The structures of CC-Di, apCC-Di, CC-Tri, CC-Tet and CC-Hex*-L24E in both its tetrameric and hexameric state were obtained from the PDBe (Figure , Table ). For CC-Di, CC-Tri and CC-Tet, any C-terminal residues missing from the X-ray structures were rebuilt with PyMOL, and the 4-iodo-phenylalanine at position 22 in CC-Di and CC-Tri was mutated to tryptophan as per the original peptide sequence. No C-terminal missing residues were rebuilt in the CC-Hex*-L24E structures, as the number of residues missing (7 residues missing from chains C and D in the tetramer, and 6 residues missing from chain E in the hexamer) implied high flexibility of these regions, and imposing a pre-defined conformation would not be realistic. All peptides were additionally capped with acetyl and amide groups at the Nand C-termini of each helix respectively in accordance with the experimental structures.