Fig. 5.

Binding and AP site cleavage by Tdp1 and its mutants. The A panel shows quantitative analysis of the data from three independent of gel shift experiments. The 5′-end labeled DNA substrates (ssAP-DNA or dsAP-DNA) were incubated with increasing concentrations of Tdp1 or its mutants (from 1 nM up to 10 nM) and subjected to native gel electrophoresis. The gels were dried and analyzed using the PhosphorImager. The B panel shows the hydrolysis of AP sites in single (lane 7–12) and double (lane 1–6) stranded DNAs by Tdp1 and its mutants. The 5′-end labeled AP-DNA was incubated with decreasing concentrations of Tdp1 (lanes 1, 2, 7, 8), SCAN1 (lanes 3, 4, 9, 10), H263A (lanes 5, 6, 11, 12). S denotes the initial substrate, the 48-mer DNA duplex.