title: Structure of Psb27 in solution: implications for transient binding to photosystem II during biogenesis and repair.
abstract: Psb27 is a membrane-extrinsic subunit of photosystem II (PSII) where it is involved in the assembly and maintenance of this large membrane protein complex that catalyzes one of the key reactions in the biosphere, the light-induced oxidation of water. Here, we report for the first time the structure of Psb27 that was not observed in the previous crystal structures of PSII due to its transient binding mode. The Psb27 structure shows that the core of the protein is a right-handed four-helix bundle with an up-down-up-down topology. The electrostatic potential of the surface generated by the amphipathic helices shows a dipolar distribution which fits perfectly to the major PsbO binding site on the PSII complex. Moreover, the presented docking model could explain the function of Psb27, which prevents the binding of PsbO to facilitate the assembly of the Mn(4)Ca cluster.
authors.affiliation: Department of Plant Biochemistry and Biomolecular NMR, Ruhr-University Bochum, D-44780 Bochum, Germany.
authors.forename: Kai U
authors.initials: KU
authors.lastname: Cormann
authors.forename: Jan-Amadé
authors.initials: JA
authors.lastname: Bangert
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ikeuchi
authors.forename: Matthias
authors.initials: M
authors.lastname: Rögner
authors.forename: Raphael
authors.initials: R
authors.lastname: Stoll
authors.forename: Marc M
authors.initials: MM
authors.lastname: Nowaczyk
mesh_terms: D017360:Arabidopsis / Q000737:chemistry / Q000382:microbiology / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D018360:Crystallography, X-Ray; D008027:Light / Q000009:adverse effects; D045332:Photosystem II Protein Complex / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism* / Q000528:radiation effects; D011485:Protein Binding / Q000528:radiation effects; D017433:Protein Structure, Secondary; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D012996:Solutions; D055672:Static Electricity; D013499:Surface Properties; D046939:Synechocystis / Q000737:chemistry* / Q000378:metabolism* / Q000528:radiation effects
chemical_list: D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D045332:Photosystem II Protein Complex; D021122:Protein Subunits; D012996:Solutions; C054266:photosystem II manganese-stabilizing protein