3AG4

Bovine Heart Cytochrome c Oxidase in the Cyanide Ion-bound Fully Reduced State at 100 K

Summary for 3AG4

• Entry DOI: 10.2210/pdb3ag4/pdb
• Related: 1occ 1oco 1ocr 1ocz 1v54 1v55 2dyr 2dys 2eij 2eik 2eil 2eim 2ein 2occ 2zxw 3AG1 3AG2 3AG3 3abk 3abl 3abm
• Descriptor: Cytochrome c oxidase subunit 1, Cytochrome c oxidase polypeptide 7A1, Cytochrome c oxidase subunit 7B, ... (29 entities in total)
• Functional Keywords: oxidoreductase, copper, electron transport, formylation, heme, iron, membrane, mitochondrion, mitochondrion inner membrane, respiratory chain, transmembrane, transport, acetylation, transit peptide, zinc, isopeptide bond, ubl conjugation
• Biological source: Bos taurus (bovine); More
• Cellular location: Mitochondrion inner membrane; Multi-pass membrane protein: P00396 P68530 P00415; Mitochondrion inner membrane: P07470 P13183 P00430 P10175 P00423 P00426 P00428 P07471 P04038; Mitochondrion intermembrane space: P00429
• Total number of polymer chains: 26
• Total formula weight: 442808.03

Authors

Muramoto, K.,Ohta, K.,Shinzawa-Itoh, K.,Kanda, K.,Taniguchi, M.,Nabekura, H.,Yamashita, E.,Tsukihara, T.,Yoshikawa, S. (deposition date: 2010-03-19, release date: 2010-04-28, Last modification date: 2023-11-01)

Primary citation

Muramoto, K.,Ohta, K.,Shinzawa-Itoh, K.,Kanda, K.,Taniguchi, M.,Nabekura, H.,Yamashita, E.,Tsukihara, T.,Yoshikawa, S.
Bovine cytochrome c oxidase structures enable O2 reduction with minimization of reactive oxygens and provide a proton-pumping gate
Proc.Natl.Acad.Sci.USA, 107:7740-7745, 2010

PubMed Abstract: The O(2) reduction site of cytochrome c oxidase (CcO), comprising iron (Fe(a3)) and copper (Cu(B)) ions, is probed by x-ray structural analyses of CO, NO, and CN(-) derivatives to investigate the mechanism of the complete reduction of O(2). Formation of the derivative contributes to the trigonal planar coordination of and displaces one of its three coordinated imidazole groups while a water molecule becomes hydrogen bonded to both the CN(-) ligand and the hydroxyl group of Tyr244. When O(2) is bound to Fe2+a3 , it is negatively polarized (O2- ), and expected to induce the same structural change induced by CN(-). This structural change allows to receive three electron equivalents nonsequentially from Cu1B+, Fe3+a3, and Tyr-OH, providing complete reduction of O(2) with minimization of production of active oxygen species. The proton-pumping pathway of bovine CcO comprises a hydrogen-bond network and a water channel which extend to the positive and negative side surfaces, respectively. Protons transferred through the water channel are pumped through the hydrogen-bond network electrostatically with positive charge created at the Fe(a) center by electron donation to the O(2) reduction site. Binding of CO or NO to induces significant narrowing of a section of the water channel near the hydrogen-bond network junction, which prevents access of water molecules to the network. In a similar manner, O(2) binding to is expected to prevent access of water molecules to the hydrogen-bond network. This blocks proton back-leak from the network and provides an efficient gate for proton-pumping.

PubMed: 20385840
DOI: 10.1073/pnas.0910410107

Experimental method

X-RAY DIFFRACTION (2.05 Å)