Résumé
Transmembrane selective transport of metabolites controls essential biological functions. During the last two decades, artificial channels have been developed and cyclic peptides have emerged as ideal platforms for efficient ion, sugar, and nucleic acids channel-translocation. Despite these tremendous developments cyclic peptides have eluded the selective water transport. Herein, we report the formation of narrow artificial β-helical tubules with a diameter ranging from 2.80 to 3.25 Å that selectively control the water translocation, akin to natural Aquaporin channels. The tubular assemblies resulted from the metal driven folding and assembly of minimal heterochiral metal binding 3-pyridyl-terminated peptides. The bent ultrashort peptide ligand coordinates with the Ag + metal ions in a head-to-tail manner which undergoes subsequent polymerization into β-helical tubular structure stabilized by inter-strand hydrogen-bonds (H-bonds) between the β-strands and π-π staking interactions between terminal pyridyl moieties. Furthermore, sequence engineering of the heterochiral peptide and subsequent Ag + ions coordination of the tailored peptides enabled the formation of distinct synthetic double βbarrel and artificial β-helical tubular assemblies, with water molecules encapsulated in the hydrophilic core of the tubes. These water-encapsulated tubes were further explored as artificial water channels in lipid bilayers. Our findings suggest that such β-helical tubular channels achieve a single-channel permeability of 10 6 water molecules / second/ channel, which is within two orders of magnitude lower than AQPs with rather good ability to sterically reject ions and preventing proton transport. These assemblies present a significant potential for engineering efficient membranes for water purification and separation sciences.