Figure 9.

Unified mechanistic model depicting catalytic strategies of small, self-cleaving ribozymes. Contacts or angles for the four previously recognized catalytic strategies (α, γ, β, and δ) in each of the small self-cleaving ribozyme classes studied are provided (N1G_γ, X_R,β1/β2 or X_S,β1/β2, and X_δ, respectively), and contacts for new identified catalytic strategies (γ′ and γ′′) are noted (N2G_γ′ or X_γ′ and X_{R,γ′′1/γ′′2} or X_{S,γ′′1/γ′′2}, respectively).