Table I. Data collection and phasing statistics.
| Data sets |
||||
|---|---|---|---|---|
| NATI1 | NATI2 | AuCl3 | DSYTC | |
| Data collection | ||||
| space group | C2 | C2 | C2 | I2(1)3 |
| asymmetric monomers | 12 | 12 | 12 | 4 |
| Vm (Å3/Da) | 2.9 | 3.1 | 3.1 | 5.5 |
| limiting resolution (Å) | 2.5 | 3.7 | 4.3 | 2.57 |
| last shell (Å) | 2.50–2.56 | 3.71–3.91 | 4.30–4.53 | 2.68–2.57 |
| unique reflections | 81 936 | 28 987 | 14 935 | 56 352 |
| mean redundancy | 2.6 (2.4) | 2.1 (1.8) | 1.9 (1.8) | 2.7 (2.1) |
| completeness (%) | 87.1 (73.3) | 92.4 (82.1) | 75.0 (57.5) | 93.2 (59.4) |
| mean I/σI | 10.2 (2.8) | 5.8 (2.4) | 2.9 (2.1) | 12.2 (2.0) |
| Rsym (%) | 5.8 (24.8) | 10.2 (27.3) | 14.4 (32.2) | 6.8 (34.9) |
| Phasing | ||||
| Riso (%) | 25.9 | – | ||
| number of sites | 12 | |||
| RCullis | 0.76 | – | ||
| phasing power | 1.43 | – | ||
NATI1 (a = 164.7 Å, b = 110.0 Å, c = 152.9 Å; β = 90.4°), native data set used for refinement; NATI2 (a = 176.5 Å, b = 110.5 Å, c = 154.2 Å; β = 94.3°), native data set used for SIR phasing and initial model building. AuCl3 (a = 175.0 Å, b = 110.3 Å, c = 153.9 Å; β = 94.3°), DSYTC (a = b = c = 223.55 Å) pentapeptide complex.
Rsym = Σ|I(h)i – <I(h)>|/Σ<I(h)>
Riso = Σ|FPH – FP|/ΣFP
RCullis = (r.m.s. lack of closure)/(r.m.s. isomorphous difference).
Phases were calculated in the resolution range 15.0–4.3 Å and had a mean figure of merit of 0.3. Cyclic 12-fold averaging resulted in a back-transformation R-factor of Rback = 18.1%.