Enzymes provide exceptional rate enhancement and stereoselectivity to reactions while maintaining mild conditions. Abiotic catalysis, in which enzymes perform reactions outside of their native physiological function, has become an effective approach to carry out various chemical transformations. To effectively control and guide protein engineering efforts for improved reaction efficiency, it is essential to bridge the existing gap in the thorough mechanistic understanding of abiotic activities. Here, we implement a computational approach to investigate catalytically determining factors of abiotic ketone reduction in human carbonic anhydrase (hCA). This reaction produces chiral alcohol, a common total synthesis intermediate that benefits from enzymes’ enhanced stereoselectivity. We employ molecular dynamics (MD) to examine the dynamical interplay between known substrates and hCA. We examine the factors that contribute to the binding of these substrates to the hCA active site at the classical level. Then, we go beyond the classical picture to employ quantum mechanical modeling with density functional theory (DFT) to investigate the electronic structure of the substrates and their interactions with the enzyme environment. Through both the dynamic and quantum mechanical approaches, we relate important contributors of the reactions to the experimentally reported yield with linear regression models. Our study demonstrates the varying effects of substrate dynamics and electronic structure on the experimental yield of hCA’s abiotic ketone reduction. As a result, we propose favorable dynamics and interactions that improve reaction yield, ensuring better control and optimization of the ketone reduction reaction’s outcome.
