First crystallographic signature of an acyclic peptide nanorod: molecular mechanism of nanorod formation by a self-assembled tetrapeptideElectronic supplementary information (ESI) available: selected backbone torsion angles for 1, Figure showing packing of 1, and a space-filling model of higher-ordered supramolecular helical assembly of 1. See http://www.rsc.org/suppdata/cc/b3/b302472p/

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 A (1 nm) starting from a double bend molecular conformation in crystals and further self-assembly of this supramolecular architecture leads to the formation of polydisperse nanorods of diameters 10-40 nm.