RESUMO
ß-Turns are one of the most common secondary structures found in proteins. In the interest of developing novel ß-turn inducers, a diastereopure azepane-derived quaternary amino acid has been incorporated into a library of simplified tetrapeptide models in order to assess the effect of the azepane position and peptide sequence on the stabilization of ß-turns. The conformational analysis of these peptides by molecular modeling, NMR spectroscopy, and X-ray crystallography showed that this azepane amino acid is an effective ß-turn inducer when incorporated at the i + 1 position. Moreover, the analysis of the supramolecular self-assembly of one of the ß-turn-containing peptide models in the solid state reveals that it forms a supramolecular helical arrangement while maintaining the ß-turn structure. The results here presented provide the basis for the use of this azepane quaternary amino acid as a strong ß-turn inducer in the search for novel peptide-based bioactive molecules, catalysts, and biomaterials.