Fig. 1

Structural analysis. a Schematic representation of different GLP-1 analogues previously reported and of the present approach based on peptide-oligourea hybrids. b–c Comparison of α-helical and oligourea backbones. b Overlay (side-views) of a peptide oligourea hybrid (derived from the crystal structures of helical peptide-oligourea hybrids¹⁶) over a peptide. c Overlay (side- and top-views) of an oligourea triad (extracted from (b), green backbone) over a tetrapeptide in α-helical conformation (grey backbone). d Chemical structures of an oligourea backbone, as well of X^u, X^uα, and X residues used in this study and their associated cartoon representations