Active Binding Modes of Caffeine with Cytochrome P450 1A2 Determine Its Metabolite Profiles.

Caffeine is a very common kind of nervous stimulant, and it is primarily metabolized by Cytochrome P450 1A2 (CYP1A2) in the human body. Over the years, determining the interactions between caffeine and CYP1A2 has been a tough issue. The active binding modes and the catalytic regioselectivity of the metabolism between CYP1A2 and caffeine remain unclear. Here, to investigate the interactions between CYP1A2 and caffeine, we constructed the all-sequence CYP1A2-caffeine-membrane system using a multiple template approach. According to our simulation results, four active binding modes between CYP1A2 and caffeine that correspond to the four metabolic sites of caffeine are determined. What is more, a pre-reaction state for the CYP1A2-catalyzed reaction at caffeine's N3 site is identified. A more preponderant active binding mode might be the reason why the N3 site of caffeine becomes the primary metabolic site. Our findings could enhance our knowledge of the interactions between CYP1A2 and caffeine and help us better understand the regioselectivity of the metabolism between CYP1A2 and caffeine.