Figure 4.

Using Protein G as an example, the straddling barrier height is plotted versus $M/N_f$ at the respective T_m for each. (Insets) Adding H-bonds (smaller values of $M/N_f$) separates the basins, thus increasing the barrier height. In addition to the native and unfolded basins, additional states (dashed) are possible, but their probabilities are generally zero; yet they do emerge when the barrier height is increased as $M/N_f\to 0$. Conversely, the barrier height is suppressed as $M/N_f\to 1$ because the basins share greater overlap, transforming into a continuous transition, and then eventually no transition without any H-bonds. (Highlighted) The wild-type value ($M/N_f=0.502$) for Protein G.