N-Methylacetamide Aqueous Solutions: A Neutron Diffraction Study.

The hydration of N-methylacetamide (NMA) in solution has been determined by neutron diffraction with isotopic Hydrogen/Deuterium substitution (NDIS), augmented by Monte Carlo simulation. This study is representative of the hydration of the peptide bonds characteristic of proteins and might shed light on aggregation phenomena in intrinsically disordered proteins. It is found that NMA forms hydrogen bonds with water at both O and H peptide sites, although of different lengths and strengths. The comparison with the case of tripeptide glutathione evidences differences in both hydration and propensity for aggregation.