A Protonated Water Cluster as a Transient Proton‐Loading Site in Cytochrome c Oxidase. Issue 39 (19th August 2016) - Supekar, Shreyas
Abstract: Cytochrome c oxidase (CcO) is a redox‐driven proton pump that powers aerobic respiratory chains. We show here by multi‐scale molecular simulations that a protonated water cluster near the active site is likely to serve as the transient proton‐loading site (PLS) that stores a proton during the pumping process. The p K a of this water cluster is sensitive to the redox states of the enzyme, showing distinct similarities to other energy converting proton pumps. Abstract : Proton‐coupled electron transfer : Structurally conserved water molecules (see picture) function as a transient proton‐loading site and provide important coupling elements in the proton‐pumping machinery of cytochrome oxidase. Quantum mechanics/molecular mechanics simulations were used to study the biomolecular mechanism.