title: Crystal structure of PsbQ from Synechocystis sp. PCC 6803 at 1.8 A: implications for binding and function in cyanobacterial photosystem II.
abstract: In Synechocystis sp. PCC 6803, PsbQ is associated with photosystem II (PSII) complexes with the highest activity and stability. However, this subunit is not found in PSII X-ray crystallographic structures from Thermosynechococcus elongatus or Thermosynechococcus vulcanus. We present the crystal structure of cyanobacterial PsbQ determined in the presence and absence of Zn(2+). The protein has a well-defined helical core, containing four helices arranged in an up-down-up-down fold. A conserved potential interaction site composed of a divalent metal binding site and adjacent hydrophobic pocket has been identified.
authors.affiliation: Department of Biochemistry, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Simon A
authors.initials: SA
authors.lastname: Jackson
authors.forename: Robert D
authors.initials: RD
authors.lastname: Fagerlund
authors.forename: Sigurd M
authors.initials: SM
authors.lastname: Wilbanks
authors.forename: Julian J
authors.initials: JJ
authors.lastname: Eaton-Rye
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D000458:Cyanobacteria; D045332:Photosystem II Protein Complex / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D021122:Protein Subunits / Q000737:chemistry; D046939:Synechocystis / Q000737:chemistry*; D015032:Zinc
chemical_list: D001426:Bacterial Proteins; D045332:Photosystem II Protein Complex; D021122:Protein Subunits; D015032:Zinc