| specific ca2+-binding motif in the lh1 complex from photosynthetic bacterium thermochromatium tepidum as revealed by optical spectroscopy and structural modeling. | native and ca(2+)-depleted light-harvesting-reaction center core complexes (lh1-rc) from the photosynthetic bacterium thermochromatium (tch.) tepidum exhibit maximal lh1-q(y) absorption at 915 and 889 nm, respectively. to understand the structural origins of the spectral variation, we performed spectroscopic and structure modeling investigations. for the 889 nm form of lh1-rc, bacteriochlorophyll a (bchl a) in the native form was found by means of near-infrared fourier-transform raman spectrosco ... | 2009 | 19226412 |
| purification and characterization of the polypeptides of core light-harvesting complexes from purple sulfur bacteria. | although the polypeptides of core light-harvesting complexes (lh1) from many purple nonsulfur bacteria have been well characterized, little information is available on the polypeptides of lh1 from purple sulfur photosynthetic organisms. we present here the results of isolation and characterization of lh1 polypeptides from two purple sulfur bacteria, thermochromatium (tch.) tepidum and allochromatium (ach.) vinosum. native lh1 complexes were extracted and purified in a reaction center (rc)-associ ... | 2003 | 16245044 |
| n-terminal methylation of the core light-harvesting complex in purple photosynthetic bacteria. | several core light-harvesting complexes from both sulfur and non-sulfur purple photosynthetic bacteria have been identified to be methylated at the n-terminal alpha-amino group of beta-polypeptides by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and nuclear magnetic resonance. monomethylation has been confirmed for the n-terminal alanine residues of the beta-polypeptides from rhodospirillum rubrum, thermochromatium tepidum and chromatium vinosum, but not for ... | 2002 | 12023037 |
| structure of the h subunit of the photosynthetic reaction center from the thermophilic purple sulfur bacterium, thermochromatium tepidum implications for the specific binding of the lipid molecule to the membrane protein complex. | the photosynthetic reaction center (rc) is a transmembrane protein complex that catalyzes light-driven electron transport across the photosynthetic membrane. the complete amino-acid sequence of the h subunit of the rc from a thermophilic purple sulfur bacterium, thermochromatium tepidum, has been determined for the first time among purple sulfur bacteria. the h subunit consists of 259 amino acids and has a molecular mass of 28 187. the deduced amino-acid sequences of this h subunit showed a sign ... | 2001 | 11322886 |
| gene sequencing and characterization of the light-harvesting complex 2 from thermophilic purple sulfur bacterium thermochromatium tepidum. | in this study, gene sequences coding for the light-harvesting (lh) 2 polypeptides from a thermophilic purple sulfur bacterium thermochromatium tepidum are reported and characterization of the lh2 complex is described. three sets of pucba genes have been identified, and the gene products have been analyzed by electrophoresis and reversed-phase chromatography. the result shows that all of the genes are expressed but the distribution of the expression is not uniform. the gene products undergo post- ... | 2011 | 21594712 |
| thiophaeococcus mangrovi gen. nov., sp. nov., a photosynthetic, marine gammaproteobacterium isolated from the bhitarkanika mangrove forest of india. | a coccoid, phototrophic purple sulfur bacterium was isolated in pure culture from a mud sample collected from brackish water in the bhitarkanika mangrove forest of orissa, india, in a medium containing 2 % nacl (w/v). this bacterium, strain ja304(t), was gram-negative and had a requirement for nacl. intracellular photosynthetic membranes were of the vesicular type. the colour of the phototrophically grown culture was saddle-brown. bacteriochlorophyll a and the carotenoid lycopene were present as ... | 2008 | 18984710 |
| purification, characterization and crystallization of the core complex from thermophilic purple sulfur bacterium thermochromatium tepidum. | a light-harvesting-reaction center (lh1-rc) core complex has been highly purified from a thermophilic purple sulfur bacterium, thermochromatium tepidum. the bacteriochlorophyll (bchl) a molecules in the lh1 exhibit a q(y) transition at 914 nm, more than 25 nm red-shift from those of its mesophilic counterparts. the lh1-rc complex was isolated in a monomeric form as confirmed by sucrose density gradient centrifugation, blue native page and size-exclusion chromatography. four subunits (l, m, h and ... | 2007 | 17658456 |
| calcium ions are required for the enhanced thermal stability of the light-harvesting-reaction center core complex from thermophilic purple sulfur bacterium thermochromatium tepidum. | thermochromatium tepidum is a thermophilic purple sulfur photosynthetic bacterium collected from the mammoth hot springs, yellowstone national park. a previous study showed that the light-harvesting-reaction center core complex (lh1-rc) purified from this bacterium is highly stable at room temperature (suzuki, h., hirano, y., kimura, y., takaichi, s., kobayashi, m., miki, k., and wang, z.-y. (2007) biochim. biophys. acta 1767, 1057-1063). in this work, we demonstrate that thermal stability of th ... | 2009 | 18977753 |
| on the role of basic residues in adapting the reaction centre-lh1 complex for growth at elevated temperatures in purple bacteria. | the purple photosynthetic bacterium thermochromatium tepidum is a moderate thermophile, with a growth optimum of 48-50 degrees c. the x-ray crystal structure of the reaction centre from this organism has been determined, and compared with that from mesophilic bacteria such as blastochloris viridis and rhodobacter sphaeroides (nogi t et al. (2000) proc natl acad sci usa 97: 13561-13566). structural features that could contribute to the enhanced thermal stability of the thermochromatium tepidum re ... | 2005 | 16172928 |
| calcium ions are involved in the unusual red shift of the light-harvesting 1 qy transition of the core complex in thermophilic purple sulfur bacterium thermochromatium tepidum. | thermophilic purple sulfur bacterium, thermochromatium tepidum, can grow at temperatures up to 58 degrees c and exhibits an unusual qy absorption at 915 nm for the core light-harvesting complex (lh1), an approximately 35-nm red shift from those of its mesophilic counterparts. we demonstrate in this study, using a highly purified lh1-reaction center complex, that the lh1 qy transition is strongly dependent on metal cations and ca2+ is involved in the unusual red shift. removal of the ca2+ resulte ... | 2008 | 18332135 |
| function of membrane protein in silica nanopores: incorporation of photosynthetic light-harvesting protein lh2 into fsm. | a high amount of functional membrane protein complex was introduced into a folded-sheet silica mesoporous material (fsm) that has nanometer-size pores of honeycomb-like hexagonal cylindrical structure inside. the photosynthetic light-harvesting complex lh2, which is a typical membrane protein, has a cylindrical structure of 7.3 nm diameter and contains 27 bacteriochlorophyll a and nine carotenoid molecules. the complex captures light energy in the anoxygenic thermophilic purple photosynthetic ba ... | 2006 | 16471652 |
| excitation dynamics of two spectral forms of the core complexes from photosynthetic bacterium thermochromatium tepidum. | the intact core antenna-reaction center (lh1-rc) core complex of thermophilic photosynthetic bacterium thermochromatium (tch.) tepidum is peculiar in its long-wavelength lh1-q(y) absorption (915 nm). we have attempted comparative studies on the excitation dynamics of bacteriochlorophyll (bchl) and carotenoid (car) between the intact core complex and the edta-treated one with the q(y) absorption at 889 nm. for both spectral forms, the overall car-to-bchl excitation energy transfer efficiency is d ... | 2008 | 18502793 |
| structural and functional studies on the tetraheme cytochrome subunit and its electron donor proteins: the possible docking mechanisms during the electron transfer reaction. | the photosynthetic reaction centers (rcs) classified as the group ii possess a peripheral cytochrome (cyt) subunit, which serves as the electron mediator to the special-pair. in the cycle of the photosynthetic electron transfer reactions, the cyt subunit accepts electrons from soluble electron carrier proteins, and re-reduces the photo-oxidized special-pair of the bacteriochlorophyll. physiologically, high-potential cytochromes such as the cytochrome c2 and the high-potential iron-sulfur protein ... | 2005 | 15977061 |
| thermochromatium tepidum photoactive yellow protein/bacteriophytochrome/diguanylate cyclase: characterization of the pyp domain. | the purple phototrophic bacterium, thermochromatium tepidum, contains a gene for a chimeric photoactive yellow protein/bacteriophytochrome/diguanylate cyclase (ppd). we produced the tc. tepidum pyp domain (tt pyp) in escherichia coli, and found that it has a wavelength maximum at 358 nm due to a leu46 substitution of the color-tuning glu46 found in the prototypic halorhodospira halophila pyp (hh pyp). however, the 358 nm dark-adapted state is in a ph-dependent equilibrium with a yellow species a ... | 2005 | 15779902 |
| reconstitution of photosynthetic reaction centers and core antenna-reaction center complexes in liposomes and their thermal stability. | photosynthetic reaction centers (rcs) and their core light-harvesting complexes (lh1-rcs), purified from a thermophile, thermochromatium (t.) tepidum, and a mesophile, allochromatium (a.) vinosum, were reconstituted into liposomes. the rc and the lh1-rc in the reconstituted liposomes were found intact from the absorption spectra at about 4 and 40 degrees c respectively. the thermal stability of the rcs of t. tepidum in the liposome was dependent on whether they were surrounded directly by lipids ... | 2005 | 15973044 |
| photoactive yellow protein, bacteriophytochrome, and sensory rhodopsin in purple phototrophic bacteria. | the purple photosynthetic bacteria contain a large variety of sensory and regulatory proteins, and those responding to light are among the most interesting. these currently include bacteriophytochrome (bph), sensory rhodopsin (sr), and photoactive yellow protein (pyp), which all appear to function as light sensors. we herein interpret new findings within the context of current knowledge. for greater detail, the reader is referred to comprehensive reviews on these topics. of the three proteins, o ... | 2004 | 15170480 |
| crystal structures of photosynthetic reaction center and high-potential iron-sulfur protein from thermochromatium tepidum: thermostability and electron transfer. | the reaction center (rc) of photosynthetic bacteria is a membrane protein complex that promotes a light-induced charge separation during the primary process of photosynthesis. in the photosynthetic electron transfer chain, the soluble electron carrier proteins transport electrons to the rc and reduce the photo-oxidized special-pair of bacteriochlorophyll. the high-potential iron-sulfur protein (hipip) is known to serve as an electron donor to the rc in some species, where the c-type cytochrome s ... | 2000 | 11095707 |
| structural basis of bacterial photosynthetic reaction centers. | the photosynthetic reaction center (rc) is the first membrane protein whose three-dimensional structure was revealed at the atomic level by x-ray crystallograph more than fifteen years ago. structural information about rc made a great contribution to the understanding of the reaction mechanism of the complicated membrane protein complex. high-resolution structures of rcs from three photosynthetic bacteria are now available, namely, those from two mesophilic purple non-sulfur bacteria, blastochlo ... | 2001 | 11530006 |
| ultrahigh-resolution structure of high-potential iron-sulfur protein from thermochromatium tepidum. | crystals of the high-potential iron-sulfur protein (hipip) from thermochromatium tepidum diffract x-rays to 0.80 a using synchrotron radiation at 100 k. the crystal structure of this hipip was refined at this ultrahigh resolution with anisotropic temperature factors for all atoms to conventional crystallographic r factors of 0.092 and 0.101 for f(o) > 4sigma(f(o)) and all reflections, respectively. the present structure provides a more precise picture than the previous 1.5 a structure and allows ... | 2002 | 12077426 |
| puf operon sequences and inferred structures of light-harvesting complexes of three closely related chromatiaceae exhibiting different absorption characteristics. | whole cells of the purple sulfur bacterium strain 970 exhibit an unusual absorption peak at 963 nm. its closest relatives, thiorhodovibrio (trv.) winogradskyi dsm6702(t) and strain 06511 display a bacteriochlorophyll (bchl) a absorption peak at 867 nm that is characteristic for most light-harvesting complexes 1 (lhc1) of proteobacteria. the puf operons encoding the lhc1 and reaction center proteins were amplified, cloned, and sequenced, and for the trv. winogradskyi, strains show the common pufb ... | 2011 | 21805371 |
| crystallization and preliminary crystallographic analysis of the high-potential iron-sulfur protein from thermochromatium tepidum. | the high-potential iron-sulfur protein (hipip) is an electron carrier between the photosynthetic reaction centre and the cytochrome bc(1) complex in the electron-transfer chain of photosynthesis. the purified hipip from thermochromatium tepidum (formerly chromatium tepidum) was crystallized in a solution of 1.4 m ammonium sulfate and 0.1 m sodium citrate ph 3.5. the crystals diffract x-rays beyond 1.4 a resolution and belong to the orthorhombic space group p2(1)2(1)2(1), with unit-cell parameter ... | 2000 | 10771441 |
| phylogenetic relationships among the chromatiaceae, their taxonomic reclassification and description of the new genera allochromatium, halochromatium, isochromatium, marichromatium, thiococcus, thiohalocapsa and thermochromatium. | sequences of the 16s rdna from all available type strains of chromatium species have been determined and were compared to those of other chromatiaceae, a few selected ectothiorhodospiraceae and escherichia coli. the clear separation of ectothiorhodospiraceae and chromatiaceae is confirmed. most significantly the sequence comparison revealed a genetic divergence between chromatium species originated from freshwater sources and those of truly marine and halophilic nature. major phylogenetic branch ... | 1998 | 9828415 |
| ultrafast time-resolved spectroscopy of the light-harvesting complex 2 (lh2) from the photosynthetic bacterium thermochromatium tepidum. | the light-harvesting complex 2 from the thermophilic purple bacterium thermochromatium tepidum was purified and studied by steady-state absorption and fluorescence, sub-nanosecond-time-resolved fluorescence and femtosecond time-resolved transient absorption spectroscopy. the measurements were performed at room temperature and at 10 k. the combination of both ultrafast and steady-state optical spectroscopy methods at ambient and cryogenic temperatures allowed the detailed study of carotenoid (car ... | 2011 | 21984346 |
| triplet excited state spectra and dynamics of carotenoids from the thermophilic purple photosynthetic bacterium thermochromatium tepidum. | light-harvesting complex 2 from the anoxygenic phototrophic purple bacterium thermochromatium tepidum was purified and studied by steady-state absorption, fluorescence and flash photolysis spectroscopy. steady-state absorption and fluorescence measurements show that carotenoids play a negligible role as supportive energy donors and transfer excitation to bacteriochlorophyll-a with low energy transfer efficiency of ~30%. hplc analysis determined that the dominant carotenoids in the complex are rh ... | 2011 | 21229315 |
| examination of the putative ca2+-binding site in the light-harvesting complex 1 of thermophilic purple sulfur bacterium thermochromatium tepidum. | the core light-harvesting complex (lh1) of purple sulfur photosynthetic bacterium thermochromatium tepidum exhibits an unusual absorption maximum at 915 nm for the q (y) transition, and is highly stable when copurified with reaction center (rc) in a lh1-rc complex form. in previous studies, we demonstrated that the calcium ions are involved in both the large red shift and the enhanced thermal stability, and possible ca(2+)-binding sites were proposed. in this study, we further examine the putati ... | 2010 | 20886371 |
| effects of aggregation on the excitation dynamics of lh2 from thermochromatium tepidum in aqueous phase and in chromatophores. | we carried out femtosecond magic-angle and polarized pump-probe spectroscopies for the light-harvesting complex 2 (lh2) from thermochromatium (tch.) tepidum in aqueous phase and in chromatophores. to examine the effects of lh2 aggregation on the dynamics of excitation energy transfer, dominant monodispersed and aggregated lh2s were prepared by controlling the surfactant concentrations. the aqueous preparations solubilized with different concentrations of n-dodecyl-β-d-maltoside (ddm) show simila ... | 2011 | 21630650 |
| a spectroscopic variant of the light-harvesting 1 core complex from the thermophilic purple sulfur bacterium thermochromatium tepidum. | thermochromatium tepidum is a purple sulfur photosynthetic bacterium, and its light-harvesting 1 reaction center (lh1rc) complexes exhibit an unusual lh1 q(y) absorption at 915 nm (b915) and possess enhanced thermal stability. these unique properties are closely related to an inorganic cofactor, ca(2+). here, we report a spectroscopic variant of lh1rc complexes from tch. tepidum cells in which ca(2+) was biosynthetically replaced with sr(2+). the photosynthetic growth of wild-type cells cannot b ... | 2011 | 21462972 |
| photosynthetic electron transfer from reaction center pigment-protein complex in silica nanopores. | a photosynthetic reaction center (rc) pigment-protein complex purified from a thermophilic purple photosynthetic bacterium, thermochromatium tepidum, was adsorbed to a folded-sheet silica mesoporous material (fsm). the rc has a molecular structure with a 7.0 x 5.0 x 13 nm diameter. the amount of rc adsorbed to the fsm compound with an average internal pore diameter of 7.9 nm (fsm(7.9)) was high at 0.29 grc/gfsm, while that to the fsm(2.7) (2.7 nm diameter) was low at 0.02 grc/gfsm, suggesting th ... | 2010 | 20695584 |
| detailed assessment of x-ray induced structural perturbation in a crystalline state protein. | the positions of hydrogen atoms significantly define protein functions. however, such information from protein crystals is easily disturbed by x-rays. the damage can not be prevented completely even in the data collection at cryogenic temperatures. therefore, the influence of x-rays should be precisely estimated in order to derive meaningful information from the crystallographic results. diffraction data from a single crystal of the high-potential iron-sulfur protein (hipip) from thermochromatiu ... | 2010 | 19782139 |