NMR Structural Investigation of a β³-Dodecapeptide with Proteinogenic Side Chains in MeOH and Water

Abstract

Oligomers of β-amino acids (β-Peptides) have made their debut as a promising class of peptidomimetics. They have been shown to fold into well-ordered secondary structures, such as helices, turns and sheets [1]. Their wide structural diversity, together with the finding that β-peptides are resistant to degradation by peptidases, make them interesting for pharmaceutical applications [2,3]. Short β-peptides built from α-amino acid homologs (insertion of a methylene group) form a left handed 3₁₄-helix in MeOH. We wondered whether β³-peptides with longer chain lengths would still form stable secondary structures in MeOH, or whether they would even form a 3₁₄-helix that is stable in water. Therefore the β³-dodecapeptide 1 was investigated by two-dimensional homonuclear NMR spectroscopy in MeOH and water.