Conformational characteristics of peptides containing α,β-dehydroamino acid residues

The structural preferences of synthetic peptides containing α,β-dehydroamino acid residues, as determined by theoretical studies, x-ray diffraction analyses, and spectroscopic studies, are reviewed. The role of ΔZPhe residues in stabilizing type II β-turn structures in small peptides and in nucleating helical structure in longer peptides is exemplified by several crystal as well as solution structural studies. From the few studies reported so far it appears that ΔZLeu influences the peptide backbone, much like the ΔZPhe residue, whereas ΔAla prefers the extended conformation, suggesting that the nature of β substituents might influence the conformation restriction behavior of the dehydroresidues. Conformational studies on synthetic peptides containing ΔE, ΔZAbu, and ΔVal have also been described