4ub6
From Proteopedia
Native structure of photosystem II (dataset-1) by a femtosecond X-ray laser
Structural highlights
Function[PSBF_THEVL] This b-type cytochrome is tightly associated with the reaction center of photosystem II (PSII). PSII is a light-driven water plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating a proton gradient subsequently used for ATP formation.[HAMAP-Rule:MF_00643] [PSBL_THEVL] This protein is a component of the reaction center of photosystem II (PSII). PSII is a light-driven water plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating a proton gradient subsequently used for ATP formation.[HAMAP-Rule:MF_01317] [PSBJ_THEVL] This protein is a component of the reaction center of photosystem II (PSII). PSII is a light-driven water plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating a proton gradient subsequently used for ATP formation.[HAMAP-Rule:MF_01305] [PSBB_THEVL] This protein binds multiple antenna chlorophylls and is part of the core of photosystem II (PSII). PSII is a light-driven water plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating a proton gradient subsequently used for ATP formation. [YCF12_THEVL] A core subunit of photosystem II (PSII). PSII is a light-driven water plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating a proton gradient subsequently used for ATP formation. [PSBT_THEVL] Seems to play a role in the dimerization of photosystem II (PSII). PSII is a light-driven water plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating a proton gradient subsequently used for ATP formation.[HAMAP-Rule:MF_00808] [PSBI_THEVL] A component of the reaction center of photosystem II (PSII). PSII is a light-driven water plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating a proton gradient subsequently used for ATP formation.[HAMAP-Rule:MF_01316] [PSBD_THEVL] D1 (PsbA) and D2 (PsbD) bind P680, the primary electron donor of photosystem II (PSII) as well as electron acceptors. PSII is a light-driven water plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating a proton gradient subsequently used for ATP formation. D2 is needed for assembly of a stable PSII complex.[HAMAP-Rule:MF_01383] [PSBX_THEVL] Involved in the binding and/or turnover of quinones at the Q(B) site of photosystem II (PSII). PSII is a light-driven water plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating a proton gradient subsequently used for ATP formation.[HAMAP-Rule:MF_01386] [PSBZ_THEVL] Controls the interaction of photosystem II (PSII) cores with the light-harvesting antenna. PSII is a light-driven water plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating a proton gradient subsequently used for ATP formation.[HAMAP-Rule:MF_00644] [PSBO_THEVL] Part of the oxygen-evolving complex associated with photosystem II (PSII). PSII is a light-driven water plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating a proton gradient subsequently used for ATP formation. [CY550_THEVL] Low-potential cytochrome c that plays a role in the oxygen-evolving complex of photosystem II (PSII). Binds to PSII in the absence of other extrinsic proteins; required for binding of the PsbU protein to photosystem II. In PSII particles without oxygen-evolving activity, maximal activity is restored only by binding of cytochrome c550, PsbU and the 33 kDa PsbO protein. PSII is a light-driven water plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating a proton gradient subsequently used for ATP formation.[1] [2] [PSBE_THEVL] This b-type cytochrome is tightly associated with the reaction center of photosystem II (PSII). PSII is a light-driven water plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating a proton gradient subsequently used for ATP formation.[HAMAP-Rule:MF_00642] Publication Abstract from PubMedPhotosynthesis converts light energy into biologically useful chemical energy vital to life on Earth. The initial reaction of photosynthesis takes place in photosystem II (PSII), a 700-kilodalton homodimeric membrane protein complex that catalyses photo-oxidation of water into dioxygen through an S-state cycle of the oxygen evolving complex (OEC). The structure of PSII has been solved by X-ray diffraction (XRD) at 1.9 angstrom resolution, which revealed that the OEC is a Mn4CaO5-cluster coordinated by a well defined protein environment. However, extended X-ray absorption fine structure (EXAFS) studies showed that the manganese cations in the OEC are easily reduced by X-ray irradiation, and slight differences were found in the Mn-Mn distances determined by XRD, EXAFS and theoretical studies. Here we report a 'radiation-damage-free' structure of PSII from Thermosynechococcus vulcanus in the S1 state at a resolution of 1.95 angstroms using femtosecond X-ray pulses of the SPring-8 angstrom compact free-electron laser (SACLA) and hundreds of large, highly isomorphous PSII crystals. Compared with the structure from XRD, the OEC in the X-ray free electron laser structure has Mn-Mn distances that are shorter by 0.1-0.2 angstroms. The valences of each manganese atom were tentatively assigned as Mn1D(III), Mn2C(IV), Mn3B(IV) and Mn4A(III), based on the average Mn-ligand distances and analysis of the Jahn-Teller axis on Mn(III). One of the oxo-bridged oxygens, O5, has significantly longer distances to Mn than do the other oxo-oxygen atoms, suggesting that O5 is a hydroxide ion instead of a normal oxygen dianion and therefore may serve as one of the substrate oxygen atoms. These findings provide a structural basis for the mechanism of oxygen evolution, and we expect that this structure will provide a blueprint for the design of artificial catalysts for water oxidation. Native structure of photosystem II at 1.95 A resolution viewed by femtosecond X-ray pulses.,Suga M, Akita F, Hirata K, Ueno G, Murakami H, Nakajima Y, Shimizu T, Yamashita K, Yamamoto M, Ago H, Shen JR Nature. 2015 Jan 1;517(7532):99-103. doi: 10.1038/nature13991. Epub 2014 Nov 26. PMID:25470056[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Photosystem II | Thermosynechococcus vulcanus | Ago, H | Akita, F | Hirata, K | Murakami, H | Nakajima, Y | Shen, J R | Shimizu, T | Suga, M | Ueno, G | Yamamoto, M | Yamashita, K | Electron transport | Membrane protein | Oxygen evolution | Photo system ii | Photosynthesis | Water splitting
