TABLE 4.
Thermodynamic parameters for binding of ETGE mutants to Keap1-DC at 25°Ca
| Alanine mutation | n | Ka (106 M−1) | ΔH (kcal/mol) | TΔS (kcal/mol) | ΔG (kcal/mol) |
|---|---|---|---|---|---|
| L76A | 0.77 ± 0.00 | 87 ± 9.5 | −26.4 ± 0.1 | −15.6 ± 0.2 | −10.8 ± 0.0 |
| D77A | 0.96 ± 0.00 | 1.7 ± 0.1 | −13.9 ± 0.5 | −5.4 ± 0.6 | −8.5 ± 0.0 |
| E78A | 1.03 ± 0.03 | 113 ± 1.6 | −19.8 ± 0.5 | −8.8 ± 0.6 | −11.0 ± 0.0 |
| E79A | 0.85 ± 0.04 | 0.2 ± 0.0 | −9.2 ± 0.5 | −1.9 ± 0.6 | −7.3 ± 0.1 |
| T80A | 1.00 ± 0.01 | 0.5 ± 0.0 | −3.7 ± 0.1 | +4.0 ± 0.1 | −7.7 ± 0.1 |
| L76A F83A | 1.03 ± 0.01 | 59 ± 4.5 | −21.9 ± 0.0 | −11.3 ± 0.1 | −10.6 ± 0.0 |
a
n is the stoichiometry, and Ka is the binding constant. ΔH, ΔS, and ΔG are the change in binding enthalpy, entropy, and Gibbs energy, respectively. −RT lnKa = ΔG = ΔH − TΔS, where T and R are the absolute temperature and gas constant, respectively. Values are shown as means ± standard deviations from triplicate runs. The first 33 residues of Neh2, including the DLG motif, were deleted from all mutants.