B3LYP study on reduction mechanisms from O2 to H2O at the catalytic sites of fully reduced and mixed-valence bovine cytochrome c oxidases.

ABSTRACT: Reduction mechanisms of oxygen molecule to water molecules in the fully reduced (FR) and mixed-valence (MV) bovine cytochrome c oxidases (CcO) have been systematically examined based on the B3LYP calculations. The catalytic cycle using four electrons and four protons has been also shown consistently. The MV CcO catalyses reduction to produce one water molecule, while the FR CcO catalyses to produce two water molecules. One water molecule is added into vacant space between His240 and His290 in the catalytic site. This water molecule constructs the network of hydrogen bonds of Tyr244, farnesyl ethyl, and Thr316 that is a terminal residue of the K-pathway. It plays crucial roles for the proton transfer to the dioxygen to produce the water molecules in both MV and FR CcOs. Tyr244 functions as

SUBMITTER: Yoshioka Y 

PROVIDER: S-EPMC2852611 | biostudies-literature | 2010

REPOSITORIES: biostudies-literature