Fig. 1. (a) Schematic representation of hydrocarbon stapled peptides for siRNA delivery. (b) Sequences and helicities of LK peptide and their stapled derivatives. (c) Design of peptides for siRNA delivery. Although both the dimer (LK-3) and stapled peptides can be delivered into cells, the latter peptide has advantages over the former owing to facile release and endosomal escape of siRNA. (d) LKH-stEK. Lowercase letters indicate positions in the heptad repeat (abcdefg), with hydrophobic residues at a, d, e, and g sites. Polar Lys, nonpolar Leu residues, alkene-bearing non-natural amino acids, and His residues are shown in black, white, gray, and red circles, respectively. Cationic hydrophilic face and hydrophobic face are marked as blue and pale blue.
