Super-WEFT

Successful use of the ID super-WEFT method for the determination of paramagnetic broadening was reported by Ma et al The method allows selective observation of broad resonances in the spectra that can be subsequently curve fitted to deduce paramagnetic broadening. 

Relaxation dispersion experiment Relaxation dispersion experiment Super-WEFT application... 

Fig. 6. (A) 500-MHz H NMR spectrum of 4Fe Tl Fd in H20, pH 7.5, at 30°, collected under nonsaturating conditions. Contact shifted Cys resonances are lalseled a-g, the Phe 24 aromatic ring protons are labeled j, k, and two upheld methyls, one strongly relaxed and the other assigned to Val 23, are labeled y, z, respectively. Slowly exchanging peptide protons in the low-field window are marked by asterisks. (B) Super-WEFT trace of the same sample collected with a repetition rate of 20 s and a delay time of 20 ms, which emphasizes very rapidly relaxed (Ti <10 ms) resonances in both the resolved (a-i, z) and unresolved (peaks l,m,n) spectral window, [Reprinted from A. Donaire, C. M. Gorst, Z. H. Zhou, M. W. W. Adams, and G. N. La Mar, J. Am. Chem. Soc. 116,6841 (1994), with permission.]...

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