FIGURE 1.

Activity on AP sites within 5′ overhangs. A, description of substrates with relative locations of radiolabel (*), 5′-phosphate (5P), abasic site (open circle), and biotin-streptavidin complex noted. Aligned boxes in opposing strands represent paired bases. Var., variable part; TEG, tetra-ethylene glycol. Bio-SA, biotin-streptavidin complex. B, representative denaturing PAGE analysis of reactions incubated for 15 min at 37 ºC with 5 nm Ku (+) and 1 nm substrates 1–5, with substrate 1–5 end structures varied as described in the graphics shown in panel C. Sub., substrates; P, product. C, average reaction velocities determined after 15 min. Standard deviations (error bars) are from the results of three independent experiments.