1ewh

STRUCTURE OF CYTOCHROME F FROM CHLAMYDOMONAS REINHARDTII

spinqualitylabelsall models 1ewh, resolution 2.35Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1ewh is a 3 chain structure with sequence from Chlre. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ACT, HEM Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [CYF_CHLRE] Component of the cytochrome b6-f complex, which mediates electron transfer between photosystem II (PSII) and photosystem I (PSI), cyclic electron flow around PSI, and state transitions.[HAMAP-Rule:MF_00610] 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 cytochrome f includes an internal chain of five water molecules and six hydrogen-bonding side chains, which are conserved throughout the phylogenetic range of photosynthetic organisms from higher plants, algae, and cyanobacteria. The in vivo electron transfer capability of Chlamydomonas reinhardtii cytochrome f was impaired in site-directed mutants of the conserved Asn and Gln residues that form hydrogen bonds with water molecules of the internal chain [Ponamarev, M. V., and Cramer, W. A. (1998) Biochemistry 37, 17199-17208]. The 251-residue extrinsic functional domain of C. reinhardtii cytochrome f was expressed in Escherichia coli without the 35 C-terminal residues of the intact cytochrome that contain the membrane anchor. Crystal structures were determined for the wild type and three "water chain" mutants (N168F, Q158L, and N153Q) having impaired photosynthetic and electron transfer function. The mutant cytochromes were produced, folded, and assembled heme at levels identical to that of the wild type in the E. coli expression system. N168F, which had a non-photosynthetic phenotype and was thus most affected by mutational substitution, also had the greatest structural perturbation with two water molecules (W4 and W5) displaced from the internal chain. Q158L, the photosynthetic mutant with the largest impairment of in vivo electron transfer, had a more weakly bound water at one position (W1). N153Q, a less impaired photosynthetic mutant, had an internal water chain with positions and hydrogen bonds identical to those of the wild type. The structure data imply that the waters of the internal chain, in addition to the surrounding protein, have a significant role in cytochrome f function. Interruption of the internal water chain of cytochrome f impairs photosynthetic function.,Sainz G, Carrell CJ, Ponamarev MV, Soriano GM, Cramer WA, Smith JL Biochemistry. 2000 Aug 8;39(31):9164-73. PMID:10924110 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cytochrome f 3D structures

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