Do interstrand hydrogen bonds contribute to β-hairpin peptide stability in solution? IR analysis of peptide folding in water

Abstract

The amide I carbonyl stretch in the IR spectrum, together with ¹H NMR Hα chemical shifts, have been used to investigate the folding of a 16-residue β-hairpin peptide in water: while Hα shifts are consistent with a significant population of the folded state (ca. 40%), we see no features in the IR spectrum in the amide I region to suggest a significant contribution from interstrand hydrogen bonds, although at high peptide concentration (10 mM) the appearance of a new band at 1616 cm⁻¹ is consistent with the onset of irreversible peptide aggregation.