FIGURE 7.

Effect of the 3′-8-oxoG:C base pair on TDG-initiated BER activity. A schematic representation of the substrate and the reaction scheme are shown in the top panel. A DNA substrate (250 nm) with G:C (T/G-G/C) or 8-oxoG:C (T/G-oxG/C) positioned 3′ to T:G was incubated with 10 nm TDG, 20 nm APE1, and 20 nm pol β with or without 100 nm Lig I at 37 °C for 5, 10, or 15 min, as indicated. Reaction products representing incorporation of labeled dCMP were isolated as described under “Experimental Procedures.”