Figure 7.

Titration with Ln³⁺ ions. The hammerhead ribozyme reaction was examined on a background of Mg²⁺ ions. (A) Data obtained by Lott et al. (24). The proposed binding of metal ions is illustrated. (B) Data obtained by Nakamatsu et al. (161). An unmodified ribozyme (R34; red curve) and a modified ribozyme (7-deaza-R34; blue curve) were used. The rate constants were normalized by reference to the maximum rate constant ([La³⁺] = 3 µM). Reactions were performed under single-turnover conditions in the presence of 80 nM ribozyme and 40 nM substrate at 37°C.