Oligomers of α‐ABpeptoid/β³‐peptide hybrid

Abstract

Peptoids, oligomers of N‐substituted glycines, have been attracting increasing interest due to their advantageous properties as peptidomimetics. However, due to the lack of chiral centers and amide hydrogen atoms, peptoids, in general, do not form folding structures except that they have α‐chiral side chains. We have recently developed “peptoids with backbone chirality” as a new class of peptoid foldamers called α‐ABpeptoids and demonstrated that they could have folding conformations owing to the methyl groups on chiral α‐carbons in the backbone structure. Here we report α‐ABpeptoid/β3‐peptide oligomers as a unique peptidomimetic structure with a heterogeneous backbone. This hybrid structure contains a mixed α‐ABpeptoid and β3‐peptide residues arranged in an alternate manner. These α‐ABpeptoid/β3‐peptide oligomers could form intramolecular hydrogen bonding and have better cell permeability relative to pure peptide sequences. These oligomers were shown to adopt ordered folding structures based on circular dichroism studies. Overall, α‐ABpeptoid/β3‐peptide oligomers may represent a novel class of peptidomimetic foldamers and will find a wide range of applications in biomedical and material sciences.

Solid‐Phase Synthesis of Peptidomimetics with Peptide Backbone Modifications

“…The most recent report was on the synthesis of α‐ABpeptoid/β 3 ‐peptide hybrids via alternative coupling of α‐ABpeptoid and β 3 ‐peptide monomers on a solid support (Scheme 7). [49] These oligomers can form intramolecular hydrogen bonds and adopt ordered folding structures according to CD studies. The hybrids were assembled on Rink amide MBHA resin and monomers incorporated under HATU/HOAt coupling conditions.…”