Table 1.
Crystal properties, data collection, refinement, and model statistics
| Crystal properties | ||
| Space group | P212121 | |
| Cell dimensions, (a × b × c), Å | 77.0 × 55.2 × 53.9 | |
| Molecules per asymmetric unit, no. | 1 | |
| Data collection statistics | Resolution limits | |
|---|---|---|
| 14–2.6 Å | 2.7–2.6 Å | |
| Measurements, no. | 39,403 | 3,891 |
| Unique reflections, no. | 7,111 | 745 |
| Completeness, % | 95.9 | 96.2 |
| Mean I/σI | 6.2 | 4.3 |
| Rmerge, % | 14.2 | 38.7 |
| Crystallographic refinement statistics | Resolution limits | |
| 6.0–2.6 Å | 2.7–2.6 Å | |
| Reflections, no. | 6,554 | 745 |
| Reflections with F > 2σF, no. | 6,307 | 708 |
| Crystallographic R factor, % | 16.1 | 19.3 |
| Free R factor, % | 24.6 | 28.0 |
| Model statistics | ||
| Total no. of nonhydrogen atoms | 2017 | |
| Protein atoms, no. | 1910 | |
| Solvent atoms, no. | 107 | |
| RMSD bond length, Å | 0.014 | |
| RMSD bond angle, degrees | 1.66 | |
| Mean B factor (SD), Å2 | ||
| Protein | 12.5 (5.9) | |
| Solvent | 22.8 (12.3) | |
| Mean real space fit (SD), % | ||
| Protein | 89.7 (3.8) | |
| Solvent | 83.1 (6.6) | |
Unit cell dimensions for the cross-linked crystal are 77.2 × 55.8 × 53.7 Å in water (3) and 77.1 × 55.4 × 53.6 Å in acetonitrile (2) and for the non-cross-linked crystal in aqueous buffer are 76.7 × 55.6 × 53.1 Å (10). Rmerge is the R factor on the intensity for symmetry-related measurements. The crystallographic R factor is the R factor on structure factors for reflections used in the refinement (90% of total). The free R factor is the R factor on structure factors for reflections randomly omitted from the refinement and used as the test set (10% of total). In model statistics, only atoms included in the refinement are shown. A Luzzati analysis revealed the average coordinate error to be 0.3 Å. RMSD is rms deviation from ideal geometric values [Enge and Huber parameter set (27)]. The mean real space fit is the real-space-fit values calculated from the 2Fo–Fc electron density maps.