Figure 1. The binding affinity (stability) for rigid (independent) and flexible (effective) binding shown in (A) heat capacity curves and (B) free energy landscapes for Lambda Cro repressor (PDB: 1cop) and Lambda repressor (PDB: 1lmb).

The solid and corresponding dotted lines represent rigid and flexible binding respectively. Free energy landscapes are plotted at the rigid binding transition temperatures, which are calculated from the peaks of heat capacity curves for binding, respectively. Free energy is in reduced unit. is the fraction of native interfacial binding contacts. "Ind" and "Eff" are the abbreviations for "Independent" and "Effective" binding, respectively.