Toward Beta-peptide Tertiary Structure: Self-association of an Amphiphilic 14-helix in Aqueous Solution

A major frontier in foldamer research is creation of unnatural oligomers that adopt discrete tertiary structures; at present, only biopolymers are known to fold into such compact conformations. We report an initial step toward helix-bundle tertiary structure in the beta-peptide realm by showing that a 10-residue beta-peptide designed to adopt an amphiphilic helical conformation forms small soluble aggregates in water. Sedimentation equilibrium data indicate that the aggregated state falls in the tetramer-hexamer size range. [structure: see text]