Helix formation in ε-amino acid oligomers

A complete overview on all possible helix types with unidirectional hydrogen bonds in oligomers of ε-amino acids is given on the basis of a systematical conformational analysis employing ab initio MO theory (HF/6-31G∗, B3LYP/6-31G∗, PCM//HF/6-31G∗). The conformational search provides a wide variety of folding patterns which makes the class of ε-peptides interesting for a rational peptide design by selection of suited backbone substituent patterns. The relationships between the predicted secondary structures for the ε-peptides and other peptide foldamer classes, as for instance α/β-hybrid peptides, are demonstrated.