Table 2. Data collection and refinement statistics.

RNase H1^WT reaction with 2 mM Mg²⁺ and 200 mM K⁺ (Fig. 1d and 2a)

	80 s	120 s	480 s
	PDB 6DO8	PDB 6DO9	PDB 6DOA
Data collection
Space group	C 1 2 1	C 1 2 1	C 1 2 1
Cell dimensions
a, b, c (Å)	81.3, 37.8, 62.1	81.3, 37.8, 62.5	81.7, 37.9, 62.7
a, b, γ (°)	90, 96.2, 90	90, 96.2, 90	90, 96.7, 90
Resolution (Å) 1	20.0 - 1.42 (1.44 - 1.42)	20.0 - 1.36 (1.38 - 1.36)	50.0 - 1.48 (1.51 - 1.48)
Rpim 1	0.031 (0.830)	0.051 (>1.0)	NA
Rsym or Rmerge 1	0.046 (>1.0)	0.073 (>1.0)	0.053 (0.67)
I/σ (I) 1	19.6 (0.80)	12.7 (0.80)	17.6 (1.38)
CC1/2 1	(0.348)	(0.173)	NA
Completeness (%) 1	96.9 (90.0)	98.2 (84.8)	99.5 (99.4)
Redundancy 1	3.1 (2.5)	2.8 (1.7)	3.1 (2.7)
Refinement
Resolution (Å)1	19.2 - 1.42	19.9 - 1.36	31.1 - 1.48
No. reflections1	34740	40176	32224
Rwork / Rfree	15.0 /16.8	15.4 / 17.6	15.6 / 18.2
No. atoms
Protein / RNA/ DNA	2054 / 122 / 121	2048 / 147 / 121	2096 / 135 / 121
Me2+	2 Mg2+	2 Mg2+	2 Mg2+
Me+ 4	2 K+	3 K+	3 K+
Halides4	4 I−	4 I−	4 I−
Water/ Solvent	191 / 37	187 / 50	196 / 55
Occupancy
RS: PS	0.80 : 0	0.65 : 0.35	0.35 : 0.65
A site	1.0 Mg2+	1.0 Mg2+	1.0 Mg2+
B site	1.0 Mg2+	1.0 Mg2+	1.0 Mg2+
U site	0.30 K+	0.25 K+	0.10 K+
W site	0	0.25 K+	0.35 K+
B-factors
Macromolecules	25.1	26.6	22.6
MeA / LigA2	19.3 / 25.6	20.9 / 32.5	17.0 / 20.3
MeB / LigB2	19.3 / 20.7	21.5 / 25.7	14.7 / 18.3
MeU / LigU2	28.8 / 30.8	28.2 / 27.7	24.9 / 23.8
MeW / LigW2	NA	24.9 / 19.1	18.4 / 16.0
Solvent3	39.8	42.3	36.8
R.m.s deviations
Bond lengths (Å)	0.007	0.009	0.009
Bond angles (°)	0.98	1.28	1.14

¹Data in the highest resolution shell is shown in the parenthesis.

²B-factors of metal ions and their protein, solvent, and nucleotide ligands.

³Water, ethylene glycol and glycerol

⁴B factors and occupancies are not listed for non-catalytic monovalent cations and halides