Fig. 5.

Excision of matched and mismatched DNA by hPolε at 20 °C. A pre-incubated solution of 100 nM hPolε (●) or p261N (■) and 20 nM 5′-radiolabeled (A) D-1 or (B) M-1 DNA was rapidly mixed with Mg²⁺ and quenched after various times with 0.37 M EDTA. The data were fit to Eq. (3) to yield k_exo. For the matched D-1 DNA (A), the measured k_exo values were 0.018 ± 0.002 s⁻¹ and 0.041 ± 0.004 s⁻¹ for hPolε and p261N, respectively. For the mismatched M-1 DNA (B), the measured k_exo values were 0.19 ± 0.03 s⁻¹ and 1.4 ± 0.2 s⁻¹ for hPolε and p261N, respectively.