Poly-L-proline type II peptide mimics based on the 3-azabicyclo[3.1.0]hexane system

This paper describes conformational studies of proline-templated amino acids (PTAAs) based on the 3-azabicyclo[3.1.0]hexane system as well as conformational studies on short peptides composed of these PTAAs. NOE data, coupling constants, and molecular modeling are consistent with a flattened boat conformation for monomeric and oligomeric residues based on this bicyclic system. NMR studies on dimeric and trimeric oligomers are consistent with a populated poly-L-proline type II conformation in CDCl₃ and D₂O. Solution studies and molecular modeling predicts φ ∼ -70°, ψ ∼ 131°, χ1 ∼ -57°, and χ2 ∼ -158° for oligomeric residues.