Binary and Ternary Binding Affinities between Exonuclease-Deficient Klenow Fragment (Kf-exo) and Various Arylamine DNA Lesions Characterized by Surface Plasmon Resonance

We used surface plasmon resonance (SPR) to characterize the binding interactions between the exonulease-free Klenow fragment (Kf-exo) and unmodified and modified dG adducts derived from arylamine carcinogens: fluorinated 2-aminofluorene (FAF), 2-acetylaminofluorene (FAAF), and 4-aminobiphenyl (FABP). Tight polymerase binding was detected with unmodified dG and the correct dCTP. The discrimination of correct versus incorrect nucleotides was pronounced with KD values in the order of dCTP ≪ dTTP < dATP < dGTP. In contrast, minimal selectivity was observed for the modified templates with Kf-exo binding tighter to the FAAF (koff: 0.02 s–1) and FABP (koff: 0.01 s–1) lesions than to FAF (koff: 0.04 s–1).