FIGURE 2.

Modifications and cleavage activity of the hammerhead ribozymes used in this study. (A) Secondary structure of the AFHH-WT (AFHH; blue), as well as the partially disrupted (AFHH-1A; green) and fully disrupted (AFHH-2A; red) mutants, based on the sequence from Avocado Sunblotch Viroid (ASBV). Several putative interactions between the internal loops of Stems I and II are indicated as thin dashes. (B) Homology model showing possible orientation of the helices. Colors are the same as in A; the green base is the mutation in AFHH-1A, the red base is the additional mutation in AFHH-2A. (C) Characterization of cleavage rate dependence on Mg²⁺ concentration under standard conditions (50 mM Tris-HCl [pH 8.0], 25°C).