Table 2.

Cryo-EM data collection, refinement and validation statistics for the 4×197 and 4×207 arrays

	4×197					4×207
	nuc 1	nuc 2	nuc 3	stack	trinuc	nuc 1	nuc 2	nuc 3	stack	trinuc
	EMD-13372	EMD-13373	EMD-13374	EMD-13371	EMD-13370	EMD-13381	EMD-13382	EMD-13383	EMD-13380	EMD-13379
	PDB 7PFD	PDB 7PFE	PDB 7PFF	PDB 7PFC	PDB 7PFA	PDB 7PFV	PDB 7PFW	PDB 7PFX	PDB 7PFU	PDB 7PFT
Data collection and processing
Magnification	×81,000	×81,000	×81,000	×81,000	×81,000	×81,000	×81,000	×81,000	×81,000	×81,000
Voltage (kV)	300	300	300	300	300	300	300	300	300	300
Electron exposure (e-/Å2)	60	60	60	60	60	60	60	60	60	60
Defocus range (μm)	0.5–3.0	0.5–3.0	0.5–3.0	0.5–3.0	0.5–3.0	0.5–2.0	0.5–2.0	0.5–2.0	0.5–2.0	0.5–2.0
Pixel size (Å/pix)	1.05	1.05	1.05	1.05	1.05	1.05	1.05	1.05	1.05	1.05
Symmetry imposed	C1	C1	C1	C1	C1	C1	C1	C1	C1	C1
Initial particle images	1,075, 418	1,075, 418	1,075, 418	1,075, 418	1,075, 418	1,259,654	1,259,654	1,259,654	1,259,654	1,259,654
Final particle images	113,924	54,212	113,924	113,924	14,348	100,339	41,441	100,339	100,339	18,025
Map resolution (Å)	4.4	4.4	4.3	6.4	9.7	4.4	5.2	4.3	5.0	9.8
FSC threshold	0.143	0.143	0.143	0.143	0.143	0.143	0.143	0.143	0.143	0.143
Map resolution range (Å)	4.0–7.5	3.9–10	3.9–8.5	4.4–12	7–13	4.2–7.4	4.5–9.9	4.1–7.6	4.1–7.6	7–14
Refinement
Initial models used (PDB code)	7K5Y	7K5Y	7K5Y			7K5Y	7K5Y	7K5Y
Model resolution (Å)	4.4	4.4	4.3	6.4	9.7	4.4	5.2	4.3	5.0	9.8
Model resolution range (Å)	4.0–7.5	3.9–10	3.9–8.5	4.4–12	7–13	4.2–7.4	4.5–9.9	4.1–7.6	4.1–7.6	7–14
Map sharpening B factor (Å2)	−50	−100	−50	−50	0	−100	−100	−100	−100	0
Model composition
Non-hydrogen atoms	13,675	13,880	12,935	26,814	42,335	13,880	13,470	13,880	27,760	44,100
Protein residues	843	843	768	1,611	2,454	843	843	843	1,686	2,529
DNA	334	354	334	688	1,122	354	334	354	708	1,182
B factors (Å2)
Protein	408	202	366	516	324	325	376	330	403	344
DNA	421	252	413	589	391	384	382	380	474	549
R.m.s. deviations
Bond lengths (Å)	0.006	0.007	0.006	0.006	0.007	0.006	0.006	0.006	0.006	0.006
Bond angles (°)	0.915	0.936	0.921	0.950	1.137	0.864	0.920	0.880	0.894	1.026
Validation
MolProbity score	1.44	1.39	1.49	1.59	1.50	1.44	1.43	1.39	1.47	1.42
Clashscore	7.78	7.08	9.19	10.58	9.43	8.13	7.86	7.13	8.78	7.69
Poor rotamers (%)	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Ramachandran plot
Favored (%)	98.0	98.5	98.4	97.8	98.3	98.8	98.9	98.7	98.1	98.7
Allowed (%)	2.0	1.5	1.6	2.2	1.7	1.2	1.1	1.3	1.9	1.3
Disallowed (%)	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0