SYNOPSIS We have investigated the problem of the onset of helicity and the influence of proximal amino acids on the helical conformation of proline oligopeptides and polymers by incorporating the four membered ring amino acid, azetidine-2-carboxylic acid, into some proline containing oligopeptides and their polymers. The tetrapeptides, Boc (L-Pro) 4-Obn, Boc-(L-Pro) gL-Aze-Opcp, and Boc-(L-Aze-L-Pro) 2-Opcp were prepared using traditional ...