The twists and turns of beta-peptides.

Recently, it has been discovered that peptides composed of beta-amino acids are capable of adopting novel secondary structures demonstrating that peptides composed of alpha-amino acids are not unique in their ability to fold into well-defined structures. Cyclic as well as acyclic peptides composed of beta-amino acid residues adopt turn, helical, and sheet-like conformations. Here, we discuss the synthesis and conformational preferences of individual, substituted beta-amino acids as well as the structures that peptides composed of these residues, beta-peptides, may adopt.