1k6l | pdb_00001k6l

Photosynethetic Reaction Center from Rhodobacter sphaeroides

spinqualitylabelsall models 1k6l, resolution 3.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1k6l 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 3.1Å Ligands: BCL, BPH, CDL, FE, LDA, SPN, U10 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RCEL_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 We report on the unexpected structural changes caused by substitution of acidic amino acids in the Q(B) binding pocket of the bacterial photosynthetic reaction center by alanines. The mutations targeted key residues L212Glu and L213Asp of this transmembrane protein-cofactor complex. The amino acid substitutions in the L212Ala-L213Ala mutant reaction center ("AA") were known to affect the delivery of protons after the light-induced generation of Q(B)(-), which renders the AA strain incapable of photosynthetic growth. The AA structure not only revealed side chain rearrangements but also showed movement of the main chain segments that are contiguous with the mutation sites. The alanine substitutions caused an expansion of the cavity rather than its collapse. In addition, Q(B) is found mainly in the binding site that is proximal to the iron-ligand complex (closest to Q(A)) as opposed to its distal binding site (furthest from Q(A)) in the structure of the wild-type reaction center. The observed rearrangements in the structure of the AA reaction center establish a new balance between charged residues of an interactive network near Q(B). This structurally and electrostatically altered complex forms the basis for future understanding of the structural basis for proton transfer in active reaction centers which retain the alanine substitutions but carry a distant compensatory mutation. The structure of a mutant photosynthetic reaction center shows unexpected changes in main chain orientations and quinone position.,Pokkuluri PR, Laible PD, Deng YL, Wong TN, Hanson DK, Schiffer M Biochemistry. 2002 May 14;41(19):5998-6007. PMID:11993994 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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