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Combination of DQ and ZQ coherences for sensitive through-bond NMR correlation experiments in biosolids under ultra-fast MAS.
- Source :
-
Chemphyschem : a European journal of chemical physics and physical chemistry [Chemphyschem] 2012 Jun 18; Vol. 13 (9), pp. 2405-11. Date of Electronic Publication: 2012 Apr 23. - Publication Year :
- 2012
-
Abstract
- A double-zero quantum (DZQ)-refocused INADEQUATE experiment is introduced for J-based NMR correlations under ultra-fast (60 kHz) magic angle spinning (MAS). The experiment records two spectra in the same dataset, a double quantum-single quantum (DQ-SQ) and zero quantum-single quantum (ZQ-SQ) spectrum, whereby the corresponding signals appear at different chemical shifts in ω(1). Furthermore, the spin-state selective excitation (S(3)E) J-decoupling block is incorporated in place of the second refocusing echo of the INADEQUATE scheme, providing an additional gain in sensitivity and resolution. The two sub-spectra acquired in this way can be treated separately by a shearing transformation, producing two diagonal-free single quantum (SQ-SQ)-type spectra, which are subsequently recombined to give an additional sensitivity enhancement, thus offering an improvement greater than a factor of two as compared to the original refocused INADEQUATE experiment. The combined DZQ scheme retains transverse magnetization on the initially polarized (I) spin, which typically exhibits a longer transverse dephasing time (T(2)') than its through-bond neighbour (S). By doing so, less magnetization is lost during the refocusing periods in the sequence to give even further gains in sensitivity for the J correlations. The experiment is demonstrated for the correlation between the carbonyl (CO) and alpha (CA) carbons in a microcrystalline sample of fully protonated, [(15)N,(13)C]-labelled Cu(II),Zn(II) superoxide dismutase, and its efficiency is discussed with respect to other J-based schemes.<br /> (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Details
- Language :
- English
- ISSN :
- 1439-7641
- Volume :
- 13
- Issue :
- 9
- Database :
- MEDLINE
- Journal :
- Chemphyschem : a European journal of chemical physics and physical chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 22528552
- Full Text :
- https://doi.org/10.1002/cphc.201200099