Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| anoxygenic degradation of aromatic substances by rhodopseudomonas palustris. | three strains of the phototrophic purple nonsulfur bacterium rhodopseudomonas palustris were isolated from different environments and were evaluated for their aromatic degradative potential under phototrophic conditions. all three strains (pfr1, pnr4, and mrl1) utilized benzoate, 4-hydroxybenzoate, 4-aminobenzoate, 4-aminophenol, cinnamate, ferulate, phloroglucinol, and 4-dimethylaminobenzaldehyde in the absence of exogenous co2. 4-aminobenzoate and 4-aminophenol served as a carbon and nitrogen ... | 1992 | 1369192 |
| the light-harvesting core-complex and the b820-subunit from rhodopseudomonas marina. part i. purification and characterisation. | the bchla-containing b880-complex (core-complex) of rhodopseudomonas marina (rhodospirillaceae) was isolated with a new purification method. the isolation of the b880-complex was performed by solubilisation of the photosynthetic membranes with the detergent ldao and subsequent fractionated ammonium-sulfate precipitation with about 50% recovery. the b880-complex retained its original spectral properties as revealed with absorption, fluorescence and circular dichroism spectroscopy. furthermore, we ... | 1992 | 1397300 |
| the light-harvesting core-complex and the b820-subunit from rhodopseudomonas marina. part ii. electron microscopic characterisation. | electron micrographs of photosynthetic membranes of the bchla-containing bacterium rp. marina showed a quasi-crystalline structure. the photoreceptor units are arranged in a hexagonal lattice with a reaction center to reaction center distance of 102 +/- 3 a. purified b880-complex was concentrated up to an od880 of 60 which induced the formation of large protein vesicles. the protein complexes within these vesicles were highly ordered and showed a hexagonal lattice with the same center to center ... | 1992 | 1397301 |
| rhodopseudomonas sphaeroides lipid a derivatives block in vitro induction of tumor necrosis factor and endotoxin tolerance by smooth lipopolysaccharide and monophosphoryl lipid a. | rhodopseudomonas (rhodobacter) sphaeroides diphosphoryl lipid a is a relatively inert species of lipid a but has been shown to antagonize the effects of toxic lipopolysaccharide (lps) both in vivo and in vitro. the antagonist and its monophosphoryl derivative were examined for the ability to block tumor necrosis factor synthesis and reverse tolerance induction in vitro in macrophage cultures stimulated with bioactive preparations of smooth lps, rough lps, diphosphoryl lipid a, and monophosphoryl ... | 1992 | 1398939 |
| dechlorination of 2,3,5,6-tetrachlorobiphenyl by a phototrophic enrichment culture. | a phototrophic enrichment culture, using acetate as carbon source, reductively dechlorinated 2,3,5,6-tetrachlorobiphenyl. ortho chlorines were removed preferentially over meta chlorines. tri- and dichlorobiphenyls were the major products. during 14 months incubation, chlorine was removed from 58% of the target molecules; 19% of the total chlorines were removed. dechlorination did not occur in a control culture incubated in the dark. | 1992 | 1426987 |
| 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 |
| a new infrared electronic transition of the oxidized primary electron donor in bacterial reaction centers: a way to assess resonance interactions between the bacteriochlorophylls. | the primary electron donor in the reaction center of purple photosynthetic bacteria consists of a pair of bacteriochlorophylls (pl and pm). the oxidized dimer (p+) is expected to have an absorption band in the mid-ir, whose energy and dipole strength depend in part on the resonance interactions between the two bacteriochlorophylls. a broad absorption band with the predicted properties was found in a previously unexplored region of the spectrum, centered near 2600 cm-1 in reaction centers of rhod ... | 1992 | 1510937 |
| anaerobic growth of rhodopseudomonas palustris on 4-hydroxybenzoate is dependent on aadr, a member of the cyclic amp receptor protein family of transcriptional regulators. | the purple nonsulfur phototrophic bacterium rhodopseudomonas palustris converts structurally diverse aromatic carboxylic acids, including lignin monomers, to benzoate and 4-hydroxybenzoate under anaerobic conditions. these compounds are then further degraded via aromatic ring-fission pathways. a gene termed aadr, for anaerobic aromatic degradation regulator, was identified by complementation of mutants unable to grow anaerobically on 4-hydroxybenzoate. the deduced amino acid sequence of the aadr ... | 1992 | 1522059 |
| a system for site-specific mutagenesis of the photosynthetic reaction center in rhodopseudomonas viridis. | the purple non-sulfur bacterium rhodopseudomonas viridis contains a photosynthetic reaction center which has been structurally resolved to 2.3 a providing a unique basis for the study of biological electron transfer processes by the method of site-specific mutagenesis. here we report the construction of a puf operon deleted mutant strain incapable of photosynthetic growth. the deletion was introduced with the help of a newly constructed suicide vector by electroporation which is with conjugation ... | 1992 | 1537348 |
| genetically modified photosynthetic antenna complexes with blueshifted absorbance bands. | light energy for photosynthesis is collected by the antenna system, creating an excited state which migrates energetically 'downhill'. to achieve efficient migration of energy the antenna is populated with a series of pigments absorbing at progressively redshifted wavelengths. this variety in absorbing species in vivo has been created in a biosynthetically economical fashion by modulating the absorbance behaviour of one kind of (bacterio)chlorophyll molecule. this modulation is poorly understood ... | 1992 | 1538765 |
| anaerobic degradation of trans-cinnamate and omega-phenylalkane carboxylic acids by the photosynthetic bacterium rhodopseudomonas palustris: evidence for a beta-oxidation mechanism. | the mechanism responsible for the initial steps in the anaerobic degradation of trans-cinnamate and omega-phenylalkane carboxylates by the purple non-sulphur photosynthetic bacterium rhodopseudomonas palustris was investigated. phenylacetate did not support growth and there was a marked co2 dependence for growth on acids with greater side-chain lengths. here, co2 was presumably acting as a redox sink for the disposal of excess reducing equivalents. growth on benzoate did not require the addition ... | 1992 | 1550442 |
| herbicide binding in the bacterial photosynthetic reaction center. | the ureas and phenolics are two major classes of herbicides that act on photosystem ii (psii) and are normally inactive in the photosynthetic reaction centers of purple bacteria. however, the triazine-resistant mutant t4 from rhodopseudomonas (rps.) viridis, which has the tyrosine residue at position 222 on the l subunit substituted for phenylalanine (tyrl222phe), is sensitive to both ureas and phenolics. since for the first time structural data on urea binding are available, t4 is a particularl ... | 1992 | 1585459 |
| the binding of triazine herbicides to the photosynthetic reaction center of rhodopseudomonas viridis. energy minimization studies. | the binding of six herbicides of the triazine family to the photosynthetic reaction center of rhodopseudomonas viridis was investigated with energy-minimization techniques, in order to correlate experimental with calculated data. the inhibitors were modeled in the active site according to the x-ray structure analysis of the complex formed between the triazine terbutryn (2-ethylamino-4-t-butylamino-6-methylthio-s-triazine) and the reaction center of r. viridis [michel, h., epp. o. & deisenhofer, ... | 1992 | 1606955 |
| potential early intermediates in anaerobic benzoate degradation by rhodopseudomonas palustris. | alkali-treated extracts of rhodopseudomonas palustris growing photosynthetically on benzoate were examined by gas chromatography/mass spectrometry for partially reduced benzoate derivatives. two cyclic dienes, cyclohexa-2,5-diene-1-carboxylate and cyclohexa-1,4-diene-1-carboxylate, were detected. either compound supported cell growth as effectively as benzoate. these results suggest that these cyclohexadienecarboxylates, probably as their coenzyme a esters, are the initial reduction products for ... | 1992 | 1610191 |
| characterization of the multiple epr line shapes of iron-semiquinones in photosystem 2. | we have compared the temperature-dependence characteristics of the epr signals of qa and qb iron-semiquinones from both purple bacterial and plant photosystems. the data obtained were analyzed and estimates of the splitting parameters of the non-heme fe2+ spin sublevels obtained. the study confirms the similarities of the g = 1.8 qa iron-semiquinone signal (d/k = 15.6 k, e/k = 3.3 k) formed in formate-treated plant photosystem 2 to the signal found in purple bacteria. however, the g = 1.9 qa iro ... | 1992 | 1312858 |
| electrochemical titration of the cytochrome hemes in the rhodopseudomonas viridis reaction center. cyclic equilibrium titrations yield midpoint potentials without evidence for heme cooperativity. | the redox and spectral characteristics of the 4-heme cytochrome c unit of the photochemical reaction center from rhodopseudomonas viridis were studied by a combination of protein electrochemistry and spectroscopy using an ultra thin-layer spectroelectrochemical cell. quantitative and reversible reduction of the high-potential and the low-potential hemes was performed in cyclic titrations to record the optical difference spectra in the alpha-band region. the titration of the absorbance from the h ... | 1992 | 1312949 |
| [comparison of a stat method of analysis of microorganisms for the presence of site-specific restriction endonuclease activity]. | sensitivity of several express-methods used for detection of bacterial endonucleases was compared. the most sensitive method is that employing triton x-100. | 1992 | 1317567 |
| electron paramagnetic resonance studies of carotenoids. | 1992 | 1331704 | |
| effect of temperature on the kinetics of electron transfer from the tetraheme cytochrome to the primary donor in rhodopseudomonas viridis. | the kinetics of electron transfer from the third highest potential heme (c-552, em = +20 mv) to the primary donor (p-960) have been measured by flash absorption spectroscopy in isolated reaction centers of rhodopseudomonas viridis between 300 k and 7 k. the data are analyzed on the basis of three exponential components with a very fast phase (t1/2 = 120 ns) dominating at high temperature and a very slow one (t1/2 = 1.2 ms) at low temperature. this multiphasic behavior is interpreted in terms of ... | 1992 | 1333411 |
| application of three-dimensional molecular hydrophobicity potential to the analysis of spatial organization of membrane domains in proteins: i. hydrophobic properties of transmembrane segments of na+, k(+)-atpase. | a new computer-aided molecular modeling approach based on the concept of three-dimensional (3d) molecular hydrophobicity potential has been developed to calculate the spatial organization of intramembrane domains in proteins. the method has been tested by calculating the arrangement of membrane-spanning segments in the photoreaction center of rhodopseudomonas viridis and comparing the results obtained with those derived from the x-ray data. we have applied this computational procedure to the ana ... | 1992 | 1334655 |
| application of three-dimensional molecular hydrophobicity potential to the analysis of spatial organization of membrane protein domains. ii. optimization of hydrophobic contacts in transmembrane hairpin structures of na+, k(+)-atpase. | a method of packing of transmembrane hairpin helices in proteins is described. the procedure is based on the optimization of hydrophobic contacts calculated using the three-dimensional (3d) molecular hydrophobicity potential technique. to verify the validity of the computational scheme, we calculated relative orientations of membrane-spanning peptides in pairs l2-l3, m2-m3, and m4-m5 from l- and m-subunits of the photoreaction center of rhodopseudomonas viridis and compared the predicted structu ... | 1992 | 1334656 |
| differentiation between transmembrane helices and peripheral helices by the deconvolution of circular dichroism spectra of membrane proteins. | the interpretation of the circular dichroism (cd) spectra of proteins to date requires additional secondary structural information of the proteins to be analyzed, such as x-ray or nmr data. therefore, these methods are inappropriate for a cd database whose secondary structures are unknown, as in the case of the membrane proteins. the convex constraint analysis algorithm (perczel, a., hollósi, m., tusnády, g., & fasman, g. d., 1991, protein eng. 4, 669-679), on the other hand, operates only on a ... | 1992 | 1338977 |
| lifetimes of bacteriochlorophyll fluorescence in rhodopseudomonas viridis and heliobacterium chlorum at low temperatures. | fluorescence lifetimes of isolated membranes of rhodopseudomonas viridis were measured in the temperature range of 77 k to 25 k. at room temperature, the main component of the fluorescence decay of bacteriochlorophyll (bchl) b had a time constant of 50 ps. in contrast to other purple bacteria, the emission at low temperature was spectrally homogeneous and showed essentially single lifetimes of 140 ps at 77 k and 180 ps at 25 k, with the primary electron donor in the oxidized state. taking int ... | 1993 | 11537866 |
| learning about photosystem ii from analogies with purple photosynthetic bacteria. | 1993 | 8132104 | |
| lipopolysaccharide (lps) binding to 73-kda and 38-kda surface proteins on lymphoreticular cells: preferential inhibition of lps binding to the former by rhodopseudomonas sphaeroides lipid a. | using a photoactivable, radioiodinated lipopolysaccharide probe, [125i]asd-lps (derivatized from purified e. coli 0111:b4 s-lps), we earlier reported the presence of a 73-kda (p73) predominant lps-binding protein on mouse lymphocytes and macrophages with specificity for the lipid a region of lps. both re-lps from salmonella minnesota and purified lipid a will inhibit the binding of lps to the p73 lps receptor. in the studies reported here, we have found that non-toxic diphosphoryl lipid a purifi ... | 1993 | 7690343 |
| cloning of a new antenna gene cluster and expression analysis of the antenna gene family of rhodopseudomonas palustris. | the genome of rhodopseudomonas palustris contains five antenna gene clusters, alpha beta a, alpha beta b, alpha beta c, alpha beta d and alpha beta e, which encode the light-harvesting peripheral antenna complex ii polypeptides. the isolation and characterisation of the gene which encodes the alpha e and beta e polypeptides are reported. the primary structure of the beta e polypeptide is identical to that of beta b whilst the structure of alpha e is different from the other alpha subunits so far ... | 1993 | 7693467 |
| 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 |
| phylogenetic tree and sequence similarity of beta-lactamases. | beta-lactamases are the main cause of beta-lactam resistance in many pathogenic bacteria. these enzymes can be detected in a variety of pathogenic as well as non-pathogenic bacteria. the cyanobacteria are also known to produce a beta-lactamase. recently, the amino acid sequences and the three-dimensional structures of some of these beta-lactamases have been clarified. on the basis of the amino acid sequences of 47 beta-lactamases and the computer-aided analysis, a phylogenetic tree is proposed i ... | 1993 | 8025724 |
| study of wild type and genetically modified reaction centers from rhodobacter capsulatus: structural comparison with rhodopseudomonas viridis and rhodobacter sphaeroides. | reaction centers from the purple bacterium rhodobacter (rb.) capsulatus and from two mutants thrl226-->ala and ilel229-->ser, modified in the binding protein pocket of the secondary quinone acceptor (qb), have been studied by flash-induced absorbance spectroscopy. in thrl226-->ala, the binding affinities for endogenous qb (ubiquinone 10) and uq6 are found to be two to three times as high as the wild type. in contrast, in ilel229-->ser, the binding affinity for uq6 is decreased about three times ... | 1993 | 8218894 |
| predicting the point at which transmembrane helices protrude from the bilayer: a model of the antenna complexes from photosynthetic bacteria. | we describe a method for predicting the point at which a transmembrane helix leaves the bilayer and enters the more polar region of the aqueous exterior. this is achieved by comparing the relative directions of the hydrophobic and internal faces of the transmembrane helices which should be opposite for the regions within the bilayer but equivalent for the regions on the outside. this information provides a strong constraint in the process of modelling membrane proteins. we go on to use the appro ... | 1993 | 8234233 |
| synthesis of the rhodopseudomonas viridis holo-cytochrome c2 in paracoccus denitrificans. | the gene encoding the rhodopseudomonas viridis cytochrome c2 (cyca) has been introduced on a broad host range vector into paracoccus denitrificans, leading to high-level expression of the holo-cytochrome with the heme moiety covalently attached to the apoprotein. the cytochrome was demonstrated to reside in the periplasmic space of the host cell. in contrast to r. viridis, aerobic rather than anaerobic growth conditions led to higher production levels of the holo-cytochrome in p. denitrificans. ... | 1993 | 8243979 |
| prediction of transmembrane helices from hydrophobic characteristics of proteins. | membrane proteins, requiring to be embedded into the lipid bilayers, have evolved to have amino acid sequences that will fold with a hydrophobic surface in contact with the alkane chains of the lipids and polar surface in contact with the aqueous phases on both sides of the membrane and the polar head groups of the lipids. it is generally assumed that the characteristics of the aqueous parts of the membrane proteins are similar to those of normal globular proteins, and the embedded parts are hig ... | 1993 | 8244628 |
| structure, spectroscopic, and redox properties of rhodobacter sphaeroides reaction centers bearing point mutations near the primary electron donor. | single mutations of three amino acid residues in the vicinity of the primary electron donor, p, in the reaction center (rc) from rhodobacter (rb.) sphaeroides were constructed and characterized in order to study the effects of hydrogen-bonding on the physical properties of p. the mutations, phe m197-->tyr, met l248-->thr, and ser l244-->gly, represent single amino acid changes near p designed to introduce residues found in rhodopseudomonas (rps.) viridis and to, thus, probe the effects of noncon ... | 1993 | 8251510 |
| is intracytoplasmic membrane structure a generic criterion? it does not coincide with phylogenetic interrelationships among phototrophic purple nonsulfur bacteria. | the 16s rrna or rrna gene sequences of the type strains of 5 species of rhodobacter, rhodopseudomonas blastica and paracoccus denitrificans were determined. the sequence analysis revealed that rhodobacter species, whose intracytoplasmic membrane systems were characteristically vesicular, composed a sole cluster. rhodopseudomonas blastica, whose intracytoplasmic membrane system was lamellar, was included in the cluster of rhodobacter. the phylogenetic co-clustering of these bacteria conformed to ... | 1993 | 8257281 |
| influence of the supramolecular structure of free lipid a on its biological activity. | the three-dimensional supramolecular structures and the states of order of the acyl chains of lipid a from different gram-negative species were investigated at 40 degrees c, high water content (80-90%), and different [lipid a]/[mg2+] molar ratios using synchrotron radiation x-ray diffraction and fourier-transform infrared spectroscopy. measurements were made on free lipid a from salmonella minnesota r595, mono- and bi-phosphoryl, as well as those from the non-enterobacterial strains rhodobacter ... | 1993 | 8269946 |
| 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 |
| energy transfer processes in rhodopseudomonas palustris grown under low-light conditions. heterogeneous composition of lh 2 complexes and parallel energy flow pathways. | excitation energy flow in the purple photosynthetic bacterium rhodopseudomonas palustris grown under a low-light intensity was studied by time-resolved fluorescence spectroscopy in the ps time range. this bacterium synthesized the b824 component under this light condition. time-resolved spectra at 20 degrees c indicated the sequential energy flow in the order of b803, b856, b882 and b900, long wavelength antenna. an emission from b803 was not observed. a remarkable feature was the emission from ... | 1993 | 8365474 |
| electron transfer from the tetraheme cytochrome to the special pair in isolated reaction centers of rhodopseudomonas viridis. | kinetics of electron transfer from the bound tetraheme cytochrome c to the primary donor (p) have been measured in isolated reaction centers of the purple bacterium rhodopseudomonas viridis by time-resolved flash absorption spectroscopy. the influence of two major parameters has been studied: temperature (7-305 k) and the redox state of the cytochrome. most experiments were done with one heme (c-559), two hemes (c-559 and c-556), or three hemes (c-559, c-556, and c-552) poised in a reduced state ... | 1993 | 8381025 |
| pathway of proton transfer in bacterial reaction centers: second-site mutation asn-m44-->asp restores electron and proton transfer in reaction centers from the photosynthetically deficient asp-l213-->asn mutant of rhodobacter sphaeroides. | site-directed mutagenesis of the photosynthetic reaction center (rc) from rhodobacter sphaeroides has shown asp-213 of the l subunit (asp-l213) to be important for photosynthetic viability. replacement of asp-l213 with asn resulted in a photosynthetically deficient mutant, due to the 10(4)-fold slower rate for the proton-coupled electron transfer reaction qa-qb- + 2h+-->qaqbh2 (k(2)ab). the detrimental effect of asn-l213 is surprising since rcs from rhodopseudomonas viridis, rhodospirillum rubru ... | 1993 | 8381964 |
| comparison between the properties of 3-nitrosalicyl-n-alkylamide and antimycin a acting on qh2:cytochrome c reductase. | 3-nitrosalicyl n-alkylamide was found to be an inhibitor different from antimycin a not only in its inhibitory nature but also in many other aspects. this difference indicated that the 11 kda component, which was identified as the antimycin a (aa) binding factor in the qh2: cytochrome c reductase of rhodopseudomonas sphaeroides by wilson et al. ((1985) j. biol. chem. 260, 10288-10292) using the radioactive photoaffinity analogue 3-azidosalicyl n-octadecylamide, was not the genuine binding site o ... | 1993 | 8384491 |
| kinetics of photooxidation of soluble cytochromes, hipip, and azurin by the photosynthetic reaction center of the purple phototrophic bacterium rhodopseudomonas viridis. | the photosynthetic reaction center of rhodopseudomonas viridis contains a bound tetraheme cytochrome c subunit which is the primary electron donor to the photooxidized special pair bacteriochlorophyll. we have tested a variety of soluble electron-transfer proteins for their ability to serve as secondary electron donors to the bacteriochlorophyll via the bound cytochrome by measuring the kinetics of reaction center heme reduction following photooxidation by a laser flash, as a function of soluble ... | 1993 | 8387812 |
| the interaction between cytochrome c2 and the cytochrome bc1 complex in the photosynthetic purple bacteria rhodobacter capsulatus and rhodopseudomonas viridis. | the rates of electron transfer from a ubiquinol analogue to cytochrome c2 catalyzed by the cytochrome bc1 complexes of rhodobacter capsulatus and rhodopseudomonas viridis were measured as a function of ionic strength. the effects of ionic strength on the kinetic parameters for the reactions are consistent with a role for electrostatic complex formation between cytochrome c2 and the cytochrome bc1 complex in the electron-transfer pathways in both photosynthetic purple non-sulfur bacteria. additio ... | 1993 | 8387815 |
| the reaction center associated tetraheme cytochrome subunit from chromatium vinosum revisited: a reexamination of its epr properties. | the heme components of chromatophore membranes from the purple bacterium chromatium vinosum have been studied by epr. five different heme species could be distinguished on the basis of their g values, redox midpoint potentials, and orientations of heme planes with respect to the membrane plane: gz = 2.94, em = +10 mv, 40 degrees-50 degrees; gz = 2.94, em = +10 mv, 0 degree; gz = 3.1, em = +330 mv, 90 degrees; gz = 3.3, em = 360 mv, 30 degrees; gz = 3.4, em = 0 mv, no detectable orientation. four ... | 1993 | 8395884 |
| structural characterization of isolated mitochondrial cytochrome c1. | resonance raman spectroscopy (rrs) has been employed to characterize cytochromes c1 isolated from bc1 complexes of beef heart mitochondria and rhodopseudomonas sphaeroides. the data obtained in this study extend the physical characterization of cytochromes c1 and focus on the effects of the local protein environment on the heme active site. while the general characteristics of the cytochromes c1 are similar to those of smaller soluble cytochromes c, the behavior of several core-size and ligation ... | 1993 | 8399285 |
| purification and characterization of homospermidine synthase in acinetobacter tartarogenes atcc 31105. | homospermidine synthase, catalyzing the formation of homospermidine [h2n(ch2)4nh-(ch2)4nh2] from putrescine and nad+ with concomitant liberation of nh3, was purified 600-fold over the crude extract with a yield of about 14% to homogeneity from acinetobacter tartarogenes atcc 31105. the enzyme had a native molecular mass of 102 kda, with a pi of 5.0, and was apparently composed of two identical subunits (52 kda), suggesting that a single protein catalyzes two serial reactions, oxidation of putres ... | 1993 | 8407874 |
| products of enzymatic reduction of benzoyl-coa, a key reaction in anaerobic aromatic metabolism. | benzoyl-coenzyme a is the most common central intermediate of anaerobic aromatic metabolism. studies with whole cells of different bacteria and in vitro had shown that benzoyl-coa is reduced to alicyclic compounds, possibly via cyclohexadiene intermediates. this reaction is considered a 'biological birch reduction'. we have elucidated by nmr techniques the structures of six products of [ring-13c6]benzoate reduction. the reaction is catalyzed by extracts from cells of a denitrifying pseudomonas s ... | 1993 | 8436125 |
| purification of glutaryl-coa dehydrogenase from pseudomonas sp., an enzyme involved in the anaerobic degradation of benzoate. | cell-free extracts of pseudomonas sp. strains kb 740 and k 172 both contained high levels of glutaryl-coa dehydrogenase when grown anaerobically on benzoate or other aromatic compounds and with nitrate as electron acceptor. these aromatic compounds have in common benzoyl-coa as the central aromatic intermediate of anaerobic metabolism. the enzymatic activity was almost absent in cells grown aerobically on benzoate regardless whether nitrate was present. glutaryl-coa dehydrogenase activity was al ... | 1993 | 8439237 |
| 1h-nmr investigation of oxidized and reduced high-potential iron-sulfur protein from rhodopseudomonas globiformis. | 1h one-dimensional and two-dimensional nmr spectra have been recorded for the oxidized and reduced forms of the high-potential iron-sulfur protein (hipip) from rhodopseudomonas globiformis which has the highest known reduction potential. the spectrum of the oxidized protein is similar to that of chromatium vinosum and rhodocyclus gelatinosus hipip but different from that of the hipip ii from ectothiorhodospira halophila. surprisingly, site-specific assignment has shown that in the oxidized prote ... | 1993 | 8444166 |
| evidence that serine l223 is involved in the proton transfer pathway to qb in the photosynthetic reaction center of rhodopseudomonas viridis. | in the reaction center of purple photosynthetic bacteria, the reducing equivalents produced by primary charge separation are exported via an ubiquinone molecule working as a two-electron shuttle. this loosely-bound quinone, called qb, accepts in successive flashes two electrons from the tightly bound primary quinone acceptor qa, along with two protons from the external medium. the surrounding protein plays an important role in stabilizing the semiquinone anion and in providing a pathway for prot ... | 1993 | 8448155 |
| a progress report on the crystallographic studies on the b800-850 antenna complex from rhodopseudomonas acidophila strain 10050. | large single crystals (up to 1 mm in each dimension) of the b800-850 antenna complex from rhodopseudomonas acidophila strain 10050 have been grown in the presence of beta-octyl-glucoside. these crystals have the space group r32 and unit cell dimensions of a = b = 119.9 a and c = 297.0 a. recently we have improved our crystallization procedures so that all crystals now diffract reliably to beyond 3.5 a, with some diffracting to below 3 a. a range of isomorphous heavy atom derivatives have been pr ... | 1993 | 8449320 |
| crystallisation of the b800-820 light-harvesting complex from rhodopseudomonas acidophila strain 7750. | 1993 | 8449321 | |
| probing the donor side of bacterial reaction centres: site-directed mutants of tyrosine l162 of rhodobacter sphaeroides and rhodopseudomonas viridis. | 1993 | 8449326 | |
| the lipids of rhodopseudomonas acidophila strain 10050 as possible influences on the crystallisation of the b800-850 complex from this bacterium. | 1993 | 8449333 | |
| the effect of changes in light intensity and temperature on the peripheral antenna of rhodopseudomonas acidophila. | 1993 | 8449342 | |
| enzymes of anaerobic metabolism of phenolic compounds. 4-hydroxybenzoyl-coa reductase (dehydroxylating) from a denitrifying pseudomonas species. | the reductive removal of aromatic hydroxyl functions plays an important role in the anaerobic metabolism of many phenolic compounds. we describe a new enzyme from a denitrifying pseudomonas sp., 4-hydroxybenzoyl-coa reductase (dehydroxylating), which reductively dehydroxylates 4-hydroxybenzoyl-coa to benzoyl-coa. the enzyme plays a role in the anaerobic degradation of phenol, 4-hydroxybenzoate, p-cresol, 4-hydroxyphenylacetate, and other aromatic compounds of which 4-hydroxybenzoyl-coa is an int ... | 1993 | 8477729 |
| diphosphoryl lipid a from rhodopseudomonas sphaeroides induces tolerance to endotoxic shock in the rat. | to examine the hemodynamic effects of diphosphoryl lipid a from rhodopseudomonas sphaeroides and to examine the ability of this substance to induce tolerance to endotoxic shock. | 1993 | 8482097 |
| fourier transform infrared spectroscopy and electrochemistry of the primary electron donor in rhodobacter sphaeroides and rhodopseudomonas viridis reaction centers: vibrational modes of the pigments in situ and evidence for protein and water modes affected by p+ formation. | protein electrochemistry in an ultra-thin-layer electrochemical cell suitable for uv/vis and ir spectroscopy has been used to characterize the vibrational modes of the primary electron donors of rhodobacter sphaeroides and rhodopseudomonas viridis reaction centers in their neutral and cation radical states (p and p+, respectively). the p-->p+ redox transitions could be well separated from redox reactions of other cofactors according to their redox midpoint potential. the ir difference bands of t ... | 1993 | 8485130 |
| the high-resolution three-dimensional structure of a membrane protein. | 1993 | 8503053 | |
| organic thiols as organolithotrophic substrates for growth of phototrophic bacteria. | rhodopseudomonas sp. strain bb1, isolated from a coastal marine sediment, immediately metabolized mercaptomalate when grown on mercaptomalate. sulfide was detected as an intermediate. extracts of cells grown on mercaptomalate converted mercaptomalate or 3-mercaptopropionate to equimolar amounts of sulfide and either fumarate or acrylate, respectively. rhodopseudomonas sp. strain bb1 gave higher growth yields on mercaptomalate than on sulfide or malate, consistent with metabolism of the carbon ch ... | 1993 | 16348862 |
| a photoinduced persistent structural transformation of the special pair of a bacterial reaction center. | structural modification of photosynthetic reaction centers is an important approach for understanding their charge-separation processes. an unprecedented persistent structural transformation of the special pair (dimer) of bacteriochlorophyll molecules can be produced by light absorption alone. the nonphotochemical hole-burned spectra for the reaction center of rhodopseudomonas viridis show that the phototransformation leads to a red shift of 150 wave numbers for the special pair's lowest energy ... | 1993 | 17793534 |
| dynamics affecting the primary charge transfer in photosynthesis. | analysis of a 60-picosecond molecular dynamics trajectory of the reaction center of rhodopseudomonas viridis provides an understanding of observations concerning vibrational coherence and the nonexponential kinetics of the primary charge transfer in photosynthesis. complex kinetics arises from energy gap correlations that persist beyond 1 picosecond. | 1994 | 17754881 |
| phylogenetic analysis of bradyrhizobium japonicum and photosynthetic stem-nodulating bacteria from aeschynomene species grown in separated geographical regions. | nearly complete and short partial 16s rrna sequences were derived from pcr-amplified ribosomal dnas of bradyrhizobium japonicum usda 136 and usda 110 and five strains of bacteriochlorophyll-synthesizing bacteria isolated from stem nodules of aeschynomene indica and other aeschynomene species growing in different geographic regions, including india, the philippines and north america. we confirmed that the five stem-nodulating strains examined synthesize bacteriochlorophyll a, and the absorption s ... | 1994 | 16349221 |
| anaerobic metabolism of cyclohex-1-ene-1-carboxylate, a proposed intermediate of benzoate degradation, by rhodopseudomonas palustris. | anaerobic benzoate degradation by the phototrophic bacterium rhodopseudomonas palustris has been proposed to proceed via aromatic ring reduction reactions leading to cyclohex-1-ene-1-carboxyl-coenzyme a (coa) formation. the alicyclic product is then proposed to undergo three beta-oxidation-like modifications resulting in ring cleavage. illuminated suspensions of benzoate-grown cells converted [7-c]cyclohex-1-ene-1-carboxylate to intermediates that comigrated with cyclohex-1-ene-1-carboxyl-coa, 2 ... | 1994 | 16349272 |
| photometabolism of heterocyclic aromatic compounds by rhodopseudomonas palustris ou 11. | rhodopseudomonas palustris ou 11 (atcc 51186; dsm 7375) isolated from a pond of chemical industry effluent could anaerobically photometabolize heterocyclic aromatic compounds belonging to the pyridine and pyrazine groups only after a period of adaptation on pyrazinoic acid of 5 to 6 weeks. growth on heterocyclic compounds was light dependent. the effects of various concentrations of heterocyclic compounds on growth suggest that higher concentrations of these compounds inhibit growth and are toxi ... | 1994 | 16349307 |
| application of an automatic molecular-replacement procedure to crystal structure analysis of cytochrome c2 from rhodopseudomonas viridis. | an automatic molecular-replacement procedure has been applied to solve the crystal structure of cytochrome c(2) from rhodopseudomonas viridis. the structure was solved on the basis of the structure of tuna cytochrome c as a search model using an automatic processing program system, automr. the refinements by molecular dynamics and restrained least-squares methods result in a current crystallographic r factor of 0.219 for diffraction data at 3 a resolution. | 1994 | 15299438 |
| determination of the number of detergent molecules associated with the reaction center protein isolated from the photosynthetic bacterium rhodopseudomonas viridis. effects of the amphiphilic molecule 1,2,3-heptanetriol. | detergent-free reaction center (rc) proteins from the photosynthetic bacterium rhodopseudomonas viridis were obtained using bio-beads sm-2. with these rcs, the amount of detergent molecules associated with the protein was measured by determining the detergent concentration at which re-solubilization occurred as a function of the rc concentration. for n,n-dimethyl dodecylamine-n-oxide (ldao), triton x-100 and beta-octylglucoside 260 +/- 30,105 +/- 10 and 360 +/- 100 detergent molecules were neces ... | 1994 | 8276109 |
| lipopolysaccharide-induced change of adp-ribosylation of a cytosolic protein in bone-marrow-derived macrophages. | treatment of bone-marrow-derived macrophages with nanogram quantities of bacterial lipopolysaccharide (lps) or with the synthetic bacterial lipopeptide analogue n-palmitoyl-(s)-[2,3-bis(palmitoyloxy)-(2rs)-propyl] (pam3)cys-ala-gly results in a change of adp-ribosylation of a cytosolic 33 kda protein. the immunostimulant-induced change is both dose- and time-dependent. it is not observed in macrophages from an lps-unresponsive c3h/hej mouse strain upon treatment with lps. non-endotoxic lps from ... | 1994 | 8280095 |
| 4-hydroxybenzoate-coenzyme a ligase from rhodopseudomonas palustris: purification, gene sequence, and role in anaerobic degradation. | anaerobic metabolism of most aromatic acids is initiated by coenzyme a thioester formation. rhodopseudomonas palustris grows well under anaerobic, phototrophic conditions with many aromatic acids, including benzoate and 4-hydroxybenzoate, as a carbon source. a coenzyme a ligase that reacts with 4-hydroxybenzoate was purified from 4-hydroxybenzoate-grown cells of r. palustris. this enzyme required mgatp, reduced coenzyme a, and 4-hydroxybenzoate, benzoate, or cyclohex-1,4-dienecarboxylate for opt ... | 1994 | 8300518 |
| primary structure and transcription of genes encoding b870 and photosynthetic reaction center apoproteins from rubrivivax gelatinosus. | we determined the nucleotide sequence of the puf operon of rubrivivax gelatinosus (formerly called rhodocyclus gelatinosus), a photosynthetic bacterium belonging to the beta subclass of purple bacteria (proteobacteria). the operon contains two unknown open reading frames (orfs) in addition to five photosynthetic genes which have been reported in species belonging to the alpha subclass. these genes include pufb, -a, -l, -m, and -c coding for the beta and alpha subunits of the b870 light-harvestin ... | 1994 | 8300574 |
| purification and properties of the squalene-hopene cyclase from rhodopseudomonas palustris, a purple non-sulfur bacterium producing hopanoids and tetrahymanol. | the squalene-hopene cyclase of the hopanoid- and tetrahymanol-producing rhodopseudomonas palustris was released from the isolated membranes by chaps and purified to homogeneity by successive chromatography on deae sephacel, octyl sepharose, and blue sepharose. the enzyme has a molecular weight of 70 kda as determined by sds-page and an isoelectric point at about ph 5.0. the enzyme activity has a maximum at 30 degrees c and at ph 6.5. no production of tetrahymanol could be demonstrated by using e ... | 1994 | 8305486 |
| enhanced rates of subpicosecond energy transfer in blue-shifted light harvesting lh2 mutants of rhodobacter sphaeroides. | energy transfer within various lh2 antenna complexes of the photosynthetic purple bacteria rhodobacter sphaeroides and rhodopseudomonas acidophila has been studied at 77 k using tunable femtosecond and subpicosecond infrared pulses. the complexes examined include the wild-type b800-850 as well as three different specifically mutated complexes. the site-directed mutant strains were altered at positions 44 and 45 near the c-terminus of the alpha-subunit, which introduces a spectral blue-shift of t ... | 1994 | 8031762 |
| anaerobic degradation of halogenated benzoic acids by photoheterotrophic bacteria. | from light-exposed enrichment cultures containing benzoate and a mixture of chlorobenzoates, a pure culture was obtained able to grow with 3-chlorobenzoate (3-cba) or 3-bromobenzoate (3-brba) as the sole growth substrate anaerobically in the light. the thus isolated organism is a photoheterotroph, designated isolate dcp3. it is preliminarily identified as a rhodopseudomonas palustris strain. it differs from rhodopseudomonas palustris ws17, the only other known photoheterotroph capable of using 3 ... | 1994 | 8039661 |
| posttranslational modification of nitrogenase. differences between the purple bacterium rhodospirillum rubrum and the cyanobacterium anabaena variabilis. | in the photosynthetic bacteria rhodospirillum rubrum and rhodopseudomonas capsulatus post-translational regulation of nitrogenase is due to adp-ribosylation of the fe-protein, the dinitrogenase reductase [burris, r. h. (1991) j. biol. chem. 266, 9339-9342]. this mechanism has been assumed to be responsible for nitrogenase modification in a variety of organisms. in the present study, we examined whether adp-ribosylation holds true for the filamentous cyanobacterium anabaena variabilis. genes codi ... | 1994 | 8119279 |
| molecular phylogenetic analysis of nitrobacter spp. | the phylogeny of bacteria belonging to the genus nitrobacter was investigated by sequencing the whole 16s rrna gene. the average level of similarity for the three nitrobacter strains examined was high (99.2%), and the similarity level between nitrobacter winogradskyi and nitrobacter sp. strain ll, which represent two different genomic species, was even higher (99.6%). when all of the nitrobacter strains and their phylogenetic neighbors bradyrhizobium and rhodopseudomonas species were considered, ... | 1994 | 8123564 |
| interaction between cytochrome c and the photosynthetic reaction center of purple bacteria: behaviour at low temperature. | in purple photosynthetic bacteria the electron donor to the special pair, after its oxidation by a light-induced reaction, is a c-type cytochrome: either a soluble monoheme cytochrome which forms a transitory complex with the reaction center, or a tetraheme cytochrome which remains permanently bound to the reaction center. the effects of low temperatures on electron transfer in the complex are presented and discussed. they provide estimates for the reorganization energy. the most prominent effec ... | 1994 | 7880896 |
| evolution of photosynthetic reaction centers and light harvesting chlorophyll proteins. | it is proposed that there is a single evolutionary origin for photosynthetic reaction centers and also for most light-harvesting chlorophyll proteins. it is generally accepted that the purple bacterial reaction center (quinone-reducing photosystem) and the plant and cyanobacterial psii (oxygen-evolving photosystem) are homologous. it is also apparent that the green sulfur bacterial reaction center is homologous to cyanobacterial psi (the pyridine nucleotide reducing photosystem). however, it is ... | 1994 | 7888608 |
| the six fold symmetry of the b880 light-harvesting complex and the structure of the photosynthetic membranes of rhodopseudomonas marina. | the reaction center free light-harvesting core complex of rp. marina was purified by deae 52 ion exchange chromatography in the presence of the detergent og. the protein complex was crystallised by microdialysis yielding two-dimensional crystals with a diameter of up to 10 microns. the crystals were negatively stained with uranyl acetate or prepared in vitrified ice and electron micrographs were taken. they exhibited a hexagonal lattice with a lattice constant of 102 +/- 3 a. the optical diffrac ... | 1994 | 7945991 |
| [the endotoxins of gram-negative bacteria: their structure and biological role]. | main attention in the paper is paid to the study of lipid a, a component possessing endotoxic activity. lipids a containing glucosamine disaccharide (representatives of enterobacteriaceae family), and variants of lipid a differing from the toxic one either in the structure of carbohydrate core or in the spectrum of fatty acids are considered. they are either phototrophic, nodulating (bradyrhyzobium species) or soil species (nitrobacter and thiobacillus) bacteria. lipid a from lipopolysaccharides ... | 1994 | 7952230 |
| the bacterial degradation of benzoic acid and benzenoid compounds under anaerobic conditions: unifying trends and new perspectives. | simple homocyclic aromatic compounds are extremely abundant in the environment and are derived largely from lignin. such compounds may enter anaerobic environments and several groups of bacteria, exhibiting diverse energy-yielding mechanisms, have evolved the capacity to overcome the thermodynamic stability of the benzene nucleus and degrade aromatic compounds under these conditions. over the last few years considerable advances have been made in our understanding of the biochemical strategies u ... | 1994 | 8011356 |
| structural and functional consequences of a glu l212-->lys mutation in the qb binding site of the photosynthetic reaction center of rhodopseudomonas viridis. | the properties of the quinone acceptor complex in the photosynthetic reaction center of the atrazine-resistant rhodopseudomonas viridis mutant a2 (glu l212-->lys) were studied by epr spectroscopy and by photoelectric measurements. the epr signal attributed to the semiquinone-iron (qb-fe2+) was significantly different from wild type and resembled that found in ps ii. essentially normal oscillations of qb-fe2+ were observed upon flash illumination. the kinetics of the first and the second electron ... | 1994 | 7727386 |
| the fnr family of transcriptional regulators. | homologues of the transcriptional regulator fnr from escherichia coli have been identified in a variety of taxonomically diverse bacterial species. despite being structurally very similar, members of the fnr family have disparate regulatory roles. those from shewanella putrefaciens, pseudomonas aeruginosa, pseudomonas stutzeri and rhodopseudomonas palustris are functionally similar to fnr in that they regulate anaerobic respiration or carbon metabolism. four rhizobial proteins (from rhizobium me ... | 1994 | 7747934 |
| the tetrahaem cytochromes associated with photosynthetic reaction centres: a model system for intraprotein redox centre interactions. | 1994 | 7821666 | |
| structure of the photosynthetic reaction centre from rhodobacter sphaeroides at 2.65 a resolution: cofactors and protein-cofactor interactions. | photosynthetic reaction centres (rcs) catalyze light-driven electron, transport across photosynthetic membranes. the photosynthetic bacterium rhodobacter, sphaeroides is often used for studies of rcs, and three groups have determined the structure of its reaction centre. there are discrepancies between these structures, however, and to resolve these we have determined the structure to higher resolution than before, using a new crystal form. | 1994 | 7866744 |
| structure of the membrane channel porin from rhodopseudomonas blastica at 2.0 a resolution. | the crystal structure of a membrane channel, homotrimeric porin from rhodopseudomonas blastica has been determined at 2.0 a resolution by multiple isomorphous replacement and structural refinement. the current model has an r-factor of 16.5% and consists of 289 amino acids, 238 water molecules, and 3 detergent molecules per subunit. the partial protein sequence and subsequently the complete dna sequence were determined. the general architecture is similar to those of the structurally known porins ... | 1994 | 8142898 |
| structural similarity of cytochrome c2 from rhodopseudomonas viridis to mitochondrial cytochromes c revealed by its crystal structure at 2.7 a resolution. | the crystal structure of cytochrome c2 from rhodopseudomonas viridis has been refined using molecular dynamics and restrained least-squares methods to a crystallographic r-factor of 0.216 at 2.7 a resolution. a structural comparison between rps. viridis cytochrome c2 and the other bacterial cytochromes c2 or mitochondrial cytochromes c indicates that the overall protein foldings are very similar to each other with the exception of the surface loop and terminal region of the polypeptide chain. ho ... | 1994 | 8194599 |
| borrelia burgdorferi and escherichia coli lipopolysaccharides induce nitric oxide and interleukin-6 production in cultured rat brain cells. | borrelia burgdorferi, the spirochetal agent of lyme disease, infects the central nervous system (cns), but the factors that mediate inflammation and neurologic dysfunction are not known. sonicated b. burgdorferi stimulated in a concentration-dependent manner the production of nitric oxide (no) in glial-enriched primary cultures of neonatal rat brain cells via induction of no synthase activity. lipopolysaccharide (lps) of escherichia coli also stimulated nitrite accumulation in a concentration-de ... | 1994 | 7513330 |
| phenotypic and genotypic characterization of bradyrhizobia nodulating the leguminous tree acacia albida. | rhizobial isolates that were obtained from both surface and deep soil samples in the sahelian and sudano-guinean areas of senegal (west africa) under acacia albida trees were compared with representative strains of known rhizobial species and genera. sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) of proteins was used to determine the taxonomic positions of these organisms and the relationships between isolates obtained from the surface and isolates obtained from deep soil. ... | 1994 | 7520737 |
| refined structure of the porin from rhodopseudomonas blastica. comparison with the porin from rhodobacter capsulatus. | the structure of the membrane channel porin from the phototrophic bacteria rhodopseudomonas blastica has been refined at 1.96 a resolution yielding an r-factor of 17.6%. the final model consists of all 289 amino acid residues, 247 water molecules and three detergent molecules modelled as n-octyltetraoxyethylene. one of these detergent molecules binds together with its two symmetry-related molecules tightly in a pocket at the molecular 3-fold axis. this pocket may bind three alkyl chains of a lip ... | 1994 | 7525973 |
| expression of tfx and sensitivity to the rhizobial peptide antibiotic trifolitoxin in a taxonomically distinct group of alpha-proteobacteria including the animal pathogen brucella abortus. | three phylogenetically distinct groups within the alpha-proteobacteria which differ in trifolitoxin sensitivity are described. trifolitoxin sensitivity was found in strains of agrobacterium, brucella, mycoplana, ochrobactrum, phyllobacterium, rhodobacter, rhodopseudomonas, rhodospirillum, and rhizobium. strains of agrobacterium, brucella, phyllobacterium, rhizobium, and rhodospirillum were capable of producing trifolitoxin upon conjugal transfer of tfxabcdefg. | 1994 | 7527627 |
| a new genus of marine budding phototrophic bacteria, rhodobium gen. nov., which includes rhodobium orientis sp. nov. and rhodobium marinum comb. nov. | strains of a previously undescribed species of purple nonsulfur phototrophic bacteria were isolated from coastal seawater in japan. these new isolates were gram-negative, motile, budding rods that contained lamellar intracytoplasmic membranes and produced pink to red cultures. cell extracts of photosynthetic cultures exhibited absorption maxima at 377, 468, 500, 530, 591, 802, and 870 nm, indicating that bacterio-chlorophyll a and carotenoids of the spirilloxanthin series were present. the new i ... | 1995 | 7537056 |
| genetic and phenetic analyses of bradyrhizobium strains nodulating peanut (arachis hypogaea l.) roots. | seventeen bradyrhizobium sp. strains and one azorhizobium strain were compared on the basis of five genetic and phenetic features: (i) partial sequence analyses of the 16s rrna gene (rdna), (ii) randomly amplified dna polymorphisms (rapd) using three oligonucleotide primers, (iii) total cellular protein profiles, (iv) utilization of 21 aliphatic and 22 aromatic substrates, and (v) intrinsic resistances to seven antibiotics. partial 16s rdna analysis revealed the presence of only two rdna homolog ... | 1995 | 7538280 |
| electron transfer from the tetraheme cytochrome to the special pair in the rhodopseudomonas viridis reaction center: effect of mutations of tyrosine l162. | the structure of the photosynthetic reaction center (rc) from rhodopseudomonas viridis is known to high resolution. it contains a firmly bound tetraheme cytochrome from which electrons are donated to a special pair (p) of bacteriochlorophylls, which is photooxidized upon absorption of light. tyrosine at position 162 of the l-subunit of the reaction center (l 162 y) is a highly conserved residue positioned halfway between p and the proximal heme group (c-559) of the cytochrome. by specific mutage ... | 1995 | 7547861 |
| binding sites of quinones in photosynthetic bacterial reaction centers investigated by light-induced ftir difference spectroscopy: symmetry of the carbonyl interactions and close equivalence of the qb vibrations in rhodobacter sphaeroides and rhodopseudomonas viridis probed by isotope labeling. | the photoreduction of the secondary quinone acceptor qb in reaction centers (rcs) of the photosynthetic bacteria rhodobacter sphaeroides and rhodopseudomonas viridis has been investigated by light-induced ftir difference spectroscopy of rcs reconstituted with several isotopically labeled ubiquinones. the labels used were 18o on both carbonyls and 13c either uniformly or selectively at the 1- or the 4-position, i.e., on either one of the two carbonyls. the qb-/qb spectra of rcs reconstituted with ... | 1995 | 7547892 |
| studies on kinetics of substrate utilization of hydrogen production from wastewater with immobilized cells of photosynthetic bacteria. | the kinetic characteristics of substrate utilization by immobilized cells of rhodopseudomonas capsulata 386 and rhodopseudomonas sp. d for h2 production was investigated. the results showed that substrate utilization did not proceed simultaneously with h2 evolution, h2 producing capacity of immobilized cells with agar was higher than that of alginate immobilized cells, but the appearance of maximum h2 producing activity was later than the last one. the kinetics of substrate utilization (glucose) ... | 1995 | 7548773 |
| lipopolysaccharide and porin of roseobacter denitrificans, confirming its phylogenetic relationship to the alpha-3 subgroup of proteobacteria. | roseobacter denitrificans has rough (r)-type lipopolysaccharide, containing 2-keto-3-deoxyoctonate but no hepatoses. its lipid a has a glucosamine-containing, phosphorylated backbone. it contains the rare 3-oxotetradecanoic (3-oxomyristic) acid as the only amide-bound fatty acid and ester-bound 3-hydroxydecanoic acid, this pattern being characteristic for the alpha-3 subgroup of proteobacteria. treatment of the major outer-membrane protein (porin, apparent molecular mass 88 kda) of roseobacter d ... | 1995 | 7551064 |
| cyclic voltammetry and 1h-nmr of rhodopseudomonas palustris cytochrome c2 ph-dependent conformational states. | the ph-induced protein conformational transitions and changes in the ligation state of the heme iron in cytochrome c2 from rhodopseudomonas palustris were monitored by electrochemical and spectroscopic measurements. in the ph range 1.5-11, the e degree values (and/or the peak potentials) determined by cyclic voltammetry, the electronic spectra and the hyperfine-shifted 1h-nmr resonances of the protein are sensitive to a number of acid/base equilibria. in particular, four equilibria have been det ... | 1995 | 7556152 |
| nucleotide sequence analysis of the 23s ribosomal rna-encoding gene of bartonella bacilliformis. | we report the cloning and characterization of the 23s ribosomal rna (rrna)-encoding gene (rdna) of bartonella bacilliformis (bb). the 2821-bp gene is preceded by an 11-nucleotide (nt) inverted repeat (ir) located 81 nt upstream in the trna(ala)-23s rdna intergenic spacer. the gene is followed by an 8-nt ir, five nt downstream in the 23s-5s rdna intergenic spacer. the nt sequence of the bb 23s rdna is most similar to the 23s rdna of rhodopseudomonas palustris (rp), with 85.4% sequence identity. t ... | 1995 | 7557421 |
| heterologous expression of genes encoding bacterial light-harvesting complexes in rhodobacter sphaeroides. | one of the major problems in structural work on membrane-spanning proteins is the identification of an expression system which will allow the production of enough pure protein for structural studies; an inadequate expression system can lead, for example, to the formation of unwanted protein inclusion bodies. in the present work we report the expression of genes encoding the light-harvesting 2 (lh2) membrane-spanning proteins from a number of species of purple bacteria in mutants of rhodobacter s ... | 1995 | 7559566 |
| lipopolysaccharide stimulates the tyrosine phosphorylation of mitogen-activated protein kinases p44, p42, and p41 in vascular endothelial cells in a soluble cd14-dependent manner. role of protein tyrosine phosphorylation in lipopolysaccharide-induced stimulation of endothelial cells. | vascular endothelial cell (ec) injury or activation by lps plays a critical role in the pathogenesis of gram-negative meningitis and endotoxic shock. ec do not express membrane cd14, but respond to lps in a soluble cd14-dependent manner. the signal transduction mechanisms involved in lps-induced ec responses are largely unknown. we used bovine and human brain microvessel ec (bbmec, and hbmec) to study lps-induced protein tyrosine phosphorylation. lps rapidly induced the tyrosine phosphorylation ... | 1995 | 7561108 |
| the asymmetry of p+ in bacterial reaction centers revealed by circular dichroism spectroscopy. | the circular dichroism anisotropy, (al-ar)/a, has been measured for the far-red absorption band of p+ in reaction centers of two purple bacteria (rhodopseudomonas viridis and rhodobacter sphaerides) and one green sulfur bacterium (chlorobium tepidum). the anisotropy values for p960+ (rps. virdis) at 1310 nm was found to be +(13 +/- 2) x 10(-4). the corresponding for p870+ (rb. sphaeroides) at 1250 nm was +(11 +/- 1) x 10(-4), but for p840+ (c. tepdium) at 1160 nm the value was negative: -(27 +/- ... | 1995 | 7578138 |