Table 1.
Data collection and structural parameters obtained by SAXS.
| TupA | TupA* | TupA W | TupA W* | TupA Mo | |
|---|---|---|---|---|---|
| Data collection parameters | |||||
| Instrument | P12 | BM29 | P12 | BM29 | P12 |
| Wavelength, Å | 1.24 | 0.99 | 1.24 | 0.99 | 1.24 |
| s-range, Å−1 | 0.0027–0.45 | 0.003–0.49 | 0.0027–0.45 | 0.003–0.49 | 0.0027–0.45 |
| Exposure time, s | 1 | 10 | 1 | 10 | 1 |
| Concentration range, mg/ml | 1.0–8.5 | 0.8–6.0 | 1.0–6.0 | 0.8–12.0 | 1.0–6.0 |
| Temperature, K | 280 | 278 | 280 | 278 | 280 |
| Structural parameters | |||||
| Rg, Å [from P(r)] | 25.5 ± 0.3 | 25.4 ± 0.3 | 24.1 ± 0.2 | 23.8 ± 0.2 | 24.4 ± 0.2 |
| Rg, Å (from Guinier) | 24.2 ± 0.4 | 24.0 ± 0.4 | 23.0 ± 0.3 | 22.8 ± 0.3 | 22.9 ± 0.3 |
| Dmax, Å | 96 ± 3 | 95 ± 3 | 90 ± 3 | 89 ± 3 | 92 ± 3 |
| Porod volume, Å3 × 103 | 51.4 ± 3.5 | 48.5 ± 3.3 | 45.7 ± 3.1 | 44.4 ± 3.0 | 45.8 ± 3.1 |
| Mol. mass determination (kDa) | |||||
| From I(0) | 29 ± 2 | 32 ± 2 | 26 ± 2 | 29 ± 2 | 26 ± 2 |
| From Porod volume | 31 ± 2 | 29 ± 2 | 28 ± 2 | 27 ± 2 | 28 ± 2 |
| Model vs. data discrepancy (χ2) | |||||
| Holo-form model | 4.0 | 2.4 | 0.9 | 2.2 | 0.9 |
| MX | 7.8 | 5.8 | 1.8 | 11.6 | 1.8 |
| Apo-form model | 1.0 | 0.7 | 2.0 | 11.9 | 1.7 |
Molecular mass (M) was estimated from forward scattering I(0) and Porod volume respectively, the theoretical molecular mass predicted from sequence is 29.7 kDa. Radius of gyration, R g (Å) was calculated using the Guinier approximation and also the distance distribution function (P(r) using GNOM), which also estimates maximum particle dimension (D max). χ2 values correspond to discrepancies between models and experimental data, the lowest χ2 value per dataset is highlighted. MX: crystal structure.
*Data collected at BM29 beamline, ESRF, Grenoble, France. The rest of the datasets were collected at EMBL P12 beamline, DESY, Hamburg, Germany.