Table 1.

X-ray data collection and refinement statistics

Data collection
Resolution range, Å	20.0–2.20
Observed reflections	119,905
Unique reflections	56,973
Completeness, %	91.2 (64.7)*
Rmerge†	0.041 (0.269)*
Refinement
Resolution range, Å	10.0–2.30
Protein nonhydrogen atoms	8073
Water molecules	888
Rcryst‡	0.233
Rfree‡	0.286
rms difference from ideal geometry
Bond lengths, Å	0.008
Bond angles, °	1.2
Average B-factor, Å2	45.4

^*Values in parentheses correspond to highest resolution shell 2.28 to 2.20 Å. 

^† R_merge = ∑∑_j | I_j (hkl) − 〈I(hkl)〉 |/∑∑_j | 〈I(hkl)〉 |, where I_j is the intensity measurement for reflection hkl and 〈I〉 is the mean intensity over j reflections. 

^‡ R_cryst (R_free) = ∑ | |F_obs(hkl) | − | F_calc(hkl) | |/∑ | F_obs (hkl) | , where F_obs and F_calc are observed and calculated structure factors, respectively. No σ-cutoff was applied. 10% of the reflections were excluded from refinement and used to calculate R_free.