FIGURE 6.

Nuclease activities of APE1 mutants in close proximity to Arg-237 and Gly-241. A, image of the surface of APE1 (41) on which the Arg-237 and Gly-241 residues reside, in addition to the locations of specific amino acids in close proximity that are mutated for testing. B, percent cleavage of naked AP-Out DNA and AP-Out nucleosome substrates after a 10-min incubation with newly created APE1 mutants E216A, E217A, P234A, and Q245R. WT APE1, R237C, and G241R data from Fig. 1 were added for comparison. Bars represent the average of at least 3 independent measurements, error bars represent standard deviations.