FIGURE 1.

Extension of ³²P-labeled primer opposite templates containing unmodified dA or 1,N⁶-γ-HMHP-dA adduct by hpol β (A) and hpol ι (B). The 13-mer primers (Scheme 2) were annealed with 18-mer template containing either unmodified dA or 1,N⁶-γ-HMHP-dA adduct. The resulting primer-template complexes (50 nm) were incubated at 37 °C in the presence of hpol β (2 units) or hpol ι (5 nm). Reactions were started by the addition of all four dNTPs (500 μm) and quenched at the indicated time points. The extension products were separated by 20% (w/v) denaturing PAGE and visualized by phosphorimaging analysis. X represents the migration of the starting primer.