Figure 6.

Detection of desulfurization. (A) The products of ribozyme-catalyzed cleavage of each substrate [S11O (lanes 4 and 5), S11SpS (lanes 2 and 3) and S11RpS (lanes 6 and 7)] in the presence of 25 mM Mg²⁺ ions as background [50 mM MES-Na, pH 6, 37°C, 3 days]. The cleavage of S11O and S11SpS was complete (lanes 4 and 3) and the extent of cleavage of S11RpS was ∼2.5% (lane 6). Hyd indicates an alkaline-hydrolysis ladder of S11RpS (lanes 1 and 8). The alkaline-hydrolysis ladder of S11SpS was almost the same as that of S11RpS (data not shown). The alkaline-hydrolysis ladder of S11O had a band that corresponded to b instead of a (data not shown). Cd treatment refers to incubation with 12.5 mM Cd²⁺ ions for 1 h after the ribozyme-catalyzed cleavage reaction. (B) Time-course of R32-mediated cleavage of S11RpS in 100 mM Ca²⁺ ions and 50 mM Cd²⁺ ions. Hyd refers to the alkaline-hydrolysis ladder of S11RpS.