A Protonated Water Cluster as a Transient Proton‐Loading Site in Cytochrome c Oxidase. Issue 39 (19th August 2016)

• Record Type: Journal Article
• Authors: Supekar, Shreyas; Gamiz‐Hernandez, Ana P.; Kaila, Ville R. I.
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 39(2016)
• Page Start: 11940
• Page End: 11944
• Publication Date: 2016-08-19
• Subjects: bioenergetics -- electron transfer -- enzymes -- molecular dynamics -- proton transfer; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201603606
• Languages: English
• ISSNs: 1433-7851

Abstract

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.