FIGURE 7.

The functional interaction between PfuUDG and PCNA. A, wild-type (WT) and mutant (T154A/L155A/F156A) PfuUDGs (20 fmol each) were incubated with 100 fmol of uracil-containing DNA substrate (G:U^*) and 0-450 nm wild-type PfuPCNA in a reaction mixture containing 0.1 m KCl, as described under “Experimental Procedures.” B, the uracil excision efficiencies are plotted as a function of the PCNA concentration as a trimer. These reactions were performed three times independently for each combination of UDG and PCNA, including the cases presented in Fig. 4, at the same time, and therefore, the plot with the error bar for PCNA WT is exactly the same as that shown in Fig. 4.