title: Crystal structure at 1.5Å resolution of the PsbV2 cytochrome from the cyanobacterium Thermosynechococcus elongatus.
abstract: PsbV2 is a c-type cytochrome present in a very low abundance in the thermophilic cyanobacterium Thermosynechococcus elongatus. We purified this cytochrome and solved its crystal structure at a resolution of 1.5Å. The protein existed as a dimer in the crystal, and has an overall structure similar to other c-type cytochromes like Cytc6 and Cytc550, for example. However, the 5th and 6th heme iron axial ligands were found to be His51 and Cys101, respectively, in contrast to the more common bis-His or His/Met ligands found in most cytochromes. Although a few other c-type cytochromes were suggested to have this axial coordination, this is the first crystal structure reported for a c-type heme with this unusual His/Cys axial coordination. Previous spectroscopic characterizations of PsbV2 are discussed in relation to its structural properties.
authors.affiliation: Laboratory of Biomacromolecular Structure, Graduate School of Natural Science and Technology, Department of Biology, Faculty of Science, Okayama University, 1-1, Naka 3-chome, Tsushima, Kita-ku, Okayama 700-8530, Japan.
authors.forename: Michihiro
authors.initials: M
authors.lastname: Suga
authors.forename: Thanh-Lan
authors.initials: TL
authors.lastname: Lai
authors.forename: Miwa
authors.initials: M
authors.lastname: Sugiura
authors.forename: Jian-Ren
authors.initials: JR
authors.lastname: Shen
authors.forename: Alain
authors.initials: A
authors.lastname: Boussac
mesh_terms: D003460:Crystallization; D000458:Cyanobacteria / Q000201:enzymology*; D003580:Cytochromes / Q000737:chemistry*; D019281:Dimerization; D008958:Models, Molecular; D011487:Protein Conformation
chemical_list: D003580:Cytochromes
keywords: Crystal structure; Cyanobacteria; Cytochrome c; His/Cys coordination; PsbV2