Figure 5
Summary of magnesium dependence of initial rates. Initial rates observed in 10 (gray bars), 5 (diagonally hatched bars), 2 (white bars) and 0.5 (black bars) mM MgCl2 are normalized to the rate observed in 5 mM MgCl2. The down arrow for RzCΔ2 indicates that no cleavage was observed under these conditions. Symbols above the bars indicate magnesium sensitivity: "++," moderate magnesium dependence indicative of tertiary stabilization; "+/-," intermediate magnesium dependence indicative of modest tertiary stabilization; "-," strong magnesium sensitivity indicative of there being no tertiary stabilization.