Table 1

Data collection and refinement statistics

 Data processing Resolution (Å) 40.0–2.20 (2.28–2.20) Number of reflections 139,486 (13,849) Redundancy 2.1 (2.1) I/σI 14.2 (3.3) Completeness (%) 98.0 (97.1) Rsym (%)* 4.5 (28.7) Refinement Data range (Å) 40.0–2.20 (2.34–2.20) Reflections in working set 131,678 (20,366) Reflections in Rfree set 2713 (419) Rcrys (%)† 20.5 (30.0) Rfree (%)‡ 24.0 (34.8) Number of protein atoms 15,716 Number of solvent atoms 1,446 rms deviation bond length (Å) 0.194 rms deviation bond angles (°) 1.9 Mean B value (Å2) 41.1
• * Rsym = Σh′〈|IhIh′|〉/Σh′Ih′, where 〈|IhIh′|〉 is the average of the absolute deviation of a reflection Ih′ from the average Ih of its symmetry and Friedel equivalents.

• Rcrys = Σ∥Fo| − |Fc∥/Σ|Fo|, where Fc is the calculated structure factor.

• Rfree is as for Rcrys but calculated for 2% of randomly chosen reflections that were omitted from the refinement.