Figure 4.

(A) Superimposed on the secondary structure of G11 (15) are nucleotides that display an inhibitory effect on self-cleavage when substituted with 2′-deoxynucleotides in a NAIM experiment (filled arrowheads) and those that display a stimulatory effect (open diamonds). Nucleotides that were tested using site-specific 2′-deoxynucleotide substitutions in a trans cleavage assay and which display inhibitory effects are indicated by filled circles. The cleavage site is indicated by the arrow. (B) Important 2′-OHs are highlighted on the alternative representation of the secondary structure model. Symbols are as in (A).