4q54

Serial Time-resolved crystallography of Photosystem II using a femtosecond X-ray laser The S state after two flashes(S3)

spinqualitylabelsall models 4q54, resolution 5.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4q54 is a 38 chain structure with sequence from Thermosynechococcus elongatus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: BCR, BCT, CA, CL, CLA, DGD, FE2, HEM, LHG, MG, OEX, PHO, PL9, SQD Related: 3arc, 2axt Activity: Photosystem II, with EC number 1.10.3.9 Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed Photosynthesis, a process catalysed by plants, algae and cyanobacteria converts sunlight to energy thus sustaining all higher life on Earth. Two large membrane protein complexes, photosystem I and II (PSI and PSII), act in series to catalyse the light-driven reactions in photosynthesis. PSII catalyses the light-driven water splitting process, which maintains the Earth's oxygenic atmosphere. In this process, the oxygen-evolving complex (OEC) of PSII cycles through five states, S0 to S4, in which four electrons are sequentially extracted from the OEC in four light-driven charge-separation events. Here we describe time resolved experiments on PSII nano/microcrystals from Thermosynechococcus elongatus performed with the recently developed technique of serial femtosecond crystallography. Structures have been determined from PSII in the dark S1 state and after double laser excitation (putative S3 state) at 5 and 5.5 A resolution, respectively. The results provide evidence that PSII undergoes significant conformational changes at the electron acceptor side and at the Mn4CaO5 core of the OEC. These include an elongation of the metal cluster, accompanied by changes in the protein environment, which could allow for binding of the second substrate water molecule between the more distant protruding Mn (referred to as the 'dangler' Mn) and the Mn3CaOx cubane in the S2 to S3 transition, as predicted by spectroscopic and computational studies. This work shows the great potential for time-resolved serial femtosecond crystallography for investigation of catalytic processes in biomolecules. Serial time-resolved crystallography of photosystem II using a femtosecond X-ray laser.,Kupitz C, Basu S, Grotjohann I, Fromme R, Zatsepin NA, Rendek KN, Hunter MS, Shoeman RL, White TA, Wang D, James D, Yang JH, Cobb DE, Reeder B, Sierra RG, Liu H, Barty A, Aquila AL, Deponte D, Kirian RA, Bari S, Bergkamp JJ, Beyerlein KR, Bogan MJ, Caleman C, Chao TC, Conrad CE, Davis KM, Fleckenstein H, Galli L, Hau-Riege SP, Kassemeyer S, Laksmono H, Liang M, Lomb L, Marchesini S, Martin AV, Messerschmidt M, Milathianaki D, Nass K, Ros A, Roy-Chowdhury S, Schmidt K, Seibert M, Steinbrener J, Stellato F, Yan L, Yoon C, Moore TA, Moore AL, Pushkar Y, Williams GJ, Boutet S, Doak RB, Weierstall U, Frank M, Chapman HN, Spence JC, Fromme P Nature. 2014 Jul 9. doi: 10.1038/nature13453. PMID:25043005 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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