Broadband finite-pulse radio-frequency-driven recoupling (fp-RFDR) with (XY8)41 super-cycling for homo-nuclear correlations in very high magnetic fields at fast and ultra-fast MAS frequencies
Broadband finite-pulse radio-frequency-driven recoupling (fp-RFDR) with (XY8)41 super-cycling for homo-nuclear correlations in very high magnetic fields at fast and ultra-fast MAS frequencies
Publication year: 2012 Source:Journal of Magnetic Resonance
Ming Shen, Bingwen Hu, Oliver Lafon, Julien Trébosc, Qun Chen, Jean-Paul Amoureux
We demonstrate that inter-residue 13C-13C proximities (of about 380 pm) in uniformly 13C-labeled proteins can be probed by applying robust first-order recoupling during several milliseconds in single-quantum single-quantum dipolar homo-nuclear correlation (SQ-SQ D-HOMCOR) 2D experiments. We show that the intensity of medium-range homo-nuclear correlations in these experiments is enhanced using broadband first-order finite-pulse radio-frequency-driven recoupling (fp-RFDR) NMR sequence with a nested (XY8)41 super-cycling. The robustness and the efficiency of the fp-RFDR-(XY8)41 method is demonstrated at high magnetic field (21.1 T) and high magic-angle spinning (MAS) speeds (up to 60 kHz). The introduced super-cycling, formed by combining phase inversion and a global four-quantum phase cycle, improves the robustness of fp-RFDR to (i) chemical shift anisotropy (CSA), (ii) spread in isotropic chemical shifts, (iii) rf-inhomogeneity and (iv) hetero-nuclear dipolar couplings for long recoupling times. We show that fp-RFDR-(XY8)41 is efficient sans 1H decoupling, which is beneficial for temperature-sensitive biomolecules. The efficiency and the robustness of fp-RFDR-(XY8)41 is investigated by spin dynamics numerical simulations as well as solid-state NMR experiments on [U-13C]-L-histdine.HCl, a tetra-peptide (Fmoc-[U-13C,15N]-Val-[U-13C,15N]-Ala-[U-13C,15N]-Phe-Gly-t-Boc) and Al(PO3)3. Graphical abstract
Graphical abstract Highlights
? Super-cycled RFDR. ? Robust to offsets. ? Robust for long-time recoupling. ? Robust to very large CSA.
Sensitive 13Câ??13C correlation spectra of amyloid fibrils at very high spinning frequencies and magnetic fields
Sensitive 13Câ??13C correlation spectra of amyloid fibrils at very high spinning frequencies and magnetic fields
Abstract Sensitive 2D solid-state 13Câ??13C correlation spectra of amyloid β fibrils have been recorded at very fast spinning frequencies and very high magnetic fields. It is demonstrated that PARIS-xy recoupling using moderate rf amplitudes can provide structural information by promoting efficient magnetization transfer even under such challenging experimental conditions. Furthermore, it has been shown both experimentally and by numerical simulations that the method is not...
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04-01-2011 09:23 AM
Radio frequency assisted homonuclear recoupling - A Floquet description of homonuclear recoupling via surrounding heteronuclei in fully protonated to fully deuterated systems
Radio frequency assisted homonuclear recoupling - A Floquet description of homonuclear recoupling via surrounding heteronuclei in fully protonated to fully deuterated systems
Publication year: 2011
Source: Journal of Magnetic Resonance, In Press, Accepted Manuscript, Available online 18 January 2011</br>
Michal, Leskes , Ümit, Akbey , Hartmut, Oschkinat , Barth-Jan, van Rossum , Shimon, Vega</br>
We present a Floquet theory approach for the analysis of homonuclear recoupling assisted by radio frequency (RF) irradiation of surrounding heteronuclear spins. This description covers a...
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01-19-2011 03:04 PM
[NMR paper] Combined frequency- and time-domain NMR spectroscopy. Application to fast protein res
Combined frequency- and time-domain NMR spectroscopy. Application to fast protein resonance assignment.
Related Articles Combined frequency- and time-domain NMR spectroscopy. Application to fast protein resonance assignment.
J Biomol NMR. 2004 May;29(1):57-64
Authors: Brutscher B
A simple and general method is presented to simplify multi-dimensional NMR spectra of isotope-labeled bio-molecules. The approach is based on band-selective Hadamard-type frequency encoding, which disperses the correlation peaks into different sub-spectra. This makes...
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11-24-2010 09:51 PM
[NMR thesis] Solid state NMR at high magnetic fields using multiple pulse techniques
Solid state NMR at high magnetic fields using multiple pulse techniques
Carson, Douglas Glenn (1981) Solid state NMR at high magnetic fields using multiple pulse techniques. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-10102006-095702
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08-27-2010 01:45 AM
[U. of Ottawa NMR Facility Blog] Fast 90 Degree Pulse Determination
Fast 90 Degree Pulse Determination
Almost all NMR measurements rely on the correct calibration of 90° pulses. This is traditionally done by collecting a series of spectra as a function of pulse duration, finding a null for the 180° or 360° pulse and calculating the 90° pulse by simple division by 2 or 4 in the case of the 180° and 360° nulls, respectively. This determination, although trivial, can be very time consuming. Wu and Otting* have presented a much faster method of determining a 90° pulse based on measuring the nutation of a magnetization vector directly. Continuous nutation is...
Broadband 15Nâ??13C dipolar recoupling via symmetry-based RF pulse schemes at high MA
Abstract An approach for generating efficient
RNnnS, nk symmetry-based dual channel RF pulse schemes for γ-encoded broadband 15Nâ??13C dipolar recoupling at high magic angle spinning frequencies is presented. The method involves the numerical optimisation of the RF phase-modulation profile of the basic â??Râ?? element so as to obtain heteronuclear double quantum dipolar recoupling sequences with satisfactory magnetisation transfer characteristics. The basic â??Râ?? element was implemented as a sandwich of a small number of short pulses of equal duration with each pulse characterised by...