title: Crystal structure of the PsbP protein of photosystem II from Nicotiana tabacum.
abstract: PsbP is a membrane-extrinsic subunit of the water-oxidizing complex photosystem II (PS II). The evolutionary origin of PsbP has long been a mystery because it specifically exists in higher plants and green algae but not in cyanobacteria. We report here the crystal structure of PsbP from Nicotiana tabacum at a resolution of 1.6 A. Its structure is mainly composed of beta-sheet, and is not similar to any structures in cyanobacterial PS II. However, the electrostatic surface potential of PsbP is similar to that of cyanobacterial PsbV (cyt c(550)), which has a function similar to PsbP. A structural homology search with the DALI algorithm indicated that the folding of PsbP is very similar to that of Mog1p, a regulatory protein for the nuclear transport of Ran GTPase. The structure of PsbP provides insight into its novel function in GTP-regulated metabolism in PS II.
authors.affiliation: Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Ifuku
authors.forename: Toru
authors.initials: T
authors.lastname: Nakatsu
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kato
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Sato
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D000458:Cyanobacteria / Q000737:chemistry; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry; D045332:Photosystem II Protein Complex / Q000737:chemistry*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000737:chemistry; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D055672:Static Electricity; D014026:Nicotiana / Q000737:chemistry*; D020931:ran GTP-Binding Protein / Q000737:chemistry
chemical_list: D009687:Nuclear Proteins; D045332:Photosystem II Protein Complex; D029701:Saccharomyces cerevisiae Proteins; C410219:MOG1 protein, S cerevisiase; D020931:ran GTP-Binding Protein