Quantum Chemical Studies of the Binding and Catalytic Hydride Transfer Reaction of Flavin with Aromatic Substrates

Abstract

A large number of chemical reactions are catalyzed by flavoenzymes- a group of enzymes that utilizes flavin ring as a cofactor. The versatility arises mainly due to the ability of enzyme matrix to modulate flavin's redox potentials by altering non-covalent interactions. These interactions include hydrogen bonding with flavin ring atoms, hydrophobic interactions due to aromatic side chains, and pi stacking interactions with aromatic substrates. Although recent theoretical studies were successful to model hydrogen bonding interactions, the effects of aromatic interactions on the redox properties of flavins have remained only partially revealed. The purpose of this study was to examine the pi stacking interactions of flavin and other aromatic molecules using improved semi-empirical and density functional theories.