Fig. 2.

Parametric changes due to mutations and the corresponding free-energy changes for (A) perturbations to $K_a$ and $K_i$, (B) changes to the allosteric energy difference ${\mathrm{\Delta }\epsilon }_{AI}$, (C) changes to repressor copy number, and (D) changes in DNA binding affinity. The 1st column schematizes the changed parameters and the 2nd column reflects which quantity in Eq. 5 is affected. The 3rd column shows representative induction profiles from mutants which have smaller (red) and larger (purple) values for the parameters than the wild type (gray). The 4th and 5th columns illustrate how the free energy is changed as a result. Purple and red arrows indicate the direction in which the points are translated about the master curve. Three concentrations (points labeled 1, 2, and 3) are shown to illustrate how each point is moved in free-energy space. An interactive version of this figure can be found on the paper website (https://www.rpgroup.caltech.edu/mwc_mutants/) (17).