubrum wh ...200919571896
protein-induced membrane curvature investigated through molecular dynamics flexible the photosynthetic purple bacterium rhodobacter (rba.) sphaeroides, light is absorbed by membrane-bound light-harvesting (lh) proteins lh1 and lh2. lh1 directly surrounds the reaction center (rc) and, together with pufx, forms a dimeric (rc-lh1-pufx)2 protein complex. in lh2-deficient rba. sphaeroides mutants, rc-lh1-pufx dimers aggregate into tubular vesicles with a radius of approximately 250-550 a, making rc-lh1-pufx one of the few integral membrane proteins known to actively induce membra ...200919580770
guanidine hydrochloride-induced unfolding of the three heme coordination states of the co-sensing transcription factor, cooa.cooa is a heme-dependent co-sensing transcription factor that has three observable heme coordination states. there is some evidence that each cooa heme state has a distinct protein conformation; the goal of this study was to characterize these conformations by measuring their structural stabilities through guanidine hydrochloride (guhcl) denaturation. by studying the denaturation processes of the fe(iii) state of wt cooa and several variants, we were able to characterize independent unfolding pr ...200919594171
quinone pathways in entire photosynthetic chromatophores of rhodospirillum photosynthetic organisms, membrane pigment-protein complexes [light-harvesting complex 1 (lh1) and light-harvesting complex 2 (lh2)] harvest solar energy and convert sunlight into an electrical and redox potential gradient (reaction center) with high efficiency. recent atomic force microscopy studies have described their organization in native membranes. however, the cytochrome (cyt) bc(1) complex remains unseen, and the important question of how reduction energy can efficiently pass from cor ...200919631224
mechanism of adp-ribosylation removal revealed by the structure and ligand complexes of the dimanganese mono-adp-ribosylhydrolase drag.adp-ribosylation is a ubiquitous regulatory posttranslational modification involved in numerous key processes such as dna repair, transcription, cell differentiation, apoptosis, and the pathogenic mechanism of certain bacterial toxins. despite the importance of this reversible process, very little is known about the structure and mechanism of the hydrolases that catalyze removal of the adp-ribose moiety. in the phototrophic bacterium rhodospirillum rubrum, dinitrogenase reductase-activating glyc ...200919706507
reduced activity of glutamine synthetase in rhodospirillum rubrum mutants lacking the adenylyltransferase the nitrogen-fixing bacterium rhodospirillum rubrum, the glne adenylyltransferase (encoded by glne) catalyzes reversible adenylylation of glutamine synthetase, thereby regulating nitrogen assimilation. we have generated glne mutant strains that are unable to adenylylate glutamine synthetase (gs). surprisingly, the activity of gs was lower in the mutants than in the wild type, even when grown in nitrogen-fixing conditions. our results support the proposal that r. rubrum can only cope with the ...200919761831
model-based high cell density cultivation of rhodospirillum rubrum under respiratory dark conditions.the potential of facultative photosynthetic bacteria as producers of photosynthetic pigments, vitamins, coenzymes and other valuable products has been recognized for decades. however, mass cultivation under photosynthetic conditions is generally inefficient due to the inevitable limitation of light supply when cell densities become very high. the previous development of a new cultivation process for maximal expression of photosynthetic genes under semi-aerobic dark conditions in common bioreacto ...201019882736
metabolic flexibility revealed in the genome of the cyst-forming alpha-1 proteobacterium rhodospirillum centenum.rhodospirillum centenum is a photosynthetic non-sulfur purple bacterium that favors growth in an anoxygenic, photosynthetic n2-fixing environment. it is emerging as a genetically amenable model organism for molecular genetic analysis of cyst formation, photosynthesis, phototaxis, and cellular development. here, we present an analysis of the genome of this bacterium.201020500872
time-dependent atomistic view on the electronic relaxation in light-harvesting system ii.aiming at a better understanding of the molecular details in light absorption during photosynthesis, spatial and temporal correlation functions as well as spectral densities have been determined. at the focus of the present study are the light-harvesting ii complexes of the purple bacterium rhodospirillum molischianum. the calculations are based on a time-dependent combination of molecular dynamics simulations and quantum chemistry methods. using a 12 ps long trajectory, different quantum chemic ...201020809619
[recent studies on gas sensors, cooa, fixl, and dos].heme-containing proteins, the heme proteins, are known to have physiologic functions in humans, mammalians, fish, plants, and bacteria. for example, hemoglobin and myoglobin, which belong to the globin family, have been studied in terms of their structures and functions with spectroscopic and mutagenic methods. recently, a new class of heme proteins has been discovered, referred to as gas sensors. these are heme-based sensor proteins that play important roles in transcriptional activation, histi ...201020823675
aniline-induced tryptophan production and identification of indole derivatives from three purple bacteria.growth on aniline by three purple non-sulfur bacteria (rhodospirillum rubrum atcc 11170, rhodobacter sphaeroides dsm 158, and rubrivivax benzoatiliticus ja2) as nitrogen, or carbon source could not be demonstrated. however in its presence, production of indole derivatives was observed with all the strains tested. at least 14 chromatographically (hplc) distinct peaks were observed at the absorption maxima of 275-280 nm from aniline induced cultures. five major indoles were identified based on hpl ...201020852980
the photosensor protein ppr of rhodocista centenaria is linked to the chemotaxis signalling pathway.rhodocista centenaria is a phototrophic α-proteobacterium exhibiting a phototactic behaviour visible as colony movement on agar plates directed to red light. as many phototrophic purple bacteria r. centenaria possesses a soluble photoactive yellow protein (pyp). it exists as a long fusion protein, designated ppr, consisting of three domains, the pyp domain, a putative bilin binding domain (bbd) and a histidine kinase domain (pph). the ppr protein is involved in the regulation of polyketide synth ...201021062468
sustaining n2-dependent growth in the presence of co.low levels of carbon monoxide inhibit the n(2)-dependent growth of rhodospirillum rubrum unless the ∼100-residue cown protein is expressed. expression requires the co-responsive regulator rcom and is maximal in cells grown in the presence of co and a poor nitrogen source, consistent with the role of cown in n(2) fixation.201021115659
two putative histidine kinases are required for cyst formation in rhodospirillum centenum.the photosynthetic bacterium, rhodospirillum centenum, has a flexible life cycle that permits it to survive starvation as dormant cyst cells. previous studies have identified some of the key regulators for encystment and demonstrated that the control of development is intricate. this complexity may arise from the need to integrate several environmental signals to mediate a switch from one mode of energy metabolism to another and to ensure that a transition to dormancy is initiated only when nece ...201021184217
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