Environment and sequence-dependence of helical type in membrane-spanning peptides composed of β3-amino acids

Transmembrane (TM) β-peptides comprised of acyclic β3-amino acids demonstrate equilibrium between 12- and 14-helical structures in an environment- and sequence-dependent manner. Circular dicroism (CD) spectra of TM β3-peptides may be described as linear combinations of the 12- and 14-helical CD spectra. The apparent malleability of β3-substituted acyclic β-peptides has practical implications for foldamer design, as it suggests that both the 14-helix as well as the 12-helix might be reasonable platforms for molecular recognition.