Before revision:  The ensemble of proteins attains the equilibrium, \psi_N= \psi_N ^{eq, where the average of \Delta \psi}  _{ N } over fixed mutants is equal to zero.
After revision:  The ensemble of proteins attains the equilibrium, \psi_N= \psi_N ^{eq, where the average of \Delta \psi} the analysis of the changes (\Delta \psi_N) of \psi_N due to single nucleotide nonsynonymous substitutions, T_s, and then glass transition temperature T_g, and \Delta G _{ N } over fixed mutants is equal to zero.