FIGURE 9.
Cysteine ladder comprising Cys-161, Cys-182, Cys-202, and Cys-231. These Cys and Ser-262 share a common orientation and lie in the turn between β-helix faces n·1 and n·2. The Asn and Ile bookends are shown. Also shown are the Cys-38–Cys-64 disulfide bridge and the active-site aspartate residues, Asp-168 and Asp-189. For clarity, residues 49–57 are omitted.