Two-dimensional POMMIE J(CH)-resolved 13C NMR spectrum editing. Application to peptide and carbohydrate derivatives

✍ Scribed by Bruce Coxon

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 626 KB
• Volume: 26
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1260260603

✦ Synopsis

A pulse sequence has been implemented for two-dimensional POMMIE J(CH)-resolved "C NMR spectroscopy and has been used to explore three methods for the automated acquisition of data for two-dimensional spectrum editing. In the first two methods, sets of three two-dimensional data matrices are acquired in either sequential or interleaved modes, by use of three values, 4 = 46, x / 2 and 5x/6, for the phase shift of the multiple quantum read pulse. Computation of linear combinations of these three data matrices by use of a Pascal program that had been written earlier for two-dimensional DEPT spectrum editing yielded two-dimensional POMMIE J(CH)-resolved CH, CH, and CH3 subspectra. In the thud method, these subspectra are constructed directly during acquisition, by rotation of the phase shifts of the multiple quantum read pulse and the receiver. Selected small peptides and carbohydrate derivatives were used as model compounds for this study, and their 'H and "C NMR assignments were confirmed by two-dimensional COSY and heteronuclear CH chemical shift correlation techniques. The results show that if appropriate equipment is available, the twodimensional POMMIE metbod is easier to implement for J(CH)-resolved spectral editing than the two-dimensional DEPT technique. However, these methods are comparable in their ability to suppress residual signals. KEY WORDS 2D POMMIE J(CH)-Resolved "C NMR Spectral editing Automated data acquisition ' Measured by 1 D 13C NMR (proton coupled with NOE, digital resolution 1.2 Hz per point), these values agreed within +1.0 to -2.3 Hz with those obtained by 2D peak-picking of the edited

2 z

Assignments may be interchanged.