Table 1.

Data and refinement statistics

Data collection statistics
Wavelength (Å)	1.0
Space group	P212121
Unit cell parameters (Å)	a = 99.6, b = 108.4, c = 169.4
No. of unique reflections	61 700
Resolution (Å)a	50–2.50 (2.59–2.50)
Rmergea,b	7.8 (49.5)
Completeness (%)a	96.0 (84.5)
I/σa	28.8 (3.3)
Refinement statistics
Number of protein residues in the final modelc	761
Number of base pairs in the DNA	146
Number of water molecules	430
Number of Mn ions	9
Number of Cl ions	4
Total number of atoms in the final model	12 475
Rwork/Rfree (%)d	22.38/27.69
R.m.s.d from ideality
Bond (Å)	0.0062
Angles (°)	1.14
Average B-factors (Å2)
Protein	28.91
DNA	51.80
Solvent	33.36

^aValues in the parentheses are for the final shell.

^b$R_{\text{merge}}=\sum \left|I_{hkl}-〈I_{hkl}〉\right|/\sum I_{hkl}$, where I_hkl is the intensity measurement for the reflection with indices hkl, and 〈I_hkl〉 is the mean intensity for multiply recorded reflections.

^cResidues included in each histone subunit: H3: 38–134, H3′: 37–135, H4: 25–102, H4′: 18–102, H2A: 11–118, H2A′: 15–118, H2B: 30–125, H2B′: 31–124. The remaining portions of the histone tails were too disordered to be included in the final model.

^d$R_{\text{work},\text{free}}=\sum \left|\left|F_{obs}\right|-\left|F_{\text{calc}}\right|\right|/\left|F_{\text{obs}}\right|$, where the R-factors were calculated using the working and free reflection sets, respectively. The free reflections comprise a random 10% of the data reserved for unbiased cross-validation throughout the refinement.