Search results for "Rhodobacter"
showing 6 items of 36 documents
Quantum Chemical Simulations of Excited-State Absorption Spectra of Photosynthetic Bacterial Reaction Center and Antenna Complexes
2011
The semiempirical ZINDO/S CIS configuration interaction method has been used to study the ground- and excited-state absorption spectra of wild type and heterodimer M202HL reaction centers from purple bacterium Rhodobacter sphaeroides as well as of peripheral LH2 and LH3 light harvesting complexes from purple bacterium Rhodopseudomonas acidophila. The calculations well reproduce the experimentally observed excited-state absorption spectra between 1000 and 17,000 cm(-1), despite the necessarily limited number of chromophores and protein subunits involved in the calculations. The electron density analysis reveals that the charge transfer between adjacent chromophores dominates the excited-stat…
Evidence for a symbiosis between bacteria of the genus Rhodobacter and the marine sponge Halichondria panicea : harbor also for putatively toxic bac…
1998
Halichondria panicea (Pallas) is a marine sponge, abundantly occurring in the Adriatic sea, North sea and Baltic sea. It was the aim of the present study to investigate if this sponge species harbors bacteria. Cross sections through H. panicea were taken and inspected by electron microscopy. The micrographs showed that this sponge species is colonized by bacteria in its mesohyl compartment. To identify the bacteria, polymerase chain reaction (PCR) analysis of the 16S rRNA gene segment, typical for bacteria, was performed. DNA was isolated from sponge material that had been collected near Rovinj (Adriatic Sea), Helgoland (North Sea), and Kiel (Baltic Sea) and was amplified with bacterial pri…
Taxogenómica en Rhodobacteraceae
2019
La familia Rhodobacteraceae es una de las principales subdivisiones de la clase Alphaproteobacteria, que comprende en ocasiones más del 25% de la comunidad bacteriana total de las aguas superficiales oceánicas. La mayoría de las especies pertenecientes a esta familia son de origen marino y presentan una elevada diversidad fenotípica. El objetivo principal de esta Tesis Doctoral ha sido ampliar nuestro conocimiento sobre los miembros de esta familia mediante el estudio de sus genomas y esclarecer las relaciones taxonómicas entre los mismos utilizando como base el análisis filogenómico de dichos genomas, así como los índices de semejanza genómica apropiados a tal efecto. Para ello se ha proce…
Thalassobius mediterraneus gen. nov., sp. nov., and reclassification of Ruegeria gelatinovorans as Thalassobius gelatinovorus comb. nov.
2005
A Gram-negative, slightly halophilic, non-pigmented, strictly aerobic, chemo-organotrophic bacterium was isolated from sea water off the western Mediterranean coast near Valencia (Spain). This strain was able to grow on several organic acids and amino acids added to a minimal medium as carbon sources, but used few carbohydrates or yielded slight growth when sugars were used. Phylogenetic analysis based on an almost complete 16S rRNA gene sequence revealed that strain XSM19T was a member of the Roseobacter group within the ‘Alphaproteobacteria’, with its closest phylogenetic neighbour being Ruegeria gelatinovorans (97·6 % sequence similarity). Following a polyphasic approach, it was conclude…
Carotenoids and the Assembly of Light-harvesting Complexes
2006
Carotenoids are constitutive components of all light-harvesting complexes in plants and many such complexes in bacteria. In the crystal structures of several light-harvesting complexes, carotenoids are seen to span the lipid bilayer and connect components of the complex on both membrane surfaces and/or to mediate the interaction of transmembrane protein helices. This important stabilizing function suggests that these pigments are also actively involved in the assembly of light-harvesting complexes. Verification of this notion appears too ambitious a goal at present, as the question of how the pigment-protein complexes of the photosynthetic apparatus are assembled is still open. However, inf…
Structural Origin of Metal Specificity in Isatin Hydrolase from Labrenzia aggregata Investigated by Computer Simulations.
2017
We performed quantum-chemical calculations, ab initio molecular dynamics, hybrid quantum mechanics/molecular mechanics (QM/MM) and enhanced sampling metadynamics simulations to investigate the origin of metal specificity in isatin hydrolase from Labrenzia aggregata. The peculiar octahedral binding geometry of the Mn2+ ion in the Michaelis complex includes both the isatin substrate and the catalytic water within the first coordination shell of the cation. Our calculations show that the same arrangement of the ligands cannot be efficiently achieved in the presence of other small divalent metal cations such as Zn2+ or Cu2+ . On the contrary, bulkier alkaline-earth cations such as Mg2+ , which …