FIGURE 7.

Polymerase β extension activity in NCPs near the dyad. A, representative gels for NCP-gO (+10) and NCP-gI (+4) pol β (100 nm) extension in the absence of APE1. B, NCP-gO (+10) and NCP-gI (+4) were incubated with pol β and APE1 at 100 and 10 nm, respectively, for the specified times. C, plot of the mean ± 1 S.D. of three independent experiments normalized to pol β (200 nm) extension on the corresponding free DNA. Normalized data points were fitted to a single phase exponential equation as described under “Experimental Procedures.” The initial rates were calculated for extension in the absence of APE1 with values of 14.1 ± 1.6 and 9.1 ± 1.2% extended per min for NCP-gI (+4) and NCP-gO (+10), respectively. For data points where the error bars are not visible, the standard deviations were smaller or similar in magnitude to the size of the symbols.