Table 1.
Thermodynamic parameters for the temperature-induced denaturation of CaM proteins as determined by DSC
| N-domain |
C-domain |
|||
|---|---|---|---|---|
| Protein | Tm (°C)∗ | ΔHd (kJ/mol) † | Tm (°C) | ΔHd (kJ/mol) |
| apo-wt-CaM | 59.5 ± 0.1 | 177 ± 3.2 | 48.3 ± 0.2 | 84 ± 3.2 |
| apo-SeMet-CaM | 66.2 ± 0.1 | 169 ± 2.7 | 54.7 ± 0.1 | 102 ± 2.7 |
| apo-Eth-CaM | 64.3 ± 0.3 | 142 ± 6.2 | 52.7 ± 0.3 | 103 ± 6.2 |
| apo-Nle-CaM‡ | 57.5 ± 0.4 | 160 ± 20 | 74.6 ± 0.9 | 86 ± 9 |
| apo-CT-CaM | 54.7 ± 0.1 | 173 ± 2.2 | 67.1 ± 0.1 | 124 ± 2.2 |
| apo-SeMet-CT-CaM | 59.9 ± 0.1 | 166 ± 4.4 | 69.2 ± 0.1 | 123 ± 4.4 |
| Ca2+-wt-CaM | 113 ± 1.0 | 93 ± 1.0 | ||
| Ca2+-SeMet-CaM | 118 ± 1.0 | 97 ± 1.0 | ||
| Ca2+-Eth-CaM | 121 ± 1.0 | 100 ± 1.0 | ||
| Ca2+-Nle-CaM | >125 ± 1.0 | 97 ± 1.0 | ||
| Ca2+-CT-CaM | 124 ± 1.0 | 85 ± 1.0 | ||
| Ca2+-SeMet-CT-CaM | >125 ± 1.0 | 92 ± 1.0 | ||
∗
Tm is the transition midpoint temperature.
†
ΔHd is the calorimetric enthalpy of denaturation.
‡
Values represent the average and standard deviation (SD) of four independent measurements. All other Ka error estimates are derived from curve-fitting uncertainties.