Thermodynamic parameters for the unfolding transition of BdpA variantsa.
| T m b (°C) | D 1/2 c (M) | ΔG°d (kcal mol−1) | ΔH°d (kcal mol−1) | ΔS°d (cal. mol−1 K−1) | m gnd (kcal mol−1 M−1) | ΔCp (kcal mol−1 K−1) | |
|---|---|---|---|---|---|---|---|
| WT | 78.5 ± 0.3 | 3.95 ± 0.02 | 5.2 ± 0.3 | 21.3 ± 0.3 | 54.1 ± 0.7 | 1.49 ± 0.02 | 0.57 ± 0.01 |
| β3-H2 | 46.7 ± 0.1 | 1.62 ± 0.01 | 1.9 ± 0.4 | 20.6 ± 0.3 | 63 ± 1 | 1.67 ± 0.02 | 0.62 ± 0.02 |
| Aib-H2 | 75.4 ± 0.1 | 3.56 ± 0.01 | 3.4 ± 0.2 | 14.1 ± 0.1 | 35.9 ± 0.4 | 1.08 ± 0.01 | 0.51 ± 0.01 |
| β3-H3 | 49.5 ± 0.1 | 1.08 ± 0.01 | 1.1 ± 0.4 | 12.5 ± 0.3 | 38.2 ± 0.8 | 1.52 ± 0.03 | 0.43 ± 0.02 |
| Aib-H3 | 81.6 ± 0.1 | 4.72 ± 0.01 | 5.1 ± 0.3 | 20.8 ± 0.2 | 52.6 ± 0.5 | 1.22 ± 0.01 | 0.51 ± 0.01 |
a
Values obtained from fits of the unfolding transition monitored by CD as a function of temperature and concentration of guanidinium chloride denaturant in 10 mM phosphate at pH 7. Reported uncertainties are the standard error for the indicated parameter from the fit.
b
Midpoint of the thermal unfolding transition at 0 M denaturant.
c
Midpoint of the chemical denaturation transition at 4 °C.
d
At 25 °C.