Effect of Aromatic Interactions on Flavin's Redox Potential : a Theoretical Study

Abstract

Flavins, substituted isoalloxazines, are redox active cofactors ubiquitous among oxidoreductases that catalyze diverse chemical reactions. They also exhibit photoinduced electron transfers and have great potentials as sensors and as light-harvesting chromophores. Versatility in chemical functions in flavin containing enzymes arise mainly due their unique ability to undergo both oneand two-electron reductions. Modulation of the redox potential is accomplished by various hydrogen bonding interactions with flavin ring atoms, as well as ?-stacking interactions with aromatic sidechains. Although, recent studies revealed the role of hydrogen bonding and electrostatics on the charge separation upon reduction, the significance of aromatic functionalities and their impact on flavin's redox potential have remained poorly understood. In the present study, these noncovalent interactions, in various flavin-aromatics, have been studied and their impact on the electrochemical properties investigated.