Fig. 2.

Sequences of two-helix α- and α/β-peptides used in this study, all of which were derived from three-helix Z-domain analogs shown in Fig. 1A. (A) Primary sequences of α- and α/β-peptides. Nonnatural residues are indicated by colored circles. Each cysteine is engaged in an intramolecular disulfide bond. (B) Structures of a generic α-residue, the Aib residue (green), a generic β³-residue (teal), and the cyclic β-residues ACPC and APC (orange).