Probing amide bond nitrogens in solids using 14N NMR spectroscopy.
A novel two-dimensional nuclear magnetic resonance (NMR) experiment is proposed for indirect observation of 14N nuclei in various types of nitrogen-containing solids. In a method somewhat similar to the heteronuclear single-quantum correlation (HSQC) experiment widely used for protein structure determination in solutions, this technique correlates spin S=1/2 nuclei, e.g., 1H, 13C, with the 14N spin I=1 nucleus in solids. The present experiment, however, transfers coherence from neighboring 1H or 13C nuclei to 14N via a combination of J-couplings and residual dipolar splittings (RDS). Projections of the two-dimensional NMR spectra onto the 14N dimension yield powder patterns that reflect the 14N quadrupolar interaction, which can be used to study molecular structure and dynamics. Indirect detection of amide nitrogen-14 via 1H and 13C is shown experimentally on a model compound of N-acetyl-glycine.
Antonijevic
Sasa
S
Department of Chemistry, University of California, Berkeley, 1 Cyclotron Road Building 11-D64, Berkeley, CA 94720, USA. antonijevic@berkeley.edu
Halpern-Manners
Nicholas
N
D000577:Amides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009587:Nitrogen Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry; D011506:Proteins / Q000737:chemistry
D000577:Amides; D009587:Nitrogen Isotopes; D010455:Peptides; D011506:Proteins