Helical self-assembly of an unusual pseudopeptide: crystallographic evidence

Abstract

Abstract Pseudopeptides are a versatile class of organic building blocks having potential applications in a wide range of domains. In the current study, N and C termini protected l -alanine based short pseudopeptide was synthesized, where 5-aminoisophthalic acid (5-AIA), a rigid non-proteogenic γ-amino butyric acid was incorporated as C-terminal residue. The single crystal X-ray analysis revealed that the l -Ala residue of the aforesaid peptide adopts ϕ and ψ values characteristic of polyproline II conformation. Self-assembly of the pseudopeptide seems to represent a supramolecular helical architecture via NH⋯O, CH⋯O hydrogen bonding and π–π interactions.