Figure 2.

Kinetic analysis of E30A_S47A (A) and E30A_T50A (B) in 50 mM NaPi, pH 6, at 295 K. Gnd, guanidine. (C) Kinetic analysis of WT and S47A mutant in 50 mM NaPi, pH 3, at 295 K. Solid lines indicate the best fit to the data with kaleidagraph. (D) Double-mutant cycle analysis to determine the interaction energy between E30A and S47A in the native (ΔΔG_U-F) and transition states (ΔΔG_U-‡). Data for the calculations are presented in Table 1. ΔΔG_U-‡ is calculated as RTln(k_f^wt/k_f^mut). Energies for the E30A_T50A double mutant are not shown explicitly but can be calculated similarly by using data from Table 1.