| structural evidence for a proton transfer pathway coupled with haem reduction of cytochrome c" from methylophilus methylotrophus. | the crystal structures of the oxidized and reduced forms of cytochrome c" from methylophilus methylotrophus were solved from x-ray synchrotron data to atomic resolution. the overall fold of the molecule in the two redox states is very similar and is comparable to that of the oxygen-binding protein from the purple phototrophic bacterium rhodobacter sphaeroides. however, significant modifications occur near the haem group, in particular the detachment from axial binding of his95 observed upon redu ... | 2006 | 16341897 |
| multi-step assembly pathway of the cbb3-type cytochrome c oxidase complex. | the cbb3-type cytochrome c oxidases as members of the heme-copper oxidase superfamily are involved in microaerobic respiration in both pathogenic and non-pathogenic proteobacteria. the biogenesis of these multisubunit enzymes, encoded by the cconoqp operon, depends on the ccoghis gene products, which are proposed to be specifically required for co-factor insertion and maturation of cbb3-type cytochrome c oxidases. here, the assembly of the cbb3-type cytochrome c oxidase from the facultative phot ... | 2006 | 16343536 |
| characterization of naturally occurring atrazine-resistant isolates of the purple non-sulfur bacteria. | six isolates of the purple non-sulfur bacteria, which upon primary isolation were naturally resistant to the herbicide atrazine, were characterized with respect to their taxonomic identity and the mechanism of their resistance. on the basis of electron microscopy, photopigment analysis, and other criteria, they were identified as strains of rhodopseudomonas acidophila, rhodopseudomonas palustris, or rhodocyclus gelatinosus. these isolates exhibited degrees of atrazine resistance which ranged fro ... | 1990 | 16348126 |
| increased nitrogenase-dependent h(2) photoproduction by hup mutants of rhodospirillum rubrum. | transposon tn5 mutagenesis was used to isolate mutants of rhodospirillum rubrum which lack uptake hydrogenase (hup) activity. three tn5 insertions mapped at different positions within the same 13-kb ecori fragment (fragment e1). hybridization experiments revealed homology to the structural hydrogenase genes hupslm from rhodobacter capsulatus and hupsl from bradyrhizobium japonicum in a 3.8-kb ecori-clai subfragment of fragment e1. it is suggested that this region contains at least some of the st ... | 1994 | 16349271 |
| small weak acids reactivate proton transfer in reaction centers from rhodobacter sphaeroides mutated at aspl210 and aspm17. | in reaction centers of rhodobacter sphaeroides, site-directed mutagenesis has implicated several acidic residues in the delivery of protons to the secondary quinone (q(b)) during reduction to quinol. in a double mutant (asp(l210) --> asn + asp(m17) --> asn) that is severely impaired in proton transfer capability over a wide ph range, proton transfer was "rescued" by added weak acids. for low pk(a) acids the total concentration of salt required near neutral ph was high. the ionic strength effect ... | 2006 | 16354664 |
| [a study of protein structure changes during hydration by diffuse x-ray scattering. i. the intensity and the shape of "10-angstrom" maximum]. | the angle dependencies of diffuse x-ray scattering intensities were studied in a wide range of angles from 3 to 80 degrees for water-soluble and membrane proteins with a different structural organization: alpha-helical protein myoglobin, alpha-helical protein serum albumen, alpha + beta protein lysozyme, and transmembrane proteins of photosynthetic reaction centers (rc) from purple bacteria rhodobacter sphaeroides, and blastochlorii (rhodopseudomonas) viridis containing cytocrome c, situated out ... | 2005 | 16358778 |
| characterization of protein matrix motions in the rb. sphaeroides photosynthetic reaction center. | we use normal mode analysis to investigate motions in the photosynthetic reaction center (rc) protein. we identify the regions involved in concerted fluctuations of the protein matrix and analyze the normalized amplitudes and the directionality of the first few dominant modes. we also seek to quantify the coupling of normal modes to long-range electron transfer (et). we find that a quasi-continuous spectrum of protein motions rather than one individual mode contributes to light-driven electron t ... | 2006 | 16369794 |
| probing the contribution of electronic coupling to the directionality of electron transfer in photosynthetic reaction centers. | subpicosecond transient absorption studies are reported for a set of rhodobacter (r.) capsulatus bacterial photosynthetic reaction centers (rcs) designed to probe the origins of the unidirectionality of charge separation via one of two electron transport chains in the native pigment-protein complex. all of the rcs have been engineered to contain a heterodimeric primary electron donor (d) consisting of a bacteriochlorophyll (bchl) and a bacteriopheophytin (bph). the bph component of the m heterod ... | 2005 | 16375408 |
| effect of the in situ electrochemical oxidation on the pigment-protein arrangement and energy transfer in light-harvesting complex from rhodobacter sphaeroides 601. | the oxidation of bacteriochlorophylls (bchls) in peripheral light-harvesting complexes (lh2) from rhodobacter sphaeroides was investigated by spectroelectrochemistry of absorption, fluorescence emission, and femtosecond (fs) pump-probe, with the aim obtaining information about the effect of in situ electrochemical oxidation on the pigment-protein arrangement and energy transfer within lh2. the experimental results revealed that: (a) the generation of the bchl radical cation in both b800 and b850 ... | 2006 | 16380087 |
| analysis of hemf gene function and expression in rhodobacter sphaeroides 2.4.1. | the hemf gene of rhodobacter sphaeroides 2.4.1 is predicted to code for an oxygen-dependent coproporphyrinogen iii oxidase. we found that a hemf- mutant strain is unable to grow under aerobic conditions. we also determined that hemf expression is controlled by oxygen, which is mediated, at least in part, by the response regulatory protein prra. | 2006 | 16385070 |
| novel ligands for the extracellular solute receptors of two bacterial trap transporters. | tripartite atp-independent periplasmic (trap) transporters are relatively common prokaryotic secondary transporters which comprise an extracytoplasmic solute receptor (esr) protein and two dissimilar membrane proteins or domains, yet the substrates and physiological functions of only a few of these systems are so far known. in this study, a biophysical approach was used to identify the ligands for the purified rhodobacter capsulatus rrc01191 and escherichia coli yiao proteins, which are members ... | 2006 | 16385129 |
| spectral analysis of the bc(1) complex components in situ: beyond the traditional difference approach. | the cytochrome (cyt) bc(1) complex (ubiquinol: cytochrome c oxidoreductase) is the central enzyme of mitochondrial and bacterial electron-transport chains. it is rich in prosthetic groups, many of which have significant but overlapping absorption bands in the visible spectrum. the kinetics of the cytochrome components of the bc(1) complex are traditionally followed by using the difference of absorbance changes at two or more different wavelengths. this difference-wavelength (dw) approach has bee ... | 2006 | 16386703 |
| on the mechanism of activation of the bluf domain of appa. | appa, a transcriptional antirepressor, regulates the steady expression of photosynthesis genes in rhodobacter sphaeroides in response to high-intensity blue light and to redox signals. its blue-light sensing is mediated by an n-terminal bluf domain, a member of a novel flavin fold. the photocycle of this domain (appa(5-125)) includes formation of a slightly red-shifted long-lived signaling state, which is formed directly from the singlet excited state of the flavin on a subnanosecond time scale ... | 2006 | 16388580 |
| aerobic anoxygenic phototrophic bacteria in the mid-atlantic bight and the north pacific gyre. | the abundance of aerobic anoxygenic phototrophic (aap) bacteria, cyanobacteria, and heterotrophs was examined in the mid-atlantic bight and the central north pacific gyre using infrared fluorescence microscopy coupled with image analysis and flow cytometry. aap bacteria comprised 5% to 16% of total prokaryotes in the atlantic ocean but only 5% or less in the pacific ocean. in the atlantic, aap bacterial abundance was as much as 2-fold higher than that of prochlorococcus spp. and 10-fold higher t ... | 2006 | 16391092 |
| spectral trends in the fluorescence of single bacterial light-harvesting complexes: experiments and modified redfield simulations. | in this work we present and discuss the single-molecule fluorescence spectra of a variety of species of light-harvesting complexes: lh2 of rhodopseudomonas acidophila, rhodobacter sphaeroides, and rhodospirillum molischianum and lh1 of rhodobacter sphaeroides. the emission spectrum of these complexes varies as a function of time as was described in earlier work. for each type of complex, we observe a pronounced and well-reproducible characteristic relationship between the fluorescence spectral p ... | 2006 | 16399834 |
| comparative study of spectral flexibilities of bacterial light-harvesting complexes: structural implications. | this work presents a comparative study of the frequencies of spectral jumping of individual light-harvesting complexes of six different types: lh2 of rhodopseudomonas acidophila, rhodobacter sphaeroides, and rhodospirillum molischianum; lh1 of rhodobacter sphaeroides; and two "domain swap mutants" of lh2 of rhodobacter sphaeroides: paclh1 and paclh2mol, in which the alpha-polypeptide c-terminus is exchanged with the corresponding sequence from lh1 of rhodobacter sphaeroides or lh2 of rhodospiril ... | 2006 | 16399835 |
| a time-resolved iron-specific x-ray absorption experiment yields no evidence for an fe2+ --> fe3+ transition during qa- --> qb electron transfer in the photosynthetic reaction center. | previous time-resolved ftir measurements suggested the involvement of an intermediary component in the electron transfer step q(a)- --> q(b) in the photosynthetic reaction center (rc) from rhodobacter sphaeroides [remy and gerwert (2003) nat. struct. biol. 10, 637]. by a kinetic x-ray absorption experiment at the fe k-edge we investigated whether oxidation occurs at the ferric non-heme iron located between the two quinones. in isolated reaction centers with a high content of functional q(b), at ... | 2006 | 16401066 |
| structure of a [2fe-2s] ferredoxin from rhodobacter capsulatus likely involved in fe-s cluster biogenesis and conformational changes observed upon reduction. | fdvi from rhodobacter capsulatus is structurally related to a group of [2fe-2s] ferredoxins involved in iron-sulfur cluster biosynthesis. comparative genomics suggested that fdvi and orthologs found in alpha-proteobacteria are involved in this process. here, the crystal structure of fdvi has been determined for both the oxidized and the reduced protein. the [2fe-2s] cluster lies 6 a below the protein surface in a hydrophobic pocket without access to the solvent. this particular cluster environme ... | 2006 | 16402206 |
| steric control of bacteriochlorophyll ligation. | the axial coordination of central mg(2+) ion in chlorophylls is of great structural and functional importance for virtually all photosynthetic chlorophyll proteins; however, little thermodynamic data are available on the ligand binding to these pigments. in the present study, spectral deconvolution of the bacteriochlorophyll q(x) band serves to determine the ligand binding equilibria and relationships between thermodynamic parameters of ligand binding, ligand properties, and steric interactions ... | 2006 | 16402831 |
| controlled uncoupling and recoupling of proton pumping in cytochrome c oxidase. | cytochrome c oxidase (cco) is the terminal enzyme of the respiratory chain and couples energetically the reduction of oxygen to water to proton pumping across the membrane. the results from previous studies showed that proton pumping can be uncoupled from the o2-reduction reaction by replacement of one single residue, asn-139 by asp (n139d), located approximately 30 a from the catalytic site, in the d-proton pathway. the uncoupling was correlated with an increase in the pk(a) of an internal prot ... | 2006 | 16407159 |
| identification of a ubiquinone-binding site that affects autophosphorylation of the sensor kinase regb. | rhodobacter capsulatus regulates many metabolic processes in response to the level of environmental oxygen and the energy state of the cell. one of the key global redox regulators of the cell's metabolic physiology is the sensor kinase regb that controls the synthesis of numerous energy generation and utilization processes. in this study, we have succeeded in purifying full-length regb containing six transmembrane-spanning elements. exogenous addition of excess oxidized coenzyme q1 is capable of ... | 2006 | 16407278 |
| the assimilatory nitrate reduction system of the phototrophic bacterium rhodobacter capsulatus e1f1. | the phototrophic bacterium rhodobacter capsulatus e1f1 assimilates nitrate under anaerobic phototrophic growth conditions. a 17 kb dna region encoding the nitrate assimilation (nas) system of this bacterium has been cloned and sequenced. this region includes the genes coding for a putative abc (atp-binding cassette)-type nitrate transporter (nasfed) and the structural genes for the enzymes nitrate reductase (nasa), nitrite reductase (nasb) and hydroxylamine reductase (hcp). three genes code for ... | 2006 | 16417500 |
| carotenoid-bacteriochlorophyll energy transfer in lh2 complexes studied with 10-fs time resolution. | in this report, we present a study of carotenoid-bacteriochlorophyll energy transfer processes in two peripheral light-harvesting complexes (known as lh2) from purple bacteria. we use transient absorption spectroscopy with approximately 10 fs temporal resolution, which is necessary to observe the very fast energy relaxation processes. by comparing excited-state dynamics of the carotenoids in organic solvents and inside the lh2 complexes, it has been possible to directly evaluate their energy tra ... | 2006 | 16428274 |
| identification of two gene loci involved in poly-beta-hydroxybutyrate production in rhodobacter sphaeroides fj1. | polyhydroxyalkanoates (phas), biopolyesters of hydroxyl fatty acids, are synthesized and deposited as cytoplasmic inclusions in many bacteria. we isolated a poly-beta-hydroxybutyrate (phb)-producing bacterium designated rhodobacter sphaeroides fj1. to characterize phb biosynthesis in this organism, we isolated the genes encoding proteins involved in phb metabolism. | 2006 | 16440119 |
| micro-scale open-tube capillary separations of functional proteins. | this article describes a novel technique whereby fully functional proteins or multiprotein complexes are efficiently extracted from biological samples to chemically derivatized walls of fused-silica open-tube capillary columns. proteins are eluted with very high yields into elution volumes that are smaller in volume than the internal volume of the open-tube capillary column itself, thereby achieving 100-fold increases in target protein concentrations from starting samples of less than 1 ml. the ... | 2006 | 16448620 |
| triplet state spectra and dynamics of geometric isomers of carotenoids. | the observation of preferential binding of cis-carotenoids in purple bacterial photosynthetic reaction centers versus trans-isomers in antenna pigment protein complexes has led to the hypothesis that the natural selection of stereoisomers has physiological significance. in order to test this hypothesis, we have undertaken a systematic series of investigations comparing the optical spectroscopic properties and excited state dynamics of cis and trans isomers of carotenoids. the present work compar ... | 2006 | 16450049 |
| tetrapyrrole biosynthesis in rhodobacter capsulatus is transcriptionally regulated by the heme-binding regulatory protein, hbrl. | we demonstrate that the expression of hem genes in rhodobacter capsulatus is transcriptionally repressed in response to the exogenous addition of heme. a high-copy suppressor screen for regulators of hem gene expression resulted in the identification of an lysr-type transcriptional regulator, called hbrl, that regulates hem promoters in response to the availability of heme. hbrl is shown to activate the expression of hema and hemz in the absence of exogenous hemin and repress hemb expression in ... | 2006 | 16452440 |
| a rhodobacter sphaeroides puf l, m and x deletion mutant and its complementation in trans with a 5.3 kb puf operon shuttle fragment. | a rhodobacter sphaeroides puf l, m and x deletion mutant was constructed using interposon mutagenesis. the puf l, m and x genes were replaced with a kanamycin resistance cartridge isolated from the transposon tn5. the deletion strain puf big up tri, openlmx 21 did not grow photoheterotrophically and was resistant to kanamycin. southern blot analysis of genomic dna from the deletion strain confirmed that the kanamycin resistance was inserted specifically into the puf operon and that the l, m and ... | 1989 | 16453868 |
| effects of substrate analogues and ph on manganese superoxide dismutases. | the effect of the substrate analogues azide and fluoride on the manganese(ii) zero-field interactions of different manganese-containing superoxide dismutases (sod) was measured using high-field electron paramagnetic resonance spectroscopy. two cambialistic types, proteins that are active with manganese or iron, were studied along with two that were only active with iron and another that was only active with manganese. it was found that azide was able to coordinate directly to the pentacoordinate ... | 2006 | 16460038 |
| improvement of growth stability of photosynthetic bacterium rhodobacter capsulatus. | using a semicontinuous culture method, in which operational parameters such as cell concentration and light intensity distribution were maintained almost constant, instability of the specific growth rate of rhodobacter capsulatus b-100, a purple bacterium, was observed to be similar to that of r. capsulatus st-410 when cultivated under high ratios of light intensity on the illuminated side to that of the transmitted light. such instability was not observed in the cultivation of chlorella vulgari ... | 2005 | 16473779 |
| protein-cofactor interactions in bacterial reaction centers from rhodobacter sphaeroides r-26: i. identification of the endor lines associated with the hydrogen bonds to the primary quinone qa*-. | hydrogen bonds are important in determining the structure and function of biomolecules. of particular interest are hydrogen bonds to quinones, which play an important role in the bioenergetics of respiration and photosynthesis. in this work we investigated the hydrogen bonds to the two carbonyl oxygens of the semiquinone qa*- in the well-characterized reaction center from the photosynthetic bacterium rhodobacter sphaeroides r-26. we used electron paramagnetic resonance and electron nuclear doubl ... | 2006 | 16473904 |
| triplet-state conformational changes in 15-cis-spheroidene bound to the reaction center from rhodobacter sphaeroides 2.4.1 as revealed by time-resolved epr spectroscopy: strengthened hypothetical mechanism of triplet-energy dissipation. | time-resolved epr spectra of 15-cis-spheroidene bound to the reaction center from rhodobacter sphaeroides 2.4.1 were recorded at low temperatures. (1) a three-component analysis of the spectral-data matrices by singular-value decomposition followed by global fitting identified the transformation of the triplet carotenoid, (3)car(i) --> (3)car(ii); during this process, the leak of the triplet population was suggested. a four-component analysis suggested the presence of a representative intermedia ... | 2006 | 16475794 |
| community structures and activities of nitrifying and denitrifying bacteria in industrial wastewater-treating biofilms. | the bacterial community structure, in situ spatial distributions and activities of nitrifying and denitrifying bacteria in biofilms treating industrial wastewater were investigated by combination of the 16s rrna gene clone analysis, fluorescence in situ hybridization (fish) and microelectrodes. these results were compared with the nitrogen removal capacity of the industrial wastewater treatment plant (iwtp). both nitrification and denitrification occurred in the primary denitrification (pd) tank ... | 2006 | 16477661 |
| differential localization of mre proteins with pbp2 in rhodobacter sphaeroides. | in rhodobacter sphaeroides, mreb, mrec, mred, pbp2, and roda are encoded at the same locus. the localizations of pbp2, mreb, and mrec, which have all been implicated in the synthesis of the peptidoglycan layer, were investigated under different growth conditions to gain insight into the relationships between these proteins. immunofluorescence microscopy showed that pbp2 localized to specific sites at the midcell of elongating cells under both aerobic and photoheterotrophic conditions. visualizin ... | 2006 | 16484180 |
| structural role of (bacterio)chlorophyll ligated in the energetically unfavorable beta-position. | chlorophyll is attached to apoprotein in diastereotopically distinct ways, by beta- and alpha-ligation. both the beta- and alpha-ligated chlorophylls of photosystem i are shown to have ample contacts to apoprotein within their proteinaceous binding sites, in particular, at c-13 of the isocyclic ring. the h-bonding patterns for the c-13(1) oxo groups, however, are clearly distinct for the beta-ligated and alpha-ligated chlorophylls. the beta-ligated chlorophylls frequently employ their c-13(1) ox ... | 2006 | 16484226 |
| the multicopper oxidase cuto confers copper tolerance to rhodobacter capsulatus. | the cuto gene of the photosynthetic purple bacterium rhodobacter capsulatus codes for a multicopper oxidase as demonstrated by the ability of the recombinant strep-tagged protein to oxidize several mono- and diphenolic compounds known as substrates of escherichia coli cueo and multicopper oxidases from other organisms. the r. capsulatus cuto gene was shown to form part of a tri-cistronic operon, orf635-cuto-cutr. expression of the cuto operon was repressed under low copper conditions by the prod ... | 2006 | 16487321 |
| investigation of the effects of different carotenoids on the absorption and cd signals of light harvesting 1 complexes. | absorption and circular dichroism (cd) spectra of light-harvesting (lh)1 complexes from the purple bacteria rhodobacter (rba.) sphaeroides and rhodospirillum (rsp.) rubrum are presented. the complexes exhibit very low intensity, highly nonconservative, near-infrared (nir) cd spectra. absorption and cd spectra from several mutant and reconstituted lh1 complexes, with the carotenoid neurosporene and the precursor phytoene replacing the wild-type (wt) carotenoids, are also examined. the experiments ... | 2006 | 16494350 |
| photodynamics of the small bluf protein blrb from rhodobacter sphaeroides. | the bluf protein blrb from the non-sulphur anoxyphototrophic purple bacterium rhodobacter sphaeroides is characterized by absorption and emission spectroscopy. blrb expressed from e. coli binding fad, fmn, and riboflavin (called brlb(i)) and recombinant blrb containing only fad (called blrb(ii)) are investigated. the dark-adapted proteins exist in two different receptor conformations (receptor states) with different sub-nanosecond fluorescence lifetimes (bluf(r,f) and bluf(r,sl)). some of the fl ... | 2006 | 16495071 |
| control of enzyme synthesis during adaptation in synchronously dividing populations of rhodopseudomonas spheroides. | | 1967 | 16496526 |
| new tetragonal form of reaction centers from rhodobacter sphaeroides and the involvement of a manganese ion at a crystal contact point. | crystals have been obtained of wild-type reaction centers from rhodobacter sphaeroides using manganese chloride as a precipitating agent. the crystals belong to the tetragonal space group p4(2)22, with unit-cell parameters a = b = 207.8, c = 107.5 a. the crystal structure has been determined to a resolution limit of 4.6 a using a previously determined structure of the reaction center as a molecular-replacement model. the calculated electron-density maps show the presence of a manganese ion at on ... | 2005 | 16511142 |
| enzymic systems proposed to be involved in the dissimilatory reduction of selenite in the purple non-sulfur bacteria rhodospirillum rubrum and rhodobacter capsulatus. | various enzymic systems, such as nitrite reductase, sulfite reductase and glutathione reductase, have been proposed for, or suspected to be involved in, the reduction of selenite in bacteria. as alphaproteobacteria have been shown to be highly tolerant to transition metal oxyanions, it seemed interesting to investigate the hypothetical involvement of these different enzymes in the reduction of selenite in the purple non-sulfur bacteria rhodospirillum rubrum and rhodobacter capsulatus. the hypoth ... | 2006 | 16514153 |
| lasers-an effective artificial source of radiation for the cultivation of anoxygenic photosynthetic bacteria. | the laser diode (ld) is a unique light source that can efficiently produce all radiant energy within the narrow wavelength range used most effectively by a photosynthetic microorganism. we have investigated the use of a single type of ld for the cultivation of the well-studied anoxygenic photosynthetic bacterium, rhodobacter capsulatus (rb. capsulatus). an array of vertical-cavity surface-emitting lasers (vcsels) was driven with a current of 25 ma, and delivered radiation at 860 nm with 0.4 nm l ... | 2006 | 16514675 |
| distance between a native cofactor and a spin label in the reaction centre of rhodobacter sphaeroides by a two-frequency pulsed electron paramagnetic resonance method and molecular dynamics simulations. | the distance between the paramagnetic state of a native cofactor and a spin label is measured in the photosynthetic reaction centre from the bacterium rhodobacter sphaeroides r26. a two-frequency pulsed electron paramagnetic resonance method [double-electron-electron spin resonance (deer)] is used. a distance of 3.05 nm between the semiquinone anion state of the primary acceptor (q(a)) and the spin label at the native cysteine at position 156 in the h-subunit is found. molecular-dynamics (md) si ... | 2006 | 16515869 |
| assessing the impact of denitrifier-produced nitric oxide on other bacteria. | a series of experiments was undertaken to learn more about the impact on other bacteria of nitric oxide (no) produced during denitrification. the denitrifier rhodobacter sphaeroides 2.4.3 was chosen as a denitrifier for these experiments. to learn more about no production by this bacterium, no levels during denitrification were measured by using differential mass spectrometry. this revealed that no levels produced during nitrate respiration by this bacterium were in the low mum range. this conce ... | 2006 | 16517672 |
| [a study of protein structure changes during hydration by means of diffuse x-ray scattering. ii. fourier transform analysis of x-ray scattering data]. | radial distribution functions were deduced by fourier transform analysis of angular dependences of diffuse x-ray scattering intensities for the following proteins with different hydration degree: water-soluble a-protein myoglobin, water-soluble alpha+beta protein lysozyme, and transmembrane proteins of photosynthetic reaction centers from purple bacteria rhodobacter sphaeroides and blastochlorii viridis. the results of fourier analysis of x-ray scattering intensities give the quantitative charac ... | 2006 | 16521549 |
| functional contribution of a conserved, mobile loop histidine of phosphoribulokinase. | in the rhodobacter sphaeroides phosphoribulokinase (prk) structure, there are several disordered regions, including a loop containing invariant residues y98 and h100. the functional importance of these residues has been unclear. prk is inactivated by diethyl pyrocarbonate (depc) and protected by the substrates atp and ru5p, as well as by the competitive inhibitor, 6-phosphogluconate, suggesting active site histidine residue(s). prk contains only three invariant histidines: h45, h100, and h134. p ... | 2006 | 16522805 |
| light induced structural changes of a full-length protein and its bluf domain in ycgf(blrp), a blue-light sensing protein that uses fad (bluf). | blue-light sensing proteins that use fad (bluf) are members of a blue-light receptor family that is widely distributed among microorganisms. the escherichia coli ycgf protein is a bluf protein consisting of the n-terminal fad-binding hold (bluf domain) and the c-terminal eal domain. the eal domain of ycgf is predicted to have cyclic-di-gmp phosphodiesterase activity. light-induced structural changes for the signaling state formation were studied using the light-induced fourier transform infrared ... | 2006 | 16533062 |
| nonpigmented and bacteriochlorophyll-containing bradyrhizobia isolated from aeschynomene indica. | the legume genus aeschynomene is unusual, since many species develop stem nodules and the bradyrhizobia isolated from these nodules produce bacteriochlorophyll (bchl). evidence is presented that the bradyrhizobia of aeschynomene indica have wide distribution throughout the world, since a. indica was nodulated when grown in 58 soils collected in 14 different countries. only 38 of 79 isolates tested synthesized bchl and carotenoids during heterotrophic growth. nine isolates produced bchl constitut ... | 1995 | 16534933 |
| halotolerance of the phototrophic bacterium rhodobacter capsulatus e1f1 is dependent on the nitrogen source. | phototrophic growth of the moderate halotolerant rhodobacter capsulatus strain e1f1 in media containing up to 0.3 m nacl was dependent on the nitrogen source used. in these media, increased growth rates and growth levels were observed in the presence of reduced nitrogen sources such as ammonium and amino acids. when the medium contained an oxidized nitrogen source (dinitrogen or nitrate), increases in salinity severely inhibited phototrophic growth. however, the addition of glycine betaine promo ... | 1995 | 16535098 |
| sinorhizobium meliloti blub is necessary for production of 5,6-dimethylbenzimidazole, the lower ligand of b12. | an insight into a previously unknown step in b(12) biosynthesis was unexpectedly obtained through our analysis of a mutant of the symbiotic nitrogen fixing bacterium sinorhizobium meliloti. this mutant was identified based on its unusually bright fluorescence on plates containing the succinoglycan binding dye calcofluor. the mutant contains a tn5 insertion in a gene that has not been characterized previously in s. meliloti. the closest known homolog is the blub gene of rhodobacter capsulatus, wh ... | 2006 | 16537439 |
| thermodynamics of carbon monoxide photodissociation from the fully reduced cytochrome aa3 oxidase from rb. sphaeroides. | photodissociation of the fully reduced carbonmonoxy bound cytochrome aa3 from rb. sphaeroides results in ultrafast ligand transfer between heme a3 and cub, which is followed by thermal dissociation from cub on longer time scales. we have utilized photoacoustic calorimetry to obtain a detailed thermodynamic description of the mechanism of ligand photodissociation and transfer between heme a3 and cub. subsequent to ligand photodissociation an additional process, which has not been characterized pr ... | 2006 | 16545339 |
| identification of a transposable genomic island of paracoccus pantotrophus dsm 11072 by its transposition to a novel entrapment vector pmmb2. | a novel shuttle entrapment vector, pmmb2, was used to identify a large transposable element, tnppa1 (44.3 kb), of paracoccus pantotrophus dsm 11072. tnppa1 has a composite structure with divergently oriented copies of a cryptic transposon, tn3434 (tn3 family), located at both termini. the core region of the element contains a large set of putative genes, whose products show similarity to enzymes involved in central intermediary metabolism (e.g. tricarboxylic acid cycle or 2-methylcitrate cycle), ... | 2006 | 16549670 |
| electronic transitions of the soret band of reaction centers from rhodobacter sphaeroides studied by femtosecond transient absorbance spectroscopy. | the soret band of reaction centers from rhodobacter sphaeroides has been systematically studied using femtosecond transient absorption spectroscopy. when the excitation wavelength was scanned over the entire soret band, the approximate absorption spectra of the bacteriochlorophyll dimer, the monomer bacteriochlorophylls, and the bacteriopheophytins within the soret band were determined by analyzing the ground state bleaching with about 100 fs resolution. the main contribution of h is on the blue ... | 2006 | 16571008 |
| stark effect spectroscopy of rhodobacter sphaeroides and rhodopseudomonas viridis reaction centers. | the nature of the initially excited state of the primary electron donor or special pair has been investigated by stark effect spectroscopy for reaction centers from the photosynthetic bacteria rhodopseudomonas viridis and rhodobacter sphaeroides at 77 k. the data provide values for the magnitude of the difference in permanent dipole moment between the ground and excited state, [unk]deltamu[unk], and the angle [unk] between deltamu and the transition dipole moment for the electronic transition. [ ... | 1988 | 16578825 |
| directed mutations affecting spectroscopic and electron transfer properties of the primary donor in the photosynthetic reaction center. | oligonucleotide-mediated mutagenesis has been used to change the histidine residues that act as axial ligands to the central mg(2+) ions of the "special pair" bacteriochlorophylls in the reaction center of rhodobacter capsulatus. histidine-173 of the l subunit has been replaced with glutamine, while histidine-200 of the m subunit has been replaced with glutamine, leucine, or phenylalanine. when leucine or phenylalanine is introduced at m200, one of the special pair bacteriochlorophylls is conver ... | 1988 | 16578836 |
| the lipopolysaccharide of rh. capsulatus suppresses the endotoxin-induced delay of apoptosis of human myeloid cells. | | 2006 | 16584000 |
| spectral and temporal dynamics of transitional processes in the reaction centers of rhodobacter sphaeroides in the region of 780-830 nm. | | 2006 | 16584005 |
| heterologous overexpression and purification of cytochrome c' from rhodobacter capsulatus and a mutant (k42e) in the dimerization region. mutation does not alter oligomerization but impacts the heme iron spin state and nitric oxide binding properties. | rhodobacter capsulatus cytochrome c' (rccp) has been overexpressed in escherichia coli, and its spectroscopic and ligand-binding properties have been investigated. it is concluded that the heterologously expressed protein is assembled correctly, as judged by uv-vis absorption, epr, and resonance raman (rr) spectroscopy of the unligated protein as well as forms in which the heme is ligated by co or no. to probe the oligomerization state of rccp and its potential influence on heme reactivity, we h ... | 2006 | 16584174 |
| selective recruitment of membrane protein complexes onto gold substrates patterned by dip-pen nanolithography. | dip-pen nanolithography (dpn) is employed to develop a generic array platform for the selective recruitment of membrane protein complexes. an atomic force microscope tip inked with hs(ch2)16nh2 is used to generate amino-terminated domains on gold. these domains can be arranged into microscopic and submicroscopic patterns, and the untreated gold substrate is subsequently blocked with hs(ch2)2conh(ch2ch2o)15ch3, a compound known to resist the unspecific binding of proteins and cells. the patterned ... | 2006 | 16584209 |
| role of charge-transfer states in bacterial photosynthesis. | photon echo, photon-echo excitation, and "hole-burning" data recorded in the 800-990 nm region of rhodobacter sphaeroides r26 and rhodopseudomonas viridis reaction centers are reported. the primary process in these reaction centers, following excitation, was found to occur in approximately 25 fsec; the long-wavelength band of the primary electron donor (p) was largely homogeneously broadened. in accordance with our previous explanation of hole-burning and photon-echo measurements on rb. sphaeroi ... | 1986 | 16593787 |
| the response of vibrio- and rhodobacter-related populations of the nw mediterranean sea to additions of dissolved organic matter, phages, or dilution. | we investigated the growth response of the heterotrophic prokaryotic community focusing on vibrio- and rhodobacter-related populations (srf3) to variation in the availability of dissolved organic matter (dom), population density-dependent effects, and prokaryotic virus (phage) infection in coastal and offshore waters of the nw mediterranean sea. we tested the response of the prokaryotic community to three different dom fractions prepared by ultrafiltration. one of the dom fractions contained pha ... | 2006 | 16598637 |
| proton pumping in the bc1 complex: a new gating mechanism that prevents short circuits. | the q-cycle mechanism of the bc1 complex explains how the electron transfer from ubihydroquinone (quinol, qh2) to cytochrome (cyt) c (or c2 in bacteria) is coupled to the pumping of protons across the membrane. the efficiency of proton pumping depends on the effectiveness of the bifurcated reaction at the q(o)-site of the complex. this directs the two electrons from qh2 down two different pathways, one to the high potential chain for delivery to an electron acceptor, and the other across the mem ... | 2006 | 16600173 |
| bacterial diversity within the planktonic community of an artesian water supply. | culture and molecular methods were used to describe the planktonic bacterial diversity of an artesian water supply in rural latah county, idaho, within the drainage of a small perennial stream, thorn creek. the surrounding depth to groundwater at this location is thought to be significant (>100 m), and this transitional zone (basalt-granite) of the palouse aquifer system is little studied. the water produced by this artesian source is consistent even in years of drought and is of high quality, b ... | 2006 | 16604121 |
| the disulfide bridge in the head domain of rhodobacter sphaeroides cytochrome c1 is needed to maintain its structural integrity. | cytochrome c(1) of rhodobacter sphaeroides ubiquinol-cytochrome c oxidoreductase contains several insertions and deletions that distinguish it from the complex of other higher organisms. additionally, this bacterial cytochrome c(1) contains two nonconserved cysteines, c145 and c169, with the latter included in the second long insertion located upstream of the sixth heme ligand, m185. the orientation of the insertions and the state of these non-heme binding cysteines remain unknown. mutating one ... | 2006 | 16605267 |
| endor of no-ligated cytochrome c'. | the five-coordinate no-bound heme in cytochrome c' from an overexpressing variant of denitrifying r. sphaeroides 2.4.3 was investigated by proton, nitrogen, and deuterium q-band endor (electron nuclear double resonance). endor was a direct probe of the unpaired electron density on the nitrogen of no and, as measured across the epr line shape, showed a hyperfine coupling range from 36 to 44 mhz for 14no and 51 to 63 mhz for 15no. the smallest no coupling occurred at an electronic g-tensor axis pe ... | 2006 | 16608336 |
| in vitro and in vivo analysis of the role of prra in rhodobacter sphaeroides 2.4.1 hema gene expression. | the hema gene codes for one of two synthases in rhodobacter sphaeroides 2.4.1 which catalyze the formation of 5-aminolevulinic acid. we have examined the role of prra, a dna binding protein that is associated with the metabolic switch between aerobic growth and anoxygenic photosynthetic growth, in hema expression and found that hema transcription is directly activated by prra. using electrophoretic mobility shift assays and dnase i protection assays, we have mapped two binding sites for prra wit ... | 2006 | 16621813 |
| electron transfer to nitrite reductase of rhodobacter sphaeroides 2.4.3: examination of cytochromes c2 and cy. | the role of cytochrome c(2), encoded by cyca, and cytochrome c(y), encoded by cycy, in electron transfer to the nitrite reductase of rhodobacter sphaeroides 2.4.3 was investigated using both in vivo and in vitro approaches. both cyca and cycy were isolated, sequenced and insertionally inactivated in strain 2.4.3. deletion of either gene alone had no apparent effect on the ability of r. sphaeroides to reduce nitrite. in a cyca-cycy double mutant, nitrite reduction was largely inhibited. however, ... | 2006 | 16622064 |
| investigation of rhodobacter capsulatus pufx interactions in the core complex of the photosynthetic apparatus. | the photosynthetic apparatus of purple bacteria in the genus rhodobacter includes a core complex consisting of the reaction centre (rc), light-harvesting complex 1 (lh1), and the pufx protein. pufx modulates lh1 structure and facilitates photosynthetic quinone/quinol exchange. we deleted rc/lh1 genes in pufx+ and pufx++ (merodiploid) strains of rhodobacter capsulatus, which reduced pufx levels regardless of pufx gene copy number and location. photosynthetic growth of rc-only strains and independ ... | 2006 | 16622783 |
| structural and functional studies of the response regulator hupr. | hupr is a response regulator that controls the synthesis of the membrane-bound [nife]hydrogenase of the photosynthetic bacterium rhodobacter capsulatus. the protein belongs to the ntrc subfamily of response regulators and is the second protein of a two-component system. we have crystallized the full-length protein hupr in the unphosphorylated state in two dimensions using the lipid monolayer technique. the 3d structure of negatively stained hupr was calculated to a resolution of approximately 23 ... | 2006 | 16631791 |
| uncoupling of electron and proton transfers in the photocycle of bacterial reaction centers under high light intensity. | photosynthetic reaction centers produce and export oxidizing and reducing equivalents in expense of absorbed light energy. the formation of fully reduced quinone (quinol) requires a strict (1:1) stoichiometric ratio between the electrons and h(+) ions entering the protein. the steady-state rates of both transports were measured separately under continuous illumination in the reaction center from the photosynthetic bacterium rhodobacter sphaeroides. the uptake of the first proton was retarded by ... | 2006 | 16634646 |
| [effect of hydrogen bonds on the energetics of electron transfer]. | for a model system consisting of a special pair of bacteriochlorophyll molecules (p) and a primary quinone with the nearest environment (qa) (which are acceptor and donor in the recombination reaction in rhodobacter sphaeroides reaction center, respectively), energies of p+qa(-) and pqa states were calculated. calculations were performed using several stable qa conformations differing by the positions of hydrogen bond protons. essential influence of proton positions on the energy of vertical tra ... | 2006 | 16637331 |
| cross-talk towards the response regulator ntrc controlling nitrogen metabolism in rhodobacter capsulatus. | rhodobacter capsulatus ntrb/ntrc two-component regulatory system controls expression of genes involved in nitrogen metabolism including urease and nitrogen fixation genes. the ntry-ntrx genes, which are located immediately downstream of the nifr3-ntrb-ntrc operon, code for a two-component system of unknown function. transcription of ntry starts within the ntrc-ntry intergenic region as shown by primer extension analysis, but maximal transcription requires, in addition, the promoter of the nifr3- ... | 2006 | 16640581 |
| application of time-resolved polarization fluorescence spectroscopy in the femtosecond range to photosynthetic systems. | time-resolved polarization fluorescence spectroscopy in the femtosecond range was applied to a photosynthetic antenna system. specific signals of excited states were obtained by simultaneous measurements of fluorescence rise and decay curves and polarized spectroscopy. relaxation processes of carotenoids, energy transfer from carotenoids to chlorophyll (chl) a, and energy migration among pigment pools of chl a and chl b were clearly resolved. two new characteristics of carotenoid molecules were ... | 2007 | 16643087 |
| nucleotide sequence of s-adenosyl-l-methionine: magnesium protoporphyrin methyltransferase from rhodobacter capsulatus. | | 1992 | 16668646 |
| purification and molecular and immunological characterization of a unique phosphoribulokinase from the green alga selenastrum minutum. | a unique phosphoribulokinase (adp:d-ribulose 5-phosphate 1-phosphotransferase, ec 2.7.1.19) has been purified to homogeneity from the green alga selenastrum minutum. the enzyme has a native molecular mass of about 83 kilodaltons and a native isoelectric point of 5.1. the enzyme consists of two different-sized subunits of 41 and 40 kilodaltons, implying that it is a heterodimer. this is the first report of a eukaryotic heterodimeric phosphoribulokinase. the in vivo existence of two nonidentical s ... | 1992 | 16668652 |
| sequence analysis of the cbb3 oxidases and an atomic model for the rhodobacter sphaeroides enzyme. | the cbb3-type oxidases are members of the heme-copper oxidase superfamily, distant by sequence comparisons, but sharing common functional characteristics. to understand the minimal common properties of the superfamily, and to learn about cbb3-type oxidases specifically, we have analyzed a wide set of heme-copper oxidase sequences and built a homology model of the catalytic subunit of the cbb3 oxidase from rhodobacter sphaeroides. we conclude that with regard to the active site surroundings, the ... | 2006 | 16669619 |
| genetic and biochemical evidence for the involvement of a molybdenum-dependent enzyme in one of the selenite reduction pathways of rhodobacter sphaeroides f. sp. denitrificans il106. | selenite reduction in rhodobacter sphaeroides f. sp. denitrificans was observed under photosynthetic conditions, following a 100-h lag period. this adaptation period was suppressed if the medium was inoculated with a culture previously grown in the presence of selenite, suggesting that selenite reduction involves an inducible enzymatic pathway. a transposon library was screened to isolate mutants affected in selenite reduction. of the eight mutants isolated, two were affected in molybdenum cofac ... | 2006 | 16672451 |
| redox-responsive in vitro modulation of the signalling state of the isolated prrb sensor kinase of rhodobacter sphaeroides ncib 8253. | prr is a global regulatory system that controls a large and diverse range of genes in rhodobacter sphaeroides in response to changing conditions of environmental redox potential. prrb is the membrane-bound sensor kinase and previously we showed that the purified, detergent-solubilised intact membrane protein is functional in autophosphorylation, phosphotransfer and phosphatase activities. here we confirm that it also senses and responds directly to its environmental signal, redox potential; stro ... | 2006 | 16684526 |
| structural and functional studies on dhc, the diheme cytochrome c from rhodobacter sphaeroides, and its interaction with shp, the sphaeroides heme protein. | the diheme cytochrome c (dhc) from rhodobacter sphaeroides is a soluble protein with a mass of 16 kda that represents a new class of c-type cytochrome [vandenberghe, i., et al. (1998) biochemistry 37, 13075-13081]. the gene encoding dhc is associated with another encoding a cytochrome known as shp (sphaeroides heme protein). it is believed that dhc is the electron donor for shp, which is known to bind oxygen. to gain further insight into the properties and role of dhc, we have carried out struct ... | 2006 | 16700547 |
| the positioning of cytoplasmic protein clusters in bacteria. | cell division is a carefully orchestrated procedure. bacterial cells have intricate mechanisms to ensure that genetic material is copied, proofread, and accurately partitioned into daughter cells. partitioning now appears to also occur for some cytoplasmic proteins. previously, using chromosomal fluorescent protein fusions, we demonstrated that a subset of rhodobacter sphaeroides chemotaxis proteins colocalize to a discrete region within the bacterial cytoplasm. using tlpt-yellow fluorescent pro ... | 2006 | 16702547 |
| enthalpy/entropy driven activation of the first interquinone electron transfer in bacterial photosynthetic reaction centers embedded in vesicles of physiologically important phospholipids. | the thermodynamics and kinetics of light-induced electron transfer in bacterial photosynthetic rcs are sensitive to physiologically important lipids (phosphatidylcholine, cardiolipin and phosphatidylglycerol) in the environment. the analysis of the temperature-dependence of the rate of the p(+)q(a)(-)q(b)-->p(+)q(a)q(b)(-) interquinone electron transfer revealed high enthalpy change of activation in zwitterionic or neutral micelles and vesicles and low enthalpy change of activation in vesicles c ... | 2007 | 16713374 |
| a spatial model of the chromatophore vesicles of rhodobacter sphaeroides and the position of the cytochrome bc1 complex. | the photosynthetic apparatus of purple bacteria is generally considered a well-studied and understood system. however, recent atomic force microscopy images of flattened chromatophore vesicles from rhodobacter sphaeroides restarted a debate about the stoichiometry and positions of the membrane proteins, with the interpretations of the observed images only partly being in agreement with earlier models. the most puzzling observation from the recent images is that the cytochrome bc(1) complex, whic ... | 2006 | 16714339 |
| architecture of the native photosynthetic apparatus of phaeospirillum molischianum. | the ubiquity and importance of photosynthetic organisms in nature has made the molecular mechanisms of photosynthesis a widely studied subject at both structural and functional levels. a current challenge is to understand the supramolecular assembly of the proteins involved in photosynthesis in native membranes. we have used atomic force microscopy to study the architecture of the photosynthetic apparatus and analyze the structure of single molecules in chromatophores of phaeospirillum molischia ... | 2005 | 16330228 |
| a tyrosine residue deprotonates during oxygen reduction by the caa3 reductase from rhodothermus marinus. | heme-copper oxygen reductases catalyze proton translocation across the cellular membrane; this takes place during the reaction of oxygen to water. we demonstrate with attenuated total reflection-fourier transform infrared (atr-ftir) difference spectroscopy that a tyrosine residue of the oxygen reductase from the thermohalophilic rhodothermus marinus becomes deprotonated in the transition from the oxidized state to the catalytic intermediate ferryl state p(m). this tyrosine residue is most probab ... | 2006 | 16466722 |
| design of a minimal polypeptide unit for bacteriochlorophyll binding and self-assembly based on photosynthetic bacterial light-harvesting proteins. | we introduce lh1beta24, a minimal 24 amino acid polypeptide that binds and assembles bacteriochlorophylls (bchls) in micelles of octyl beta-glucoside (og) into complexes with spectral properties that resemble those of b820, a universal intermediate in the assembly of native purple bacterial light-harvesting complexes (lhs). lh1beta24 was designed by a survey of sequences and crystal structures of bacterial lh proteins from different organisms combined with currently available information from in ... | 2006 | 16475799 |
| the observation of ultrafast excited-state dynamical evolution in b800- partially or completely released lh2 of rhodobacter sphaeroides 601 at room temperature. | photodynamics of two kinds of peripheral antenna complexes (lh2 of rhodobacter sphaeroides, native lh2 (rs601) and b800-released lh2 where b800-bchls were partially or completely removed with different ph treatments), were studied using femtosecond pump-probe technique at different laser wavelengths. the obtained results for these samples with different b800/b850 ratios demonstrated that under the excitation around b800 nm, the photoabsorption and photobleaching dynamics were caused by the direc ... | 2006 | 16494502 |
| analysis of absorption spectra of purple bacterial reaction centers in the near infrared region by higher order derivative spectroscopy. | reaction centers (rcs) of purple bacteria are uniquely suited objects to study the mechanisms of the photosynthetic conversion of light energy into chemical energy. a recently introduced method of higher order derivative spectroscopy [i.k. mikhailyuk, h. lokstein, a.p. razjivin, a method of spectral subband decomposition by simultaneous fitting the initial spectrum and a set of its derivatives, j. biochem. biophys. methods 63 (2005) 10-23] was used to analyze the nir absorption spectra of rc pre ... | 2006 | 16513249 |
| kinetic analysis of the thermal stability of the photosynthetic reaction center from rhodobacter sphaeroides. | the temperature-induced denaturation of the photosynthetic reaction center from rhodobacter sphaeroides has been studied through the changes that occur in the absorption spectrum of the bound chromophores on heating. at elevated temperatures, the characteristic absorbance bands of the bacteriochlorins bound to the polypeptides within the reaction center are lost, and are replaced by features typical of unbound bacteriochlorophyll and bacteriopheophytin. the kinetics of the spectral changes canno ... | 2006 | 16533858 |
| high yield of m-side electron transfer in mutants of rhodobacter capsulatus reaction centers lacking the l-side bacteriopheophytin. | we present studies on a series of photosynthetic reaction center (rc) mutants created in the background of the rhodobacter capsulatus d(ll) mutant, in which the d helix of the m subunit has been substituted with that from the l subunit. previous work on the d(ll) mutant in chromatophore preparations showed that rcs assembled without the bacteriopheophytin h(l) electron acceptor and performed no charge separation following light absorption. we have successfully isolated poly-his-tagged d(ll) rcs ... | 2006 | 16548512 |
| a second nitrogenase-like enzyme for bacteriochlorophyll biosynthesis: reconstitution of chlorophyllide a reductase with purified x-protein (bchx) and yz-protein (bchy-bchz) from rhodobacter capsulatus. | in most photosynthetic organisms, the chlorin ring structure of chlorophyll a is formed by the reduction of the porphyrin d-ring by the dark-operative nitrogenase-like enzyme, protochlorophyllide reductase (dpor). subsequently, the chlorin b-ring is reduced in bacteriochlorophyll biosynthesis to form a bacteriochlorin ring structure. phenotypic analysis of mutants lacking one of three genes, bchx, bchy, or bchz, which show significant sequence similarity to the structural genes of nitrogenase, s ... | 2006 | 16571720 |
| rhodobacter capsulatus xdhc is involved in molybdenum cofactor binding and insertion into xanthine dehydrogenase. | rhodobacter capsulatus xanthine dehydrogenase (xdh) is a cytoplasmic enzyme with an (alphabeta)2 heterodimeric structure that is highly identical to homodimeric eukaryotic xanthine oxidoreductases. the crystal structure revealed that the molybdenum cofactor (moco) is deeply buried within the protein. a protein involved in moco insertion and xdh maturation has been identified, which was designated xdhc. xdhc was shown to be essential for the production of active xdh but is not a subunit of the pu ... | 2006 | 16597619 |
| orientational control of the physiological reaction of cytochrome c oxidase tethered to a gold electrode. | the physiological reaction of a membrane protein is reconstituted on a solid-supported electrode by orientational control via the position of an affinity tag. recombinant cytochrome c oxidase (cco) from rhodobacter sphaeroides is immobilized on a chemically modified gold surface via the affinity of a histidine tag (his-tag) to a nickel chelating nitrilotriacetic acid surface. control of the orientation is achieved by the adsorption of cco through the his-tag engineered into the two opposite site ... | 2006 | 16671753 |
| reconstruction of a kinetic model of the chromatophore vesicles from rhodobacter sphaeroides. | we present a molecular model of a chromatophore vesicle from rhodobacter sphaeroides. these vesicles are ideal benchmark systems for molecular and systemic simulations, because they have been well studied, they are small, and they are naturally separated from their cellular environment. to set up a photosynthetic chain working under steady-state conditions, we compiled from the experimental literature the specific activities and geometries that have been determined for their constituents. this d ... | 2006 | 16714340 |
| spectral and kinetic resolution of the bc1 complex components in situ: a simple and robust alternative to the traditional difference wavelength approach. | the kinetics of the cytochrome (cyt) components of the bc(1) complex (ubiquinol: cytochrome c oxidoreductase, complex iii) are traditionally followed by using the difference of absorbance changes at two or more different wavelengths. however, this difference-wavelength (dw) approach is of limited accuracy in the separation of absorbance changes of components with overlapping spectral bands. to resolve the kinetics of individual components in rhodobacter sphaeroides chromatophores, we have tested ... | 2006 | 16730321 |
| light-dependent transformation of aniline to indole esters by the purple bacterium rhodobacter sphaeroides ou5. | in an attempt to understand the aromatic hydrocarbon metabolism by purple bacteria that do not grow at their expense, we earlier reported 2-aminobenzoate transformation by a purple non-sulfur bacterium, rhodobacter sphaeroides ou5 (sunayana et al., 2005, j ind microbiol biotech 32:41-45), which is extended in the present study with aniline, a major environmental pollutant. aniline did not support photo (light anaerobic) or chemo (dark aerobic) heterotrophic growth of rhodobacter sphaeroides ou5 ... | 2006 | 16732448 |
| rubellimicrobium thermophilum gen. nov., sp. nov., a red-pigmented, moderately thermophilic bacterium isolated from coloured slime deposits in paper machines. | six red-pigmented strains of the alphaproteobacteria with optimal growth between 45 and 54 degrees c were previously isolated from coloured biofilms in two fine-paper machines and one pulp dryer. the strains were found to be resistant to 15 p.p.m. 2,2-dibromo-3-nitrilopropionamide, a common industrial biocide. 16s rna gene sequence similarity of the isolates was 99.7-100 %. ribotyping using the restriction enzymes pvuii and ecori showed that four of the isolates (c-lvk-r2a-1, c-lvk-r2a-2(t), c-r ... | 2006 | 16738114 |
| identification of the dna bases of a dnase i footprint by the use of dye primer sequencing on an automated capillary dna analysis instrument. | we have adapted the techniques of dna footprint analysis to an applied biosystems 3730 dna analyzer. the use of fluorescently labeled primers eliminates the need for radioactively labeled nucleotides, as well as slab gel electrophoresis, and takes advantage of commonly available automated fluorescent capillary electrophoresis instruments. with fluorescently labeled primers and dideoxynucleotide dna sequencing, we have shown that the terminal base of each digested fragment may be accurately ident ... | 2006 | 16741237 |
| the alkyl tert-butyl ether intermediate 2-hydroxyisobutyrate is degraded via a novel cobalamin-dependent mutase pathway. | fuel oxygenates such as methyl and ethyl tert-butyl ether (mtbe and etbe, respectively) are degraded only by a limited number of bacterial strains. the aerobic pathway is generally thought to run via tert-butyl alcohol (tba) and 2-hydroxyisobutyrate (2-hiba), whereas further steps are unclear. we have now demonstrated for the newly isolated beta-proteobacterial strains l108 and l10, as well as for the closely related strain cip i-2052, that 2-hiba was degraded by a cobalamin-dependent enzymatic ... | 2006 | 16751524 |
| determination of the rate and yield of b-side quinone reduction in rhodobacter capsulatus reaction centers. | in the native purple bacterial reaction center (rc), light-driven charge separation utilizes only the a-side cofactors, with the symmetry related b-side inactive. the process is initiated by electron transfer from the excited primary donor (p*) to the a-side bacteriopheophytin (p* --> p+ h(a)-) in approximately 3 ps. this is followed by electron transfer to the a-side quinone (p+ h(a)- --> p+ q(a)-) in approximately 200 ps, with an overall quantum yield of approximately 100%. using nanosecond fl ... | 2006 | 16752920 |
| 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 ... | 2007 | 16752956 |