1izl
From Proteopedia
|
Crystal Structure of Photosystem II
Overview
Photosystem II (PSII) is a multisubunit membrane protein complex, performing light-induced electron transfer and water-splitting reactions, leading to the formation of molecular oxygen. The first crystal structure, of PSII from a thermophilic cyanobacterium Thermosynechococcus elongatus, was reported recently [Zouni, A., Witt, H. T., Kern, J., Fromme, P., Krauss, N., Saenger, W. & Orth, P. (2001) Nature 409, 739-743)] at 3.8-A, resolution. To analyze the PSII structure in more detail, we have obtained, the crystal structure of PSII from another thermophilic cyanobacterium, Thermosynechococcus vulcanus, at 3.7-A resolution. The present structure, was built on the basis of the sequences of PSII large subunits D1, D2, CP47, and CP43; extrinsic 33- and 12-kDa proteins and cytochrome c550; and, several low molecular mass subunits, among which the structure of the, 12-kDa protein was not reported previously. This yielded much information, concerning the molecular interactions within this large protein complex., We also show the arrangement of chlorophylls and cofactors, including two, beta-carotenes recently identified in a region close to the reaction, center, which provided important clues to the secondary electron transfer, pathways around the reaction center. Furthermore, possible ligands for the, Mn-cluster were determined. In particular, the C terminus of D1, polypeptide was shown to be connected to the Mn cluster directly. The, structural information obtained here provides important insights into the, mechanism of PSII reactions.
About this Structure
1IZL is a Protein complex structure of sequences from Bacteria and Thermosynechococcus vulcanus with MN, FE, CLA, PHO, HEM, PLA and BCR as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structure of oxygen-evolving photosystem II from Thermosynechococcus vulcanus at 3.7-A resolution., Kamiya N, Shen JR, Proc Natl Acad Sci U S A. 2003 Jan 7;100(1):98-103. Epub 2002 Dec 23. PMID:12518057
Page seeded by OCA on Tue Nov 20 17:48:14 2007
