Measurement of Homonuclear Proton Couplings Based on Cross-Peak Nulling in CT-COSY

✍ Scribed by Zhengrong Wu; Ad Bax

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 427 KB
• Volume: 151
• Category: Article
• ISSN: 1090-7807
• DOI: 10.1006/jmre.2001.2358

✦ Synopsis

A method in which 1 H-1 H scalar and dipolar couplings are obtained from the cross-peak nulling condition in a series of constanttime (CT) COSY spectra, as a function of the duration of the CT period, is described. The method is best suited for measurement of 1 H-1 H couplings in the range 5-20 Hz. It is shown, however, that results can be sensitive to cross-correlated relaxation effects. Also, artifactual resonances, resulting from strong coupling, can be quite pronounced in CT-COSY spectra, even when |J AB /(δ A -δ B )| < 0.1. The experiments are demonstrated for the DNA dodecamer d(CGCGAATTCGCG) 2 , both in isotropic solution and in a liquid crystalline phase.