Conformational properties of azapeptides

The conformation of several model compounds for azapeptides was systematically examined on the basis of ab initio MO theory at various approximation levels. The calculations show the azapeptide conformation essentially determined by the hydrazine and urea constituents along the sequence. This leads to a characteristic conformer pattern which excludes the possibility of β sheet conformations, but indicates a high potency for the formation of helix and β turn structures. The N atom may change between planar and pyramid structures. The peculiar conformation properties make azaamino acids an attractive tool for secondary structure design in peptides and proteins.