NMR experiments for the sign determination of homonuclear scalar and residual dipolar couplings

• Published in: Journal of biomolecular NMR Vol. 16; no. 4; pp. 343 - 346
• Main Authors: Otting, G, Rückert, M, Levitt, M H, Moshref, A
• Format: Journal Article
• Language: English
• Published: Netherlands Springer Nature B.V 01-04-2000
• Subjects: Aprotinin - chemistry; Carbon Isotopes; Gels - chemistry; Magnetics; Medicin och hälsovetenskap; Models, Chemical; Nitrogen Isotopes; Nuclear Magnetic Resonance, Biomolecular - methods
• ISSN: 0925-2738; 1573-5001
• DOI: 10.1023/A:1008372630606

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.