title: Measurement of 15N-13C J couplings in staphylococcal nuclease.
abstract: 15N-C alpha and 15N-C' J couplings were measured for the backbone of staphylococcal nuclease, uniformly enriched with 15N and 13C. It is found that the 1JC'N coupling is similar for beta-sheet, J = 14.8 +/- 0.5 and for alpha-helix, J = 14.8 +/- 0.4 but tends to be larger for the unstructured N- and C-terminal ends of the protein (J = 15.6 +/- 0.5). On average, 1JNC alpha are smaller for alpha-helical residues (J = 9.6 +/- 0.3 Hz) compared to beta-sheet (J = 10.9 +/- 0.8 Hz) and a substantial difference is observed for 2JNC alpha in alpha-helices (J = 6.4 +/- 0.4 Hz) and beta-sheets (J = 8.3 +/- 0.8 Hz).
authors.affiliation: Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
authors.forename: F
authors.initials: F
authors.lastname: Delaglio
authors.forename: D A
authors.initials: DA
authors.lastname: Torchia
authors.forename: A
authors.initials: A
authors.lastname: Bax
mesh_terms: D000595:Amino Acid Sequence; D002247:Carbon Isotopes; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008433:Mathematics; D008836:Micrococcal Nuclease / Q000737:chemistry*; D008969:Molecular Sequence Data; D009587:Nitrogen Isotopes; D011487:Protein Conformation
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D008836:Micrococcal Nuclease