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Structure of Psb27 from Thermosynechococcus elongatusStructure of Psb27 from Thermosynechococcus elongatus
Structural highlights
FunctionPSB27_THEVB Plays a role in the repair and/or biogenesis of the calcium-manganese-oxide cluster on the lumenal face of the thylakoid membrane. Its presence in a photosystem II (PSII) preparation prevents binding of other extrinsic subunits PsbO, PsbU and PsbV, and thus assembly of calcium-manganese-oxide cluster. Psb27-containing complexes lack oxygen evolving activity and an oxidizable calcium-manganese-oxide cluster, but have a normal reaction center.[1] Publication Abstract from PubMedThe biogenesis and oxygen-evolving activity of cyanobacterial Photosystem II (PSII) is dependent on a number of accessory proteins not found in the crystallised dimeric complex. These include Psb27, a small lipoprotein attached to the lumenal side of PSII, which has been assigned a role in regulating the assembly of the Mn(4)Ca cluster catalysing water oxidation. To gain a better understanding of Psb27, we have determined in this study the crystal structure of the soluble domain of Psb27 from Thermosynechococcus elongatus to a resolution of 1.6 A. The structure is a four-helix bundle, similar to the recently published solution structures of Psb27 from Synechocystis PCC 6803 obtained by nuclear magnetic resonance (NMR) spectroscopy. Importantly, the crystal structure presented here helps us resolve the differences between the NMR-derived structural models. Potential binding sites for Psb27 within PSII are discussed in light of recent biochemical data in the literature. Crystal structure of the Psb27 assembly factor at 1.6 A: implications for binding to Photosystem II.,Michoux F, Takasaka K, Boehm M, Komenda J, Nixon PJ, Murray JW Photosynth Res. 2011 Dec 23. PMID:22193820[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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