4mu8

Crystal structure of an oxidized form of yeast iso-1-cytochrome c at pH 8.8

spinqualitylabelsall models 4mu8, resolution 1.45Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4mu8 is a 2 chain structure with sequence from Saccharomyces cerevisiae S288C. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.45Å Ligands: GOL, HEC, SO4, TBU Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CYC1_YEAST Electron carrier protein. The oxidized form of the cytochrome c heme group can accept an electron from the heme group of the cytochrome c1 subunit of cytochrome reductase. Cytochrome c then transfers this electron to the cytochrome oxidase complex, the final protein carrier in the mitochondrial electron-transport chain. Publication Abstract from PubMed At the onset of apoptosis, the peroxidation of cardiolipin at the inner mitochondrial membrane by cytochrome c requires an open coordination site on the heme. We report a 1.45-A resolution structure of yeast iso-1-cytochrome c with the Met80 heme ligand swung out of the heme crevice and replaced by a water molecule. This conformational change requires modest adjustments to the main chain of the heme crevice loop and is facilitated by a trimethyllysine 72-to-alanine mutation. This mutation also enhances the peroxidase activity of iso-1-cytochrome c. The structure shows a buried water channel capable of facilitating peroxide access to the active site and of moving protons produced during peroxidase activity to the protein surface. Alternate positions of the side chain of Arg38 appear to mediate opening and closing of the buried water channel. In addition, two buried water molecules can adopt alternate positions that change the network of hydrogen bonds in the buried water channel. Taken together, these observations suggest that low and high proton conductivity states may mediate peroxidase function. Comparison of yeast and mammalian cytochrome c sequences, in the context of the steric factors that permit opening of the heme crevice, suggests that higher organisms have evolved to inhibit peroxidase activity, providing a more stringent barrier to the onset of apoptosis. Structure of a mitochondrial cytochrome c conformer competent for peroxidase activity.,McClelland LJ, Mou TC, Jeakins-Cooley ME, Sprang SR, Bowler BE Proc Natl Acad Sci U S A. 2014 May 6;111(18):6648-53. doi:, 10.1073/pnas.1323828111. Epub 2014 Apr 23. PMID:24760830 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cytochrome C 3D structures

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