TABLE 4.

Reactivity of the closed ternary complex of the WT and A261H ribozymes (see Scheme 2).^*

Ribozyme	Nucleophile	kc
		(min-1)	Relative
WT	AUCG	0.48	(1.0)
	AUCI	0.13	3.7
A261H	AUCG	0.023	21
	AUCI	0.065	7.4

^*Values of $K_{\text{dock}}^{\text{ES}•\text{AUCX}}$ were > 1 for both the WT and A261H ribozymes (Table 3). Thus, both ribozymes reacted from the docked conformation.