2ux3 | pdb_00002ux3

X-ray high resolution structure of the photosynthetic reaction center from Rb. sphaeroides at pH 9 in the neutral state

spinqualitylabelsall models 2ux3, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2ux3 is a 3 chain structure with sequence from Cereibacter sphaeroides. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.5Å Ligands: BCL, BPH, CDL, FE, GOL, HTO, LDA, PO4, SPO, U10, UQ2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RCEH_CERSP The reaction center is a membrane-bound complex that mediates the initial photochemical event in the electron transfer process of photosynthesis. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The structure of the photosynthetic reaction-center from Rhodobacter sphaeroides has been determined at four different pH values (6.5, 8.0, 9.0, 10.0) in the neutral and in charge separated states. At pH 8.0, in the neutral state, we obtain a resolution of 1.87 A, which is the best ever reported for the bacterial reaction center protein. Our crystallographic data confirm the existence of two different binding positions of the secondary quinone (QB). We observe a new orientation of QB in its distal position, which shows no ring-flip compared to the orientation in the proximal position. Datasets collected for the different pH values show a pH-dependence of the population of the proximal position. The new orientation of QB in the distal position and the pH-dependence could be confirmed by continuum electrostatics calculations. Our calculations are in agreement with the experimentally observed proton uptake upon charge separation. The high resolution of our crystallographic data allows us to identify new water molecules and external residues being involved in two previously described hydrogen bond proton channels. These extended proton-transfer pathways, ending at either of the two oxo-groups of QB in its proximal position, provide additional evidence that ring-flipping is not required for complete protonation of QB upon reduction. pH modulates the quinone position in the photosynthetic reaction center from Rhodobacter sphaeroides in the neutral and charge separated states.,Koepke J, Krammer EM, Klingen AR, Sebban P, Ullmann GM, Fritzsch G J Mol Biol. 2007 Aug 10;371(2):396-409. Epub 2007 May 10. PMID:17570397 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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