Peptide [4]Catenane by Folding and Assembly

A topologically complex peptide [4]catenane with the crossing number of 12 was synthesized by a folding and assembly strategy wherein the folding and metal‐directed self‐assembly of a short peptide fragment occur simultaneously. The latent Ω‐looped conformation of the Pro‐Gly‐Pro sequence was found only when pyridines at the C‐ and N‐termini coordinatively bind metal ions (Ag I or Au I ). Crystallographic studies revealed that the Ω‐looped motifs formed four M 3 L 3 macrocycles that were intermolecularly entwined to generate an unprecedented peptide [4]catenane topology.