Figure 1.

(a) Binary code. Experiments show that a primarily binary hydrophobic-polar code is sufficient to fold helix-bundle proteins (112). Reprinted from Reference 112 with permission from AAAS.

(b) Compactness stabilizes secondary structure, in proteins, from lattice models. (c) Experiments supporting panel b, showing that compactness correlates with secondary structure content in nonnative states of many different proteins (218). Reprinted from Reference 218 with permission.