Figure 2.

Characterization of the AP lyase activity. (A) Creation of AP substrate containing a single abasic site using uracil DNA glycosylase (UDG). (B) 15% denaturing SDS–PAGE. Four micrograms per lane of each protein was loaded onto the gel. (C) Determination of the chemical nature of DNA ends generated by HMGA2. Cleavage products obtained with the following E. coli proteins: formamidopyrimidine N-glycosylase (Fpg), endonucleases III (endo III) and IV (endo IV), as indicated, can be separated from substrates through denaturing polyacrylamide gel electrophoresis. The 31-mer incubated under the same conditions, but in the absence of protein is shown as control in lane 1. (D) Quantification of AP lyase activities. After electrophoresis and autoradiography, bands corresponding to substrate and products were quantified and plotted against the molar protein to DNA ratio.