Homonuclear Hartmann–Hahn transfer with reduced relaxation losses by use of the MOCCA-XY16 multiple pulse sequence

Furrer, Julien; Marino, John P.; Glaser, Steffen J.; Luy, Burkhard

doi:10.1016/j.jmr.2003.09.013

Cited by 31 publications

(30 citation statements)

References 48 publications

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“…Clearly the reduction of small artifacts is visible throughout the spectra. HSQC-TOCSY-IP and HSQC-TOCSY-AP spectra were acquired with 50 ms mixing time using the DIPSI-2 mixing sequence [68] applied at 6.38 kHz RF-power and the MOC-CA-XY16 scheme as described in [40,41] with D/d = 2.2, respectively. 8192 data points in 8 scans (strychnine) and 4096 data points in 2 scans (menthol), respectively, were collected for each of the 640 increments in the indirect dimension.…”

Section: Methodsmentioning

confidence: 99%

“…Due to the repeating inversion elements with typically an XY16 supercycle [38,39], TOCSY conditions are fulfilled for scalar couplings [40,27,41,37], leading to inphase transfer solely via undetectable ZQ-coherences. The absence of observable homonuclear antiphase coherences during the CPMG periods finally allows the phase sensitive detection of heteronuclear long-range correlations in pure absorption and with higher efficiency than previously published methods.…”

Section: Cpmg-based Experimentsmentioning

confidence: 99%

“…In this case modifications to the mixing scheme can be tried like varying the mixing time, using tailored TOCSY sequences like for example the HNHA or COIN-TACSY [66,67], or even applying a totally different homonuclear mixing scheme like a NOESY period. For partially aligned samples, also the use of MOCCA-XY16 multiple pulse sequence might be considered which simultaneously allows efficient transfer also via homonuclear J HH and D HH couplings [40,41].…”

Section: Hsqc-tocsy-ipapmentioning

confidence: 99%

See 2 more Smart Citations

Analyses, extensions and comparison of three experimental schemes for measuring (nJCH+DCH)-couplings at natural abundance

Kobzar

Luy

2007

Journal of Magnetic Resonance

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Section: Methodsmentioning

confidence: 99%

Section: Cpmg-based Experimentsmentioning

confidence: 99%

Section: Hsqc-tocsy-ipapmentioning

confidence: 99%

See 1 more Smart Citation

Analyses, extensions and comparison of three experimental schemes for measuring (nJCH+DCH)-couplings at natural abundance

Kobzar

Luy

2007

Journal of Magnetic Resonance

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“…Imperfections and the limited bandwidth of these pulses must, however, be compensated by appropriate phase cycling (Gullion et al, 1990) to ensure sufficient, broadband H N decoupling as well as preservation of recovered H u polarisation. Such phase-cycled derivatives of the classic CPMG sequence perform excellently even for broadband isotropic Hartmann-Hahn mixing (Furrer et al, 2004), corroborating their equal suitability for the less demanding task of broadband H N decoupling. The echo delay d CPMG should then be chosen long enough to maintain a low duty cycle and reduce sample heating, but short enough to prevent substantial 2H z N y anti-phase formation and reduce T 2 relaxation losses for interim stray H u coherence produced by imperfect inversion pulses and partially recovered through the phase cycling scheme.…”

Section: Optimised Proton Decoupling Schemesmentioning

confidence: 55%

Extended Flip-back Schemes for Sensitivity Enhancement in Multidimensional HSQC-type Out-and-back Experiments

2005

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In many NMR experiments, only polarisation of a limited sub-set of all protons is converted into observable coherence. As recently shown by the ''longitudinal'' TROSY implementation (Pervushin et al. (2002) J. Am. Chem. Soc., 124, 12898-12902) and SOFAST-HMQC (Schanda and Brutscher (2005) J. Am. Chem. Soc., 127, 8014-8015), recovery of unused polarisation can be used indirectly and unspecifically to cool the proton lattice and, thus, accelerate re-equilibration for the selected proton subset. Here we illustrate transfer of this principle to HSQC-based multi-dimensional out-and-back experiments that exploit only polarisation of 15 N-bound protons. The presented modifications to the pulse sequences can be implemented broadly and easily, extending standard flip-back of water polarisation to a much larger pool of protons that may comprise all non) 15 N-bound protons. The underlying orthogonal separation of H N polarisation (selected by the main transfer path) from unused H u polarisation (flipped-back on the recovery path) is thereby achieved through positive or negative selection by J-coupling, or using band-selective pulses. In practice, H u polarisation recovery degrades mostly through cumulative pulse imperfections and transverse relaxation; we present, however, strategies to substantially minimise such losses particularly during interim proton decoupling. Depending on the protein's relaxation properties and the extended flipback scheme employed, we recovered up to 60% H u equilibrium polarisation. The concomitant cooling of the proton lattice afforded substantial gains of more than 40%, relative to the water-only flip-back version, in the fast pulsing regime with re-equilibration delays s much shorter than optimal ðs opt ¼ 1:25 Á T 1 ðH N ÞÞ. These would be typically employed if resolution requirements dominate the total measurement time. Contrarily, if sensitivity is limiting and optimal interscan delays s opt can be set (optimal pulsing regime), the best of the presented flip-back schemes may still afford up to ca. 10% absolute sensitivity enhancement.Abbreviations: bsfb -band-selective flip-back; cpd -continuous pulsing decoupling; efb -extended flip-back; H u -unselected proton magnetisation; H C fb -H C flip-back; ufb -universal flip-back; wfb -water flip-back

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“…The method of invariant trajectories predicts relaxation based on simulated or calculated periodic magnetization trajectories on the Bloch sphere. 7,[27][28][29] The transverse weight σ T is the timeaveraged component of magnetization in the x-y plane,…”

Section: Autorelaxation By Invariant Trajectoriesmentioning

confidence: 99%

A new broadband homonuclear mixing pulse for NMR with low applied power

Coote

Leigh

et al. 2014

The Journal of Chemical Physics

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Broadband homonuclear mixing pulses with low radiofrequency power are essential for NMR spectroscopy of proteins and small molecules, especially for emerging applications in high field NMR. We have analytically designed a mixing pulse with high bandwidth-to-power ratio, using our recently developed multi-frame method. Here, we compare the new pulse, NF4 (mixing in the fourth nutating frame), to the best currently available sequence, focusing on the low-power regime. We use simulations and experiments to compare the two pulses' relaxation properties and bandwidth, and demonstrate that NF4 has approximately 1.35 times higher bandwidth, with similar effective relaxation. Therefore, NF4 is a good choice for broadband homonuclear mixing, particularly when the available radiofrequency power is limited.

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Homonuclear Hartmann–Hahn transfer with reduced relaxation losses by use of the MOCCA-XY16 multiple pulse sequence

Cited by 31 publications

References 48 publications

Analyses, extensions and comparison of three experimental schemes for measuring (nJCH+DCH)-couplings at natural abundance

Analyses, extensions and comparison of three experimental schemes for measuring (nJCH+DCH)-couplings at natural abundance

Extended Flip-back Schemes for Sensitivity Enhancement in Multidimensional HSQC-type Out-and-back Experiments

A new broadband homonuclear mixing pulse for NMR with low applied power

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