Publications

complementation analysis and regulation of co2 fixation gene expression in a ribulose 1,5-bisphosphate carboxylase-oxygenase deletion strain of rhodospirillum rubrum.	a ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) deletion strain of rhodospirillum rubrum that was incapable of photolithoautotrophic growth was constructed. photoheterotrophic growth, however, was possible for the r. rubrum rubisco deletion strain when oxidized carbon compounds such as malate were supplied. the r. rubrum rubisco-deficient strain was not complemented to photolithoautotrophic growth by various r. rubrum dna fragments that contain the gene encoding rubisco, cbbm. when t ...	1993	8349547
amplification of ribulose biphosphate carboxylase/oxygenase large subunit (rubisco lsu) gene fragments from thiobacillus ferrooxidans and a moderate thermophile using polymerase chain reaction.	southern blot analysis of dna from an iron-oxidising moderate thermophile nmw-6 and from thiobacillus ferrooxidans strain tfi-35 demonstrated sequences homologous to the rubisco lsu gene of synechococcus. dna fragments (457 bp) encoding part of the rubisco lsu gene (amino acids 73-200) were amplified from the genomic dna of thiobacillus ferrooxidans and the moderate thermophile nmw-6 using the polymerase chain reaction (pcr) technique (saiki et al. (1985) science 233, 1350-1354). a comparison wi ...	1993	8357616
a role for the epsilon-amino group of lysine-334 of ribulose-1,5-bisphosphate carboxylase in the addition of carbon dioxide to the 2,3-enediol(ate) of ribulose 1,5-bisphosphate.	earlier structural and functional studies of ribulose-1,5-bisphosphate carboxylase/oxygenase imply that k334 facilitates the addition of gaseous substrate to the 2,3-enediol(ate) derived from ribulose 1,5-bisphosphate. crystallographic analysis of the activated spinach enzyme [knight et al. (1990) j. mol. biol. 215, 113-160] shows that the lysyl side chain is appropriately positioned to stabilize the transition state for the addition of co2 to the enediol(ate). furthermore, despite total impairm ...	1993	8369274
atomic structure of a cytochrome c' with an unusual ligand-controlled dimer dissociation at 1.8 a resolution.	the crystallographic structure of cytochrome c' from the purple phototrophic bacterium chromatium vinosum (cvcp) has been determined at 1.8 a resolution using multiple isomorphous replacement. the molecule is a dimer, with each 131-residue chain folding as a four-helical bundle incorporating a covalently bound heme group at the core. this structure is the third of the ubiquitous cytochromes c' to be solved and is similar to the known structures of cytochrome c' from r. molischianum (rmcp) and r. ...	1993	8230224
construction of a synechocystis pcc6803 mutant suitable for the study of variant hexadecameric ribulose bisphosphate carboxylase/oxygenase enzymes.	the cyanobacterium synechocystis pcc6803 was chosen as a target organism for construction of a suitable photosynthetic host to enable selection of variant plant-like ribulose bisphosphate carboxylase/oxygenase (rubisco) enzymes. the dna region containing the operon encoding rubisco (rbc) was cloned, sequenced and used for the construction of a transformation vector bearing flanking sequences to the rbc genes. this vector was utilized for the construction of a cyanobacterial rbc null mutant in wh ...	1993	8219082
excitonic interactions in the light-harvesting antenna of photosynthetic purple bacteria and their influence on picosecond absorbance difference spectra.	a new model of the light-harvesting antenna (core complex) of purple photosynthetic bacteria is proposed based on excitonic interactions in circular aggregates of bacteriochlorophyll molecules. the calculated absorbance difference spectra of circular aggregates demonstrate all special features observed in the experimental spectra of purple bacteria. in particular, the absorption changes with high amplitude of bleaching at the long-wavelength side of the absorption band at different excitation en ...	1993	8370458
modulation of the proton-translocation stoichiometry of h(+)-atp synthases in two phototrophic prokaryotes by external ph.	the stoichiometry between proton translocation and atp synthesis/hydrolysis was studied in two different photosynthetic prokaryotes, the thermophilic cyanobacterium synechococcus 6716 and the purple bacterium rhodospirillum rubrum. the h+/atp ratio was determined by acid-base transitions as a function of the external ph. the h+/atp ratio of the synechococcus 6716 atp synthase was found to increase with increasing ph. in contrast, in r. rubrum this ratio decreased with increasing ph. these result ...	1993	8379927
reversible dissociation and conformational stability of dimeric ribulose bisphosphate carboxylase.	dimer-monomer dissociation of ribulosebisphosphate carboxylase/oxygenase from rhodospirillum rubrum was investigated using hydrostatic pressure in the range 1-2 kbar to promote dissociation. intrinsic fluorescence emission and polarization, along with the polarization of the fluorescence of single-labeled aedans conjugates, were used to follow the dissociation. full reversibility after dissociation was observed to depend on the presence of small ligands: glycerol, mg2+, and nahco3, the last two ...	1993	8388254
differential sensitivity of membrane-associated pyrophosphatases to inhibition by diphosphonates and fluoride delineates two classes of enzyme.	1,1-diphosphonate analogs of pyrophosphate, containing an amino or a hydroxyl group on the bridge carbon atom, are potent inhibitors of the h(+)-translocating pyrophosphatases of chromatophores prepared from the bacterium rhodospirillum rubrum and vacuolar membrane vesicles prepared from the plant vigna radiata. the inhibition constant for aminomethylenediphosphonate, which binds competitively with respect to substrate, is below 2 microm. rat liver mitochondrial pyrophosphatase is two orders of ...	1993	8392953
gene expression of the b875 light-harvesting prepolypeptides from rhodospirillum rubrum in escherichia coli.	the gene coding for the prepolypeptides of alpha and beta, obtained as a 429 bp fragment from chromosomal dna of rhodospirillum rubrum s1 by polymerase chain reaction amplification, were cloned in tandem into the high-level expression vector potsnco 12 for expression in escherichia coli. the vector potsnco12 is a derivative of the pas vector system, which contains the strong lambda pl promotor and is under tight control by the ci857 repressor encoded by the expression strain ar58. induction of t ...	1993	8451297
precise location of the cu(ii)-inhibitory binding site in higher plant and bacterial photosynthetic reaction centers as probed by light-induced absorption changes.	light-dependent absorption change at 325 nm, ascribed to qa activity, was strongly reduced in the presence of cu(ii) in oxygen-evolving core complex. this change was much less affected in the presence of the herbicide 3-(3,4-dichlorophenyl)-1,1-dimethylurea (dcmu), indicating that the cu(ii)-binding site is different from that of the dcmu and that cu(ii) blocks qa reduction. cu(ii) did not eliminate the absorption change at 545 nm, ascribed to pheophytin reduction, in na2s2o4-treated oxygen-evol ...	1993	8420944
site-specific mutations in a loop region of the c-terminal domain of the large subunit of ribulose bisphosphate carboxylase/oxygenase that influence substrate partitioning.	amino acids composing a flexible loop (loop 6) of the eight-stranded barrel domain of the l-subunit of synechococcus ribulose bisphosphate carboxylase/oxygenase (ec 4.1.1.39) involved in reaction intermediate stabilization have been modified by site-specific mutagenesis. changes at positions both distant and within the active site affect overall catalysis and substrate partitioning. most significantly, replacement of the active site lys (lys-334) with arg at the apex of the loop almost completel ...	1993	8463309
unexpected similarities of the b800-850 light-harvesting complex from rhodospirillum molischianum to the b870 light-harvesting complexes from other purple photosynthetic bacteria.	the b800-850 light-harvesting complex (also called lh2) was isolated from photosynthetic membranes of rhodospirillum molischianum dsm 119 using molecular sieve and ion-exchange chromatography. its two bacteriochlorophyll a-binding polypeptides (alpha-subunit and beta-subunit) were purified with a reverse-phase hplc system. the complete amino acid sequences of both subunits have been determined. the alpha- and beta-subunits consist of 56 and 45 amino acids, respectively, corresponding to molecula ...	1993	8504081
molecular cloning and sequencing of the ferredoxin i fdxn gene of the photosynthetic bacterium rhodospirillum rubrum.	using an oligonucleotide probe derived from the amino acid sequence of rhodospirillum rubrum ferredoxin i, the gene (fdxn) was identified, cloned and sequenced. the fdxn coding region is 183 nucleotides which codes for a 61 amino acid (7267 da) protein. phylogenetic comparisons between the r. rubrum fdi and other 8fe-8s nif-coupled ferredoxins showed only moderate degrees of similarity between the amino acid sequences. r. rubrum fdi synthesis was stimulated by nif derepressing conditions, but wa ...	1993	8399287
the structure and function of omega loop a replacements in cytochrome c.	the structural and functional consequences of replacing omega-loop a (residues 18-32) in yeast iso-1-cytochrome c with the corresponding loop of rhodospirillum rubrum cytochrome c2 have been examined. the three-dimensional structure of this loop replacement mutant repa2 cytochrome c, and a second mutant repa2(val 20) cytochrome c in which residue 20 was back substituted to valine, were determined using x-ray diffraction techniques. a change in the molecular packing is evident in the repa2 mutant ...	1993	8401228
inhibition of proton-translocating transhydrogenase from photosynthetic bacteria by n,n'-dicyclohexylcarbodiimide.	the effects of n,n'-dicyclohexylcarbodiimide [(chxn)2c] on the proton-translocating enzyme, nad(p) h(+)-transhydrogenase (h(+)-thase), from two species of phototrophic bacteria have been investigated. the polypeptides of h(+)-thase from rhodobacter capsulatus are membrane-associated, requiring detergent to maintain solubility. the enzyme from rhodospirillum rubrum, however, has a water soluble polypeptide (ths) and a membrane-associated component (thm) which, separately, have no activity but whi ...	1993	8436126
expression study with the escherichia coli lep gene for leader peptidase in phototrophic purple bacteria.	synthesis and assembly of leader peptidase of escherichia coli (signal peptidase i), was studied by heterologous expression of its lep gene in three species of phototrophic purple bacteria. cell extracts of the recipient species showed neither cross reaction with antibodies against e. coli leader peptidase nor cleavage of the model substrate m13-procoat in vitro. the lep gene was transferred via conjugation using the plasmid expression vector for phototrophic bacteria pjaj9. plasmid-borne leader ...	1993	8439231
two-dimensional crystallization of the light-harvesting complex from rhodospirillum rubrum.	homogeneous detergent-solubilized b873 light-harvesting complexes from a carotenoid-less mutant of the purple non-sulfur bacterium, rhodospirillum rubrum g9, were reassembled spontaneously into two-dimensional (2d) hexagonal arrays during extensive and controlled dialysis. as the complexes contain only 1 to 2 mol phospholipid per mol alpha beta dimer, the arrays formed by a self assembly process are primary due to protein-protein interactions. the hexagonal lattices were analyzed by negative sta ...	1993	8510160
role of phenylalanine-327 in the closure of loop 6 of ribulosebisphosphate carboxylase/oxygenase from rhodospirillum rubrum.	phenylalanine-327 of ribulosebisphosphate carboxylase/oxygenase (rubisco) from rhodospirillum rubrum was mutated to tryptophan, leucine, valine, alanine, and glycine, and was also deleted. the least active mutant, the deletion mutant, exhibits less than 0.5% of the carboxylase activity of the wild-type enzyme. steady-state kinetic analysis of f327-->leu, val, ala, gly mutant enzymes reveals that kcat and the co2/o2 specificity are unchanged while km(rubp) (rubp = ribulose 1,5-bisphosphate) is dr ...	1993	8448152
identification and partial sequence of the bcha gene of rhodospirillum rubrum.	the dna sequence was determined for a region upstream of the puf operon of rhodospirillum rubrum. a partial orf was identified. the dna sequence and the inferred amino acid sequences were aligned with those of bcha of rhodobacter capsulatus and other phototrophic bacteria. based on this alignment and genetic evidence, this orf was identified as r. rubrum bcha, which encodes an enzyme involved in bacteriochlorophyll biosynthesis. an additional orf was identified in the intergenic region between b ...	1993	7763790
photolithoautotrophic growth and control of co2 fixation in rhodobacter sphaeroides and rhodospirillum rubrum in the absence of ribulose bisphosphate carboxylase-oxygenase.	rhodospirillum rubrum and rhodobacter sphaeroides were shown to be capable of photolithoautotrophic growth in the absence of the reductive pentose phosphate (calvin) cycle. ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) deletion strains were incapable of photolithoautotrophic growth using hydrogen as an electron donor but were able to grow in the absence of organic carbon using less reduced inorganic electron donors, i.e., thiosulfate or sulfide. wild-type r. rubrum grown in the prese ...	1993	8226655
evolutionary relationships among magnetospirillum strains inferred from phylogenetic analysis of 16s rdna sequences.	we have investigated the evolutionary relationships between two facultatively anaerobic magnetospirillum strains (amb-1 and mgt-1) and fastidious, obligately microaerophilic species, such as magnetospirillum magnetotacticum, using a molecular phylogenetic approach. genomic dna from strains mgt-1 and amb-1 was used as a template for amplification of the genes coding for 16s rrna (16s rdna) by the polymerase chain reaction. amplified dna fragments were sequenced (1,424 bp) and compared with sequen ...	1993	7691800
modification of the fe protein of nitrogenase in natural populations of trichodesmium thiebautii.	the fe protein of nitrogenase in the marine nonheterocystous cyanobacterium trichodesmium thiebautii is interconverted between two forms, which is reminiscent of the adp-ribosylation described in the purple bacterium rhodospirillum rubrum. in natural populations of t. thiebautii during the day, when nitrogenase activity (na) is present and while photosynthetic rates are high, a low-molecular-mass form of the fe protein is present. in the late afternoon, the low-molecular-mass form is partially c ...	1993	16348883
on the long-wavelength component of the light-harvesting complex of some photosynthetic bacteria.	the effect of the presence of a minor antenna component in light-harvesting complexes of photosynthetic bacteria is investigated with numerical simulation employing the transition probability matrix method. a model antenna system of hexagonal symmetry is adopted, using as a working hypothesis that the minor component forms a ring around the trap. three cases have been considered: (a) the minor component is isoenergetic with the trap, which is at lower energy than the antennas (the "supertrap"), ...	1992	19431850
kinetic model of primary energy transfer and trapping in photosynthetic membranes.	the picosecond time-domain incoherent singlet excitation transfer and trapping kinetics in core antenna of photosynthetic bacteria are studied in case of low excitation intensities by numerical integration of the appropriate master equation in a wide temperature range of 4-300 k. the essential features of our two-dimensional-lattice model are as follows: förster excitation transfer theory, spectral heterogeneity of both the light-harvesting antenna and the reaction center, treatment of temperatu ...	1992	19431849
simple determination of the co(2)/o(2) specificity of ribulose-1,5-bisphosphate carboxylase/oxygenase by the specific radioactivity of [c]glycerate 3-phosphate.	a new method is presented for measurement of the co(2)/o(2) specificity factor of ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco). the [(14)c]3-phosphoglycerate (pga) from the rubisco carboxylase reaction and its dilution by the rubisco oxygenase reaction was monitored by directly measuring the specific radioactivity of pga. (14)co(2) fixation with rubisco occurred under two reaction conditions: carboxylase with oxygenase with 40 micromolar co(2) in o(2)-saturated water and carboxylase ...	1992	16668709
characterization of lhi- and lhi+ rhodobacter capsulatus pufa mutants.	the nh2 termini of light-harvesting complex i (lhi) polypeptides alpha and beta of rhodobacter capsulatus are thought to be involved in the assembly of the lhi complex. for a more detailed study of the role of the nh2-terminal segment of the lhi alpha protein in insertion into the intracytoplasmic membrane (icm) of r. capsulatus, amino acids 6 to 8, 9 to 11, 12 and 13, or 14 and 15 of the lhi alpha protein were deleted. additionally, the hydrophobic stretch of the amino acids 7 to 11 was lengthe ...	1992	1569029
role of asparagine-111 at the active site of ribulose-1,5-bisphosphate carboxylase/oxygenase from rhodospirillum rubrum as explored by site-directed mutagenesis.	crystallographic studies of ribulose-1,5-bisphosphate carboxylase/oxygenase from rhodospirillum rubrum suggest that active-site asn111 interacts with mg2+ and/or substrate (lundqvist, t., and schneider, g. (1991) j. biol. chem. 266, 12604-12611). to examine possible catalytic roles of asn111, we have used site-directed mutagenesis to replace it with a glutaminyl, aspartyl, seryl, or lysyl residue. although the mutant proteins are devoid of detectable carboxylase activity, their ability to form a ...	1992	1569095
on the structure of the nickel/iron/sulfur center of the carbon monoxide dehydrogenase from rhodospirillum rubrum: an x-ray absorption spectroscopy study.	the nickel/iron/sulfur center of the carbon monoxide dehydrogenase (carbon monoxide:(acceptor)oxidoreductase; ec 1.2.99.2) enzyme from rhodospirillum rubrum (rr-codh) was studied by x-ray absorption spectroscopy at the ni k edge. extended x-ray absorption fine structure data show that the first ni coordination shell consists of 2 s atoms at 2.23 a and 2-3 n/o atoms at 1.87 a. the edge structure indicates a distorted tetrahedral or five-coordinate ni environment in both oxidized and reduced rr-co ...	1992	1584775
mutation of asparagine 111 of rubisco from rhodospirillum rubrum alters the carboxylase/oxygenase specificity.	the conserved asparagine 111 of ribulose-1,5-bisphosphate carboxylase/oxygenase from the photosynthetic bacteria rhodospirillum rubrum was identified as a candidate for a side-chain that might be involved in the carboxylase/oxygenase specificity. it was replaced by site-directed mutagenesis with aspartic acid, leucine, glutamine or glycine residues. the mutant enzymes exhibit a very low carboxylase activity compared with the wild-type enzyme. the values of km(rubp) and kcat for asn111----gly, th ...	1992	1602488
electrostatic fields at the active site of ribulose-1,5-bisphosphate carboxylase.	a macroscopic approach has been employed to calculate the electrostatic potential field of nonactivated ribulose-1,5-bisphosphate carboxylase and of some complexes of the enzyme with activator and substrate. the overall electrostatic field of the l2-type enzyme from the photosynthetic bacterium rhodospirillum rubrum shows that the core of the dimer, consisting of the two c-terminal domains, has a predominantly positive potential. these domains provide the binding sites for the negatively charged ...	1992	1603801
purification and characterization of glutathione reductase from rhodospirillum rubrum.	glutathione reductase (nad(p)h:gssg oxidoreductase ec 1.6.4.2.) was purified 1160-fold to homogeneity from the nonsulfurous purple bacteria rhodospirillum rubrum (wild type). specific activity of the pure preparation was 102 u/mg. the enzyme displayed a typical flavoprotein absorption spectrum with maxima at 274,365, and 459 nm and an absorbance ratio a280/a459 of 7.6. the amino acid analysis revealed an unusually high content of glycine and arginine residues. titration of the enzyme with 5,5'-d ...	1992	1524433
enhanced co2/o2 specificity of a site-directed mutant of ribulose-bisphosphate carboxylase/oxygenase.	the co2/o2 specificity factor of ribulose-bisphosphate carboxylase/oxygenase partially determines the efficiency of photosynthetic carbon assimilation. heretofore, engineered alterations of the enzyme have only decreased the selectivity for co2 utilization. we show that alanyl replacement of active-site ser-368 of the rhodospirillum rubrum carboxylase enhances the carboxylation selectivity approximately 1.6-fold over the wild-type level. this enhancement reflects a greater relative decline in ox ...	1992	1551863
prokaryotic triterpenoids: o-alpha-d-glucuronopyranosyl bacteriohopanetetrol, a novel hopanoid from the bacterium rhodospirillum rubrum.	a novel hopanoid bearing a glucuronopyranosyl residue linked via an alpha-glycosidic bond to the hydroxyl group of c-35 in bacteriohopanetetrol was isolated, from the type strain of rhodospirillum rubrum as well as from a mutant lacking blue carotenoid.	1992	1417769
surface-enhanced raman scattering spectroscopy of photosynthetic membranes and complexes.		1992	1435308
[the evolutionary changes in the amino acid sequences and properties of the atp-synthase in chloroplasts, mitochondria and bacteria].	studies have been made on atpase from chloroplasts, cyanobacteria and mitochondria of higher plants and animals. no intraspecies and interspecies variability of chloroplast and mitochondrial atpase was found with respect to ph optimum of the activity, to specificity to cations as substrate components, to sensitivity to stimulating and inhibiting anions and ethanol, to optimal stimulating ethanol concentration. intergenus variation of these properties of atpase from chloroplasts, plant mitochondr ...	1992	1441793
conservation of the photosynthesis gene cluster in rhodospirillum centenum.	intraspecies and intergenus complementation analysis were utilized to demonstrate that photosynthesis genes are clustered in distantly related purple photosynthetic bacteria. specifically, we show that the linkage order for genes involved in bacteriochlorophyll and carotenoid biosynthesis in rhodospirillum centenum are arranged essentially as in rhodobacter capsulatus and rhodobacter sphaeroides. in addition, the location and relative distance observed between the puf and puh operons which encod ...	1992	1447976
restoration of the wild-type locus in an rubp carboxylase/oxygenase mutant of synechocystis pcc 6803 via targeted gene recombination.	the interaction between homologous dna sequences, distant from each other in the chromosome, was examined in the cyanobacterium synechocystis pcc 6803. most of the rbcl gene encoding the large subunit of ribulose bisphosphate carboxylase/oxygenase (rubisco) was duplicated in the genome by a targeted insertion of a 3'-truncated gene copy into the psb a-i locus. both rbcl genes, in the psb a-i region and at the rbc locus, were non-functional; the former due to the 3' truncation, and the latter due ...	1992	1465099
molecular basis for biosynthesis and accumulation of polyhydroxyalkanoic acids in bacteria.	the current knowledge on the structure and on the organization of polyhydroxyalkanoic acid (pha)-biosynthetic genes from a wide range of different bacteria, which rely on different pathways for biosynthesis of this storage polyesters, is provided. molecular data will be shown for genes of alcaligenes eutrophus, purple non-sulfur bacteria, such as rhodospirillum rubrum, purple sulfur bacteria, such as chromatium vinosum, pseudomonads belonging to rrna homology group i, such as pseudomonas aerugin ...	1992	1476773
cloning of poly(3-hydroxybutyric acid) synthase genes of rhodobacter sphaeroides and rhodospirillum rubrum and heterologous expression in alcaligenes eutrophus.	from genomic libraries of the purple non-sulfur bacteria rhodospirillum rubrum ha and rhodobacter sphaeroides atcc 17023 in the broad-host range cosmid pvk100, we cloned a 15- and a 14-kbp hindiii restriction fragment, respectively. each of these fragments restored the ability to accumulate poly(3-hydroxybutyrate) (phb), in the phb-negative mutant alcaligenes eutrophus phb-4. these hybrid cosmids also complemented phb-negative mutants derived from wild-type r. rubrum or r. sphaeroides. both frag ...	1992	1499989
dynamics of energy transfer and trapping in the light-harvesting antenna of rhodopseudomonas viridis.	by low intensity picosecond absorption spectroscopy it is shown that the exciton lifetime in the light-harvesting antenna of rhodopseudomonas (rps.) viridis membranes with photochemically active reaction centers at room temperature is 60 +/- 10 ps. this lifetime reflects the overall trapping rate of the excitation energy by the reaction center. with photochemically inactive reaction centers, in the presence of p+, the exciton lifetime increases to 150 +/- 15 ps. prereducing the secondary electro ...	1992	1504241
studies on the effect of nad(h) on nitrogenase activity in rhodospirillum rubrum.	the effect of nad(p) and analogs of this nucleotide on nitrogenase activity in rhodospirillum rubrum has been studied. addition of nad+ to nitrogen fixing rsp. rubrum leads to inhibition of nitrogenase. nadp+ has the same effect but nadh or analogs modified in the nicotinamide portion do not cause inhibition. in contrast to ammonium ions, addition of nad+ leads to inhibition of nitrogenase in cells that have been n-starved under argon. the inhibitory effect of nad+ is more pronounced at lower li ...	1992	1510568
cloning, sequencing, mutagenesis, and functional characterization of drat and drag genes from azospirillum brasilense.	the azospirillum brasilense drat gene, encoding dinitrogenase reductase atp-ribosyltransferase, and drag gene, encoding dinitrogenase reductase activating glycohydrolase, were cloned and sequenced. two genes were contiguous on the a. brasilense chromosome and showed extensive similarity to the same genes from rhodospirillum rubrum. analysis of mutations introduced into the dra region on the a. brasilense chromosome showed that mutants affected in drat were incapable of regulating nitrogenase act ...	1992	1577701
genetic and physiological characterization of the rhodospirillum rubrum carbon monoxide dehydrogenase system.	a 3.7-kb dna region encoding part of the rhodospirillum rubrum co oxidation (coo) system was identified by using oligonucleotide probes. sequence analysis of the cloned region indicated four complete or partial open reading frames (orfs) with acceptable codon usage. the complete orfs, the 573-bp coof and the 1,920-bp coos, encode an fe/s protein and the ni-containing carbon monoxide dehydrogenase (codh), respectively. the four 4-cysteine motifs encoded by coof are typical of a class of proteins ...	1992	1644755
mg2+ is an essential activator of hydrolytic activity of membrane-bound pyrophosphatase of rhodospirillum rubrum.	the substrate for the hydrolytic activity of membrane-bound pyrophosphatase is the pp(i)-mg2+ complex. the enzyme has no activity when the free mg2+ concentration is lower than 10 microm (at 0.5 mm-pp(i)-mg2+), and therefore free mg2+ is an essential activator of the hydrolytic activity. the km for the substrate changes in response to variation in free mg2+ concentration, from 10.25 to 0.6 mm when free mg2+ is increased from 0.03 to 1.0 mm respectively. the km for mg2+ depends on the substrate c ...	1992	1315519
three-dimensional structure of ferricytochrome c' from rhodospirillum rubrum at 2.8 a resolution.	the structure of ferricytochrome c' extracted from rhodospirillum rubrum has been determined by the x-ray crystallographic method. crystals in hexagonal space group p6(1), with unit-cell dimensions a = b = 51.72 a and c = 155.49 a, contain one dimer molecule composed of chemically identical polypeptide chains (monomer i and monomer ii) per asymmetric unit. an electron density map has been calculated at a resolution of 2.8 a by the multiple isomorphous replacement method using four-circle diffrac ...	1992	1316891
isolation and characterisation of a functional alpha beta heterodimer from the atp synthase of rhodospirillum rubrum.	an alpha beta heterodimer of the f1-atpase of rhodospirillum rubrum was isolated by extraction of chromatophores with licl. each alpha beta heterodimer contains one tightly bound adp, which is released upon removal of medium mg2+. the dimer can be reversibly dissociated by removal of mg(2+)-ions. the alpha beta heterodimer restores both atp-synthetic and -hydrolytic activities to licl-treated chromatophores, saturation being achieved at approximately 2 mmol alpha beta.mol bchl-1. the heterodimer ...	1992	1327870
evidence of an essential carboxyl residue in membrane-bound pyrophosphatase of rhodospirillum rubrum.	chemical modifications with water-soluble carbodiimides (edc and cmc) were performed to elucidate whether some carboxyl residues are involved in the catalytic activity of membrane-bound pyrophosphatase of rhodospirillum rubrum. edc and cmc cause a loss of hydrolytic activity following pseudo-first-order kinetics up to 10 min of reaction. the enzyme was completely protected against edc inhibition by ppi or mg2+, whereas ppi or mg2+ gave partial protection against cmc inactivation. mg-ppi protecte ...	1992	1334073
conformational states of ribulosebisphosphate carboxylase and their interaction with chaperonin 60.	conformational states of ribulosebisphosphate carboxylase (rubisco) from rhodospirillum rubrum were examined by far-uv circular dichroism (cd), tryptophan fluorescence, and 1-anilino-naphthalenesulfonate (ans) binding. at ph 2 and low ionic strength (i = 0.01), rubisco adopts an unfolded, monomeric conformation (ua1 state) as judged by far-uv cd and tryptophan fluorescence. as with other acid-unfolded proteins [goto, y., calciano, l. j., & fink, a. l. (1990) proc. natl. acad. sci. u.s.a. 87, 573 ...	1992	1348956
purified chaperonin 60 (groel) interacts with the nonnative states of a multitude of escherichia coli proteins.	in vitro experiments employing the soluble proteins from escherichia coli reveal that about half of them, in their unfolded or partially folded states, but not in their native states, can form stable binary complexes with chaperonin 60 (groel). these complexes can be isolated by gel filtration chromatography and are efficiently discharged upon the addition of mg.atp. binary complex formation is substantially reduced if chaperonin 60 is presaturated with rubisco-i, the folding intermediate of rub ...	1992	1363913
nucleotide sequence of cdna clones encoding the beta subunit of mitochondrial atp synthase from the green alga chlamydomonas reinhardtii: the precursor protein encoded by the cdna contains both an n-terminal presequence and a c-terminal extension.	cdna and genomic clones encoding the beta subunit of mitochondrial atp synthase from chlamydomonas reinhardtii have been isolated using heterologous dna probes from the photosynthetic bacterium rhodospirillum rubrum. the protein encoded by the cdna is 79-83% identical to corresponding proteins from higher-plant and mammalian mitochondria, and 75% identical to the r. rubrum protein. it contains both an n-terminal presequence and a unique c-terminal extension. the presequence, which is the first m ...	1992	1386535
tentoxin sensitivity of chloroplasts determined by codon 83 of beta subunit of proton-atpase.	tentoxin is a naturally occurring phytotoxic peptide that causes seedling chlorosis and arrests growth in sensitive plants and algae. in vitro, it inhibits activity of the beta subunit of the plastid proton-adenosine triphosphatase (atpase) from sensitive species. plastid atpb genes from six closely related, tentoxin-sensitive or -resistant nicotiana species differ at codon 83, according to their response to the toxin: glutamate correlated with resistance and aspartate correlated with sensitivit ...	1992	1387730
in vitro activation of dinitrogenase reductase from the cyanobacterium anabaena variabilis (atcc 29413).	nitrogenase of the heterocystous cyanobacterium anabaena variabilis was inactivated in vivo (s. reich, h. almon, and p. böger, fems microbiol. lett. 34:53-56, 1986). partially purified and modified (inactivated) dinitrogenase reductase (fe-protein) of such cells was reactivated by isolated membrane fractions of a. variabilis or of rhodospirillum rubrum, and acetylene reduction was measured. reactivation requires atp, mg2+, and mn2+. the activating principle is localized in the heterocyst and was ...	1992	1400166
substitution of asp193 to asn at the active site of ribulose-1,5-bisphosphate carboxylase results in conformational changes.	the crystal structure of a mutant of ribulose bisphosphate carboxylase/oxygenase from rhodospirillium rubrum, where asp193, one of the ligands of the magnesium ion at the activator site, is replaced by asn, has been determined to a nominal resolution of 0.26 nm. the mutation of asp to asn induces both local and global conformation changes as follows. the side chain of asn193 moves away from the active site and interacts with main-chain oxygen of residue 165, located in the neighbouring strand be ...	1992	1606957
the relation between the soluble factor associated with h(+)-transhydrogenase of rhodospirillum rubrum and the enzyme from mitochondria and escherichia coli.	although in mitochondria, escherichia coli and rhodobacter capsulatus the h(+)-transhydrogenases are intrinsic membrane proteins, in rhodospirillum rubrum a water-soluble component (ths) and a membrane-bound component are together required for activity. ths was selectively removed from chromatophore membranes of rhs. rubrum and was purified to homogeneity by precipitation with (nh4)2so4 and ion-exchange, affinity dye and gel exclusion chromatography. the latter indicated an mr of approx. 74,000 ...	1992	1610876
enhancement of carotenoid-to-chlorophyll singlet energy transfer by carotenoid-carotenoid interaction.	the apparent quantum yield of singlet-singlet spirilloxanthin-to-bacteriochlorophyll a energy transfer increases linearly with the residual spirilloxanthin content in rhodospirillum rubrum membrane vesicles from which this carotenoid has been partially removed. since it has been previously shown that carotenoid-carotenoid interaction is a linear function of the residual spirilloxanthin level in the major pigment-protein complex of those vesicles (zurdo, j., r. m. lozano, c. fernandez-cabrera, an ...	1992	1617133
direct electrochemical studies of hydrogenase and co dehydrogenase.	the reduction potentials of two relatively high-molecular-mass enzymes were determined directly at an edge pyrolytic graphite electrode by using square-wave voltammetry. the equilibrium reduction potential versus standard hydrogen electrode was determined for clostridium pasteurianum hydrogenase i (e'0 = -377 +/- 10 mv; molecular mass 60 kda) and rhodospirillum rubrum carbon monoxide dehydrogenase (e'0 = -418 +/- 7 mv; molecular mass 62 kda). the reduction potential of each enzyme was ph-indepen ...	1992	1637298
mutations affecting nitrogenase switch-off in rhodobacter capsulatus.	in vivo 'switch-off' and subsequent reactivation of nitrogenase activity in rhodobacter capsulatus or rhodospirillum rubrum in response to a variety of environmental stimuli, including the addition of fixed nitrogen, is thought to be due to the action of two nitrogenase fe protein modifying activities; drat (dinitrogenase reductase adp-ribosyl transferase) and drag (dinitrogenase reductase-activating glycohydrolase). here it is demonstrated that strains, including one mutated in glnb, that const ...	1992	1730034
crystal structure of the ternary complex of ribulose-1,5-bisphosphate carboxylase, mg(ii), and activator co2 at 2.3-a resolution.	the activated ternary complex, enzyme-co2-mg(ii), of the dimeric ribulose-1,5-bisphosphate carboxylase/oxygenase from rhodospirillum rubrum can be prepared in the same crystal form that was used for the crystallographic structure determination of the native nonactivated enzyme (schneider, g., bränden, c.-i., & lorimer, g. (1986) j. mol. biol. 187, 141-143). the three-dimensional structure of the activated enzyme has been determined to a nominal resolution of 2.3 a by protein crystallographic met ...	1991	1899197
probing the primary quinone environment in photosynthetic bacterial reaction centers by light-induced ftir difference spectroscopy.	the photoreduction of the primary electron acceptor, qa, has been characterized by light-induced fourier transform infrared difference spectroscopy for rb. sphaeroides reaction centers and for rsp. rubrum and rp. viridis chromatophores. the samples were treated both with redox compounds, which rapidly reduce the photooxidized primary electron p+, and with inhibitors of electron transfer from qa- to the secondary quinone qb. this approach yields spectra free from p and p+ contributions which make ...	1991	1899390
expression of endogenous and foreign ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) genes in a rubisco deletion mutant of rhodobacter sphaeroides.	a rhodobacter sphaeroides ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) deletion strain was constructed that was complemented by plasmids containing either the form i or form ii co2 fixation gene cluster. this strain was also complemented by genes encoding foreign rubisco enzymes expressed from a rhodospirillum rubrum rubisco promoter. in r. sphaeroides, the r. rubrum promoter was regulated, resulting in variable levels of disparate rubisco molecules under different growth conditions ...	1991	1900508
dimeric carotenoid interaction in the light-harvesting antenna of purple phototrophic bacteria.	the carotenoid content of intracytoplasmic membrane vesicles isolated from purple phototrophic bacteria was reduced to a variable extent by mild extraction with light petroleum. using preparations obtained from rhodobacter capsulatus strains that contained the light harvesting system i (lhi) complex as the only major photosynthetic holochrome, it was shown that the visible circular dichroism of the carotenoids increased with the square of the membrane carotenoid content, as expected from being c ...	1991	1901490
the puh structural gene coding for the h subunit of the rhodospirillum rubrum photoreaction center.	the rhodospirillum rubrum structural gene puh, coding for the photoreaction center h polypeptide, and three other putative genes that surround puh were cloned and sequenced. the deduced 257 amino acid h polypeptide has a molecular weight of 27,909, in close agreement with polyacrylamide gel electrophoresis determination. hydropathy plots predict a single hydrophobic alpha helix. the h polypeptide of rhodospirillum rubrum shares only 23% of its residues with all three of the h polypeptides from r ...	1991	1903263
pyruvate is a by-product of catalysis by ribulosebisphosphate carboxylase/oxygenase.	pyruvate is a minor product of the reaction catalyzed by ribulosebisphosphate carboxylase/oxygenase from spinach leaves. labeled pyruvate was detected, in addition to the major labeled product, 3-phosphoglycerate, when 14co2 was the substrate. pyruvate production was also measured spectrophotometrically in the presence of lactate dehydrogenase and nadh. the km for co2 of the pyruvate-producing activity was 12.5 microm, similar to the co2 affinity of the 3-phosphoglycerate-producing activity. no ...	1991	1903385
demonstration of a functional requirement for the carbamate nitrogen of ribulosebisphosphate carboxylase/oxygenase by chemical rescue.	ribulosebisphosphate carboxylase/oxygenase is reversibly activated by the reaction of co2 with a specific lysyl residue (lys191 of the rhodospirillum rubrum enzyme) to form a carbamate that coordinates an essential mg2+ cation. surprisingly, the lys191----cys mutant protein, in the presence of co2 and mg2+, exhibits tight binding of the reaction intermediate analogue 2-carboxyarabinitol bisphosphate [smith, h. b., larimer, f. w., & hartman, f. c. (1988) biochem. biophys. res. commun. 152, 579-58 ...	1991	1903652
fluorescence polarization and low-temperature absorption spectroscopy of a subunit form of light-harvesting complex i from purple photosynthetic bacteria.	measurements of polarized fluorescence and cd were made on light-harvesting complex 1 and a subunit form of this complex from rhodospirillum rubrum, rhodobacter sphaeroides, and rhodobacter capsulatus. the subunit form of lh1, characterized by a near-infrared absorbance band at approximately 820 nm, was obtained by titration of carotenoid-depleted lh1 complexes with the detergent n-octyl beta-d-glucopyranoside as reported by miller et al. (1987) [miller j. f., hinchigeri, s. b., parkes-loach, p. ...	1991	1904275
crystal structure of activated ribulose-1,5-bisphosphate carboxylase complexed with its substrate, ribulose-1,5-bisphosphate.	the three-dimensional structure of the complex of ribulose-1,5-bisphosphate carboxylase from rhodospirillum rubrum, co2, mg2+, and ribulose bisphosphate has been determined with x-ray crystallographic methods to 2.6-a resolution. ribulose-1,5-bisphosphate binds across the active site with the two phosphate groups in the two phosphate binding sites of the beta/alpha barrel. the oxygen atoms of the carbamate and the side chain of asp-193 provide the protein ligands to the bound mg2+ ion. the c2 an ...	1991	1905726
identification of an alternative nitrogenase system in rhodospirillum rubrum.	a second nitrogenase activity has been demonstrated in rhodospirillum rubrum. this nitrogenase is expressed whenever a strain lacks an active mo nitrogenase because of physiological or genetic inactivation. the alternative nitrogenase is able to support growth on n2 in the absence of fixed n. v does not stimulate, nor does mo or w inhibit, growth or activity under the conditions tested. the proteins responsible for this activity were identified by electrophoretic and immunological properties. th ...	1991	1909322
glycine 100 in the dinitrogenase reductase of rhodospirillum rubrum is required for nitrogen fixation but not for adp-ribosylation.	dinitrogenase reductase (rr2) is required for reduction of the molybdenum dinitrogenase in the nitrogen fixation reaction and is the target of posttranslational regulation in rhodospirillum rubrum. this posttranslational regulation involves the adp-ribosylation of rr2. to study the structural requirements for these two functions of rr2, i.e., activity and regulation, two site-directed mutations in nifh, the gene encoding rr2, were constructed and analyzed. the mutations both affected a region of ...	1991	1917849
characterization of the co oxidation/h2 evolution system of rhodospirillum rubrum. role of a 22-kda iron-sulfur protein in mediating electron transfer between carbon monoxide dehydrogenase and hydrogenase.	the response of the membrane-associated carbon monoxide dehydrogenase (codh) from rhodospirillum rubrum to solubilization by detergents and organic solvents, the properties of solubilized codh, and the mechanism for coupling co oxidation to hydrogen evolution via a co-induced hydrogenase activity have been investigated. the release of codh by a variety of ionic and nonionic detergents occurs in a redox-dependent fashion: codh is solubilized in the presence of low-potential reductants (dithionite ...	1991	1917963
performance of trickle-bed bioreactors for converting synthesis gas to methane.	carbon monoxide, h2, and co2 in synthesis gas can be converted to ch4 by employing a triculture of rhodospirillum rubrum, methanosarcina barkeri, and methanobacterium formicicum. trickle-bed reactors have been found to be effective for this conversion because of their high mass-transfer coefficients. this paper compares results obtained for the conversion of synthesis gas to ch4 in 5-cm- and 16.5-cm-diameter trickle-bed reactors. mass-transfer and scale-up parameters are defined, and light requi ...	1991	1929378
cos degradation by selected co-utilizing bacteria. scientific note.		1991	1929384
purification and partial characterization of glutamate synthase from rhodospirillum rubrum grown under nitrogen-fixing conditions.	glutamate synthase, a key enzyme in ammonia assimilation, has been purified from the photosynthetic bacterium rhodospirillum rubrum. the purification procedure involves ion-exchange chromatography, affinity chromatography and gel filtration. the recovery in the procedure is high (62%) and the specific activity is 21 mumol of nadph oxidized/min per mg. the enzyme is specific for its substrates, and no activity was demonstrated with nadh or nh4+ ions substituting for nadph and glutamine respective ...	1991	1930133
purification and partial characterization of a pyruvate oxidoreductase from the photosynthetic bacterium rhodospirillum rubrum grown under nitrogen-fixing conditions.	a pyruvate oxidoreductase with the capacity to support pyruvate-dependent nitrogenase activity in vitro has been purified from the photosynthetic bacterium rhodospirillum rubrum. the enzyme requires coa for activity and is irreversibly inactivated by oxygen. the molecular properties and km values for the substrates have been studied. in supporting nitrogenase activity addition of ferredoxin is required. overall the enzyme is similar to the nif-specific pyruvate: flavodoxin oxidoreductase purifie ...	1991	1930134
mutations in the drat and drag genes of rhodospirillum rubrum result in loss of regulation of nitrogenase by reversible adp-ribosylation.	reversible adp-ribosylation of dinitrogenase reductase forms the basis of posttranslational regulation of nitrogenase activity in rhodospirillum rubrum. this report describes the physiological effects of mutations in the genes encoding the enzymes that add and remove the adp-ribosyl moiety. mutants lacking a functional drat gene had no dinitrogenase reductase adp-ribosyltransferase (drat, the drat gene product) activity in vitro and were incapable of modifying dinitrogenase reductase with adp-ri ...	1991	1938894
possible role of the highly conserved amino acids trp-8 and pro-13 in the n-terminal segment of the pigment-binding polypeptide lhi alpha of rhodobacter capsulatus.	trp-8 and pro-13 of the rhodobacter capsulatus light-harvesting (lh) i alpha polypeptide are highly conserved among lhi and lhii alpha proteins of several species of the rhodospirillaceae. exchange of trp-8 and pro-13 to other amino acyl residues similar in structure and/or hydrophobicity indicates that trp-8 is involved in the insertion of the lhi alpha polypeptide into the intracytoplasmic membrane (icm). pro-13, however, seems not to participate in the integration process of the lhi alpha pro ...	1991	2065784
purification and properties of the h(+)-nicotinamide nucleotide transhydrogenase from rhodobacter capsulatus.	1. h(+)-transhydrogenase from rhodobacter capsulatus is an integral membrane protein which, unlike the enzyme from rhodospirillum rubrum, does not require the presence of a water-soluble component for activity. 2. the enzyme from rb. capsulatus was solubilised in triton x-100 and subjected to ion-exchange, hydroxyapatite and then gel-exclusion column chromatography. sds/page of the purified enzyme revealed the presence of two polypeptides with apparent mr 53,000 and 48,000. other minor component ...	1991	1849819
[the role of propionyl-coa carboxylase in the biosynthesis of antibiotics].		1991	1892432
phylogenetic analysis and evolution of rnase p rna in proteobacteria.	the secondary structures of the eubacterial rnase p rnas are being elucidated by a phylogenetic comparative approach. sequences of genes encoding rnase p rna from each of the recognized subgroups (alpha, beta, gamma, and delta) of the proteobacteria have now been determined. these sequences allow the refinement, to nearly the base pair level, of the phylogenetic model for rnase p rna secondary structure. evolutionary change among the rnase p rnas was found to occur primarily in four discrete str ...	1991	1711030
construction, characterization, and complementation of rhodospirillum rubrum puf region mutants.	rhodospirillum rubrum is a facultatively phototrophic bacterium that, under certain growth conditions, forms an intracytoplasmic chromatophore membrane (icm) housing the photochemical apparatus. the puf operon of r. rubrum encodes protein subunits of the photochemical reaction center and the b880 light-harvesting antenna complex. mutant strains of r. rubrum were constructed by interposon mutagenesis through which a kanamycin resistance gene cartridge was inserted into restriction sites and in pl ...	1991	1715861
ligand binding properties of cytochromes c'.	the cytochromes c' bind co, alkylisocyanides and cn- with rate and equilibrium constants which are 10(2)- to 10(6)-fold smaller than other high-spin hemoproteins. the decreased affinity for exogenous ligands is largely associated with steric interactions at the heme coordination site. while co and alkylisocyanides bind noncooperatively to the dimeric rhodospirillum molischianum cytochrome c', co, alkylisocyanides and cn- appear to bind cooperatively to the dimeric chromatium vinosum cytochrome c ...	1991	1646027
sequence variability in bacterial cytochromes c.	cytochromes c are proteins that can be defined both phenotypically and by their possession of a characteristic sequence motif. many sequences from bacterial sources are known, and new ones are being reported every year. an analysis can be made as to what fraction of new sequences are members of already known classes or subclasses, and how many map into previously uninhabited regions of sequence space.	1991	1646017
high-resolution 1h- and 15n-nmr studies of rhodospirillum rubrum cytochrome c2.	rhodospirillum rubrum cytochrome c2 was uniformly enriched in 15n and studied by 1h- and 15n-nmr spectroscopy. relaxation and noe data allowed determination of the rotational correlation time and indicated more rapid side-chain motion in the native protein and increased segmental motion in the base-denatured protein. the pi nitrogen of the ligand histidine and the indolic nitrogen of the invariant tryptophan both remain protonated and act as proton-donors in hydrogen bonds over a wide ph range a ...	1991	1646025
the rhodospirillum rubrum cytochrome bc1 complex: redox properties, inhibitor sensitivity and proton pumping.	a detergent-solubilized, three-subunit-containing cytochrome bc1 complex, isolated from the photosynthetic bacterium r. rubrum, has been shown to be highly sensitive to stigmatellin, myxothiazol, antimycin a and uhdbt, four specific inhibitors of these complexes. oxidation-reduction titrations have allowed the determination of em values for all the electron-carrying prosthetic groups in the complex. antimycin a has been shown to produce a red shift in the alpha-band absorbance maximum of one of ...	1991	1646633
rapid purification and characterization of homoserine dehydrogenase from saccharomyces cerevisiae.	homoserine dehydrogenase of saccharomyces cerevisiae has been rapidly purified to homogeneity by heat and acid treatments, ammonium sulfate fractionation, and chromatography on matrex gel red a and q-sepharose columns. the final preparation migrated as a single entity upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a mr of 40,000. the mr of the native enzyme was 81,000 as determined by gel filtration, suggesting that the enzyme is composed of two identical subunits. this feat ...	1991	1897932
genetic analysis of photosynthesis in rhodospirillum centenum.	a genetic system has been developed for studying bacterial photosynthesis in the recently described nonsulfur purple photosynthetic bacterium rhodospirillum centenum. nonphotosynthetic mutants of r. centenum were obtained by enrichment for spontaneous mutations, by ethyl methanesulfonate mutagenesis coupled to penicillin selection on solid medium, and by tn5 transposition mutagenesis with an incp plasmid vector containing a temperature-sensitive origin of replication. in vivo and in vitro charac ...	1991	1648078
functional analysis of the putative catalytic bases his-321 and ser-368 of rhodospirillum rubrum ribulose bisphosphate carboxylase/oxygenase by site-directed mutagenesis.	numerous candidates have been suggested according to chemical and structural criteria for the active site base of ribulose bisphosphate carboxylase/oxygenase that catalyzes substrate enolization. we evaluate the functional significance of two such candidates, his-321 and ser-368 of the rhodospirillum rubrum enzyme, by site-directed mutagenesis. position 321 mutants retain 3-12% of wild-type rates of both overall carboxylation and the initial enolization, with little effect on km for co2 or ribul ...	1991	1761567
molecular structure of cytochrome c2 isolated from rhodobacter capsulatus determined at 2.5 a resolution.	the molecular structure of the cytochrome c2, isolated from the purple photosynthetic bacterium rhodobacter capsulatus, has been solved to a nominal resolution of 2.5 a and refined to a crystallographic r-factor of 16.8% for all observed x-ray data. crystals used for this investigation belong to the space group r32 with two molecules in the asymmetric unit and unit cell dimensions of a = b = 100.03 a, c = 162.10 a as expressed in the hexagonal setting. an interpretable electron density map calcu ...	1991	1651396
protein engineering of rubisco.	modification of the kinetic parameters of enzymes by protein engineering requires extensive knowledge of the structural details of the enzyme and its complexes with different reaction intermediate analogues. such structural studies are described here for rubisco, ribulose-1,5-bisphosphate carboxylase/oxygenase, which catalyzes the initial reactions of two important but competing physiological events in green plants; carbon dioxide fixation and photorespiration. observed functional changes in mut ...	1991	1772628
cytochrome c' of paracoccus denitrificans.	cytochrome c' was identified in periplasmic extracts of the paracoccus denitrificans strains lmd 22.21 and lmd 52.44. the cytochrome c' was purified from the latter using the device of sequential molecular exclusion chromatography in the dimeric and monomeric states. although showing the overall spectroscopic features of the cytochrome c' family, the paracoccus cytochrome c' is unusual in having a red-shifted oxidised soret band at 407 nm. also unusual is the midpoint potential of 202 mv, well a ...	1991	1653018
electrostatic effects on the kinetics of electron transfer reactions of cytochrome c caused by binding to negatively charged lipid bilayer vesicles.	the effect of binding reduced tuna mitochondrial cytochrome c to negatively charged lipid bilayer vesicles at low ionic strength on the kinetics of electron transfer to various oxidants was studied by stopped-flow spectrophotometry. binding strongly stimulated (up to 100-fold) the rate of reaction with the positively charged cobalt phenanthroline ion, whereas the rate of reaction with the negatively charged ferricyanide ion was greatly inhibited (up to 60-fold), as compared with the same systems ...	1991	1654779
dna sequencing and complementation/deletion analysis of the bcha-puf operon region of rhodobacter sphaeroides: in vivo mapping of the oxygen-regulated puf promoter.	within the photosynthetic gene cluster of rhodobacter sphaeroides the genes encoding light-harvesting lhi and reaction-centre complexes are transcriptionally linked in the order pufbalmx. the region stretching 1.6 kb upstream of pufb has been examined by dna sequencing and by complementation/deletion analysis. these studies demonstrate that three open reading frames are located upstream of pufb. one open reading frame, designated bcha, terminates just inside pufq, which is located proximal to pu ...	1991	1779756
electron transfer proteins of the purple phototrophic bacterium, rhodopseudomonas rutila.	the soluble electron transfer protein content of rhodopseudomonas rutila was found to consist of two basic cytochromes and a (4fe-4s) ferredoxin. cytochrome c' was easily identified by its characteristic high spin absorption spectra. the native molecular weight is 29,000 and the subunit is 14,000. cytochrome c-550 has low spin absorption spectra and a high redox potential (376 mv) typical of cytochromes c2. the molecular weight is about 14,000. the ferredoxin is apparently a dimer (43,000) of ap ...	1991	1654788
extraction and purification of the beta subunit and an active alpha beta-core complex from the spinach chloroplast cfof1-atp synthase.	incubation of rhodospirillum rubrum chromatophores with 2 m licl in the presence of mgatp has been shown to remove their f1 beta subunit leaving inactive but fully reconstitutable beta-less chromatophores (gromet-elhanan, z., and khanashvili, d., (1986) methods enzymol, 126, 528-538). a similar treatment of thoroughly washed spinach thylakoids has now been shown to release the cf1 beta subunit (cf1 beta) together with a complex containing equal amounts of cf1 alpha and cf1 beta (cf1 (alpha beta] ...	1991	1826683
proton-translocating transhydrogenase from photosynthetic bacteria.		1991	1838340
electron spin echo envelope modulation spectroscopy supports the suggested coordination of two histidine ligands to the rieske fe-s centers of the cytochrome b6f complex of spinach and the cytochrome bc1 complexes of rhodospirillum rubrum, rhodobacter sphaeroides r-26, and bovine heart mitochondria.	electron spin echo envelope modulation (eseem) experiments performed on the rieske fe-s clusters of the cytochrome b6f complex of spinach chloroplasts and of the cytochrome bc1 complexes of rhodospirillum rubrum, rhodobacter sphaeroides r-26, and bovine heart mitochondria show modulation components resulting from two distinct classes of 14n ligands. at the g = 1.92 region of the rieske epr spectrum of the cytochrome b6f complex, the measured hyperfine couplings for the two classes of coupled nit ...	1991	1847076
proton-pumping n,n'-dicyclohexylcarbodiimide-sensitive inorganic pyrophosphate synthase from rhodospirillum rubrum: purification, characterization, and reconstitution.	a new method has been developed for the isolation of the proton-pumping n,n'-dicyclohexylcarbodiimide-sensitive ppi synthase (h(+)-ppi synthase) from chromatophores of rhodospirillum rubrum. the h(+)-ppi synthase was purified by extraction of chromatophores with a mixture of nonanoyl-n-methylglucamide and cholate, by fractionation with poly(ethylene glycol) 4000, hydroxyapatite chromatography, and affinity chromatography. the purified enzyme is homogeneous and has a specific activity of 20.4 mum ...	1991	1848779
structural and functional features of pseudomonas cytochrome c peroxidase.	the secondary structure of pseudomonas cytochrome c peroxidase (ferrocytochrome c: hydrogen-peroxide oxidoreductase, ec 1.11.1.5) has been predicted from the established amino acid sequence of the enzyme using a chou-fasman-type algorithm. the amount of alpha-helicity thus obtained is in agreement with previously obtained results based on circular dichroic measurements at far uv. the two heme c moieties of the enzyme have earlier been shown to have widely different characteristics, e.g., the red ...	1991	1657179
an improved tn7-based system for the single-copy insertion of cloned genes into chromosomes of gram-negative bacteria.	a system is described for the single-copy, stable insertion of cloned dna sequences into the chromosomes of gram- bacteria. two narrow-host-range plasmids form the basis of this system: the 'carrier' plasmid contains the mini tn7-km transposon, into which foreign dna can be cloned; the 'helper' plasmid provides the tn7 transposition functions in trans. both plasmids are readily transferred into gram- bacteria by conjugation. the functionality of this system has been demonstrated in rhodospirillu ...	1991	1661697
attenuated effect of oxygen on photopigment synthesis in rhodospirillum centenum.	rhodospirillum centenum resembles typical nonsulfur photosynthetic bacteria in a number of respects, including its ability to grow either anaerobically as a phototroph or aerobically as a heterotroph. we demonstrate, however, that r. centenum is unusual in its ability to synthesize a functional photosynthetic apparatus regardless of the presence of molecular oxygen. aerobically expressed photopigments were shown to be functionally active, as demonstrated by the ability of heterotrophically grown ...	1991	1885527