Unprecedented torsional preferences in trans-β^2,3-amino acid residues and formation of 11-helices in α,β^2,3-hybrid peptides

Anti or gauche? trans-β2,3-Amino acid residues that are known to promote extended structures in their peptides show specific rotamer preferences in response to an intramolecular hydrogen-bonding possibility, which facilitates the 11-helical structures in their 1:1 α,β-hybrid peptides (see figure). Preferences for the gauche conformation for all internal β residues and anti for the C-terminal residue in these peptides were confirmed by NMR spectroscopic and X-ray diffraction experiments. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.