Fully oxidized cytochrome c oxidase (CcO) under enzymatic turnover is capable of pumping protons, while fully oxidized CcO as isolated is not able to do so upon one-electron reduction. The functional difference is expected to be a consequence of structural differences: [Fe 3+-OH -] under enzymatic turnover versus [Fe 3+-O 2 2--Cu 2+] for the as-isolated CcO. However, the electron density for O2 2- is equally assignable to Cl -. An anomalous dispersion analysis was performed in order to conclusively demonstrate the absence of Cl - between the Fe 3+ and Cu 2+. Thus, the peroxide moiety receives electron equivalents from cytochrome c without affecting the oxidation states of the metal sites. The metal-site reduction is coupled to the proton pump.
|Number of pages||3|
|Journal||Acta Crystallographica Section D: Biological Crystallography|
|Publication status||Published - Aug 2011|
- cytochrome c oxidase
ASJC Scopus subject areas
- Structural Biology