Reductive cleavage of the O–O bond in multicopper oxidases: a QM/MM and QM study†
Abstract
The key step in the reaction mechanism of multicopper oxidases (MCOs)—the cleavage of the O–O bond in O2—has been investigated using combined quantum mechanical and molecular mechanical (QM/MM) methods. This process represents a reaction pathway from the peroxy intermediate after it accepts one electron from the nearby type-1 Cu site to the experimentally-observed native intermediate, which is the only fully oxidised catalytically relevant state in MCOs. Scans of the QM(DFT)/MM potential energy surface have allowed us to obtain estimates of the activation energies. Furthermore, vacuum calculations on a smaller model of the active site have allowed us to estimate the entropy contributions to the barrier height and to obtain further insight into the reaction by comparing the small cluster model with the QM/MM model, which includes the entire
- This article is part of the themed collection: Spectroscopy, Theory and Mechanism in Bioinorganic Chemistry