title: Structure of the membrane-bound protein photosynthetic reaction center from Rhodobacter sphaeroides.
abstract: The structure of the photosynthetic reaction center (RC) from Rhodobacter sphaeroides was determined at 3.1-A resolution by the molecular replacement method, using the Rhodopseudomonas viridis RC as the search structure. Atomic coordinates were refined with the difference Fourier method and restrained least-squares refinement techniques to a current R factor of 22%. The tertiary structure of the RC complex is stabilized by hydrophobic interactions between the L and M chains, by interactions of the pigments with each other and with the L and M chains, by residues from the L and M chains that coordinate to the Fe2+, by salt bridges that are formed between the L and M chains and the H chain, and possibly by electrostatic forces between the ends of helices. The conserved residues at the N-termini of the L and M chains were identified as recognition sites for the H chain.
authors.affiliation: Biological and Medical Research Division, Argonne National Laboratory, Illinois 60439.
authors.forename: C H
authors.initials: CH
authors.lastname: Chang
authors.forename: O
authors.initials: O
authors.lastname: el-Kabbani
authors.forename: D
authors.initials: D
authors.lastname: Tiede
authors.forename: J
authors.initials: J
authors.lastname: Norris
authors.forename: M
authors.initials: M
authors.lastname: Schiffer
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D003198:Computer Simulation; D004563:Electrochemistry; D005583:Fourier Analysis; D008051:Lipid Bilayers / Q000737:chemistry; D008958:Models, Molecular; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D011487:Protein Conformation; D012242:Rhodobacter sphaeroides / Q000032:analysis*; D012492:Salts / Q000737:chemistry; D012995:Solubility; D013237:Stereoisomerism; D014961:X-Ray Diffraction
chemical_list: D000596:Amino Acids; D008051:Lipid Bilayers; D045322:Photosynthetic Reaction Center Complex Proteins; D012492:Salts