Table 1.
ΔGH2O and mGdHCl values obtained for staphylococcal nucleases at room temperature ~25°C using the HX ESI-MS kinetic-based method. ΔGH2O and mGdHCl values from fluorescence studies [5,6,36] are at 20°C unless otherwise stated. ΔG and m units are kcal mol−1 and kcal mol−1 M−1. Estimated average uncertainty for the ΔG is ~0.3 kcal mol−1 and for m is 0.1 kcal mol−1 M−1.
| Staphylococcal Nuclease | Δ GH2O (MS) | ΔGH2O (Fluoresence) | mGdHCl (MS) | mGdHCl (Fluoresence) |
|---|---|---|---|---|
| Wild Type | 6.7 | 5.0* | 5.6 | 6.5* |
| 23L/25I/66L/72V | 3.8 | 2.8 | 3.0 | 6.4 |
| 23I/25I/66L/72L | 4.1 | 2.7 | 3.9 | 6.9 |
| 23I/25V/66L/72L | 3.8 | 2.8 | 2.6 | 6.2 |
| 23I/25V/66I/72V | 3.5 | 2.4 | 1.9 | 6.4 |
| 23L/25V/66L/72V | 3.9 | 3.0 | 2.2 | 6.9 |
| 23L/25I/66L/72L | 4.1 | 3.0 | 2.5 | 5.9 |
| 23I/25I/66I/72V | 3.7 | 2.3 | 3.1 | 6.2 |
| 23I/25I/66L/72V | 4.0 | 2.8 | 2.4 | 6.0 |
| 66I/72V/92V/99L | 4.5 | 3.7 | 3.2 | 6.9 |
| 66I/72L/92V/99I | 4.6 | 4.0 | 3.0 | 6.7 |
| 66I/72V/92L/99L | 4.4 | 2.8 | 2.9 | 6.7 |
| 66I/72V/92L/99I | 4.5 | 3.4 | 2.5 | 6.7 |
| D21N | 7.0 | 6.6 | 4.8 | 6.3 |
| 117G/124L/128A/41I/59A/21K/21N | 10.4 | 11.0 | 3.6 | 5.3 |
*
measured at 25°C