FIGURE 8.

Mss116p did not affect the internal equilibrium between cleavage and ligation of bound products. (A) Kinetic mechanism of a natural ribozyme with 20 bp in H1, which undergoes product dissociation much more slowly than re-ligation. Chimeric HP420 mRNAs were coexpressed in yeast with (B) active Mss116p (Δmts), (C) catalytically inactive Mss116p (ΔmtsE268Q), or (D) empty vector. Mss116p expression had no detectable effect on HP44 self-cleavage. Mss116p expression had no detectable effect on HP420 self-cleavage activity. Plots display results from a representative pair of experiments with functional (▪) and mutationally inactivated (□) chimeric HP420 mRNAs. Reported values represent the mean and standard deviation obtained from two or more pairs of experiments. Intracellular cleavage, ligation, and dissociation rate constants in the absence of Mss116p overexpression were reported previously (Yadava et al. 2001).