Hydride transfer reaction catalyzed by hyperthermophilic dihydrofolate reductase is dominated by quantum mechanical tunneling and is promoted by both inter- and intramonomeric correlated motions

Simulations of hydride and deuteride transfer catalyzed by dihydrofolate reductase from the hyperthermophile Thermotoga maritima (TmDHFR) are presented using ensemble-averaged variational transition theory with multidimensional tunneling. The results suggest that quantum mechanical tunneling makes a significant contribution to the reaction rate at all temperatures and dimerization is important for thermal stability of TmDHFR and its catalytic activity.