The amide proton NMR chemical shift and hydrogen-bonded structure of glycine-containing peptides and polypeptides in the solid state as studied by multi-pulse-associated high-speed MAS 1H NMR

Abstract

High-resolution 1H NMR spectra of glycine(Gly)-containing peptides and polypeptides in the solid state were measured for the study of the hydrogen-bonded structure to elucidate the relationship between the hydrogen bond length and 1H NMR chemical shift. In this study, higher spinning magic angle spinning (MAS) rotation was combined with the FSLG-2 (frequency-switched Lee–Goldburg) homo-nuclear dipolar decoupling method, in order to measure the solid-state 1H NMR signal for the amide proton bonded directly to the amide 14N of peptides and polypeptides in the crystalline state. By using this method, the solid-state high-resolution 1H NMR spectra of peptides and polypeptides in the solid state were successfully measured and given more reasonable resolution for the amide proton signals as compared by other solid-state high-resolution 1H NMR methods. From these results, it was found that the obtained amide 1H chemical shifts provide useful information about the hydrogen-bonded structure.