FIGURE 4.

Ribonuclease activity of SSO1404 against a series of the truncated RNA5 substrates. A, autoradiograph of the 15% PAA, 8 m urea gel showing the activity of SSO1404 against the RNA5 substrate and its five truncated derivatives (the substrate lengths are shown on the right). B, sequences of the substrates used in the experiment and the positions of the cleavage sites of SSO1404. RNA substrates (0.1 μm) were incubated for 15 min (37 °C) in the absence (lanes 1, 3, 5, 7, 9, and 11) or in the presence (lanes 2, 4, 6, 8, 10, and 12) of SSO1404 (30 μg/ml). Reaction products were processed and visualized as described under “Experimental Procedures.” Lanes T1 and Im represent the products of the RNA5 cleavage by RNase T1 and 2 m imidazole (pH 7.0), respectively.