Characterization of peptide O⋯HN hydrogen bonds via 1 H-detected 15 N/ 17 O solid-state NMR spectroscopy.

High sensitivity and resolution solid-state NMR methods are reported, that straightforwardly select hydrogen-bonded 15 N- 17 O pairs from amongst all other nitrogen and oxygen sites in peptides, to aid protein secondary and tertiary structure determination. Significantly improved sensitivity is obtained with indirect 1 H detection under fast MAS and stronger relayed dipole couplings.