2yk3

CRITHIDIA FASCICULATA CYTOCHROME CCRITHIDIA FASCICULATA CYTOCHROME C

Structural highlights 2yk3 is a 3 chain structure with sequence from Crithidia fasciculata. This structure supersedes the now removed PDB entry 2w9k. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.55Å Ligands: , , Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CYC_CRIFA 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 The principal physiological role of mitochondrial cytochrome c is electron transfer during oxidative phosphorylation. c-Type cytochromes are almost always characterized by covalent attachment of heme to protein through two thioether bonds between the heme vinyl groups and the thiols of cysteine residues in a Cys-Xxx-Xxx-Cys-His motif. Uniquely, however, members of the evolutionarily divergent protist phylum Euglenozoa, which includes Trypanosoma and Leishmania species, have mitochondrial cytochromes c with heme attached through only one thioether bond [to an (A/F)XXCH motif]; the implications of this for the cytochrome structures are unclear. Here we present the 1.55 A resolution X-ray crystal structure of cytochrome c from the trypanosomatid Crithidia fasciculata. Despite the fundamental difference in heme attachment and in the cytochrome c biogenesis machinery of the Euglenozoa, the structure is remarkably similar to that of typical (CXXCH) mitochondrial cytochromes c, both in overall fold and, other than the missing thioether bond, in the details of the heme attachment. Notably, this similarity includes the stereochemistry of the covalent heme attachment to the protein. The structure has implications for the maturation of c-type cytochromes in the Euglenozoa; it also hints at a distinctive redox environment in the mitochondrial intermembrane space of trypanosomes. Surprisingly, Saccharomyces cerevisiae cytochrome c heme lyase (the yeast cytochrome c biogenesis system) cannot efficiently mature Trypanosoma brucei cytochrome c or a CXXCH variant when expressed in the cytoplasm of Escherichia coli, despite their great structural similarity to yeast cytochrome c, suggesting that heme lyase requires specific recognition features in the apocytochrome. Structure of a trypanosomatid mitochondrial cytochrome c with heme attached via only one thioether bond and implications for the substrate recognition requirements of heme lyase.,Fulop V, Sam KA, Ferguson SJ, Ginger ML, Allen JW FEBS J. 2009 May;276(10):2822-32. PMID:19459937 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cytochrome C 3D structures

spinqualitylabelsall models 2yk3, resolution 1.55Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image