Table 1.

Data collection and refinement statistics

	Sulfate-bound form	Nt-free	AMPPNP	ADP·MgF3
Data collection
Space group	P21212	P212121	P21	P21
Resolution (Å)1	50 - 2.9 (3.00 - 2.90)	50 - 3.0 (3.11 - 3.00)	50 - 2.6 (2.69 - 2.6)	50 - 2.2 (2.28 - 2.2)
Completeness (%)1	99.2 (92.5)	87.0 (57.9)	89.7 (51.5)	93.5 (63.0)
Rmerge 1,2	8.8 (58.4)	7.7 (46.9)	6.1 (20.6)	6.8 (29.3)
I / σ(I) 1	21.7 (2.17)	22.8 (2.56)	23.3 (4.1)	30.1 (2.67)
Refinement
Unique reflections	48,037	37,494	61,012	102,202
Protein + DNA atoms	10,815	11,484	10,969	11,214
Metal + Solvent atoms	87	23	182	577
R-factor (Rfree) (%)1,3	23.7 (29.6)	23.0 (28.5)	21.5 (25.7)	21.0 (24.0)
Average B-factor (Wilson) (Å2)4	55.31 (32.36)	76.27 (61.35)	77.04 (46.42)	56.05 (42.29)
R.m.s. deviations
Bonds (Å)	0.0080	0.0080	0.0067	0.0060
Angles (°)	1.38	1.41	1.23	1.13

¹Values for the highest resolution shell are indicated in parentheses.

²$\mathrm{R}\text{merge}={\Sigma }_{\mathrm{h}}{\Sigma }_{\mathrm{i}}\mid \mathrm{I}{\left(\mathrm{h}\right)}_{\mathrm{i}}-<\mathrm{I}\left(\mathrm{h}\right)>\mid ∕{\Sigma }_{\mathrm{h}}{\Sigma }_{\mathrm{i}}\mathrm{I}{\left(\mathrm{h}\right)}_{\mathrm{i}}$, where I(h) is the intensity of reflection h, Σh is the sum over all reflections, and Σi is the sum over i measurements of reflection h.

³$\mathrm{R}-\text{factor}=\Sigma \mid \mid {\mathrm{F}}_{\mathrm{o}}\mid -\mid {\mathrm{F}}_{\mathrm{c}}\mid \mid ∕\Sigma \mid {\mathrm{F}}_{\mathrm{o}}\mid$, where F_o and F_c are the observed and calculated structure factor amplitudes. R_free is calculated for a randomly chosen 10% of reflections which were not used for structure refinement and R-factor is calculated for the remaining reflections.