FIGURE 8.
Ligation reaction by the G8Imidazole hairpin ribozyme. (A) The ligation reaction at 25°C in 20 mM MES (pH 6.5) 10 mM MgCl2, 50 mM NaCl together with a residual 0.6 mM HEPES (pH 7.5) from the hybridization. The extent of product formation is plotted as a function of time and fitted to two exponential functions, the faster yielding an observed rate of 0.024 min−1. The corresponding electrophoretic separation of substrate (S) and product (P) is shown as an inset. Reaction time (minutes) is shown above each lane. (B) The pH dependence of ligation rate. Each point is the average and standard deviation of at least three independent experiments. The data were fitted to equation 1, giving estimated pKA values of 6.1 ± 0.3 and 6.9 ± 0.3.