Download MendeleyDistinguishing between Cl- and O2(2-) as the bridging element between Fe3+ and Cu2+ in resting-oxidized cytochrome c oxidase
Suga, M., Yano, N., Muramoto, K., Shinzawa-Itoh, K., Maeda, T., Yamashita, E., Tsukihara, T., Yoshikawa, S.(2011) Acta Crystallogr D Biol Crystallogr 67: 742-744
- PubMed: 21795816
- DOI: https://doi.org/10.1107/S0907444911022803
- Primary Citation of Related Structures:
3ASN, 3ASO - PubMed Abstract:
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 O(2)(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.
Organizational Affiliation:
Institute for Protein Research, Osaka University, 3-2 Yamada-oka, Suita, Osaka 565-0871, Japan.
