Non-protein amino acids in peptide design

An overview of the use of non-protein amino acids in the design of conformationally well-defined peptides, based on work from the author’s laboratory, is discussed. The crystal structures of several designed oligopeptides illustrate the use alpha aminoisobutyric acid (Aib) in the construction of helices,D-amino acids in the design of helix termination segments and DPro–Xxx segments for nucleating of beta-hairpin structures. beta and gamma amino acid residues have been used to expand the range of designed polypeptide structures.