A Heterocyclic Peptide Nanotube

An open-ended hollow tubular structure is designed based on hydrogen-bond-directed self-assembly of a chimeric cyclic peptide subunit comprised of alternating α- and ε-amino acids. The design
features a novel 1,4-disubstituted-1,2,3-triazole ε-amino acid and its utility as a peptide backbone substitute.
The N-Fmoc-protected ε-amino acid was synthesized in high yield and optical purity in three steps from
readily available starting materials and was employed in solid-phase peptide synthesis to afford the desired
cyclic peptide structure. The cyclic peptide self-assembly has been studied in solution by 1H NMR and
mass spectrometry and the resulting tubular ensemble characterized in the solid state by X-ray
crystallography.