5e7c
From Proteopedia
Macromolecular diffractive imaging using imperfect crystals - Bragg data
Structural highlights
Function[PSBL_THEEB] Required for PSII activity (By similarity). [YCF12_THEEB] A core subunit of photosystem II (PSII).[HAMAP-Rule:MF_01329] [PSBB_THEEB] One of the components of the core complex of photosystem II (PSII). It binds chlorophyll and helps catalyze the primary light-induced photochemical processes of PSII. PSII is a light-driven water:plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating O(2) and a proton gradient subsequently used for ATP formation.[HAMAP-Rule:MF_01495][1] [2] [3] [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.[4] [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] [PSBO_THEEB] MSP binds to a putative Mn-binding protein and keeps 2 of the 4 Mn-atoms associated with PSII (By similarity). [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] [PSBC_THEEB] One of the components of the core complex of photosystem II (PSII). It binds chlorophyll and helps catalyze the primary light-induced photochemical processes of PSII. PSII is a light-driven water:plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating O(2) and a proton gradient subsequently used for ATP formation.[HAMAP-Rule:MF_01496][5] [6] [7] [PSBJ_THEEB] This protein is a component of the reaction center of photosystem II (By similarity). [PSBT_THEEB] Seems to play a role in the dimerization of PSII.[8] [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] [PSBI_THEEB] This protein is a component of the reaction center of photosystem II.[HAMAP-Rule:MF_01316] [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.[9] [PSBK_THEEB] This protein is a component of the reaction center of photosystem II.[HAMAP-Rule:MF_00441] [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] Publication Abstract from PubMedThe three-dimensional structures of macromolecules and their complexes are mainly elucidated by X-ray protein crystallography. A major limitation of this method is access to high-quality crystals, which is necessary to ensure X-ray diffraction extends to sufficiently large scattering angles and hence yields information of sufficiently high resolution with which to solve the crystal structure. The observation that crystals with reduced unit-cell volumes and tighter macromolecular packing often produce higher-resolution Bragg peaks suggests that crystallographic resolution for some macromolecules may be limited not by their heterogeneity, but by a deviation of strict positional ordering of the crystalline lattice. Such displacements of molecules from the ideal lattice give rise to a continuous diffraction pattern that is equal to the incoherent sum of diffraction from rigid individual molecular complexes aligned along several discrete crystallographic orientations and that, consequently, contains more information than Bragg peaks alone. Although such continuous diffraction patterns have long been observed--and are of interest as a source of information about the dynamics of proteins--they have not been used for structure determination. Here we show for crystals of the integral membrane protein complex photosystem II that lattice disorder increases the information content and the resolution of the diffraction pattern well beyond the 4.5-angstrom limit of measurable Bragg peaks, which allows us to phase the pattern directly. Using the molecular envelope conventionally determined at 4.5 angstroms as a constraint, we obtain a static image of the photosystem II dimer at a resolution of 3.5 angstroms. This result shows that continuous diffraction can be used to overcome what have long been supposed to be the resolution limits of macromolecular crystallography, using a method that exploits commonly encountered imperfect crystals and enables model-free phasing. Macromolecular diffractive imaging using imperfect crystals.,Ayyer K, Yefanov OM, Oberthur D, Roy-Chowdhury S, Galli L, Mariani V, Basu S, Coe J, Conrad CE, Fromme R, Schaffer A, Dorner K, James D, Kupitz C, Metz M, Nelson G, Xavier PL, Beyerlein KR, Schmidt M, Sarrou I, Spence JC, Weierstall U, White TA, Yang JH, Zhao Y, Liang M, Aquila A, Hunter MS, Robinson JS, Koglin JE, Boutet S, Fromme P, Barty A, Chapman HN Nature. 2016 Feb 11;530(7589):202-6. doi: 10.1038/nature16949. PMID:26863980[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Photosystem II | Aquila, A | Ayyer, K | Barty, A | Basu, S | Beyerlein, K R | Boutet, S | Chapman, H N | Coe, J | Conrad, C E | Doerner, K | Fromme, P | Fromme, R | Galli, L | Hunter, M S | James, D | Koglin, J E | Kupitz, C | Liang, M | Mariani, V | Metz, M | Nelson, G | Oberthuer, D | Robinson, J S | Roy-Chowdhury, S | Sarrou, I | Schaffner, A | Schmidt, M | Spence, J C.H | Weierstall, U | White, T A | Xavier, P L | Yang, J H | Yefanov, O | Zhao, Y | Photosynthesis | Photosystem ii | Sfx | Xfel
