(A). Tth111II digestion of pZZTB1 (Nb.BsmI pre-nicked) with the addition of different concentrations of oligos in 30 min at 65°C (+320 μM SAM). Lane 1, 1 kb DNA ladder; Lane 2–9; Tth111II digestion of pZZTB1 (Nb.BsmI pre-nicked) in the presence of 0, 0.067, 0.13, 0.27, 0.53, 1.1, 2.1, 4.3 μM of duplex oligo 1 (one Tth111II site). The final cleavage product is linear DNA. (B). Graphic representation of the relationship of dsDNA cut ratio and concentration of the duplex oligo 1 as shown in panel A. (C). Same reaction condition as in A. Lane 2, uncut pZZTB1; lane 3–12: Tth111II digestion of pZZTB1 (Nb.BsmI pre-nicked) in the presence of 0.017, 0.033, 0.067, 0.13, 0.27, 0.53, 1.1, 2.1, 4.3 μM of duplex oligos 2 (no Tth111II site). (D). Same as in C except the duplex oligos is #3 with one Tth111II star site. (E). Same reaction condition as in A. Lane 2–7, Tth111II digestion of pZZT1 by decreasing amount of Tth111II enzyme without additional duplex oligos. Lane 8–13, Tth111II digestion of pZZTB1 by decreasing amount of Tth111II enzyme plus duplex oligos 1. Lane 14–19, same as lanes 8–13, except the duplex oligo is #4 (cleavage product-like oligos).