Fig 2. Schematic representations of protein models.

SP model with: a) Two designable sites; b) Three designable sites; c) Six designable sites with I) three, II) four, and III) five pair-wise interactions. MR model with: d) Two designable sites; e) Three designable sites. The designable sites are shown as circles with numbers. The red dashed lines represent the interactions among the designable sites. In a–c) the pattern of interactions between the sites are provided for each structure. The checkered circles are non-interacting residues. In this study, there are no geometrical differences between residues, and all are being treated as identical beads represented with circles. In d) and e) the $d_{ij}^{-1}$ is the corresponding distance reciprocal between designable sites i and j.