TABLE 1.

Kinetic parameters for cis- and trans-cleaving hRz

	Cis-reactionsb
	MgCl2, mM	Temp. °C	kobs min−1	plateaua
GG	0.1	37	0.56	0.61
CG	0.1	37	1.2	0.91
UG	0.1	37	1.2	0.85
AG	0.1	37	1.3	0.64
GC	0.1	37	1.2	0.65
HH2	0.1	37	0.041	0.16
SMα1	0.1	37	0.93	0.67
GG	0.1	37	2.8	1.0
CG	0.1	37	1.8	0.97
GA	0.1	37	2.1	0.83
HH2	0.1	37	0.042	0.16
PLMV	0.1	37	0.36	0.46

	Trans-reactions
	MgCl2, mM	Temp. °C	kobs min−1	plateaua
Observed initial cleavage rates (kobs) and fraction converted to product for constructs described in this study. Reported values are derived from averages of at least two measurements, which were usually within 5%–10% of each other. Uncertainties of fit to single-exponential kinetic models for calculated kobs were generally ±10% using the averaged data. Dashes indicate that no cleavage was observed under these conditions during 1 h reaction.
aCalculated plateau value, f∞, as described in methods.
bIndividual isolates are designated by the dinucleotide present at the variable positions within the selected motifs: xxGCUACG for LibA (top set) and UGxxAU for LibB (bottom set).
cThese reaction conditions gave complex, multiphasic kinetics with rapid cleavage of 20%–70% of the input material, followed by nearly complete religation within 1–2 min. Reported rates are for initial cleavage only.
RzA	1.0	25	1.7	0.69
	0.5	25	1.2	0.15
	0.1	25	—	—
RzA-4	10	37	—	—
	20	25	1.3	(c)
	20	37	1.6	(c)
	50	25	3.5	(c)
	50	37	4.7	(c)
RzB	0.5	25	2.0	0.56
	0.1	25	1.4	0.47
	0.5	37	1.8	0.63
	0.1	37	0.04	(c)
RzB-1	0.5	25	2.2	0.39
	0.1	25	0.28	0.28
	0.5	37	2.0	0.39
	0.1	37	0.20	0.29
RzB-2	0.5	25	1.3	0.38
	0.1	25	1.3	0.09
	0.5	37	3.2	0.31
	0.1	37	(c)	(c)
RzB-3	0.5	25	1.9	0.46
	0.1	25	1.2	0.06
	0.5	37	1.6	0.29
	0.1	37	1.3	0.05
RzB-4	0.5	25	1.9	0.56
	0.1	25	1.2	0.45
	0.5	37	1.5	0.51
	0.1	37	0.59	0.55
RzB-5	0.5	25	—	—
	0.5	37	—	—
	10	25	1.1	0.53
	10	37	≈1.2	≈0.6