Figure 4.

Lattice-model test of robustness of the coevolutionary model for determining SC. (A) The most designable 27-mer structure for the HP model. (B) The logarithm of the density of sequences on the HP energy. (C) Native contact predictions from the fitness model. Native contacts are shown as red circles and the (top 27) predicted contacts based on the sequences ${\left\{x_{\text{HP}}\right\}}_{\text{s}90}$ as blue crosses. (D) Correlation of the energy in the HP model, $E_{\text{HP}}$, with the evolutionary energy, $E_{\text{EH}}$, for all the sequences ${\left\{x_{\text{HP}}\right\}}_{\text{s}90}$. The green line is $E_{\text{EH}}^{\text{fold}}$, which is obtained by fitting the correlation between $E_{\text{HP}}$ and $E_{\text{EH}}$ with a black line at position $E_{\text{HP}}^{\text{fold}}$ (red line). (E) The logarithms of the exact density of sequences on $E_{\text{EH}}$ from enumeration of the HP model are shown in black; corresponding results from Monte Carlo simulations using the energy $E_{\text{EH}}$ are shown in purple. To see this figure in color, go online.