Location of the Heme in Horse Heart Ferricytochrome c by X-Ray Diffraction

摘要: Abstract A low resolution (4A) electron density map of horse heart cytochrome c crystals has been obtained by x-ray diffraction methods. The molecule is a prolate spheroid, approximately 25 x 37 A. It cleft or crevice along one side into which the heme inserted, normal to surface, with only edges porphyrin ring exposed solvent. ligands occupying coordination positions 5 and 6 iron extend out from either cleft. thioether links binding vinyl chains cysteinyl residues in 14 17 amino acid sequence are visible. One can be identified its shape location as imidazole chain histidyl residue position 18. other not an probably located carboxyl-terminal half sequence. There little no α-helix present, body being extended shell around core packed hydrophobic chains.