Helical structures of unnatural peptides for biological applications

Many important biological functions involve the recognition of helical domains of natural proteins. A number of strategies have been developed to mimic natural helices in proteins. Unnatural peptides are constructed with incorporation of artificial building blocks other than α-amino acid residues, and could adopt stable helical conformations. These nontraditional helical oligomers have been explored to mimic biological functions involved with helical domains of natural proteins. This review provides representative examples of the mimicry of natural peptide helices with unnatural ones and related biological applications.