title: Recent progress in the crystallographic studies of photosystem II.
abstract: The photosynthetic oxygen-evolving photosystem II (PSII) is the only known biochemical system that is able to oxidize water molecules and thereby generates almost all oxygen in the Earth's atmosphere. The elucidation of the structural and mechanistic aspects of PSII keeps scientists all over the world engaged since several decades. In this Minireview, we outline the progress in understanding PSII based on the most recent crystal structure at 2.9 A resolution. A likely position of the chloride ion, which is known to be required for the fast turnover of water oxidation, could be determined in native PSII and is compared with work on bromide and iodide substituted PSII. Moreover, eleven new integral lipids could be assigned, emphasizing the importance of lipids for the perfect function of PSII. A third plastoquinone molecule (Q(C)) and a second quinone transfer channel are revealed, making it possible to consider different mechanisms for the exchange of plastoquinone/plastoquinol molecules. In addition, possible transport channels for water, dioxygen and protons are identified.
authors.affiliation: Institute of Chemistry and Biochemistry/Crystallography, Freie Universität Berlin, Takustrasse 6, D-14195 Berlin, Germany.
authors.forename: Albert
authors.initials: A
authors.lastname: Guskov
authors.forename: Azat
authors.initials: A
authors.lastname: Gabdulkhakov
authors.forename: Matthias
authors.initials: M
authors.lastname: Broser
authors.forename: Carina
authors.initials: C
authors.lastname: Glöckner
authors.forename: Julia
authors.initials: J
authors.lastname: Hellmich
authors.forename: Jan
authors.initials: J
authors.lastname: Kern
authors.forename: Joachim
authors.initials: J
authors.lastname: Frank
authors.forename: Frank
authors.initials: F
authors.lastname: Müh
authors.forename: Wolfram
authors.initials: W
authors.lastname: Saenger
authors.forename: Athina
authors.initials: A
authors.lastname: Zouni
mesh_terms: D001665:Binding Sites; D018360:Crystallography, X-Ray; D000458:Cyanobacteria / Q000201:enzymology; D008055:Lipids / Q000737:chemistry; D010084:Oxidation-Reduction; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000378:metabolism; D010971:Plastoquinone / Q000737:chemistry; D011487:Protein Conformation; D014867:Water / Q000737:chemistry
chemical_list: D008055:Lipids; D045332:Photosystem II Protein Complex; D014867:Water; D010971:Plastoquinone