Table 1.
| Parameter | Native | Iodide (NaI) | Cadmium (CdCl2) |
|---|---|---|---|
| Experimental Details | |||
| X-ray source | CuKα | CuKα | CuKα |
| Heavy atom compound | Sodium iodide | Cadmium Chloride | |
| Soak conc. | 75 mM | 50 mM | |
| Soak duration | 50–70 min | 60–70 min | |
| Crystallographic Data | |||
| Space group | P65 | P65 | P65 |
| Cell Dimensions (Å; °) |
a=b=55.0Å,c=59.6Å α=β=90°; γ=120° |
a=b=55.2Å,c=59.7Å α=β=90°; γ=120° |
a=b=55.0Å,c=59.5Å α=β=90°; γ=120° |
| Unit cell volume (Å3) | 155874 | 157654 | 156204 |
| Resolution range (Å)a | 25.0-1.88 (1.95-1.88) | 25.0-1.9 (1.97-1.9) | 25.0-2.5 (25.0-2.5) |
| Observations | 38569 | 69358 | 13916 |
| Unique reflections | 8382 (810) | 8240 (811) | 3545 (313) |
| Redundancy | 4.6 (3.2) | 8.4 (7.7) | 3.9 (2.6) |
| Completion (%) | 99.6 (96.8) | 99.9 (99.8) | 98.7 (91.8) |
| I/σ(I) | 13.8 (1.9) | 20.4 (4.4) | 7.07 (1.78) |
| Rsym (%)b | 9.7 (44.4) | 9.3 (35.0) | 13.7 (39.0) |
| Molecules/A.U | 1 | 1 | 1 |
| Refinement | |||
| RMSD bonds (Å) | 0.005 | ||
| RMSD angles (°) | 1.27 | ||
| Rcryst (%)c | 18.14 | ||
| Rfree (%) | 23.2 | ||
| No. of residues | 93 | ||
| No. of atoms | 859 | ||
| Protein | 740 | ||
| Water | 113 | ||
| Glycerol | 6 | ||
| Ramachandran plot: | |||
| Residues in: | |||
| Most favored region | 71 (90%) | ||
| Addtnl allowed regions | 6 (7.6%) | ||
| Generously allowed regions | 1(1.3%) | ||
| Disallowed regions | 1 (1.3%) | ||
| Average B-factors (Å2): | |||
| Protein (overall) | 20.38 | ||
| Solvent atoms | 33.15 | ||
| Glycerol atoms | 26.4 | ||
a
Values in parentheses are for the highest resolution shell
b
Rsym = ∑|I(h)−<I(h)>|/∑I(h), where I (h) is the observed intensity and <I(h)> is the mean intensity of reflection h over all measurements of I(h).
c
Rcryst and Rfree = ∑h‖F(h)obs|−|F(h)calc‖/∑h|F(h)obs|.
Throughout refinement, 5% of the total reflections were held aside for Rfree. Refinement was carried out in repeated cycles using the CNS package. Stereochemical quality was assessed using Procheck.