In this work, we analyzed the ability to incorporate 8-oxo-dATP by several human DNA polymerases: replicative Pol ε (exo-) from Family B; base excision repair (BER) enzymes Pol β and Pol λ from Family X; and translesion Pol η, Pol ι, and Pol κ from Family Y. We demonstrated that human DNA polymerases differ in their abilities to discriminate against 8-oxo-dATP. Among the tested DNA polymerases, Pol λ exhibited the worst ability to discriminate against 8-oxo-dATP opposite template T on DNA substrates with a protruding single-stranded 5′-end and a double-stranded DNA with a 1 nt gap. Pol β and DNA polymerases of Family Y showed relatively high accuracy. Pol η demonstrated the most effective discrimination against 8-oxo-dATP on templates T and G. Pol ι exclusively incorporated 8-oxo-dATP opposite template G but not T. Unexpectedly, the catalytic subunit of high-fidelity Pol ε (exo-) incorporated 8-oxo-dATP opposite templates T and G with higher efficiency compared with the error-prone polymerases of Family Y and Pol β. While the structures of human polymerases with incoming 8-oxo-dATP are not available, we speculate on a possible mechanism of 8-oxo-dATP discrimination.

In this work, we analyzed the ability to incorporate 8-oxo-dATP by several human DNA polymerases: replicative Pol ε (exo-), BER enzymes Pol β and Pol λ, and trans-lesion Pol η, Pol ι, and Pol κ. We demonstrated that human DNA polymerases differ in their abilities to discriminate against 8-oxo-dATP. Among tested DNA polymerases, Pol λ demonstrated the worst ability to discriminate against 8-oxo-dATP opposite template T on both singles-stranded DNA and double-stranded DNA substrates with a 1 nt gap. In contrast, Pol β was quite accurate on singe-stranded DNA substrate but incorporated 8-oxo-dATP opposite template T in a 1 nt gap. Unexpectedly, the catalytic subunit of high-fidelity Pol ε (exo-) incorporated 8-oxodATP opposite templates T and G with weak but higher efficiency compare to error-prone polymerases of Family Y. While structures of human polymerases with incoming 8oxo-dATP are not available, we speculate possible mechanism of 8-oxo-dATP discriminations.