TABLE 3.
Sedimentation equilibrium analyses of SMN·Gemin2 complexes
All experiments were performed at 4 °C. Calculated complex molecular masses are for a 1:1 stoichiometry. Mfixed, fixed molecular mass of the smallest species in equilibrium models; Mfit, best fit molecular mass for single species models. S, single species; D, dimer; T, tetramer; O, octamer. NA, not applicable.
| Complex | Mcalc | Concentrations | Rotor speeds | Mfixed | Mfit | Model | Kd |
|---|---|---|---|---|---|---|---|
| kDa | μm | krpm | kDa | kDa | μm | ||
| hSMN(14–156)·Gemin2 | 46.6 | 10.5, 14.8, 19.6 | 18, 22, 25 | NA | 42.4 ± 0.3 | S | NA |
| hSMN·Gemin2 | 62.3 | 2.6, 3.8, 5.2 | 8, 10, 12 | 249.2 | NA | T-O | 0.5 ± 0.9 |
| hSMNΔ5·Gemin2 (20) | 58.4 | 3.0, 4.3 | 8, 10, 12, 16 | 116.8 | NA | D-T-O | 0.4 ± 0.6 (D-T) |
| 3.0 ± 0.6 (T-O) | |||||||
| ySMN·Gemin2 | 44.7 | 3.5, 8.8, 14.0 | 8,10, 12 | 89.4 | NA | D-T | 1.0 ± 0.9 |
| MBP-hSMN(229–294) | 48.3 | 4.9, 7.3, 8.3 | 12, 14, 16 | 193.2 | NA | T-O | 9.7 ± 0.9 |