First crystallographic signature of an acyclic peptide nanorod: molecular mechanism of nanorod formation by a self-assembled tetrapeptide

A terminally protected acyclic tetrapeptide Boc-Aib-Val-Aib-(beta)-Ala-OMe 1 (Aib: (alpha)-aminoisobutyric acid, (beta)-Ala: (beta)-Alanine) self-assembles into a continuous hydrogen-bonded supramolecular helix with an average diameter of 10(angstrom) 1nm) starting from a double bend molecular conformation in crystals and further self-assembly of this supramolecular rchitecture leads to the formation of polydisperse nanorods of diameters 10–40 nm.