Table 3. Diffraction data and structure-quality indicators.
Values in parentheses are for the highest resolution shell. Because of the perfect hemihedral twinning, the data were integrated and scaled in space group I432. A greater than 90% complete data set with a resolution of 2.1 Å was obtained from the first 160 images (0.1° oscillation per frame) that were least affected by radiation damage. For refinement, the data were expanded to space group I23.
| Twinned crystal processed in space group | Primitive cell | |||
|---|---|---|---|---|
| I23 | I432 | I23 expanded from I432 | P4232 | |
| Unit-cell parameter a (Å) | 350.8 | 350.8 | 351.1 | |
| Resolution | 72.0–2.3 (2.34–2.30) | 72.0–2.1 (2.14–2.10) | 68.0–3.5 (3.56–3.50) | |
| No. of observations | 902384 (43198) | 719342 (21777) | 247619 (12984) | |
| No. of unique observations | 282853 (14471) | 186646 (8521) | 367359 (16771) | 86648 (4550) |
| Observation multiplicity | 3.2 (3.0) | 3.9 (2.6) | 2.9 (2.9) | |
| Completeness (%) | 91.0 (94.0) | 90.0 (83.6) | 93.6 (94.1) | |
| R merge † | 0.154 (0.628) | 0.166 (0.872) | 0.252 (1.04) | |
| 〈I/σ(I)〉 | 6.0 (1.8) | 5.5 (1.1) | 4.5 (0.9) | |
| R factor‡ | 0.33 | |||
| No. of protein atoms§ | 5791 | |||
| No. of water atoms§ | 147 | |||
| Average B factor (Å2) | 22.9 | |||
| Ramachandran statistics¶ | ||||
| Preferred regions (%) | 95.7 | |||
| Allowed regions (%) | 4.0 | |||
| Disallowed regions (%) | 0.3 | |||
| R.m.s.d., bond angles (°) | 1.43 | |||
| R.m.s.d., bond lengths (Å) | 0.013 | |||
R
merge = 
.
The value of the crystallographic R factor is relatively high when compared with the R merge of the 2.1 Å resolution data set. The high value might be owing to the complicated refinement when using the twinned data and/or because the crystal might have been also affected by defects other than the perfect hemihedral twinning.
Data are given for one icosahedral asymmetric unit.
According to MolProbity (Chen et al., 2010 ▸).