Self-assembly of β-turn forming synthetic tripeptides into supramolecular β-sheets and amyloid-like fibrils in the solid state

We have described here the self-assembling properties of the synthetic tripeptides Boc-Ala(1)-Aib(2)-Val(3)-OMe , Boc-Ala(1)-Aib(2)-Ile(3)-OMe and Boc-Ala(1)-Gly(2)-Val(3)-OMe (Aib=α-amino isobutyric acid, β-Ala=β-alanine) which have distorted β-turn conformations in their respective crystals. These turn-forming tripeptides self-assemble to form supramolecular β-sheet structures through intermolecular hydrogen bonding and other noncovalent interactions. The scanning electron micrographs of these peptides revealed that these compounds form amyloid-like fibrils, the causative factor for many neurodegenerative diseases including Alzheimerʹs disease, Huntingtonʹs disease and Prion-related encephalopathies.