Fig. 4.
The effect of binding energy on the optimum distribution for allosteric coupling. Plot of the folding probability of the ligand A site (i.e., PN + P1) vs. the folding probability of the ligand B site (i.e., PN + P2) showing only those parameter combinations where the CR exceeds a specified response threshold. Shown is the dependence of the optimum distribution on the binding free energy available to induce the allosteric transition. For binding energies of −0.01, −1.0, and −3.0 kcal/mol the corresponding values of Ka[A] (from Eq. 4) are 0.02, 4.4, and 157, respectively. For clarity, response thresholds of 0.23, 0.21, and 0.15 were used to show the maxima for ΔgLig,A = −0.01, −1.0, and −3.0 kcal/mol, respectively.