Table 1. Data-collection and structure-refinement statistics.
The SeMet data were used for phasing and initial model building and the apo IF2 structure was refined against the native data; the other data sets were used for the IF2–GTP and IF2–GDP complexes. The varying atom numbers are owing to partial disorder of the switch I and II regions and the beginning of domain III. Values in parentheses are for the highest resolution shell. R merge is defined according to XDS (Kabsch, 2010 ▶); R work and R free are crystallographic R factors calculated for the work and test data sets (Brünger, 1992 ▶).
| SeMet | ||||||
|---|---|---|---|---|---|---|
| Peak | Inflection | Remote | Native | IF2–GTP | IF2–GDP | |
| Data collection | ||||||
| Beamline | PX, SLS | PX, SLS | PXIII, SLS | PXIII, SLS | ||
| Space group | P212121 | P212121 | P212121 | P212121 | ||
| Unit-cell parameters | ||||||
| a (Å) | 45.19 | 45.42 | 45.02 | 44.75 | ||
| b (Å) | 60.93 | 61.46 | 61.95 | 62.45 | ||
| c (Å) | 160.74 | 162.40 | 160.42 | 160.11 | ||
| Resolution (Å) | 50–2.4 (2.5–2.4) | 50–2.4 (2.5–2.4) | 50–2.4 (2.6–2.5) | 50–1.95 (2.05–1.95) | 60–2.8 (2.82–2.8) | 50–2.3 (2.4–2.3) |
| R merge (%) | 7.1 (30.9) | 6.5 (28.3) | 15.6 (60.4) | 9.7 (43.7) | 12.1 (88.2) | 13.6 (80.2) |
| No. of reflections | 18011 | 18029 | 15688 | 36057 | 11636 | 15818 |
| Completeness (%) | 99.6 (99.7) | 99.5 (99.4) | 98.7 (99.6) | 100.0 (100.0) | 99.9 (100.0) | 76.4 (49.8) |
| Multiplicity | 4.7 (4.3) | 4.8 (4.5) | 5.0 (4.9) | 11.0 (11.1) | 6.3 (6.2) | 3.3 (3.1) |
| 〈I/σ(I)〉 | 15.7 (6.1) | 16.7 (6.6) | 13.9 (4.7) | 17.6 (4.2) | 15.4 (2.6) | 12.4 (2.2) |
| Refinement | ||||||
| Resolution limits (Å) | 49.0–1.95 (2.0–1.95) | 43.3–2.8 (3.1–2.8) | 40.6–2.3 (2.4–2.3) | |||
| No. of reflections | 34052 | 11629 | 15810 | |||
| Protein atoms | 2909 | 2692 | 2705 | |||
| Water molecules | 204 | 21 | 71 | |||
| R work/R free (%) | 17.9/21.9 (21.7/27.0) | 22.6/30.4 (32.2/40.6) | 21.7/28.6 (30.0/41.3) | |||
| Average B value for all atoms (Å2) | 47.7 | 89.9 | 70.9 | |||
| R.m.s. deviations from ideal values | ||||||
| Bond lengths (Å) | 0.013 | 0.005 | 0.004 | |||
| Bond angles (°) | 1.38 | 1.08 | 0.91 | |||
| Dihedral angles (°) | 16.2 | 18.5 | 15.2 | |||
| Planar groups (Å) | 0.007 | 0.004 | 0.003 | |||
| Ramachandran statistics (%) | ||||||
| Favoured | 95.73 | 95.36 | 96.54 | |||
| Allowed | 4.00 | 4.64 | 3.46 | |||
| Outliers | 0.27 | 0.00 | 0.00 | |||