3kzi
Crystal Structure of Monomeric Form of Cyanobacterial Photosystem IICrystal Structure of Monomeric Form of Cyanobacterial Photosystem II
Structural highlights
Function[PSBF_THEEB] This b-type cytochrome is tightly associated with the reaction center of photosystem II and possibly is part of the water-oxidation complex (By similarity).[HAMAP-Rule:MF_00643] [PSBL_THEEB] Required for PSII activity (By similarity). [PSBJ_THEEB] This protein is a component of the reaction center of photosystem II (By similarity). [YCF12_THEEB] A core subunit of photosystem II (PSII).[HAMAP-Rule:MF_01329] [PSBU_THEEB] Stabilizes the structure of photosystem II oxygen-evolving complex (OEC), the ion environment of oxygen evolution and protects the OEC against heat-induced inactivation (By similarity).[HAMAP-Rule:MF_00589] [PSBT_THEEB] Seems to play a role in the dimerization of PSII.[1] [PSBI_THEEB] This protein is a component of the reaction center of photosystem II.[HAMAP-Rule:MF_01316] [PSBA1_THEEB] This is one of the two reaction center proteins of photosystem II. [PSBX_THEEB] Involved in the binding and/or turnover of quinones at the Q(B) site of Photosystem II.[2] [PSBZ_THEEB] Controls the interaction of photosystem II (PSII) cores with the light-harvesting antenna. May also aid in binding of PsbK, Ycf12 and the oxygen-evolving complex to PSII, at least in vitro.[3] [PSBK_THEEB] This protein is a component of the reaction center of photosystem II.[HAMAP-Rule:MF_00441] [PSBO_THEEB] MSP binds to a putative Mn-binding protein and keeps 2 of the 4 Mn-atoms associated with PSII (By similarity). [CY550_THEEB] Low-potential cytochrome c that plays a role in the oxygen-evolving complex of photosystem II. It is not essential for growth under normal conditions but is required under low CO(2) concentrations.[HAMAP-Rule:MF_01378] [PSBE_THEEB] This b-type cytochrome is tightly associated with the reaction center of photosystem II and possibly is part of the water-oxidation complex.[HAMAP-Rule:MF_00642] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe membrane-embedded photosystem II core complex (PSIIcc) uses light energy to oxidize water in photosynthesis. Information about the spatial structure of PSIIcc obtained from x-ray crystallography was so far derived from homodimeric PSIIcc of thermophilic cyanobacteria. Here, we report the first crystallization and structural analysis of the monomeric form of PSIIcc with high oxygen evolution capacity, isolated from Thermosynechococcus elongatus. The crystals belong to the space group C222(1), contain one monomer per asymmetric unit, and diffract to a resolution of 3.6 A. The x-ray diffraction pattern of the PSIIcc-monomer crystals exhibit less anisotropy (dependence of resolution on crystal orientation) compared with crystals of dimeric PSIIcc, and the packing of the molecules within the unit cell is different. In the monomer, 19 protein subunits, 35 chlorophylls, two pheophytins, the non-heme iron, the primary plastoquinone Q(A), two heme groups, 11 beta-carotenes, 22 lipids, seven detergent molecules, and the Mn(4)Ca cluster of the water oxidizing complex could be assigned analogous to the dimer. Based on the new structural information, the roles of lipids and protein subunits in dimer formation of PSIIcc are discussed. Due to the lack of non-crystallographic symmetry and the orientation of the membrane normal of PSIIcc perpendicular ( approximately 87 degrees ) to the crystallographic b-axis, further information about the structure of the Mn(4)Ca cluster is expected to become available from orientation-dependent spectroscopy on this new crystal form. Crystal structure of monomeric photosystem II from Thermosynechococcus elongatus at 3.6-a resolution.,Broser M, Gabdulkhakov A, Kern J, Guskov A, Muh F, Saenger W, Zouni A J Biol Chem. 2010 Aug 20;285(34):26255-62. Epub 2010 Jun 17. PMID:20558739[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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