Extended Data Table 3.

X-ray data collection and refinement statistics.

	3d3mA•T-DNA 9-mer A	3d3mA•T-DNA 9-mer B	1aR•T-DNA/3mA	THF•T-DNA/3mA
Data collection
Space group	C2	C2	P21	P21
Cell dimensions
a, b, c (Å)	127.44, 55.41, 47.97	127.40, 55.45, 47.56	38.20, 92.83, 48.31	38.49, 93.29, 48.16
α, β, γ (°)	90.00, 105.70, 90.00	90.00, 106.36, 90.00	90.00, 113.71, 90.00	90.00, 112.84, 90.00
Resolution (Å)	50.00–1.77 (1.83–1.77)*	50.00–1.73 (1.79–1.73)	50.00–1.54 (1.57–1.54)	50.00–1.73 (1.79–1.73)
Rmerge	0.088 (0.414)	0.072 (0.362)	0.057 (0.255)	0.067 (0.443)
Avg. I/σI	15.0 (2.7)	21.3 (5.1)	78.6 (7.0)	23.2 (3.4)
Completeness (%)	96.7 (80.0)	100.0 (99.9)	97.2 (92.2)	99.9 (99.6)
Redundancy	4.6 (4.2)	5.3 (4.8)	7.1 (6.4)	4.9 (4.6)
Refinement
Resolution (Å)	46.20–1.77 (1.82–1.77)	45.65–1.73 (1.78–1.73)	35.00–1.54 (1.58–1.54)	40.09–1.73 (1.78–1.73)
No. reflections	30,638 (2,200)	33,412 (2,770)	44,194 (3,013)	32,539 (2,620)
Rwork	0.163 (0.228)	0.154 (0.196)	0.149 (0.153)	0.155 (0.211)
Rfree†	0.203 (0.277)	0.186 (0.252)	0.179 (0.179)	0.192 (0.288)
No. atoms
Protein	1,898	1,898	1,951	1,951
DNA	364	364	487	487
Water	253	284	415	271
Avg. B-factors‡ (Å2)
Protein	24.2	23.6	14.6	21.2
DNA	38.3	32.2	33.1	39.5
Water	34.0	34.3	31.9	35.5
R.m.s. deviations
Bond lengths (Å)	0.007	0.007	0.006	0.007
Bond angles (°)	1.030	1.074	1.049	1.009
Ramachandran distribution (%)
Favored	97.7	97.3	97.9	97.8
Allowed	2.3	2.7	2.1	2.2
Disallowed	0.0	0.0	0.0	0.0
PDB accession code	5CLB	5CLC	5CLD	5CLE

^*Statistics for the highest resolution shell are shown in parentheses.

^†R_free was determined from the 5% of reflections excluded from refinement.

^‡Equivalent isotropic B-factors were calculated in conjunction with TLS-derived anisotropic B-factors.