Proton-coupled electron transfer dynamics in the alternative oxidase.

The alternative oxidase (AOX) is a membrane-bound di-iron enzyme that catalyzes O-driven quinol oxidation in the respiratory chains of plants, fungi, and several pathogenic protists of biomedical and industrial interest. Yet, despite significant biochemical and structural efforts over the last decades, the catalytic principles of AOX remain poorly understood. We develop here multi-scale quantum and classical molecular simulations in combination with biochemical experiments to address the proton-coupled electron transfer (PCET) reactions responsible for catalysis in AOX from , the causative agent of sleeping sickness.