Dependence of probabilities of energetic states on the concentration of ligands. Probabilities of states S1 − S8 (yellow for S1 and S5; blue for S2 and S6; orange for S3 and S7; and cyan for S4 and S8) are plotted against the concentration of Arg+ (with fitted curves in blue) or Agm2+ (with fitted curves in green). All data are presented as mean ± SEM. The probability values are calculated using Eq. S31 from the rate constants plotted in Fig. 9. The values for the apo and ligand-bound states are given in Table S10. The curves superimposed on the data are fits of Eq. 4. Fitted parameter values for equilibrium dissociation constants are given in Table S11, and the remaining equilibrium constants in Table S12.