title: New tetragonal form of reaction centers from Rhodobacter sphaeroides and the involvement of a manganese ion at a crystal contact point.
abstract: Crystals have been obtained of wild-type reaction centers from Rhodobacter sphaeroides using manganese chloride as a precipitating agent. The crystals belong to the tetragonal space group P4(2)22, with unit-cell parameters a = b = 207.8, c = 107.5 A. The crystal structure has been determined to a resolution limit of 4.6 A using a previously determined structure of the reaction center as a molecular-replacement model. The calculated electron-density maps show the presence of a manganese ion at one of the crystal contact points bridging two symmetry-related histidine residues, suggesting that the metal plays a key role in facilitating the crystallization of the protein in this form.
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: G
authors.initials: G
authors.lastname: Uyeda
authors.forename: A
authors.initials: A
authors.lastname: Cámara-Artigas
authors.forename: J C
authors.initials: JC
authors.lastname: Williams
authors.forename: J P
authors.initials: JP
authors.lastname: Allen
mesh_terms: D003460:Crystallization; D004058:Diffusion; D008345:Manganese / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D012242:Rhodobacter sphaeroides / Q000737:chemistry*
chemical_list: D008345:Manganese