Figure 4.

Selectivity of nucleotide incorporation by ApPolη opposite undamaged TT (a), CPD (b), 6–4 pp (c), and Dewar (d). ApPolη (12 fmol in lanes 2–7) was incubated with each primer-template in the presence of the four dNTPs (lane 3), the indicated dNTP (lanes 4–7), or the absence of dNTP (lane 2). Lane 1 contained no enzyme. The reactions were incubated at 37°C for 5 minutes, and then were subjected to 15% polyacrylamide/7.5 M urea gel electrophoresis. The autoradiograms of the gels are shown.