Aromatic-Aromatic Interactions Enable α-Helix to β-Sheet Transition of Peptides to Form Supramolecular Hydrogels

Isolated short peptides usually are unable to maintain their original secondary structures due to the lack of the restriction from proteins. Here we show that two complementary pentapeptides from a beta-sheet motif of a protein, being connected to an aromatic motif (i.e., pyrene) at their C-terminal, self-assemble to form beta-sheet like structures upon mixing. Besides enabling the self-assembly to result in supramolecular hydrogels upon mixing, aromatic aromatic interactions promote the pentapeptides transform from alpha-helix to beta-sheet conformation. As the first example of using aromatic aromatic interactions to mimic the conformational restriction in a protein, this work illustrates a bioinspired way to generate peptide nanofibers with predefined secondary structures of the peptides by a rational design using protein structures as the blueprint.