Supramolecular Assembly of C-3-Peptides into Helical Fibers Stabilized through Dynamic Covalent Chemistry

The supramolecular assembly of C-3-peptides carrying glycine-cysteine (Gly-Cys) dipeptide pendants into helical fibers is described. A Gly-Cys dipeptide sequence was selected to ensure the chirality, and at the same time, to provide a chance to crosslink the structure through oxidation of the thiol into dynamic covalent disulfide, and transfer supramolecular helical fibers into covalent ones. Supramolecular assembly in aprotic solvents affords long helical fibers with left-handedness, which can be stabilized through formation of disulfide. Transformation of supramolecular helical fibers into covalent ones was examined by NMR and FTIR spectroscopies as well as atom force microscopy.