Table 1.
Data collection and refinement statistics
| Form I (SeMet)* | Form II (native) | Form III (native) | |
|---|---|---|---|
| Data collection | |||
| Space group | P212121 | P212121 | P321 |
| Cell dimensions | |||
| a, b, c (Å) | 83.9, 89.3, 101.5 | 76.5, 90.4, 102.4 | 86.1, 86.1, 73.0 |
| α, β, γ (°) | 90, 90, 90 | 90, 90, 90 | 90, 90, 120 |
| Peak | |||
| Resolution (Å) | 101.5-2.2 (2.27- 2.21) |
61.3-1.7 (1.73- 1.68) |
43.0-3.5 (3.69- 3.50) |
| Rsym (%) | 11.3 (81.0) | 8.6 (27.7) | 9.8 (63.9) |
| I / бI | 19.4 (4.0) | 4.7 (2.2) | 10.7 (3.2) |
| Completeness (%) | 100 (100) | 96.2 (95.6) | 99.7 (99.8) |
| Redundancy | 14.4 (14.7) | 3.5 (3.6) | 7.9 (8.2) |
| Refinement | |||
| Resolution (Å) | 101.5-2.2 | 61.3-1.7 | 43-3.5 |
| No. of unique reflections | 38676 | 78019 | 4149 |
| Rwork/Rfree | 20.1/23.7 | 16.3/21.3 | 28.5/33.7 |
| No. atoms Protein | 5056 | 5026 | 1553 |
| Ca2+ ion | 3 | 3 | 1 |
| Water | 179 | 398 | 1 |
| B-factors | |||
| Protein (A/B/C) | 31.7/27.7/43.1 | 21.1/22.1/21.5 | 70.8 |
| Ligand/Ca2+ | 40/21.3 | 36/15.4 | n.a./47.0 |
| Water | 29.8 | 27.6 | 61.0 |
| R.m.s. deviations | |||
| Bond lengths (Å) | 0.009 | 0.009 | 0.010 |
| Bond angles (°) | 1.3 | 1.2 | 1.4 |
Values in parentheses are for highest-resolution shell.
*
Four selenomethionine residues were identified in each polypeptide chain. This compares with a total of six methionines in the amino acid sequence, the remaining two being present in the stalk region which was not resolved in forms I and II. These data compare with approximately five selenomethionine residues per chain detected by mass spectrometry36.