Figure 3.

Determination of substrate specificity. (A) The schematic structures of partial duplex DNA substrates used are shown at the top of each figure. The asterisks indicate ³²P-labeled ends. The oligonucleotides used to construct each substrate in individual experiments are indicated as circled numbers that are listed in Table 1. Reaction mixtures (20 µl) containing the indicated amounts of hDna2 and 15 fmol of each substrate were incubated at 37°C for 10 min, and the reaction products were analyzed as described under Materials and Methods. B denotes the boiled substrate. Graphs on right indicate quantitation of the results in each row. (A) 5′-overhang (a), 3′-overhang (b) and flush (c) substrates. (B) 5′-flap (d), 5′-labeled fork (e) and 3′-labeled fork (f) substrates. (C) 3′-flap (g), 5′-labeled double-flap (h) and 3′-labeled double-flap (i) substrates.