Simplified Multiplet Pattern HSQC-TOCSY Experiment for Accurate Determination of Long-Range Heteronuclear Coupling Constants

✍ Scribed by Wiktor Koźmiński

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 76 KB
• Volume: 137
• Category: Article
• ISSN: 1090-7807
• DOI: 10.1006/jmre.1998.1700

✦ Synopsis

A new two-dimensional pulse sequence for accurately determining heteronuclear coupling constants is presented. It is derived from HSQC and HECADE techniques with B 0 gradient coherence selection. The main feature of the proposed method is spectra with only one component of the IS doublet; i.e., the final result is equivalent to a selective broadband excitation of either S ␣ or S ␤ spin states and a preservation of these states during the entire experiment. The effect is obtained by an appropriate combination of in-and antiphase coherences. It is demonstrated that heteronuclear single-bond as well as long-range coupling constants and their relative signs are readily evaluated. The proposed sequence is equally or less sensitive to a variation of heteronuclear one-bond couplings than previously published, closely related sequences. The new method is applied to a peptide sample for determination of 3 J N,H␤ .