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the photochemical determination of an oxidase of the photoheterotroph, rhodospirillum rubrum, and the action spectrum of the inhibition of respiration by light. 196514285523
the biosynthesis of ubiquinone and rhodoquinone from p-hydroxybenzoate and p-hydroxybenzaldehyde in rhodospirillum rubrum. 196514285535
observations on the structure of rhodospirillum molischianum.the lamellae of the bacterium rhodospirillum molischianum originate as extensions of the cytoplasmic membrane into the cytoplasm of the cell. initially, these extensions are narrow folds and occur independently of one another. the first lamellae to appear average about 80 a in width, representing one side of the infolded cytoplasmic membrane, or 160 a when the two sides of the fold are closely appressed. the 160-a lamellae increase in number and may associate to form larger lamellae, which repre ...196514287179
observations on the structure of rhodospirillum rubum.sections of rhodospirillum rubrum cells from cultures of different ages have been examined to obtain information on the development of chromatophores in this organism. cells from the 12-hour cultures studied contain neither distinct invaginations of the cytoplasmic membrane nor distinct chromatophores. the first structures that can be related to chromatophore development occur peripherally in the cells, are relatively few in number, relatively high in density, and have an indistinct membrane. in ...196514287180
location of chlorophyll in rhodospirillum rubrum.holt, stanley c. (university of california, davis), and allen g. marr. location of chlorophyll in rhodospirillum rubrum. j. bacteriol. 89:1402-1412. 1965.-if cells of rhodospirillum rubrum are broken by sonic and ballistic disruption, the chlorophyll is not found in discrete cytoplasmic structures, but is located in a more extensive structure of the cell, the intracytoplasmic membrane. direct electron microscopy of sonically disrupted cells of r. rubrum and stereo-electron microscopy of osmotica ...196514293014
isolation and purification of the intracytoplasmic membranes of rhodospirillum rubrum.holt, stanley c. (university of california, davis), and allen g. marr. isolation and purification of the intracytoplasmic membranes of rhodospirillum rubrum. j. bacteriol. 89:1413-1420. 1965.-when rhodospirillum rubrum was disrupted in a french pressure cell, two colored bands were observed after density-gradient centrifugation: an upper band containing chromatophores and a lower band containing cell envelopes. a similar analysis of the pigmented components after disruption by osmotic shock reve ...196514293015
effect of light intensity on the formation of intracytoplasmic membrane in rhodospirillum rubrum.holt, stanley c. (university of california, davis), and allen g. marr. effect of light intensity on the formation of intracytoplasmic membrane in rhodospirillum rubrum. j. bacteriol. 89:1421-1429. 1965.-cells of rhodospirillum rubrum grown at low light intensity were found to contain much more internal membrane than cells grown at high light intensity. highly purified membranes (chromatophores) from cells grown at low to moderate light intensity had a constant content of chlorophyll. thus, the r ...196514293016
reactivity of photosynthetic bacterial c cytochromes with two cytochrome oxidases. 196514298836
possible partial reactions of the photophosphorylation process in chromatophores from rhodospirillum rubrum. 196514314346
fluorescence decline in purple bacteria resulting from carotenoid absorption. 196514314376
the oxidase system of heterotrophically-grown rhodospirillum rubrum. 196514314381
thin-layer countercurrent distribution. 196514328632
lysis of bacterial cell walls by an enzyme isolated from a myxobacter.ensign, j. c. (university of illinois, urbana), and r. s. wolfe. lysis of bacterial cell walls by an enzyme isolated from a myxobacter. j. bacteriol. 90:395-402. 1965.-an exoenzyme which lyses intact cells, heat-killed cells, and cell walls of arthrobacter crystallopoietes was purified 60-fold from the growth liquor obtained from a myxobacter (strain al-1). the lytic enzyme was produced during growth of the organism in a number of complex media, the maximal amount of enzyme being produced in yea ...196514330733
[the effect of uranyl salts on the structure of bacterial nucleoids. i]. 196414335076
nitrogen fixation: hydrosulfite as electron donor with cell-free preparations of azotobacter vinelandii and rhodospirillum rubrum. 196514338231
an intermediate in the conversion of p-hydroxybenzoate-u-c-14 to ubiquinone in rhodospirillum rubrum. 196514338239
haemoproteins and haem synthesis in facultative photosynthetic and denitrifying bacteria.1. a simple spectrophotometric method is described for the measurement of various haemoproteins in extracts of photosynthetic and non-photosynthetic bacteria. the method is based on measurements of difference spectra at the soret maxima. 2. in photosynthetic bacteria of the athiorhodaceae group the concentration of carbon monoxide-binding haemoprotein and of cytochromes of the b and c types is two to three times as high in anaerobically grown cells as in those grown aerobically. 3. during the ad ...196514342218
homoserine dehydrogenase of rhodospirillum rubrum. purification, properties, and feedback control of activity. 196514342328
the photo-oxidation of succinate by chromatophores of rhodospirillum rubrum.1. the stoicheiometry of the photo-oxidation of succinate by chromatophores has been investigated with [2,3-(14)c(2)]succinate. it was found that there is a stoicheiometric relationship between the amount of succinate oxidized and the nad reduced, and that fumarate is the only product of succinate oxidation. 2. the possibility of a direct hydrogen transfer from succinate to nad in this reaction was investigated with tritiated substrates. with tritiated succinate less than 3% of the activity expe ...196514342500
the photoassimilation of succinate to hexose by rhodospirillum rubrum.1. a pathway for the synthesis of hexose from succinate by rhodospirillum rubrum is proposed. 2. with 2,3-(14)c(2)-labelled succinate and fumarate as substrates in experiments with chromatophores and a soluble enzyme fraction of r. rubrum it was found that the products of succinate metabolism by the extracts were the same as in whole cells. it was also found that the light-dependent oxidation of succinate was catalysed by the chromatophores, but that all the other enzymes involved were in the so ...196514342501
studies on the amoeba-to-flagellate transformation of tetramitus rostratus. 196514346118
the acetate-activating enzyme of rhodospirillum rubrum. 195514363230
the succinic dehydrogenase from rhodospirillum rubrum. 195514367286
respiratory pigments of rhodospirillum rubrum. 195514370222
the structure of rhodospirillum rubrum.cells from serial cultures of r. rubrum, grown anaerobically in the light, were harvested at intervals from (1/2) to 15 days and sectioned for electron microscopy by conventional methods. cells of this species possess a multilayered outer envelope, and the external cell surface is differentiated into ridges extending parallel or obliquely to the long axis of the cell. cells from very young cultures resemble non-photosynthetic bacteria and contain only a granular cytoplasm, scattered high-density ...195914401694
optimal oxidation-reduction potentials and endogenous co-factors in bacterial photophosphorylation. 196214448915
the photometabolism of propionate by rhodospirillum rubrum. 196214457247
an x-ray crystallographic study of a heme protein from rhodospirillum rubrum. 196114462184
immunochemical studies on disulfide bonding in the photochemical apparatus of rhodospirillum rubrum. 196214479361
studies on bacterial photophosphorylation. iii. a sensitive and rapid method of determination of photophosphorylation. 196214479975
studies on bacterial photophosphorylation. i. kinetics of photophosphorylation in rhodospirillum rubrum chromatophores by flashing light. 196214479977
studies on bacterial photophosphorylation. ii. effects of reagents and temperature on light-induced and dark phases of photophosphorylation in rhodospirillum rubrum chromatophores. 196214479978
studies on bacterial photophosphorylation. iv. on the maximum amount of delayed photophosphorylation induced by a single flash. 196214479979
acid and alkali denaturation of rhodospirillum haem protein. 196214482253
removal of organics and nutrients from tannery effluent by advanced integrated wastewater pond systems technology.in this study, a pilot-scale experiment was carried out on a pre-settled combined tannery effluent from modjo tannery, ethiopia, to evaluate the feasibility of the advanced integrated wastewater pond systems or aiwps technology, for the treatment of tannery effluent. the pilot-scale aiwps facility was comprised of an advanced facultative pond (afp), secondary facultative pond (sfp) and maturation pond (mp) all arranged in series. three feed phases with low, moderate and overloading organic loadi ...200314510225
probing the transmembrane potential of bacterial cells by voltage-sensitive dyes.fluorescent dyes have been widely employed as optical indicators of the membrane potential difference in cells, isolated organelles and lipid vesicles that are too small to make microelectrode measurements feasible. we describe here the application of a carbocyanine dye, 3,3'-dipropylthiodicarbocyanine iodide [dis-c3-(5)], to monitor the transmembrane potential changes induced by a variation of the k+ concentration for the cells of escherichia (e.) coli and photosynthetic bacterium rhodospirillu ...200314516073
determination of the b820 subunit size of a bacterial core light-harvesting complex by small-angle neutron scattering.the b820 subunit is an integral pigment-membrane protein complex and can be obtained by both dissociation of the core light-harvesting complex (lh1) in photosynthetic bacteria and reconstitution from its component parts in the presence of n-octyl beta-d-glucopyranoside (og). intrinsic size of the b820 subunit from rhodospirillum rubrum lh1 complex was measured by small-angle neutron scattering in perdeuterated og solution and evaluated by guinier analysis. both the b820 subunits prepared by diss ...200314516207
a functional link between rubisco-like protein of bacillus and photosynthetic rubisco.the genomes of several nonphotosynthetic bacteria, such as bacillus subtilis, and some archaea include genes for proteins with sequence homology to the large subunit of ribulose bisphosphate carboxylase/oxygenase (rubisco). we found that such a rubisco-like protein (rlp) from b. subtilis catalyzed the 2,3-diketo-5-methylthiopentyl-1-phosphate enolase reaction in the methionine salvage pathway. a growth-defective mutant, in which the gene for this rlp had been disrupted, was rescued by the gene f ...200314551435
conformational change in the nadp(h) binding domain of transhydrogenase defines four states.proton-translocating transhydrogenase (th) couples direct and stereospecific hydride transfer between nad(h) and nadp(h), bound to soluble domains di and diii, respectively, to proton translocation across a membrane bound domain, dii. the reaction occurs with proton-gradient coupled conformational changes, which affect the energetics of substrate binding and interdomain interactions. the crystal structure of th diii from rhodospirillum rubrum has been determined in the presence of nadph (2.4 a) ...200314567675
structural analysis of the reaction center light-harvesting complex i photosynthetic core complex of rhodospirillum rubrum using atomic force microscopy.the bacterium rhodospirillum rubrum contains a simple photosynthetic system, in which the reaction center (rc) receives energy from the light-harvesting (lh1) complex. we have used high-resolution atomic force microscopy (afm) to image two-dimensional crystals of the rc-lh1 complex of r. rubrum. the afm topographs show that the rc-lh1 complex is approximately 94 a in height, the rc-h subunit protrudes from the cytoplasmic face of the membrane by 40 a, and it sits 21 a above the highest point of ...200414578348
microaerophilic cooperation of reductive and oxidative pathways allows maximal photosynthetic membrane biosynthesis in rhodospirillum rubrum.the purple nonsulfur bacterium rhodospirillum rubrum has been employed to study physiological adaptation to limiting oxygen tensions (microaerophilic conditions). r. rubrum produces maximal levels of photosynthetic membranes when grown with both succinate and fructose as carbon sources under microaerophilic conditions in comparison to the level (only about 20% of the maximum) seen in the absence of fructose. employing a unique partial o(2) pressure (po(2)) control strategy to reliably adjust the ...200314602616
biochemical and biophysical properties of the co-sensing transcriptional activator cooa.studies of heme-containing gas sensor proteins have revealed a novel function for heme, which acts as an active site for sensing the corresponding gas molecule of a physiological effector. heme-based o(2), no, and co sensor proteins have now been described in which these gas molecules act as a signaling factor that regulates the functional activity of the sensor proteins. cooa is a co-sensing transcriptional activator found in the photosynthetic bacterium rhodospirillum rubrum. the binding of co ...200314622029
proton translocation by transhydrogenase. 200314630339
identification and distribution of insertion sequences of paracoccus solventivorans.three novel insertion sequences (iss) (ispso1, ispso2, and ispso3) of the soil bacterium paracoccus solventivorans dsm 11592 were identified by transposition into entrapment vector pmec1. ispso1 (1,400 bp) carries one large open reading frame (orf) encoding a putative basic protein (with a dde motif conserved among transposases [tnps] of elements belonging to the is256 family) with the highest levels of similarity with the hypothetical tnps of rhodospirillum rubrum and sphingopyxis macrogoltabid ...200314660342
properties of mutated rhodospirillum rubrum h+-pyrophosphatase expressed in escherichia coli.the membrane-bound proton pumping inorganic pyrophosphate synthase/pyrophosphatase (h(+)-ppi synthase/h(+)-ppase) from the photosynthetic bacterium rhodospirillum rubrum was functionally expressed in escherichia coli c43(de3) cells. based on a new topology model of the enzyme, charged residues predicted to be located near or within the membrane were selected for site-directed mutagenesis. several of these mutations resulted in an almost complete inactivation of the enzyme. four mutated residues ...200314670604
direct observation of tiers in the energy landscape of a chromoprotein: a single-molecule study.single-molecule spectroscopic techniques were applied to individual pigments embedded in a chromoprotein. a sensitive tool to monitor structural fluctuations of the protein backbone in the local environment of the chromophore is provided by recording the changes of the spectral positions of the pigment absorptions as a function of time. the data provide information about the organization of the energy landscape of the protein in tiers that can be characterized by an average barrier height. addit ...200314671325
role of the c-terminal extrinsic region of the alpha polypeptide of the light-harvesting 2 complex of rhodobacter sphaeroides: a domain swap study.the lh1 and lh2 complexes of rhodobacter sphaeroides form ring structures of 16 and 9 protomers, respectively, comprising alpha and beta polypeptides, bacteriochlorophylls (bchl), and carotenoids. using the lh2 complex as a starting point, two chimeric lh complexes were constructed incorporating the alphac-terminal domain of either the rb. sphaeroides lh1 complex or the rhodospirillum molischianum lh2 complex. the lh1 domain swap produced a new red-shifted component that comprised approximately ...200314690421
hydrophobic pockets at the membrane interface: an original mechanism for membrane protein interactions.the effect of partial digestion by trypsin and gluc protease on the association of the membrane polypeptides of lh1 from rhodospirillum (rsp.) rubrum was studied. trypsin and gluc protease treatments of lh1 result in the cleavage of the first three amino acids from the alpha polypeptide and of the first 18 amino acids from the beta polypeptide, respectively, without any noticeable reorganization of their secondary structure, as measured by attenuated total reflectance fourier transform ir spectr ...200414756563
the activator of the rhodospirillum rubrum phb depolymerase is a polypeptide that is extremely resistant to high temperature (121 degrees c) and other physical or chemical stresses.hydrolysis of native (amorphous) polyhydroxybutyrate (nphb) granules isolated from different sources by soluble phb depolymerase of rhodospirillum rubrum in vitro requires the presence of a heat-stable compound (activator). the activator was purified and was resistant against various physical and chemical stresses such as heat (up to 130 degrees c), ph 1-12, dryness, oxidation by h2o2, reducing and denaturing compounds (2-mercaptoethanol, 5 m guanidinium-hcl) and many solvents including phenol/c ...200414757249
characterization of cyst cell formation in the purple photosynthetic bacterium rhodospirillum centenum.rhodospirillum centenum is an anoxygenic photosynthetic bacterium that is capable of differentiating into several cell types. when grown phototrophically in liquid, cells exhibit a vibrioid shape and have a single polar flagellum. when grown on a solid surface, r. centenum will differentiate into rod-shaped swarm cells that display numerous lateral flagella. upon starvation for nutrients, r. centenum also forms desiccation-resistant cysts. in this study, it was determined that r. centenum has he ...200414766916
carbon monoxide dehydrogenase from rhodospirillum rubrum: effect of redox potential on catalysis.the ni-fe-s-containing c-cluster of carbon monoxide dehydrogenases is the active site for catalyzing the reversible oxidation of co to co(2). this cluster can be stabilized in redox states designated c(ox), c(red1), c(int), and c(red2). what had until recently been the best-supported mechanism of catalysis involves a one-electron reductive activation of c(ox) to c(red1) and a catalytic cycle in which the c(red1) state binds and oxidizes co, forming c(red2) and releasing co(2). recent experiments ...200414769031
on the relation between phototaxis and photosynthesis in rhodospirillum rubrum. 195014800998
nonequivalence of methyl and carboxyl groups in photometabolism of acetate by rhodospirillum rubrum. 195114817280
a comparative study of the light and dark fermentations of organic acids by rhodo-spirillum rubrum. 195114824109
chromatophores of rhodospirillum rubrum. 195214910754
studies on the metabolism of photosynthetic bacteria. xii. comparative light and dark metabolism of acetate and carbonate by rhodospirillum rubrum. 195214924662
properties of cell-free hydrogenases of escherichia coli and rhodospirillum rubrum. 195214927554
studies on the metabolism of photosynthetic bacteria. xiv. quantitative relations between malate dissimilation, photoproduction of hydrogen, and nitrogen metabolism in rhodospirillum rubrum. 195214934264
characterization of altered regulation variants of dinitrogenase reductase-activating glycohydrolase from rhodospirillum rubrum.in rhodospirillum rubrum, nitrogenase activity is subject to posttranslational regulation through the adenosine diphosphate (adp)-ribosylation of dinitrogenase reductase by dinitrogenase reductase adp-ribosyltransferase (drat) and dinitrogenase reductase-activating glycohydrolase (drag). to study the posttranslational regulation of drag, its gene was mutagenized and colonies screened for altered drag regulation. three different mutants were found and the drag variants displayed different biochem ...200414960312
identification of critical residues in glnb for its activation of nifa activity in the photosynthetic bacterium rhodospirillum rubrum.the p(ii) regulatory protein family is unusually widely distributed, being found in all three domains of life. three p(ii) homologs called glnb, glnk, and glnj have been identified in the photosynthetic bacterium rhodospirillum rubrum. these have roles in at least four distinct functions, one of which is activation of the nitrogen fixation-specific regulatory protein nifa. the activation of nifa requires only the covalently modified (uridylylated) form of glnb. glnk and glnj are not involved. ho ...200414970346
functionally critical elements of cooa-related co sensors.cooa is a heme-containing transcriptional activator that enables rhodospirillum rubrum to sense and grow on co as a sole energy source. we have identified a number of cooa homologs through database searches, expressed these heterologously in escherichia coli, and monitored their ability to respond to co in vivo. further in vitro analysis of two cooa homologs from azotobacter vinelandii and carboxydothermus hydrogenoformans corroborated the in vivo data by revealing the ability of co to bind to t ...200414973040
dynamics of carbon monoxide binding to cooa.cooa is a dimeric co-sensing heme protein from rhodospirillum rubrum. the heme iron in reduced cooa is six-coordinate; the axial ligands are his-77 and pro-2. co displaces pro-2 and induces a conformation change that allows cooa to bind dna and activate transcription of coo genes. equilibrium co binding is cooperative, with a hill coefficient of n = 1.4, p(50) = 2.2 microm, and estimated adair constants k(1) = 0.16 and k(2) = 1.3 microm(-1). the rates of co binding and release are both strongly ...200414990568
flexibility and size heterogeneity of the lh1 light harvesting complex revealed by atomic force microscopy: functional significance for bacterial photosynthesis.previous electron microscopic studies of bacterial rclh1 complexes demonstrated both circular and elliptical conformations of the lh1 ring, and this implied flexibility has been suggested to allow passage of quinol from the q(b) site of the rc to the quinone pool prior to reduction of the cytochrome bc(1) complex. we have used atomic force microscopy to demonstrate that these are just two of many conformations for the lh1 ring, which displays large molecule-to-molecule variations, in terms of bo ...200414993213
roles of heme axial ligands in the regulation of co binding to cooa.cooa is a co-dependent transcription factor of the bacterium rhodospirillum rubrum that contains a six-coordinate heme. it has as its heme axial ligands pro(2) and cys(75) in the ferric state and pro(2) and his(77) in the ferrous state. to probe the regulation of co binding and the ligand switching mechanism in cooa, we have prepared site-directed mutants in which the residues contributing the axial ligands are substituted. the properties of these mutants were investigated by resonance raman and ...200415026411
the fixabcx genes in rhodospirillum rubrum encode a putative membrane complex participating in electron transfer to nitrogenase.in our efforts to identify the components participating in electron transport to nitrogenase in rhodospirillum rubrum, we used mini-tn5 mutagenesis followed by metronidazole selection. one of the mutants isolated, snt-1, exhibited a decreased growth rate and about 25% of the in vivo nitrogenase activity compared to the wild-type values. the in vitro nitrogenase activity was essentially wild type, indicating that the mutation affects electron transport to nitrogenase. sequencing showed that the t ...200415028689
unraveling the function of the rhodospirillum rubrum activator of polyhydroxybutyrate (phb) degradation: the activator is a phb-granule-bound protein (phasin).efficient hydrolysis of native poly(3-hydroxybutyrate) (nphb) granules in vitro by soluble phb depolymerase of rhodospirillum rubrum requires pretreatment of nphb with an activator compound present in r. rubrum cells (j. m. merrick and m. doudoroff, j. bacteriol. 88:60-71, 1964). edman sequencing of the purified activator (17.4 kda; matrix-assisted laser desorption ionization-time of flight mass spectrometry) revealed identity to a hypothetical protein deduced from a partially sequenced r. rubru ...200415060050
low-lying excited states of light-harvesting system ii in purple bacteria.the low-lying excited states of a b850 ring of rhodospirillum (rs.) molischianum are determined accurately by a semiempirical indo/s method. results obtained are found to fit extremely well with a frenkel exciton model with long-range dipolar interactions, and the spatial size of the electron-hole pair is confirmed to fall predominantly within one bacteriochlorophyll with a small leakage to its nearest neighbors. more importantly, the nearest neighbor exciton coupling constants are found to be c ...200415089341
elucidating the role of conserved glutamates in h+-pyrophosphatase of rhodospirillum rubrum.h(+)-pyrophosphatase (h(+)-ppase) catalyzes pyrophosphate-driven proton transport against the electrochemical potential gradient in various biological membranes. all 50 of the known h(+)-ppase amino acid sequences contain four invariant glutamate residues. in this study, we use site-directed mutagenesis in conjunction with functional studies to determine the roles of the glutamate residues glu(197), glu(202), glu(550), and glu(649) in the h(+)-ppase of rhodospirillum rubrum (r-ppase). all residu ...200415107429
carbon monoxide induced decomposition of the active site [ni-4fe-5s] cluster of co dehydrogenase.during the past two years, crystal structures of cu- and mo-containing carbon monoxide dehydrogenases (codhs) and ni- and fe-containing codhs have been reported. the active site of codhs from anaerobic bacteria (cluster c) is composed of ni, fe, and s for which crystallographic studies of the enzymes from carboxydothermus hydrogenoformans, rhodospirillum rubrum, and moorella thermoaceticarevealed structural similarities in the overall protein fold but showed substantial differences in the essent ...200415113209
initial structure modification of tetrahedral to planar nickel(ii) in a nickel-iron-sulfur cluster related to the c-cluster of carbon monoxide dehydrogenase.a method has been devised that creates a planar ni(ii) site from a tetrahedral site in a nife(3)s(4) cubane-type cluster. reaction of [(ph(3)p)nife(3)s(4)(ls(3))](2)(-) (2) with 1,2-bis(dimethylphosphino)ethane affords [(dmpe)nife(3)s(4)(ls(3))](2)(-) (3), isolated in ca. 45% yield as (et(4)n)(2)[3a].2.5mecn and (et(4)n)(2)[3b].0.25mecn, both of which occur in triclinic space group p. each crystalline form contains two crystallographically inequivalent clusters with the same overall structure bu ...200415149242
a genome phylogeny for mitochondria among alpha-proteobacteria and a predominantly eubacterial ancestry of yeast nuclear genes.analyses of 55 individual and 31 concatenated protein data sets encoded in reclinomonas americana and marchantia polymorpha mitochondrial genomes revealed that current methods for constructing phylogenetic trees are insufficiently sensitive (or artifact-insensitive) to ascertain the sister of mitochondria among the current sample of eight alpha-proteobacterial genomes using mitochondrially-encoded proteins. however, rhodospirillum rubrum came as close to mitochondria as any alpha-proteobacterium ...200415155797
interactions stabilizing the structure of the core light-harvesting complex (lh1) of photosynthetic bacteria and its subunit (b820).reconstitution experiments with a chemically synthesized core light-harvesting (lh1) beta-polypeptide analogue having 3-methylhistidine instead of histidine in the position that normally donates the coordinating ligand to bacteriochlorophyll (bchl) have provided the experimental data needed to assign to b820 one of the two possible alphabeta.2bchl pairs that are observed in the crystal structure of lh2 from phaeospirillum (formerly rhodospirillum) molischianum, the one with rings iii and v of bc ...200415170338
dual flagellar systems enable motility under different circumstances.flagella are extremely effective organelles of locomotion used by a variety of bacteria and archaea. some bacteria, including aeromonas, azospirillum, rhodospirillum, and vibrio species, possess dual flagellar systems that are suited for movement under different circumstances. swimming in liquid is promoted by a single polar flagellum. swarming over surfaces or in viscous environments is enabled by the production of numerous peritrichous, or lateral, flagella. the polar flagellum is produced con ...200415170400
inhibition studies on rhodospirillum rubrum h(+)-pyrophosphatase expressed in escherichia coli.the membrane-bound proton-pumping inorganic pyrophosphatase from rhodospirillum rubrum was heterologously expressed in escherichia coli c43(de3) cells and was inhibited by 4-bromophenacyl bromide (bpb), n,n'-dicyclohexylcarbodiimid (dccd), diethyl pyrocarbonate (depc) and fluorescein 5'-isothiocyanate (fitc). in each case, the enzyme activity was rather well protected against inhibitory action by the substrate mg(2)ppi. site-directed mutagenesis was employed in attempts to identify target residu ...200415178477
the structure and function of bacterial light-harvesting complexes.the harvesting of solar radiation by purple photosynthetic bacteria is achieved by circular, integral membrane pigment-protein complexes. there are two main types of light-harvesting complex, termed lh2 and lh1, that function to absorb light energy and to transfer that energy rapidly and efficiently to the photochemical reaction centres where it is trapped. this mini-review describes our present understanding of the structure and function of the purple bacterial light-harvesting complexes.200415204626
the nitrogen-fixing gene (nifh) of rhodopseudomonas palustris: a case of lateral gene transfer?nitrogen fixation is catalysed by some photosynthetic bacteria. this paper presents a phylogenetic comparison of a nitrogen fixation gene (nifh) with the aim of elucidating the processes underlying the evolutionary history of rhodopseudomonas palustris. in the nifh phylogeny, strains of rps. palustris were placed in close association with rhodobacter spp. and other phototrophic purple non-sulfur bacteria belonging to the alpha-proteobacteria, separated from its close relatives bradyrhizobium jap ...200415256566
effect of sodium sulfide on ni-containing carbon monoxide dehydrogenases.the structure of the active-site c-cluster in co dehydrogenase from carboxydothermus hydrogenoformans includes a mu(2)-sulfide ion bridged to the ni and unique fe, whereas the same cluster in enzymes from rhodospirillum rubrum (codh(rr)) and moorella thermoacetica (codh(mt)) lack this ion. this difference was investigated by exploring the effects of sodium sulfide on activity and spectral properties. sulfide partially inhibited the co oxidation activity of codh(rr) and generated a lag prior to s ...200415264843
watching the photosynthetic apparatus in native membranes.over the last 9 years, the structures of the various components of the bacterial photosynthetic apparatus or their homologues have been determined by x-ray crystallography to at least 4.8-a resolution. despite this wealth of structural information on the individual proteins, there remains an urgent need to examine the architecture of the photosynthetic apparatus in intact photosynthetic membranes. information on the arrangement of the different complexes in a native system will help us to unders ...200415273291
oxygen-dependent h2o2 production by rubisco.oxygen and ribulose-1,5-bisphosphate dependent, h(2)o(2) production was observed with several wild type rubisco enzymes using a sensitive assay. h(2)o(2) and d-glycero-2,3-pentodiulose-1,5-bisphosphate, a known and potent inhibitor of rubisco activity, are predicted products arising from elimination of h(2)o(2) from a peroxyketone intermediate, specific to oxygenase activity. parallel assays using varying co(2) and o(2) concentrations revealed that the partitioning to h(2)o(2) during o(2) consum ...200415280029
activation mechanisms of transcriptional regulator cooa revealed by small-angle x-ray scattering.cooa, a heme-containing transcriptional activator, binds co to the heme moiety and then undergoes a structural change that promotes the specific binding to the target dna. to elucidate the activation mechanism coupled to co binding, we investigated the co-dependent structural transition of cooa with small-angle x-ray scattering (saxs). in the absence of co, the radius of gyration rg and the second virial coefficient (a2) were 25.3(+/-0.5)a and -0.39(+/-0.25) x 10(-4)ml mol g(-2), respectively. c ...200415288777
differential regulation of soluble and membrane-bound inorganic pyrophosphatases in the photosynthetic bacterium rhodospirillum rubrum provides insights into pyrophosphate-based stress bioenergetics.soluble and membrane-bound inorganic pyrophosphatases (sppase and h(+)-ppase, respectively) of the purple nonsulfur bacterium rhodospirillum rubrum are differentially regulated by environmental growth conditions. both proteins and their transcripts were found in cells of anaerobic phototrophic batch cultures along all growth phases, although they displayed different time patterns. however, in aerobic cells that grow in the dark, which exhibited the highest growth rates, northern and western blot ...200415292143
use of iron anomalous scattering with multiple models and data sets to identify and refine a weak molecular replacement solution: structure analysis of cytochrome c' from two bacterial species.the structure of cytochrome c' from two bacterial species, alcaligenes sp and alcaligenes denitrificans, have been determined from x-ray diffraction data to 3.0 a resolution using the anomalous scattering of the single fe atom in each to identify and refine a weak molecular-replacement solution. molecular-replacement studies, with the program amore, used two isomorphous data sets (from the two species), two independent search models (the cytochromes c' from rhodospirillum molischianum and rhodos ...199515299294
[an oligonucleotide primer system for amplification of the ribulose-1,5-bisphosphate carboxylase/oxygenase genes of bacteria of various taxonomic groups].based on the analysis of genbank nucleotide sequences of the cbbl and cbbm genes, coding for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (rubpc), the key enzyme of the calvin cycle, a primer system was designed that allows about 800-bp-long fragments of these genes to be pcr-ampliflied in various photo- and chemotrophic bacteria. the efficiency of the designed primer system in detection of rubpc genes was demonstrated in pcr with dna of taxonomically diverse bacteria pos ...200415315232
the reaction center h subunit is not required for high levels of light-harvesting complex 1 in rhodospirillum rubrum mutants.the gene (puha) encoding the h subunit of the reaction center (rc) was deleted by site-directed interposon mutagenesis by using a kanamycin resistance cassette lacking transcriptional terminators to eliminate polar effects in both the wild-type strain rhodospirillum rubrum s1 and the carotenoid-less strain r. rubrum g9. the puha interposon mutants were incapable of photoheterotrophic growth but grew normally under aerobic chemoheterotrophic conditions. absorption spectroscopy and sodium dodecyl ...200415317762
hypercyst mutants in rhodospirillum centenum identify regulatory loci involved in cyst cell differentiation.rhodospirillum centenum is a purple photosynthetic bacterium that forms resting cyst cells when starved for nutrients. in this study, we demonstrate that chalcone synthase gene (chsa) expression is developmentally regulated, with expression of chsa increasing up to 86-fold upon induction of the cyst developmental cycle. screening for mini-tn5-induced mutants that exhibit elevated chsa::lacz expression has led to the isolation of a set of r. centenum mutants that display increased chsa gene expre ...200415317789
active-site conformational changes associated with hydride transfer in proton-translocating transhydrogenase.transhydrogenase couples the redox (hydride-transfer) reaction between nad(h) and nadp(h) to proton translocation across a membrane. the redox reaction is catalyzed at the interface between two components (di and diii) which protrude from the membrane. a complex formed from recombinant di and diii (the di(2)diii(1) complex) from rhodospirillum rubrum transhydrogenase catalyzes fast single-turnover hydride transfer between bound nucleotides. in this report we describe three new crystal structures ...200415323555
circular dichroism of carotenoids in bacterial light-harvesting complexes: experiments and modeling.in this work we investigate the origin and characteristics of the circular dichroism (cd) spectrum of rhodopin glucoside and lycopene in the light-harvesting 2 complex of rhodopseudomonas acidophila and rhodospirillum molischianum, respectively. we successfully model their absorption and cd spectra based on the high-resolution structures. we assume that these spectra originate from seven interacting transition dipole moments: the first corresponds to the 0-0 transition of the carotenoid, whereas ...200415326029
the c-helix in cooa rolls upon co binding to ferrous heme.cooa is a homodimeric transcriptional activator from rhodospirillum rubrum containing one heme in each subunit. co binding to the heme in its sensor domain activates cooa, facilitating the binding to dna by its dna-binding domain. the c-helix links the two domains and shapes an interface between the subunits. to probe the nature of co activation, residues at positions 112-121 on the c-helix were replaced by asn or gln and their effects were evaluated by resonance raman spectroscopy and by the me ...200415326178
changing the ligand specificity of cooa, a highly specific heme-based co sensor.the co-specific heme-based sensor cooa regulates the ability of rhodospirillum rubrum to grow on co as an energy source. only co triggers the conformational change of cooa essential for the protein to function as a transcriptional activator. a structurally informed mutagenesis, followed by an in vivo screening method, allowed the isolation of a series of novel cooa variants that show very substantial response to imidazole. compared with wild-type cooa, the ligand selectivity between imidazole an ...200415326187
co-sensing mechanisms.carbon monoxide (co) has long been known to have dramatic physiological effects on organisms ranging from bacteria to humans, but recently there have a number of suggestions that organisms might have specific sensors for co. this article reviews the current evidence for a variety of proteins with demonstrated or potential co-sensing ability. particular emphasis is placed on the molecular description of cooa, a heme-containing co sensor from rhodospirillum rubrum, since its biological role as a c ...200415353565
the h(+)-pyrophosphatase of rhodospirillum rubrum is predominantly located in polyphosphate-rich acidocalcisomes.acidocalcisomes are acidic, calcium storage compartments with a h(+) pump located in their membrane that have been described in several unicellular eukaryotes, including trypanosomatid and apicomplexan parasites, algae, and slime molds, and have also been found in the bacterium agrobacterium tumefaciens. in this work, we report that the h(+)-pyrophosphatase (h(+)-ppase) of rhodospirillum rubrum, the first enzyme of this type that was identified and thought to be localized only to chromatophore m ...200415371423
similarities between the abiotic reduction of selenite with glutathione and the dissimilatory reaction mediated by rhodospirillum rubrum and escherichia coli.various mechanisms have been proposed to explain the biological dissimilatory reduction of selenite (seo3(2-)) to elemental selenium (se(o)), although none is without controversy. glutathione, the most abundant thiol in the eukaryotic cells, the cyanobacteria, and the alpha, beta, and gamma groups of the proteobacteria, has long been suspected to be involved in selenium metabolism. experiments with the phototrophic alpha proteobacterium rhodospirillum rubrum showed that the rate of selenite redu ...200415371444
importance of rhodospirillum rubrum h(+)-pyrophosphatase under low-energy conditions.the physiological role of the membrane-bound pyrophosphatase of rhodospirillum rubrum was investigated by the characterization of a mutant strain. comparisons of growth levels between the wild type and the mutant under different low-potential conditions and during transitions between different metabolisms indicate that this enzyme provides r. rubrum with an alternative energy source that is important for growth in low-energy states.200415375148
observation of calcium-dependent unidirectional rotational motion in recombinant photosynthetic f1-atpase molecules.atp hydrolysis and synthesis by the f(0)f(1)-atp synthase are coupled to proton translocation across the membrane in the presence of magnesium. calcium is known, however, to disrupt this coupling in the photosynthetic enzyme in a unique way: it does not support atp synthesis, and caatp hydrolysis is decoupled from any proton translocation, but the membrane does not become leaky to protons. understanding the molecular basis of these calcium-dependent effects can shed light on the as yet unclear m ...200415377671
functional expression and characterization of a bacterial light-harvesting membrane protein in escherichia coli and cell-free synthesis systems.heterologous expression of a bacterial light-harvesting (lh) integral membrane protein was attempted using escherichia coli cells and cell-free synthesis systems prepared from e. coli extracts. the alpha-apoprotein of lh1 complex from purple photosynthetic bacterium rhodospirillum rubrum was overexpressed as a recombinant protein with a histidine (his6) tag added to the carboxyl terminus. both of the expression systems produced alpha-apoprotein in a fully functional form as can judged by its abi ...200415388971
on the role of the carotenoids in photosynthesis in rhodospirillum rubrum. 195015433994
variable lh2 stoichiometry and core clustering in native membranes of rhodospirillum photometricum.the individual components of the photosynthetic unit (psu), the light-harvesting complexes (lh2 and lh1) and the reaction center (rc), are structurally and functionally known in great detail. an important current challenge is the study of their assembly within native membranes. here, we present afm topographs at 12 a resolution of native membranes containing all constituents of the psu from rhodospirillum photometricum. besides the major technical advance represented by the acquisition of such h ...200415457213
expansion and compression of a protein folding intermediate by groel.the groel-groes chaperonin system is required for the assisted folding of many essential proteins. the precise nature of this assistance remains unclear, however. here we show that denatured rubisco from rhodospirillum rubrum populates a stable, nonaggregating, and kinetically trapped monomeric state at low temperature. productive folding of this nonnative intermediate is fully dependent on groel, groes, and atp. reactivation of the trapped rubisco monomer proceeds through a series of groel-indu ...200415469819
the "intracellular" poly(3-hydroxybutyrate) (phb) depolymerase of rhodospirillum rubrum is a periplasm-located protein with specificity for native phb and with structural similarity to extracellular phb depolymerases.rhodospirillum rubrum possesses a putative intracellular poly(3-hydroxybutyrate) (phb) depolymerase system consisting of a soluble phb depolymerase, a heat-stable activator, and a 3-hydroxybutyrate dimer hydrolase (j. m. merrick and m. doudoroff, j. bacteriol. 88:60-71, 1964). in this study we reinvestigated the soluble r. rubrum phb depolymerase (phaz1). it turned out that phaz1 is a novel type of phb depolymerase with unique properties. purified phaz1 was specific for amorphous short-chain-len ...200415489436
fluorescence spectroscopy of conformational changes of single lh2 complexes.we have investigated the energy landscape of the bacterial photosynthetic peripheral light-harvesting complex lh2 of purple bacterium rhodopseudomonas acidophila by monitoring sequences of fluorescence spectra of single lh2 assemblies, at room temperature, with different excitation intensities as well as at elevated temperatures, utilizing a confocal microscope. the fluorescence peak wavelength of individual lh2 complexes was found to abruptly move between long-lived quasi-stable levels differin ...200515501944
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