Figure 6.

Cleavage of 3′ end-labeled ssDNA. Reaction mixtures (70 μL) containing 20 mM Tris-HCl (pH 8.0), 2 mM MgCl₂, 0.5 mM DTT, 0.1 μM 3′ ³²P-labeled 25-mer DNA substrate (depicted at the bottom), either no nucleotide or 1 mM ATP as indicated, and AdnAB (60 ng of AdnB) were incubated at 37°C. Aliquots (10 μL) were withdrawn at the times specified and quenched with formamide/EDTA. The reaction products were analyzed by Urea-PAGE and visualized by autoradiography. The principal sites of AdnAB incision of the 25-mer DNA in the absence of ATP are indicated by arrows above the sequence; the cleavage site induced by ATP is indicated below the sequence.