Recent progress in the crystallographic studies of photosystem II.
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.
Guskov
Albert
A
Institute of Chemistry and Biochemistry/Crystallography, Freie Universität Berlin, Takustrasse 6, D-14195 Berlin, Germany.
Gabdulkhakov
Azat
A
Broser
Matthias
M
Glöckner
Carina
C
Hellmich
Julia
J
Kern
Jan
J
Frank
Joachim
J
Müh
Frank
F
Saenger
Wolfram
W
Zouni
Athina
A
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
D008055:Lipids; D045332:Photosystem II Protein Complex; D014867:Water; D010971:Plastoquinone