FIGURE 2.

Extension of ³²P-labeled primers opposite G, N²-MeG, N²-EtG, N²-IbG, N²-BzG, N²-NaphG, and N²-AnthG by Dpo4 with all four dNTPs present. A primer(24-mer) was annealed with each of the seven different 36-mer templates (Table 1) containing an unmodified G or N²-alkylG placed at the 25th position from the 3′-end. Reactions were done for 20 min with increasing concentrations of Dpo4 (0, 0.5, 2, or 10 nm) and 100 nm DNA substrate (primer/template) as indicated. The ³²P-labeled 24-mer primer was extended in the presence of all four dNTPs (100 μm each). Reaction products were resolved by denaturing gel electrophoresis, with subsequent phosphorimaging analysis.