The Substrate Activity of ( S )-9-[3-Hydroxy-(2-phosphonomethoxy)Propyl]Adenine Diphosphate toward DNA Polymerases α,δ and ε

Abstract

In this study, we examined the substrate potency of (S)-9-[3-hydroxy-(2-phosphonomethoxy)prop-yl]-adenine diphosphate (HPMPApp) toward DNA polymerases α, δ and ε The efficiency of HPMPApp incorporation decreased in the order pol ε >pol δ=pol α and was from 5.4- to 23-fold lower than that of dATP. Depending on which template-primer was used, the ^HPMPAppKm value was 3.3- and 8.3- (pol α), 3- and 0.82- (pol δ) or 2-fold (pol δ) higher than ^dATPK_m. The ability of HPMPA to accumulate in DNA decreased in the order pol δ >pol α >pol δ. The difference between the elongation rate of DNA with and without one HPMPA molecule at 3′ termini was about 1.1–2.3 fold. The 3′-5′-exonuclease activity of pol δ and ε can excise HPMPA from DNA. These observations indicate that interaction of HPMPApp with pol α, δ and ε may contribute to its cellular toxicity and explain its antiviral activity against polyomavirus.