Helix formation in beta/delta-hybrid peptides: correspondence between helices of different peptide foldamer classes.

An overview on all hydrogen-bonded helix types, which can be expected in the novel class of beta/delta-hybrid peptides, is provided on the basis of ab initio molecular orbital theory. The results show a considerable potential of different folding patterns, which makes this novel class of peptide foldamers interesting for peptide and protein design. Thus, this study may stimulate the synthesis of such hybrid peptides. The large number of helix types found for beta/delta-hybrid peptides together with the many helices experimentally found and theoretically predicted in the other classes of peptide and hybrid peptide foldamers provide a good basis to establish general correspondence rules for their mutual exchange in peptide sequences. This is done by introduction of the concept of pattern and shape correspondence. (c) 2010 Wiley Periodicals, Inc.