High length-diameter ratio nanotubes self-assembled from a facial cyclopeptide

A six-residue facial cyclopeptide was designed with the following sequence: c-[d-Leu-l-Lys-d-Ala-l-Lys-d-Leu-l-Gln] (CP). Extensive hydrogen bonding between the cyclopeptide backbones mainly regulated CP to self-assemble into single-walled nanotubes. Simultaneously, the hydrophobic interaction among facial hydrophobic side chains of CP was introduced to stabilize the hydrogen bonding, resulting in the formation of the thick-walled nanotubes with high length-diameter ratios.