Table 3.
Thermodynamic properties of F226 HCA II Variants.
| Property | HCA II | F226I | F226L | F226W |
|---|---|---|---|---|
| TM (K)a | 330.2 ± 0.1 | 326.1 ± 0.1 | 326.3 ± 0.1 | 324.1± 0.2 327.2± 0.7 329.2 ± 0.2 |
| ΔH°m(kcal mol−1)a | 223 ± 5 | 104 ± 4 | 208 ± 9 | 110 ± 9 71 ± 11 25 ± 3 |
| ΔHvH(kcal mol−1)b | 195 ± 6 | 113 ± 10 | 114 ± 6 | 140 ± 3 240 ± 20 480 ± 40 |
| ΔCp (kcal mol−1 K−1)c | 0.69 | 0.32 | 0.65 | 0.32 0.22 0.67 |
| ΔGT (kcal mol−1)d | 1.98 | −0.63 | −1.21 | −1.31 −0.21 0.081 |
| ΔHT (kcal mol−1)e | 311 | 103 | 212 | 107 25 71 |
| ΔST (kcal mol−1 K−1)f | 0.93 | 0.32 | 0.65 | 0.33 0.67 0.076 |
Calorimetric parameters determined by DSC.
van't Hoff enthalpy (ΔHvH) was determined by fitting thermograms to a two-state reversible unfolding model.
Heat capacity (ΔCp) of protein unfolding obtained by plotting calorimetric enthalpy (ΔH°m) versus melting temperature (TM).
Thermodynamic parameter extrapolated to reference temperature of 328.2 K using Eq. 5.
Thermodynamic parameter extrapolated to reference temperature of 328.2 K using Eq. 6.
Thermodynamic parameter extrapolated to reference temperature of 328.2 K using Eq. 7.