Oligomers composed of beta(3)-amino acid residues and a mixture of alpha- and beta(3)-residues have emerged as proteolytically stable structural mimics of alpha-helices. An attractive feature of these oligomers is that they adopt defined conformations in short sequences. In this manuscript, we evaluate the impact of beta(3)-residues as compared to their alpha-amino acid analogs in Prenucleated helices. Our hydrogen deuterium exchange results suggest that heterogeneous sequences composed of "alpha alpha alpha beta" repeats are conformationally more rigid than the corresponding homogeneous a-peptide helices, with the macrocycle templating the helical conformation having a significant influence.