Orthanilic acid-promoted reverse turn formation in peptides.

Orthanilic acid (2-aminobenzenesulfonic acid, (S)Ant), an aromatic β-amino acid, has been shown to be highly useful in inducing a folded conformation in peptides. When incorporated into peptide sequences (Xaa-(S)Ant-Yaa), this rigid aromatic β-amino acid strongly imparts a reverse-turn conformation to the peptide backbone, featuring robust 11-membered-ring hydrogen-bonding.