title: Cyclic peptoids.
abstract: Foldamers are an intriguing family of biomimetic oligomers that exhibit a propensity to adopt stable secondary structures. N-Substituted glycine oligomers, or "peptoids", are a prototypical example of these foldamer systems and are known to form a helix resembling that of polyproline type I. Ongoing studies seek to improve the stability of peptoid folding and to discover new secondary structure motifs. Here, we report that peptoids undergo highly efficient head-to-tail macrocyclization reactions. A diverse array of peptoid sequences from pentamers to 20mers were converted to macrocyclic products within 5 min at room temperature. The introduction of the covalent constraint enhances conformational ordering, allowing for the crystallization of a cyclic peptoid hexamer and octamer. We present the first X-ray crystallographic structures of peptoid hetero-oligomers, revealing that peptoid macrocycles can form a reverse-turn conformation.
authors.affiliation: Department of Chemistry, New York University, 100 Washington Square East, New York, New York 10003-6688, USA.
authors.forename: Sung Bin Y
authors.initials: SB
authors.lastname: Shin
authors.forename: Barney
authors.initials: B
authors.lastname: Yoo
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Todaro
authors.forename: Kent
authors.initials: K
authors.lastname: Kirshenbaum
mesh_terms: D018360:Crystallography, X-Ray; D008958:Models, Molecular; D010456:Peptides, Cyclic / Q000138:chemical synthesis / Q000737:chemistry*; D034444:Peptoids / Q000138:chemical synthesis / Q000737:chemistry*; D017510:Protein Folding; D017433:Protein Structure, Secondary
chemical_list: D010456:Peptides, Cyclic; D034444:Peptoids