Cyanobacterial photosystem II at 2.9-A resolution and the role of quinones, lipids, channels and chlorideGuskov, A., Kern, J., Gabdulkhakov, A., Broser, M., Zouni, A. & Saenger, W., Mar-2009, In : Nature Structural & Molecular Biology. 16, 3, p. 334-342 9 p.
Research output: Contribution to journal › Article › Academic › peer-review
Photosystem II (PSII) is a large homodimeric protein-cofactor complex located in the photosynthetic thylakoid membrane that acts as light-driven water:plastoquinone oxidoreductase. The crystal structure of PSII from Thermosynechococcus elongatus at 2.9-A resolution allowed the unambiguous assignment of all 20 protein subunits and complete modeling of all 35 chlorophyll a molecules and 12 carotenoid molecules, 25 integral lipids and 1 chloride ion per monomer. The presence of a third plastoquinone Q(C) and a second plastoquinone-transfer channel, which were not observed before, suggests mechanisms for plastoquinol-plastoquinone exchange, and we calculated other possible water or dioxygen and proton channels. Putative oxygen positions obtained from a Xenon derivative indicate a role for lipids in oxygen diffusion to the cytoplasmic side of PSII. The chloride position suggests a role in proton-transfer reactions because it is bound through a putative water molecule to the Mn(4)Ca cluster at a distance of 6.5 A and is close to two possible proton channels.
|Number of pages||9|
|Journal||Nature Structural & Molecular Biology|
|Publication status||Published - Mar-2009|
- Bacterial Proteins, Binding Sites, Chlorides, Crystallography, X-Ray, Cyanobacteria, Lipids, Models, Molecular, Photosystem II Protein Complex, Protein Structure, Quaternary, Protein Subunits, Quinones