Phenylalanine 171 is a molecular brake for translesion synthesis across benzo[a]pyrene-guanine adducts by human DNA polymerase kappa

▶ Phenylalanine 171 is inhibitory for translesion bypass by human DNA polymerase kappa. ▶ The change of the amino acid to alanine enhanced translesion efficiency. ▶ The derivative passed benzo[a]pyrene adducts in DNA about 20 times more efficiently. ▶ The finding raises a question of why it has a molecular brake for error-free bypass.