A new sensitive isotropic–anisotropic separation experiment—SPEED MAS

Strohmeier, Mark; Grant, David M.

doi:10.1016/j.jmr.2004.03.003

Cited by 21 publications

(25 citation statements)

References 27 publications

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“…Simulated best fits are illustrated by the overlaid lines and asterisks, together with the CSA and asymmetry parameters used. Table 2 Comparison of 2D CSA-amplified PASS sequences with CSA amplification [11,12], XCS [10] and SPEED [14] N 2D CSA-amplified PASS CSA amplification [11,12] XCS [10]/SPEED [14] p-pulses Length a /s r p-pulses Length a /s r p-pulses Length a /s r phase cycling using a practical number of steps, can be implemented to select a single coherence pathway, which compensates for the effects of pulse imperfections, field inhomogeneity and other artefacts. In practice it may be possible to use cogwheel phase cycling in the other experiments discussed, to enable a reduction in the number of phase cycles.…”

Section: Resultsmentioning

confidence: 99%

“…This has led to interest in developing 2D experiments that correlate an isotropic spectrum in one dimension with sideband intensities similar to those obtained if the CSA were a factor of N larger, or equivalently the sample spinning rate reduced by a factor of 1/N, in the other dimension [9][10][11][12][13][14]. These experiments can be grouped into those that give identical sideband intensities to those obtained in the MAS spectra at the effective spinning rate (x r /N), and experiments where intensities are altered.…”

Section: Introductionmentioning

confidence: 99%

“…This leads to favourably efficient sampling of the indirect dimension, as the number of t 1 increments is only twice the maximum order of spinning sideband to be measured. The SPEED MAS experiment of Strohmeier and Grant uses essentially the same pulse sequence as XCS [14]. Implemented as they propose, it does not eliminate the isotropic shift in the x 1 dimension.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Correlating fast and slow chemical shift spinning sideband patterns in solid-state NMR

Orr

Duer

Ashbrook

2005

Journal of Magnetic Resonance

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Correlating fast and slow chemical shift spinning sideband patterns in solid-state NMR

Orr

Duer

Ashbrook

2005

Journal of Magnetic Resonance

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“…Numerous methods have been developed to reintroduce the anisotropic chemical shift interactions in the indirect dimensions under MAS conditions. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] For most of these recoupling methods, determination of the CSA parameters requires analysis of the spinning sideband patterns 16, 21, 23, 26-29, 31, 32 or powder patterns, 15, 17-20, 22, 24, 25, 30 and usually periodic radio frequency (rf) field irradiation is applied in synchrony with the MAS sample rotation during the evolution period. In these recoupling techniques, the required rf field strengths are generally so high that, in practice, these sequences are only applicable under low or moderate MAS conditions.…”

Section: Introductionmentioning

confidence: 99%

Recoupling of chemical shift anisotropy by R-symmetry sequences in magic angle spinning NMR spectroscopy

Hou

Byeon

Ahn

et al. 2012

The Journal of Chemical Physics

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C and15 N chemical shift (CS) interaction is a sensitive probe of structure and dynamics in a wide variety of biological and inorganic systems, and in the recent years several magic angle spinning NMR approaches have emerged for residue-specific measurements of chemical shift anisotropy (CSA) tensors in uniformly and sparsely enriched proteins. All of the currently existing methods are applicable to slow and moderate magic angle spinning (MAS) regime, i.e., MAS frequencies below 20 kHz. With the advent of fast and ultrafast MAS probes capable of spinning frequencies of 40-100 kHz, and with the superior resolution and sensitivity attained at such high frequencies, development of CSA recoupling techniques working under such conditions is necessary. In this work, we present a family of R-symmetry based pulse sequences for recoupling of 13 C/ 15 N CSA interactions that work well in both natural abundance and isotopically enriched systems. We demonstrate that efficient recoupling of either first-rank (σ 1 ) or second-rank (σ 2 ) spatial components of CSA interaction is attained with appropriately chosen γ -encoded RN n v symmetry sequences. The advantage of these γ -encoded RN n v -symmetry based CSA (RNCSA) recoupling schemes is that they are suitable for CSA recoupling under a wide range of MAS frequencies, including fast MAS regime. Comprehensive analysis of the recoupling properties of these RN n v symmetry sequences reveals that the σ 1 -CSA recoupling symmetry sequences exhibit large scaling factors; however, the partial homonuclear dipolar Hamiltonian components are symmetry allowed, which makes this family of sequences suitable for CSA measurements in systems with weak homonuclear dipolar interactions. On the other hand, the γ -encoded symmetry sequences for σ 2 -CSA recoupling have smaller scaling factors but they efficiently suppress the homonuclear dipole-dipole interactions. Therefore, the latter family of sequences is applicable for measurements of CSA parameters in systems with strong homonuclear dipolar couplings, such as uniformly-13 C labeled biological solids. We demonstrate RNCSA NMR experiments and numerical simulations establishing the utility of this approach to the measurements of 13

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“…In such techniques, an isotropic chemical shift dimension is correlated with a pattern in the second spectral dimension that represents the chemical shift anisotropy (CSA) [4,5]. These methods fall into two broad groups, with the chemical shift anisotropy pattern being represented by (i) spinning sideband patterns [6][7][8][9][10][11][12][13] or (ii) powder patterns [14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%