Figure 3.

Energetic impact of Ala/Val mutations on the modulation of K-Shaw2 by 1-BuOH. (A) Apparent free-energy changes induced by single S4-S5 and S6 mutations. These changes are calculated relative to the wild-type apparent free-energy change as indicated in the main text. (B) Absolute coupling energies for double K-Shaw2 mutants; note that A326V appears on both axes due to intra-S4-S5 mutations. DMCA was used to calculate these energies as described in Table S1. Dark gray bars depict coupling energies > 2 kcal/mol. (C) Scatter plot of ΔΔG versus n_H. The line is the best-fit linear regression (R² = 0.75). Two outliers with high n_H-values were excluded from the regression analysis. These mutants exhibit very low 1-BuOH sensitivities, and very high doses were not investigated, which limited the estimation of the Hill equation parameters (Table S1).