5e79

Macromolecular diffractive imaging using imperfect crystals

spinqualitylabelsall models 5e79, resolution 3.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5e79 is a 20 chain structure with sequence from Thermosynechococcus vestitus BP-1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.5Å Ligands: BCR, BCT, CA, CL, CLA, DGD, FE2, HEM, LHG, LMG, MG, PHO, PL9, SQD Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PSBA1_THEVB Photosystem II (PSII) is a light-driven water:plastoquinone oxidoreductase that uses light energy to abstract electrons from H(2)O, generating O(2) and a proton gradient subsequently used for ATP formation. It consists of a core antenna complex that captures photons, and an electron transfer chain that converts photonic excitation into a charge separation. The D1/D2 (PsbA/PsbD) reaction center heterodimer binds P680, the primary electron donor of PSII as well as several subsequent electron acceptors.[HAMAP-Rule:MF_01379] Publication Abstract from PubMed The 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 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cytochrome C 3D structures Photosystem II 3D structures

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