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Abstract
In the last two decades, solid-state nuclear magnetic resonance (ssNMR) spectroscopy has transformed from a spectroscopic technique investigating small molecules and industrial polymers to a potent tool decrypting structure and underlying dynamics of complex biological systems, such as membrane proteins, fibrils, and assemblies, in near-physiological environments and temperatures. This transformation can be ascribed to improvements in hardware design, sample preparation, pulsed methods, isotope labeling strategies, resolution, and sensitivity. The fundamental engagement between nuclear spins and radio-frequency pulses in the presence of a strong static magnetic field is identical between solution and ssNMR, but the experimental procedures vastly differ because of the absence of molecular tumbling in solids. This review discusses routinely employed state-of-the-art static and MAS pulsed NMR methods relevant for biological samples with rotational correlation times exceeding 100's of nanoseconds. Recent developments in signal filtering approaches, proton methodologies, and multiple acquisition techniques to boost sensitivity and speed up data acquisition at fast MAS are also discussed. Several examples of protein structures (globular, membrane, fibrils, and assemblies) solved with ssNMR spectroscopy have been considered. We also discuss integrated approaches to structurally characterize challenging biological systems and some newly emanating subdisciplines in ssNMR spectroscopy.
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Affiliation(s)
- Sahil Ahlawat
- Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P Gopanpally, Serilingampally, Ranga Reddy District, Hyderabad 500046, Telangana, India
| | - Kaustubh R Mote
- Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P Gopanpally, Serilingampally, Ranga Reddy District, Hyderabad 500046, Telangana, India
| | - Nils-Alexander Lakomek
- University of Düsseldorf, Institute for Physical Biology, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Vipin Agarwal
- Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P Gopanpally, Serilingampally, Ranga Reddy District, Hyderabad 500046, Telangana, India
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Hellwagner J, Grunwald L, Ochsner M, Zindel D, Meier BH, Ernst M. Origin of the residual line width under frequency-switched Lee-Goldburg decoupling in MAS solid-state NMR. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2020; 1:13-25. [PMID: 37904890 PMCID: PMC10500695 DOI: 10.5194/mr-1-13-2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 01/21/2020] [Indexed: 11/01/2023]
Abstract
Homonuclear decoupling sequences in solid-state nuclear magnetic resonance (NMR) under magic-angle spinning (MAS) show experimentally significantly larger residual line width than expected from Floquet theory to second order. We present an in-depth theoretical and experimental analysis of the origin of the residual line width under decoupling based on frequency-switched Lee-Goldburg (FSLG) sequences. We analyze the effect of experimental pulse-shape errors (e.g., pulse transients and B 1 -field inhomogeneities) and use a Floquet-theory-based description of higher-order error terms that arise from the interference between the MAS rotation and the pulse sequence. It is shown that the magnitude of the third-order auto term of a single homo- or heteronuclear coupled spin pair is important and leads to significant line broadening under FSLG decoupling. Furthermore, we show the dependence of these third-order error terms on the angle of the effective field with the B 0 field. An analysis of second-order cross terms is presented that shows that the influence of three-spin terms is small since they are averaged by the pulse sequence. The importance of the inhomogeneity of the radio-frequency (rf) field is discussed and shown to be the main source of residual line broadening while pulse transients do not seem to play an important role. Experimentally, the influence of the combination of these error terms is shown by using restricted samples and pulse-transient compensation. The results show that all terms are additive but the major contribution to the residual line width comes from the rf-field inhomogeneity for the standard implementation of FSLG sequences, which is significant even for samples with a restricted volume.
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Affiliation(s)
| | - Liam Grunwald
- Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Manuel Ochsner
- Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Daniel Zindel
- Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Beat H. Meier
- Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Matthias Ernst
- Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
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Mote KR, Madhu PK. Simultaneous homonuclear and heteronuclear spin decoupling in magic-angle spinning solid-state NMR. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2018; 90:7-12. [PMID: 29370958 DOI: 10.1016/j.ssnmr.2018.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/08/2018] [Accepted: 01/09/2018] [Indexed: 06/07/2023]
Abstract
We show here an effective way of implementing simultaneously homonuclear and heteronuclear dipolar decoupling in magic-angle spinning (MAS) solid-state NMR. Whilst the homonuclear spin decoupling is applied on the 1H channel, heteronuclear spin decoupling is applied on the 13C channel. The 1H spins are observed in a windowed fashion in this case. The resultant 1H spectrum has higher resolution due to the attenuation of broadening arising from both homonuclear 1H-1H and heteronuclear 1H-13C interactions, with the latter normally leading to additional line broadening in 13C labelled samples. The experiments are performed at MAS frequencies of ca. 60 kHz.
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Affiliation(s)
- Kaustubh R Mote
- Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P, Gopanapally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, 500 107, India.
| | - Perunthiruthy K Madhu
- Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P, Gopanapally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, 500 107, India; Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai, 400 005, India.
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Hanrahan MP, Venkatesh A, Carnahan SL, Calahan JL, Lubach JW, Munson EJ, Rossini AJ. Enhancing the resolution of 1H and 13C solid-state NMR spectra by reduction of anisotropic bulk magnetic susceptibility broadening. Phys Chem Chem Phys 2018; 19:28153-28162. [PMID: 29022618 DOI: 10.1039/c7cp04223j] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We demonstrate that natural isotopic abundance 2D heteronuclear correlation (HETCOR) solid-state NMR spectra can be used to significantly reduce or eliminate the broadening of 1H and 13C solid-state NMR spectra of organic solids due to anisotropic bulk magnetic susceptibility (ABMS). ABMS often manifests in solids with aromatic groups, such as active pharmaceutical ingredients (APIs), and inhomogeneously broadens the NMR peaks of all nuclei in the sample. Inhomogeneous peaks with full widths at half maximum (FWHM) of ∼1 ppm typically result from ABMS broadening and the low spectral resolution impedes the analysis of solid-state NMR spectra. ABMS broadening of solid-state NMR spectra has previously been eliminated using 2D multiple-quantum correlation experiments, or by performing NMR experiments on diluted materials or single crystals. However, these experiments are often infeasible due to their poor sensitivity and/or provide limited gains in resolution. 2D 1H-13C HETCOR experiments have previously been applied to reduce susceptibility broadening in paramagnetic solids and we show that this strategy can significantly reduce ABMS broadening in diamagnetic organic solids. Comparisons of 1D solid-state NMR spectra and 1H and 13C solid-state NMR spectra obtained from 2D 1H-13C HETCOR NMR spectra show that the HETCOR spectrum directly increases resolution by a factor of 1.5 to 8. The direct gain in resolution is determined by the ratio of the inhomogeneous 13C/1H linewidth to the homogeneous 1H linewidth, with the former depending on the magnitude of the ABMS broadening and the strength of the applied field and the latter on the efficiency of homonuclear decoupling. The direct gains in resolution obtained using the 2D HETCOR experiments are better than that obtained by dilution. For solids with long proton longitudinal relaxation times, dynamic nuclear polarization (DNP) was applied to enhance sensitivity and enable the acquisition of 2D 1H-13C HETCOR NMR spectra. 2D 1H-13C HETCOR experiments were applied to resolve and partially assign the NMR signals of the form I and form II polymorphs of aspirin in a sample containing both forms. These findings have important implications for ultra-high field NMR experiments, optimization of decoupling schemes and assessment of the fundamental limits on the resolution of solid-state NMR spectra.
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Shen M, Wegner S, Trébosc J, Hu B, Lafon O, Amoureux JP. Minimizing the t 1-noise when using an indirect 1H high-resolution detection of unlabeled samples. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2017; 87:111-116. [PMID: 28688541 DOI: 10.1016/j.ssnmr.2017.06.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 06/25/2017] [Accepted: 06/26/2017] [Indexed: 06/07/2023]
Abstract
The most utilized through-space correlation 1H-{X} methods with proton indirect detection use two consecutive transfers, 1H → X and then X → 1H, with the evolution time t1 in the middle. When the X isotope is not 100% naturally abundant (NA), only the signal of the protons close to these isotopes is modulated by the 1H-X dipolar interactions. This signal is theoretically disentangled with phase-cycling from the un-modulated one. However, this separation is never perfect and it may lead to t1-noise in case of isotopes with very small NA, such as 13C or even worse 15N. One way to reduce this t1-noise is to minimize, 'purge', during t1 the un-modulated 1H magnetization before trying to suppress it with phase-cycling. We analyze experimentally several sequences following the HORROR condition, which allow purging the 1H transverse magnetization. The comparison is made at three spinning speeds, including very fast ones for 1H resolution: 27.75, 55.5 and 111 kHz. We show (i) that the efficiency of this purging process increases with the spinning speed, and (ii) that the best recoupling sequences are the two simplest ones: XY and S1 = SR212. We then compare the S/N that can be achieved with the two most used 1H-{X} 2D methods, called D-HMQC and CP-CP. The only difference in between these two methods is that the transfers are done with either two π/2-pulses on X channel (D-HMQC), or two Cross-Polarization (CP) transfers (CP-CP). The first method, D-HMQC, is very robust and should be preferred when indirectly detecting nuclei with high NA. The second method, CP-CP, (i) requires experimental precautions to limit the t1-noise, and (ii) is difficult to use with quadrupolar nuclei because the two CP transfers are then not efficient nor robust. However, CP-CP is presently the best method to indirectly detect isotopes with small NA, such as 13C and 15N.
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Affiliation(s)
- M Shen
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Materials Science, East China Normal University, Shanghai 200062, PR China
| | - S Wegner
- Bruker BioSpin GmbH, 4 Silberstreifen, 76287 Rheinstetten, Germany
| | - J Trébosc
- Univ. Lille, UMR 8181, UCCS: Unit of Catalysis and Chemistry of Solids, 59000 Lille, France
| | - B Hu
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Materials Science, East China Normal University, Shanghai 200062, PR China
| | - O Lafon
- Univ. Lille, UMR 8181, UCCS: Unit of Catalysis and Chemistry of Solids, 59000 Lille, France; Institut Universitaire de France, 1 Rue Descartes, 75231 Paris, France
| | - J P Amoureux
- Univ. Lille, UMR 8181, UCCS: Unit of Catalysis and Chemistry of Solids, 59000 Lille, France; Bruker France, 34 Rue de l'Industrie, 67166 Wissembourg, France.
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Mote KR, Agarwal V, Madhu PK. Five decades of homonuclear dipolar decoupling in solid-state NMR: Status and outlook. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2016; 97:1-39. [PMID: 27888838 DOI: 10.1016/j.pnmrs.2016.08.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 07/11/2016] [Accepted: 08/02/2016] [Indexed: 06/06/2023]
Abstract
It has been slightly more than fifty years since the first homonuclear spin decoupling scheme, Lee-Goldburg decoupling, was proposed for removing homonuclear dipolar interactions in solid-state nuclear magnetic resonance. A family of such schemes has made observation of high-resolution NMR spectra of abundant spins possible in various applications in solid state. This review outlines the strategies used in this field and the future prospects of homonuclear spin decoupling in solid-state NMR.
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Affiliation(s)
- Kaustubh R Mote
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 21 Brundavan Colony, Narsingi, Hyderabad 500 075, India
| | - Vipin Agarwal
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 21 Brundavan Colony, Narsingi, Hyderabad 500 075, India
| | - P K Madhu
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 21 Brundavan Colony, Narsingi, Hyderabad 500 075, India; Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
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Brauckmann JO, Janssen JWGH, Kentgens APM. High resolution triple resonance micro magic angle spinning NMR spectroscopy of nanoliter sample volumes. Phys Chem Chem Phys 2016; 18:4902-10. [PMID: 26806199 DOI: 10.1039/c5cp07857a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
To be able to study mass-limited samples and small single crystals, a triple resonance micro-magic angle spinning (μMAS) probehead for the application of high-resolution solid-state NMR of nanoliter samples was developed. Due to its excellent rf performance this allows us to explore the limits of proton NMR resolution in strongly coupled solids. Using homonuclear decoupling we obtain unprecedented (1)H linewidths for a single crystal of glycine (Δν(CH2) = 0.14 ppm) at high field (20 T) in a directly detected spectrum. The triple channel design allowed the recording of high-resolution μMAS (13)C-(15)N correlations of [U-(13)C-(15)N] arginine HCl and shows that the superior (1)H resolution opens the way for high-sensitivity inverse detection of heteronuclei even at moderate spinning speeds and rf-fields. Efficient decoupling leads to long coherence times which can be exploited in many correlation experiments.
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Affiliation(s)
- J Ole Brauckmann
- Institute of Molecules and Materials, Radboud University, 6500 GL Nijmegen, Netherlands. and TI-COAST, Science Park 904, 1098 XH Amsterdam, Netherlands
| | - J W G Hans Janssen
- Institute of Molecules and Materials, Radboud University, 6500 GL Nijmegen, Netherlands.
| | - Arno P M Kentgens
- Institute of Molecules and Materials, Radboud University, 6500 GL Nijmegen, Netherlands.
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Nishiyama Y, Malon M, Potrzebowski MJ, Paluch P, Amoureux JP. Accurate NMR determination of C-H or N-H distances for unlabeled molecules. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2016; 73:15-21. [PMID: 26169913 DOI: 10.1016/j.ssnmr.2015.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 06/19/2015] [Accepted: 06/28/2015] [Indexed: 06/04/2023]
Abstract
Cross-Polarization with Variable Contact-time (CP-VC) is very efficient at ultra-fast MAS (νR ≥ 60 kHz) to measure accurately the dipolar interactions corresponding to C-H or N-H short distances, which are very useful for resonance assignment and for analysis of dynamics. Here, we demonstrate the CP-VC experiment with (1)H detection. In the case of C-H distances, we compare the CP-VC signals with direct ((13)C) and indirect ((1)H) detection and find that the latter allows a S/N gain of ca. 2.5, which means a gain of ca. 6 in experimental time. The main powerful characteristics of CP-VC methods are related to the ultra-fast spinning speed and to the fact that most of the time only the value of the dipolar peak separation has to be used to obtain the information. As a result, CP-VC methods are: (i) easy to set up and to use, and robust with respect to (ii) rf-inhomogeneity thus allowing the use of full rotor samples, (iii) rf mismatch, and (iv) offsets and chemical shift anisotropies. It must be noted that the CP-VC 2D method with indirect (1)H detection requires the proton resolution and is thus mainly applicable to small or perdeuterated molecules. We also show that an analysis of the dynamics can even be performed, with a reasonable experimental time, on unlabeled samples with (13)C or even (15)N natural abundance.
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Affiliation(s)
- Y Nishiyama
- JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan; RIKEN CLST-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan
| | - M Malon
- JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan; RIKEN CLST-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan
| | - M J Potrzebowski
- Polish Academy of Sciences, Centre of Molecular and Macromolecular Studies, 90-363 Lodz, Poland
| | - P Paluch
- Polish Academy of Sciences, Centre of Molecular and Macromolecular Studies, 90-363 Lodz, Poland
| | - J P Amoureux
- Physics Department & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China; UCCS, University Lille North of France, Villeneuve d'Ascq 59652, France.
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Brouwer DH, Horvath M. Minimizing the effects of RF inhomogeneity and phase transients allows resolution of two peaks in the (1)H CRAMPS NMR spectrum of adamantane. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2015; 71:30-40. [PMID: 26483329 DOI: 10.1016/j.ssnmr.2015.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 09/23/2015] [Accepted: 10/07/2015] [Indexed: 06/05/2023]
Abstract
One of the limiting factors to achieving highly resolved (1)H NMR spectra with (1)H homonuclear decoupling sequences is imperfections in the applied radiofrequency (RF) pulses, most notably phase transients and RF inhomogeneity. Through a series of simulations and solid-state NMR experiments, it is demonstrated that the combined effects of phase transients and RF inhomogeneity can be minimized by a combination of (i) restricting the sample to small volume of the rotor, (ii) by employing a super-cycled version of the DUMBO decoupling sequence, and (iii) by carefully adjusting the probe tuning such that the asymmetric component of phase transients is minimized. Under these optimal conditions, it was possible to clearly resolve two signals in the (1)H CRAMPS NMR spectrum of adamantane arising from the CH and CH2 protons in the molecule. It is proposed that adamantane could be a very useful setup sample for (1)H CRAMPS NMR as the two peaks are only resolved when the effects of RF inhomogeneity and phase transients are minimized.
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Affiliation(s)
- Darren H Brouwer
- Department of Chemistry, Redeemer University College, Ancaster, ON, Canada L9K 1J4.
| | - Matthew Horvath
- Department of Chemistry, Redeemer University College, Ancaster, ON, Canada L9K 1J4
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Rossini AJ, Schlagnitweit J, Lesage A, Emsley L. High-resolution NMR of hydrogen in organic solids by DNP enhanced natural abundance deuterium spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 259:192-198. [PMID: 26363582 DOI: 10.1016/j.jmr.2015.08.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Revised: 08/21/2015] [Accepted: 08/28/2015] [Indexed: 06/05/2023]
Abstract
We demonstrate that high field (9.4 T) dynamic nuclear polarization (DNP) at cryogenic (∼100 K) sample temperatures enables the rapid acquisition of natural abundance (1)H-(2)H cross-polarization magic angle spinning (CPMAS) solid-state NMR spectra of organic solids. Spectra were obtained by impregnating substrates with a solution of the stable DNP polarizing agent TEKPol in tetrachloroethane. Tetrachloroethane is a non-solvent for the solids, and the unmodified substrates are then polarized through spin diffusion. High quality natural abundance (2)H CPMAS spectra of histidine hydrochloride monohydrate, glycylglycine and theophylline were acquired in less than 2h, providing direct access to hydrogen chemical shifts and quadrupolar couplings. The spectral resolution of the (2)H solid-state NMR spectra is comparable to that of (1)H spectra obtained with state of the art homonuclear decoupling techniques.
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Affiliation(s)
- Aaron J Rossini
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland; Institut des Sciences Analytiques, Centre de RMN à très hauts champs (CNRS/ENS-Lyon, UCB-Lyon1), Université de Lyon, 69100 Villeurbanne, France
| | - Judith Schlagnitweit
- Institut des Sciences Analytiques, Centre de RMN à très hauts champs (CNRS/ENS-Lyon, UCB-Lyon1), Université de Lyon, 69100 Villeurbanne, France
| | - Anne Lesage
- Institut des Sciences Analytiques, Centre de RMN à très hauts champs (CNRS/ENS-Lyon, UCB-Lyon1), Université de Lyon, 69100 Villeurbanne, France
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland; Institut des Sciences Analytiques, Centre de RMN à très hauts champs (CNRS/ENS-Lyon, UCB-Lyon1), Université de Lyon, 69100 Villeurbanne, France.
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Zhang R, Pandey MK, Nishiyama Y, Ramamoorthy A. A Novel High-Resolution and Sensitivity-Enhanced Three-Dimensional Solid-State NMR Experiment Under Ultrafast Magic Angle Spinning Conditions. Sci Rep 2015; 5:11810. [PMID: 26138791 PMCID: PMC4490345 DOI: 10.1038/srep11810] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 05/19/2015] [Indexed: 12/22/2022] Open
Abstract
Although magic angle spinning (MAS) solid-state NMR is a powerful technique to obtain atomic-resolution insights into the structure and dynamics of a variety of chemical and biological solids, poor sensitivity has severely limited its applications. In this study, we demonstrate an approach that suitably combines proton-detection, ultrafast-MAS and multiple frequency dimensions to overcome this limitation. With the utilization of proton-proton dipolar recoupling and double quantum (DQ) coherence excitation/reconversion radio-frequency pulses, very high-resolution proton-based 3D NMR spectra that correlate single-quantum (SQ), DQ and SQ coherences of biological solids have been obtained successfully for the first time. The proposed technique requires a very small amount of sample and does not need multiple radio-frequency (RF) channels. It also reveals information about the proximity between a spin and a certain other dipolar-coupled pair of spins in addition to regular SQ/DQ and SQ/SQ correlations. Although 1H spectral resolution is still limited for densely proton-coupled systems, the 3D technique is valuable to study dilute proton systems, such as zeolites, small molecules, or deuterated samples. We also believe that this new methodology will aid in the design of a plethora of multidimensional NMR techniques and enable high-throughput investigation of an exciting class of solids at atomic-level resolution.
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Affiliation(s)
- Rongchun Zhang
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Manoj Kumar Pandey
- RIKEN CLST-JEOL collaboration center, RIKEN, Yokohama, Kanagawa 230-0045, Japan
| | - Yusuke Nishiyama
- 1] RIKEN CLST-JEOL collaboration center, RIKEN, Yokohama, Kanagawa 230-0045, Japan [2] JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
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Nishiyama Y, Kobayashi T, Malon M, Singappuli-Arachchige D, Slowing II, Pruski M. Studies of minute quantities of natural abundance molecules using 2D heteronuclear correlation spectroscopy under 100 kHz MAS. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2015; 66-67:56-61. [PMID: 25773137 DOI: 10.1016/j.ssnmr.2015.02.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 02/05/2015] [Accepted: 02/07/2015] [Indexed: 06/04/2023]
Abstract
Two-dimensional (1)H{(13)C} heteronuclear correlation solid-state NMR spectra of naturally abundant solid materials are presented, acquired using the 0.75-mm magic angle spinning (MAS) probe at spinning rates up to 100 kHz. In spite of the miniscule sample volume (290 nL), high-quality HSQC-type spectra of bulk samples as well as surface-bound molecules can be obtained within hours of experimental time. The experiments are compared with those carried out at 40 kHz MAS using a 1.6-mm probe, which offered higher overall sensitivity due to a larger rotor volume. The benefits of ultrafast MAS in such experiments include superior resolution in (1)H dimension without resorting to (1)H-(1)H homonuclear RF decoupling, easy optimization, and applicability to mass-limited samples. The HMQC spectra of surface-bound species can be also acquired under 100 kHz MAS, although the dephasing of transverse magnetization has significant effect on the efficiency transfer under MAS alone.
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Affiliation(s)
- Y Nishiyama
- JEOL Resonance Inc., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan; RIKEN CLST-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan.
| | - T Kobayashi
- U.S. DOE Ames Laboratory, Ames, IA 50011-3020, USA
| | - M Malon
- JEOL Resonance Inc., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan; RIKEN CLST-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan
| | - D Singappuli-Arachchige
- U.S. DOE Ames Laboratory, Ames, IA 50011-3020, USA; Department of Chemistry, Iowa State University, Ames, IA 50011-3020, USA
| | - I I Slowing
- U.S. DOE Ames Laboratory, Ames, IA 50011-3020, USA; Department of Chemistry, Iowa State University, Ames, IA 50011-3020, USA
| | - M Pruski
- U.S. DOE Ames Laboratory, Ames, IA 50011-3020, USA; Department of Chemistry, Iowa State University, Ames, IA 50011-3020, USA.
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Paluch P, Trébosc J, Nishiyama Y, Potrzebowski MJ, Malon M, Amoureux JP. Theoretical study of CP-VC: a simple, robust and accurate MAS NMR method for analysis of dipolar C-H interactions under rotation speeds faster than ca. 60 kHz. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 252:67-77. [PMID: 25662360 DOI: 10.1016/j.jmr.2015.01.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 12/24/2014] [Accepted: 01/05/2015] [Indexed: 06/04/2023]
Abstract
We show that Cross-Polarization with Variable Contact-time (CP-VC) allows an accurate determination of C-H dipolar interactions, which permits an easy detailed analysis of bond lengths and local dynamics, e.g. in biomolecules. The method presents a large dipolar scaling factor of 1/√2, leading to a better determination of dipolar interactions, especially for long C-H distances, and it allows the observation of very small local details such as those related either to CH(2) three spin systems, or even to hydrogen bonds. CP-VC is very simple to set up and very robust with respect to most experimental parameters, such as: rf-offsets, chemical-shift anisotropies, imperfect Hartmann-Hahn setting, and rf-inhomogeneity. The only required condition is the use of a sufficiently fast MAS spinning speed of at least ca. 60 kHz.
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Affiliation(s)
- P Paluch
- Polish Academy of Sciences, Centre of Molecular and Macromolecular Studies, Lodz 90-363, Poland
| | - J Trébosc
- UCCS, University Lille North of France, Villeneuve d'Ascq 59652, France
| | - Y Nishiyama
- JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan; RIKEN CLST-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan
| | - M J Potrzebowski
- Polish Academy of Sciences, Centre of Molecular and Macromolecular Studies, Lodz 90-363, Poland
| | - M Malon
- JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan; RIKEN CLST-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan
| | - J P Amoureux
- UCCS, University Lille North of France, Villeneuve d'Ascq 59652, France; Physics Department, Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China.
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14
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Shen M, Trébosc J, Lafon O, Pourpoint F, Hu B, Chen Q, Amoureux JP. Improving the resolution in proton-detected through-space heteronuclear multiple quantum correlation NMR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 245:38-49. [PMID: 24929867 DOI: 10.1016/j.jmr.2014.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 05/02/2014] [Accepted: 05/05/2014] [Indexed: 06/03/2023]
Abstract
Connectivities and proximities between protons and low-gamma nuclei can be probed in solid-state NMR spectroscopy using two-dimensional (2D) proton-detected heteronuclear correlation, through Heteronuclear Multiple Quantum Correlation (HMQC) pulse sequence. The indirect detection via protons dramatically enhances the sensitivity. However, the spectra are often broadened along the indirect F1 dimension by the decay of heteronuclear multiple-quantum coherences under the strong (1)H-(1)H dipolar couplings. This work presents a systematic comparison of the performances of various decoupling schemes during the indirect t1 evolution period of dipolar-mediated HMQC (D-HMQC) experiment. We demonstrate that (1)H-(1)H dipolar decoupling sequences during t1, such as symmetry-based schemes, phase-modulated Lee-Goldburg (PMLG) and Decoupling Using Mind-Boggling Optimization (DUMBO), provide better resolution than continuous wave (1)H irradiation. We also report that high resolution requires the preservation of (1)H isotropic chemical shifts during the decoupling sequences. When observing indirectly broad spectra presenting numerous spinning sidebands, the D-HMQC sequence must be fully rotor-synchronized owing to the rotor-synchronized indirect sampling and dipolar recoupling sequence employed. In this case, we propose a solution to reduce artefact sidebands caused by the modulation of window delays before and after the decoupling application during the t1 period. Moreover, we show that (1)H-(1)H dipolar decoupling sequence using Smooth Amplitude Modulation (SAM) minimizes the t1-noise. The performances of the various decoupling schemes are assessed via numerical simulations and compared to 2D (1)H-{(13)C} D-HMQC experiments on [U-(13)C]-L-histidine⋅HCl⋅H2O at various magnetic fields and Magic Angle spinning (MAS) frequencies. Great resolution and sensitivity enhancements resulting from decoupling during t1 period enable the detection of heteronuclear correlation between aliphatic protons and ammonium (14)N sites in L-histidine⋅HCl⋅H2O.
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Affiliation(s)
- Ming Shen
- Physics Department & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China; UCCS, University Lille North of France, Villeneuve d'Ascq 59652, France
| | - J Trébosc
- UCCS, University Lille North of France, Villeneuve d'Ascq 59652, France
| | - O Lafon
- UCCS, University Lille North of France, Villeneuve d'Ascq 59652, France
| | - F Pourpoint
- UCCS, University Lille North of France, Villeneuve d'Ascq 59652, France
| | - Bingwen Hu
- Physics Department & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China
| | - Qun Chen
- Physics Department & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China
| | - J-P Amoureux
- Physics Department & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China; UCCS, University Lille North of France, Villeneuve d'Ascq 59652, France.
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15
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Zhang R, Ramamoorthy A. Performance of RINEPT is amplified by dipolar couplings under ultrafast MAS conditions. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 243:85-92. [PMID: 24792960 PMCID: PMC4057659 DOI: 10.1016/j.jmr.2014.03.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 03/27/2014] [Accepted: 03/31/2014] [Indexed: 05/04/2023]
Abstract
The refocused insensitive nuclei enhanced by polarization transfer (RINEPT) technique is commonly used for heteronuclear polarization transfer in solution and solid-state NMR spectroscopy. Suppression of dipolar couplings, either by fast molecular motions in solution or by a combination of MAS and multiple pulse sequences in solids, enables the polarization transfer via scalar couplings. However, the presence of unsuppressed dipolar couplings could alter the functioning of RINEPT, particularly under fast/ultrafast MAS conditions. In this study, we demonstrate, through experiments on rigid solids complemented by numerical simulations, that the polarization transfer efficiency of RINEPT is dependent on the MAS frequency. In addition, we show that heteronuclear dipolar coupling is the dominant factor in the polarization transfer, which is strengthened by the presence of (1)H-(1)H dipolar couplings. In fact, the simultaneous presence of homonuclear and heteronuclear dipolar couplings is the premise for the polarization transfer by RINEPT, whereas the scalar coupling plays an insignificant role under ultrafast MAS conditions on rigid solids. Our results additionally reveal that the polarization transfer efficiency decreases with the increasing duration of RF pulses used in the RINEPT sequence.
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Affiliation(s)
- Rongchun Zhang
- Biophysics and Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, USA; School of Physics, Nankai University, Tianjin 300071, PR China
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, USA.
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16
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Miloslavina Y, Gupta KBSS, Tank M, Bryant DA, de Groot HJM. wPMLG-5 Spectroscopy of Self-Aggregated BChlein Natural Chlorosomes ofChlorobaculum Limnaeum. Isr J Chem 2014. [DOI: 10.1002/ijch.201300129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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17
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Miah HK, Bennett DA, Iuga D, Titman JJ. Measuring proton shift tensors with ultrafast MAS NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 235:1-5. [PMID: 23911900 DOI: 10.1016/j.jmr.2013.07.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 07/04/2013] [Accepted: 07/09/2013] [Indexed: 06/02/2023]
Abstract
A new proton anisotropic-isotropic shift correlation experiment is described which operates with ultrafast MAS, resulting in good resolution of isotropic proton shifts in the detection dimension. The new experiment makes use of a recoupling sequence designed using symmetry principles which reintroduces the proton chemical shift anisotropy in the indirect dimension. The experiment has been used to measure the proton shift tensor parameters for the OH hydrogen-bonded protons in tyrosine·HCl and citric acid at Larmor frequencies of up to 850 MHz.
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Affiliation(s)
- Habeeba K Miah
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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18
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Paluch P, Pawlak T, Amoureux JP, Potrzebowski MJ. Simple and accurate determination of X-H distances under ultra-fast MAS NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 233:56-63. [PMID: 23727588 DOI: 10.1016/j.jmr.2013.05.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 04/30/2013] [Accepted: 05/06/2013] [Indexed: 05/14/2023]
Abstract
We demonstrate that a very simple experiment, Cross-Polarization with Variable Contact-time (CP-VC), is very efficient at ultra-fast MAS (νR ≥ 60 kHz) to measure accurately the C-H and N-H distances, and to analyze the dynamics of bio-molecules. This experiment can be performed with samples that are either (13)C or (15)N labeled or without any labeling. The method is very robust experimentally with respect to imperfect Hartman-Hahn setting, and presents a large scaling factor allowing a better dipolar determination, especially for long C-H or N-H distances, or for CH3 or NH3 moieties with three-site hopping. At ultra-fast MAS, it can be used quantitatively in a 2D way, because its scaling factor is then little dependent on the offsets. This robustness with respect to offset is related to the ultra-fast spinning speed, and hence to the related small rotor diameter. Indeed, these two specifications lead to efficient n = ±1 zero-quantum Hartman-Hahn CP-transfers with large RF-fields on proton and carbon or nitrogen channels, and large dipolar scaling factor.
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Affiliation(s)
- Piotr Paluch
- Polish Academy of Sciences, Centre of Molecular and Macromolecular Studies, Sienkiewicza 112, PL-90-363 Lodz, Poland
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