title: NMR experiments for the sign determination of homonuclear scalar and residual dipolar couplings.
abstract: A modified version of the JHH-TOCSY experiment, 'signed COSY', is presented that allows the determination of the sign of residual dipolar 1H-1H coupling constants with respect to the sign of one-bond 1H-X coupling constants in linear three-spin systems X-1H-1H, where X = 13C or 15N. In contrast to the original JHH-TOCSY experiments, the signs of J(HH) couplings may be determined for CH2-CH2 moieties and for uniformly 13C/15N-labelled samples. In addition, sensitivity is enhanced, diagonal peaks are suppressed and cross peaks are observed only between directly coupled protons, as in a COSY spectrum.
authors.affiliation: Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden. gottfried.otting@mbb.ki.se
authors.forename: G
authors.initials: G
authors.lastname: Otting
authors.forename: M
authors.initials: M
authors.lastname: Rückert
authors.forename: M H
authors.initials: MH
authors.lastname: Levitt
authors.forename: A
authors.initials: A
authors.lastname: Moshref
mesh_terms: D007611:Aprotinin / Q000737:chemistry; D002247:Carbon Isotopes; D005782:Gels / Q000737:chemistry; D008280:Magnetics; D008956:Models, Chemical; D009587:Nitrogen Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*
chemical_list: D002247:Carbon Isotopes; D005782:Gels; D009587:Nitrogen Isotopes; D007611:Aprotinin