Structures of Metal Sites of Oxidized Bovine Heart Cytochrome c Oxidase at 2.8 Å

• DOI: 10.1126/science.7652554
• Publication Date: 2006-10-27T18:19:42Z
• Authors: Tomitake Tsukihara; Hiroshi Aoyama; Eiki Yamashita; Takashi Tomizaki; Hiroshi Yamaguchi; Kyoko Shinzawa-Itoh; Ryosuke Nakashima; Rieko Yaono; Shinya Yoshikawa
• Keywords: Imidazole; Heme A

The high resolution three-dimensional x-ray structure of the metal sites bovine heart cytochrome c oxidase is reported. Cytochrome largest membrane protein yet crystallized and analyzed at atomic resolution. Electron density distribution oxidized 2.8 Å indicates a dinuclear copper center with an unexpected similar to [2Fe-2S]-type iron-sulfur center. Previously predicted zinc magnesium have been located, former bound by nuclear encoded subunit on matrix side membrane, latter situated between heme 3 Cu A , interface subunits I II. O 2 binding site contains iron atoms (Cu B ) interatomic distance 4.5 Å; there no detectable bridging ligand in spite strong antiferromagnetic coupling them. hydrogen bond present hydroxyl group hydroxyfarnesylethyl chain OH tyrosine. tyrosine phenol plane immediately adjacent perpendicular imidazole bonded suggesting possible role intramolecular electron transfer or conformational control, which could induce redox-coupled proton pumping. phenyl located halfway pyrrole liganded other (heme a) also influence control.