Figure 4.

A ribbon diagram of the three-dimensional structure of lysozyme. Spheres are drawn at the positions of the appropriate amide nitrogens and color-coded by the stability factor class (see text): S_f measured to be <1 (red spheres), S_f measured or estimated to be >1 (green spheres), and S_f that could not be reliably estimated from our data (gray spheres). This figure was prepared with molmol (45) using the Protein Data Bank file 1hew. The NH₂ and COOH groups mark the amino and carboxyl termini, respectively, of the protein.