Figure 1. Proposed model and design of super-helical sequence composed of single heptad repeats.

(a) Depiction of helical single heptad peptide module in which the positions a and d are displayed in pink colours. Assembly of these single heptad modules via dimerization may afford the formation of super-helical assembly. (b) Ramachandran plot of the sterically allowed dihedral angles of Aib residues, showing preference for helical conformation (blue colour region). (c) Chemical structure of the designed peptides in which Aib residues are illustrated in blue and a and d positions of heptad repeats are shaded with pink.