Genetically Expanded Reactive-Oxygen-Tolerant Alcohol Dehydrogenase II

Herein, we report the site-specific incorporation of l-3,4-dihydroxyphenylalanine as a promising method to engineer an oxygen-tolerant alcohol dehydrogenase II. The engineered mutant alcohol dehydrogenase II binds Zn²⁺ with high binding affinity and is functional under aerobic and oxidative conditions for a longer time than the wild-type, Fe²⁺-binding alcohol dehydrogenase II. Overall, the mutant enzyme demonstrated electrochemical activity toward both acetaldehyde reduction and ethanol oxidation reactions. This enzyme could have a potential use in efficient biofuel production under aerobic conditions in photosynthetic organisms despite the inherent oxygen evolution reaction by photosystem II.