Table 1. Cryo-EM data collection, refinement and validation statistics of condensin apo states.

	#1 Non-engaged overall (EMD-10951, PDB 6YVU)*	#2 Non-engaged arm segment (EMD-10948)	#3 Non-engaged head segment (EMD-10947)	#4 Bridged overall (EMD-10954)	#5 Bridged arm segment (EMD-10953	#6 Bridged head segment (EMD-10952, PDB 6YVV)
Data collection and processing
Magnification	130k	105k, 130k	105k, 130k	130k	130k	130k
Voltage (kV)	300	300	300	300	300	300
Electron exposure (e–/Å2)	46.5	40 ~ 55	40 ~ 55	46.5	46.5	46.5
Defocus range (μm)	-0.5 ~ -0.9	-0.5 ~ -0.9, - 1.6 ~ -3.6	-0.5 ~ -0.9, - 1.6 ~ -3.6	-0.5 ~ -0.9	-0.5 ~ -0.9	-0.5 ~ -0.9
Pixel size (Å)	1.065	1.05, 1.065, 1.085, 1.15	1.05, 1.065, 1.085, 1.15	1.065	1.065	1.065
Symmetry imposed	C1	C1	C1	C1	C1	C1
Initial particle images (no.)	4,052,794	2,369,713	1,683,081	1,683,081	1,683,081	1,683,081
Final particle images (no.)	100,388	636,446	576,016	37,639		24,593
Map resolution (Å)	8.1	5.3	4.2	9.1	7.8	7.5
FSC threshold	0.143	0.143	0.143	0.143	0.143	0.143
Map resolution range (Å)	8.1 to >10	5.3 to >10	4.2 to >10	9.1 to >10	7.8 to >10	7.5 to >10
Refinement
Initial model used		Ab initio and 4RSI	Homology model derived from 6QJ2, 6QJ4, 4UX3, 6Q6E			Homology model derived from 6QJ2, 6QJ4, 4UX3, 6Q6E
Model resolution (Å)		5.5	4.2			7.5
FSC threshold		0.143	0.143			0.143
Model resolution range (Å)		n/a	4.2 ~ 6.5			n/a
Map sharpening B factor (Å2)		-276	-200			-334
Model composition
Non-hydrogen atoms			14,952
Protein residues			1,893
Ligands
B factors (Å2)
Protein			166.71
Ligand
R.m.s. deviations			0.004
Bond lengths (Å)			0.941
Bond angles (°)
Validation
MolProbity score			2.46
Clashscore			24.58
Poor rotamers (%)			0.89
Ramachandran plot
Favored (%)			88.77
Allowed (%)			10.69
Disallowed (%)			0.55

^*Pseudo-atomic sub-models of the entire complex were built and refined against the maps #2 (arm) and #3 (head segments), before being assembled into the holo-complex using the overall maps at lower resolution #1