Hydrogen-bonding structural study of solid peptides and polypeptides containing a glycine residue by 17O NMR spectroscopy

Abstract

Abstract Static 17 O NMR spectra of polyglycines I and II and glycylglycine peptides in the solid state were measured by the cross polarization technique. By computer simulations of these spectra, three NMR parameters (quadrupolar coupling constant ( e 2 qQ / h ), electric field gradient asymmetry parameter (η Q ), and chemical shift (δ)) were determined. From these results, it was found that as the hydrogen bond length decreased, the e 2 qQ / h value decreased. Furthermore, the principal values of the 17 O chemical shift tensor for both the peptides and polypeptides moved upfield with a decrease in the hydrogen bond length. From these experimental findings, it was clarified that 17 O NMR spectroscopy can provide a useful means of elucidating the hydrogen-bonding structure in solid peptides and polypeptides.