Altered Endoribonuclease Activity of Apurinic/Apyrimidinic Endonuclease 1 Variants Identified in the Human Population
Figure 1
AP-DNA endonuclease activity of recombinant APE1 proteins.
(A) AP-DNA endonuclease activities of WT APE1 (lanes 1 and 3) and APE1 variants (lanes 4–11) were assessed as described in the Experimental Procedures. Recombinant proteins (0.14 nM; lanes 1 and 3–11) were incubated with 5′-γ-32P-radiolabeled AP-DNA. The negative control (lane 2) has water added rather than protein samples, and the two WT APE1 (lanes 1 and 3) were from different batches of protein preparation. The 18-nt AP-DNA substrates and the 9-nt incised product are shown with arrows. (B) The structure and sequence of the AP-DNA substrate strand and the 9-nt single-stranded product are shown. The 18-mer oligonucleotide contains the model analog of an AP site, tetrahydrofuran (F).