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Ahlawat S, Mopidevi SMV, Taware PP, Raran-Kurussi S, Mote KR, Agarwal V. Assignment of aromatic side-chain spins and characterization of their distance restraints at fast MAS. J Struct Biol X 2022; 7:100082. [PMID: 36618437 PMCID: PMC9817166 DOI: 10.1016/j.yjsbx.2022.100082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/18/2022] [Accepted: 12/27/2022] [Indexed: 12/30/2022] Open
Abstract
The assignment of aromatic side-chain spins has always been more challenging than assigning backbone and aliphatic spins. Selective labeling combined with mutagenesis has been the approach for assigning aromatic spins. This manuscript reports a method for assigning aromatic spins in a fully protonated protein by connecting them to the backbone atoms using a low-power TOBSY sequence. The pulse sequence employs residual polarization and sequential acquisitions techniques to record HN- and HC-detected spectra in a single experiment. The unambiguous assignment of aromatic spins also enables the characterization of 1H-1H distance restraints involving aromatic spins. Broadband (RFDR) and selective (BASS-SD) recoupling sequences were used to generate HN-ΗC, HC-HN and HC-HC restraints involving the side-chain proton spins of aromatic residues. This approach has been demonstrated on a fully protonated U-[13C,15N] labeled GB1 sample at 95-100 kHz MAS.
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2
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Lends A, Ravotti F, Zandomeneghi G, Böckmann A, Ernst M, Meier BH. Direct amide 15N to 13C transfers for solid-state assignment experiments in deuterated proteins. JOURNAL OF BIOMOLECULAR NMR 2018; 72:69-78. [PMID: 30206780 DOI: 10.1007/s10858-018-0207-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 09/01/2018] [Indexed: 06/08/2023]
Abstract
The assignment of protein backbone and side-chain NMR chemical shifts is the first step towards the characterization of protein structure. The recent introduction of proton detection in combination with fast MAS has opened up novel opportunities for assignment experiments. However, typical 3D sequential-assignment experiments using proton detection under fast MAS lead to signal intensities much smaller than the theoretically expected ones due to the low transfer efficiency of some of the steps. Here, we present a selective 3D experiment for deuterated and (amide) proton back-exchanged proteins where polarization is directly transferred from backbone nitrogen to selected backbone or sidechain carbons. The proposed pulse sequence uses only 1H-15N cross-polarization (CP) transfers, which are, for deuterated proteins, about 30% more efficient than 1H-13C CP transfers, and employs a dipolar version of the INEPT experiment for N-C transfer. By avoiding HN-C (HN stands for amide protons) and C-C CP transfers, we could achieve higher selectivity and increased signal intensities compared to other pulse sequences containing long-range CP transfers. The REDOR transfer is designed with an additional selective π pulse, which enables the selective transfer of the polarization to the desired 13C spins.
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Affiliation(s)
- Alons Lends
- Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland
| | - Francesco Ravotti
- Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland
| | - Giorgia Zandomeneghi
- Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland
| | - Anja Böckmann
- Molecular Microbiology and Structural Biochemistry, Labex Ecofect, UMR 5086 CNRS/Université de Lyon, 69367, Lyon, France
| | - Matthias Ernst
- Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland.
| | - Beat H Meier
- Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland.
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3
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Nagashima H, Lilly Thankamony AS, Trébosc J, Montagne L, Kerven G, Amoureux JP, Lafon O. Observation of proximities between spin-1/2 and quadrupolar nuclei in solids: Improved robustness to chemical shielding using adiabatic symmetry-based recoupling. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2018; 94:7-19. [PMID: 30103084 DOI: 10.1016/j.ssnmr.2018.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 07/17/2018] [Accepted: 07/17/2018] [Indexed: 06/08/2023]
Abstract
We introduce a novel heteronuclear dipolar recoupling based on the R21-1 symmetry, which uses the tanh/tan (tt) shaped pulse as a basic inversion element and is denoted R21-1(tt). Using first-order average Hamiltonian theory, we show that this sequence is non-γ-encoded and that it reintroduces the |m| = 1 spatial component of the Chemical Shift Anisotropy (CSA) of the irradiated isotope and its heteronuclear dipolar interactions. Using numerical simulations and one-dimensional (1D) 27Al-{31P} through-space D-HMQC (Dipolar Heteronuclear Multiple-Quantum Correlation) experiments on VPI-5, we compare the performances of this recoupling to those of other non-γ-encoded |m| = 1 heteronuclear recoupling schemes: REDOR (Rotational-Echo DOuble Resonance), SFAM (Simultaneous Frequency and Amplitude Modulation) and R42-1(tt). Such comparison indicates that the R21-1(tt) scheme is more robust to CSA, offset and radiofrequency field inhomogeneities than the other schemes. We take advantage of the high robustness of R21-1(tt) to CSA and offset to demonstrate the possibility to correlate the signals of 207Pb isotope with those of neighboring half-integer spin quadrupolar nuclei. Such approach is demonstrated experimentally by acquiring 11B-{207Pb} D-HMQC 2D spectra of Pb4O(BO3)2 crystalline powder.
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Affiliation(s)
- Hiroki Nagashima
- Univ. Lille, CNRS-8181, UCCS-Unit of Catalysis and Chemistry of Solids, F-59000, Lille, France; Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan
| | | | - Julien Trébosc
- Univ. Lille, CNRS-8181, UCCS-Unit of Catalysis and Chemistry of Solids, F-59000, Lille, France
| | - Lionel Montagne
- Univ. Lille, CNRS-8181, UCCS-Unit of Catalysis and Chemistry of Solids, F-59000, Lille, France
| | - Gwendal Kerven
- Univ. Lorraine, CNRS-7036, CRM2, F-54506, Vandœuvre-lès-Nancy, France
| | - Jean-Paul Amoureux
- Univ. Lille, CNRS-8181, UCCS-Unit of Catalysis and Chemistry of Solids, F-59000, Lille, France; Bruker Biospin, 34 rue de l'industrie, F-67166, Wissembourg, France.
| | - Olivier Lafon
- Univ. Lille, CNRS-8181, UCCS-Unit of Catalysis and Chemistry of Solids, F-59000, Lille, France; Institut Universitaire de France, 1 rue Descartes, F-75231, Paris, France.
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4
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Tan KO, Agarwal V, Lakomek NA, Penzel S, Meier BH, Ernst M. Efficient low-power TOBSY sequences for fast MAS. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2018; 89:27-34. [PMID: 29233617 DOI: 10.1016/j.ssnmr.2017.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 11/28/2017] [Accepted: 11/28/2017] [Indexed: 06/07/2023]
Abstract
Through-bond J-coupling based experiments in solid-state NMR spectroscopy are challenging because the J couplings are typically much smaller than the dipolar couplings. This often leads to a lower transfer efficiency compared to dipolar-coupling based sequences. One of the reasons for the low transfer efficiency are the second-order cross terms involving the strong heteronuclear dipolar couplings leading to fast magnetization decay. Here, we show that by employing a symmetry-based C9 sequence, which was carefully selected to suppress second-order terms, efficient polarization transfers of up to 80% can be achieved without decoupling on fully protonated two-spin model systems at a MAS frequency of 55.5 kHz with rf-field amplitudes of about 25 kHz. In addition, we analyse the effects of rf inhomogeneity and crystallites selection due to the polarization preparation method on the TOBSY transfer efficiency. We demonstrate on small model substances as well as on deuterated and 100% back-exchanged ubiquitin that C9391 and C9481 are efficient and practical TOBSY sequences at experimental conditions ranging from proton Larmor frequencies of 400-850 MHz, and MAS frequencies ranging from 55.5 to 111.1 kHz.
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Affiliation(s)
- Kong Ooi Tan
- Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland
| | - Vipin Agarwal
- Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland
| | | | - Susanne Penzel
- Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland
| | - Beat H Meier
- Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland.
| | - Matthias Ernst
- Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland.
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5
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Identification and Structural Characterization of the N-terminal Amyloid Core of Orb2 isoform A. Sci Rep 2016; 6:38265. [PMID: 27922050 PMCID: PMC5138630 DOI: 10.1038/srep38265] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 11/07/2016] [Indexed: 12/12/2022] Open
Abstract
Orb2 is a functional amyloid that plays a key role in Drosophila long-term memory formation. Orb2 has two isoforms that differ in their N-termini. The N-terminus of the A isoform (Orb2A) that precedes its Q-rich prion-like domain has been shown to be important for Orb2 aggregation and long-term memory. However, besides the fact that it forms fibrillar aggregates, structural information of Orb2 is largely absent. To understand the importance of the N-terminus of Orb2A and its relation to the fibril core, we recorded solid-state NMR and EPR data on fibrils formed by the first 88 residues of Orb2A (Orb2A88). These data show that the N-terminus of Orb2A not only promotes the formation of fibrils, but also forms the fibril core of Orb2A88. This fibril core has an in-register parallel β-sheet structure and does not include the Q-rich, prion-like domain of Orb2. The Q-rich domain is part of the unstructured region, which becomes increasingly dynamic towards the C-terminus.
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6
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Dekhil M, Mollica G, Bonniot TT, Ziarelli F, Thureau P, Viel S. Determining carbon-carbon connectivities in natural abundance organic powders using dipolar couplings. Chem Commun (Camb) 2016; 52:8565-8. [PMID: 27319808 DOI: 10.1039/c6cc04202c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a solid-state NMR methodology capable of investigating the carbon skeleton of natural abundance organic powders. The methodology is based on the (13)C-(13)C dipolar coupling interaction and allows carbon-carbon connectivities to be unambiguously established for a wide range of organic solids. This methodology is particularly suitable for disordered solids, such as natural or synthetic macromolecules, which cannot be studied using conventional diffraction or NMR techniques.
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Affiliation(s)
- Myriam Dekhil
- Aix-Marseille Université, CNRS, ICR (UMR 7273), 13397 Marseille, France.
| | - Giulia Mollica
- Aix-Marseille Université, CNRS, ICR (UMR 7273), 13397 Marseille, France.
| | | | - Fabio Ziarelli
- Aix-Marseille Université, Centrale Marseille, CNRS, Fédération des Sciences Chimiques de Marseille (FR 1739), 13397 Marseille, France
| | - Pierre Thureau
- Aix-Marseille Université, CNRS, ICR (UMR 7273), 13397 Marseille, France.
| | - Stéphane Viel
- Aix-Marseille Université, CNRS, ICR (UMR 7273), 13397 Marseille, France. and Institut Universitaire de France, 75005 Paris, France
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7
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Tan KO, Rajeswari M, Madhu PK, Ernst M. Asynchronous symmetry-based sequences for homonuclear dipolar recoupling in solid-state nuclear magnetic resonance. J Chem Phys 2015; 142:065101. [PMID: 25681942 DOI: 10.1063/1.4907275] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We show a theoretical framework, based on triple-mode Floquet theory, to analyze recoupling sequences derived from symmetry-based pulse sequences, which have a non-vanishing effective field and are not rotor synchronized. We analyze the properties of one such sequence, a homonuclear double-quantum recoupling sequence derived from the C72 (1) sequence. The new asynchronous sequence outperforms the rotor-synchronized version for spin pairs with small dipolar couplings in the presence of large chemical-shift anisotropy. The resonance condition of the new sequence is analyzed using triple-mode Floquet theory. Analytical calculations of second-order effective Hamiltonian are performed to compare the efficiency in suppressing second-order cross terms. Experiments and numerical simulations are shown to corroborate the results of the theoretical analysis.
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Affiliation(s)
- Kong Ooi Tan
- Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - M Rajeswari
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
| | - P K Madhu
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
| | - Matthias Ernst
- Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
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8
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Tan KO, Scholz I, van Beek JD, Meier BH, Ernst M. Improved decoupling during symmetry-based C9-TOBSY sequences. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 239:61-68. [PMID: 24384065 DOI: 10.1016/j.jmr.2013.11.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 11/26/2013] [Accepted: 11/29/2013] [Indexed: 06/03/2023]
Abstract
We show that heteronuclear decoupling during symmetry-based C9 TOBSY sequences can be improved by using phase-alternating pulse sequences (XiX) instead of cw irradiation. The use of XiX sequences makes the optimization of the decoupling rf-field amplitude simpler and lowers the decoupling rf-field requirements to attain a comparable performance. A Floquet analysis of the first-order resonance conditions was used to determine the correct timing of the XiX sequence to avoid interference between the C sequence and the decoupling. The decoupling performance is analyzed analytically using Floquet theory and verified using numerical simulations as well as experimental results.
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Affiliation(s)
- Kong Ooi Tan
- Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
| | - Ingo Scholz
- Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
| | - Jacco D van Beek
- Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
| | - Beat H Meier
- Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland.
| | - Matthias Ernst
- Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland.
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9
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O'Dell LA. The WURST kind of pulses in solid-state NMR. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2013; 55-56:28-41. [PMID: 24183812 DOI: 10.1016/j.ssnmr.2013.10.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/07/2013] [Accepted: 10/07/2013] [Indexed: 06/02/2023]
Abstract
WURST pulses (wideband, uniform rate, smooth truncation) were first introduced two decades ago by Kupče and Freeman as a means of achieving broadband adiabatic inversion of magnetisation for solution-state (13)C decoupling at high magnetic field strengths. In more recent years these pulses have found use in an increasingly diverse range of applications in solid-state NMR. This article reviews a number of recent developments that take advantage of WURST pulses, including broadband excitation, refocusing and cross polarisation for the acquisition of ultra-wideline powder patterns, signal enhancement for half-integer and integer spin quadrupolar nuclei, spectral editing, direct and indirectly observed (14)N overtone MAS, and symmetry-based homonuclear recoupling. Simple mathematical descriptions of WURST pulses and some brief theory behind their operation in the adiabatic and non-adiabatic regimes are provided, and various practical considerations for their use are also discussed.
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Affiliation(s)
- Luke A O'Dell
- Institute for Frontier Materials, Deakin University, Waurn Ponds Campus, Geelong, Victoria 3220, Australia.
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10
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Herbst C, Herbst J, Leppert J, Ohlenschläger O, Görlach M, Ramachandran R. Chemical shift correlation at high MAS frequencies employing low-power symmetry-based mixing schemes. JOURNAL OF BIOMOLECULAR NMR 2011; 50:277-284. [PMID: 21674236 DOI: 10.1007/s10858-011-9516-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 05/11/2011] [Indexed: 05/30/2023]
Abstract
An approach for conveniently implementing low-power CN ( n ) (ν) and RN ( n ) (ν) symmetry-based band-selective mixing sequences for generating homo- and heteronuclear chemical shift correlation NMR spectra of low γ nuclei in biological solids is demonstrated. Efficient magnetisation transfer characteristics are achieved by selecting appropriate symmetries requiring the application of basic RF elements of relatively long duration and numerically tailoring the RF field modulation profile of the basic element. The efficacy of the approach is experimentally shown by the acquisition of (15)N-(13)C dipolar and (13)C-(13)C scalar and dipolar coupling mediated chemical shift correlation spectra at representative MAS frequencies.
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11
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Baltisberger JH, Musapelo T, Sutton B, Reynolds A, Gurung L. Reduction of spin diffusion artifacts from 2D zfr-INADEQUATE MAS NMR spectra. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 208:70-75. [PMID: 21036081 DOI: 10.1016/j.jmr.2010.10.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 10/06/2010] [Accepted: 10/07/2010] [Indexed: 05/30/2023]
Abstract
The primary shortcoming of the z-filtered refocused INADEQUATE MAS NMR pulse sequence is the possibility of artifacts introduced during the z-filter due to spin diffusion where by extra peaks in the single-quantum dimension (from other sites in the molecule) appear correlated with a given double-quantum frequency. This is a problem when the spinning speeds are too slow (less than 15 kHz) to sufficiently average the proton-proton homonuclear dipolar couplings. This would be especially important when working with large volume rotors that are difficult to spin fast enough to completely average the homonuclear couplings. In our experiments we used the frequency-switched Lee-Goldberg (FSLG) method of homonuclear decoupling during the z-filter to remove the artifact peaks. This method has the advantage of being quite easy to setup and implement on most modern NMR spectrometers.
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12
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Huang KY, Siemer AB, McDermott AE. Homonuclear mixing sequences for perdeuterated proteins. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 208:122-7. [PMID: 21094063 PMCID: PMC3021637 DOI: 10.1016/j.jmr.2010.10.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 10/18/2010] [Accepted: 10/21/2010] [Indexed: 05/08/2023]
Abstract
We tested the performance of several (13)C homonuclear mixing sequences on perdeuterated microcrystalline ubiquitin. All sequences were applied without (1)H decoupling and at relatively low MAS frequencies. We found that RFDR gave the highest overall transfer efficiency and that DREAM performs surprisingly well under these conditions being twice as efficient in the aliphatic region of the spectrum than the other mixing sequences tested.
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Affiliation(s)
- Kuo-Ying Huang
- Department of Chemistry MC3113, Columbia University, 3000 Broadway, New York, NY 10027, USA
| | - Ansgar B. Siemer
- Department of Chemistry MC3113, Columbia University, 3000 Broadway, New York, NY 10027, USA
| | - Ann E. McDermott
- Department of Chemistry MC3113, Columbia University, 3000 Broadway, New York, NY 10027, USA
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13
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14
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Chan JCC. Solid-state NMR techniques for the structural determination of amyloid fibrils. Top Curr Chem (Cham) 2011; 306:47-88. [PMID: 21630137 DOI: 10.1007/128_2011_154] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This review discusses the solid-state NMR techniques developed for the study of amyloid fibrils. Literature up to the end of 2010 has been surveyed and the materials are organized according to five categories, viz. homonuclear dipolar recoupling and polarization transfer via J-coupling, heteronuclear dipolar recoupling, correlation spectroscopy, recoupling of chemical shift anisotropy, and tensor correlation. Our emphasis is on the NMR techniques and their practical aspects. The biological implications of the results obtained for amyloid fibrils are only briefly discussed. Our main objective is to showcase the power of NMR in the study of biological unoriented solids.
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Affiliation(s)
- Jerry C C Chan
- Department of Chemistry, National Taiwan University, Taipei, Taiwan.
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15
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Köneke SG, van Beek JD, Ernst M, Meier BH. Characteristics of zero-quantum correlation spectroscopy in MAS NMR experiments. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 207:197-205. [PMID: 20920869 DOI: 10.1016/j.jmr.2010.08.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 08/29/2010] [Accepted: 08/31/2010] [Indexed: 05/29/2023]
Abstract
Zero-quantum coherence generation and reconversion in magic-angle spinning solid-state NMR is analyzed. Two methods are discussed based on implementations using symmetry-based pulse sequences that utilize either isotropic J couplings or dipolar couplings. In either case, the decoupling of abundant proton spins plays a crucial role for the efficiency of the zero-quantum generation. We present optimized sequences for measuring zero-quantum single-quantum correlation spectra in solids, achieving an efficiency of 50% in ubiquitin. The advantages and disadvantages of zero-quantum single-quantum over single-quantum single-quantum correlation spectroscopy are explored, and similarities and differences with double-quantum single-quantum correlation spectroscopy are discussed. Finally, possible application of zero-quantum single-quantum experiments to polypeptides, where it can lead to better spectral resolution is investigated using ubiquitin, where we find high efficiency and high selectivity, but also increased line widths in the MQ dimension.
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Affiliation(s)
- Stephanie G Köneke
- ETH Zürich, Physical Chemistry, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
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16
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Scholz I, van Beek JD, Ernst M. Operator-based Floquet theory in solid-state NMR. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2010; 37:39-59. [PMID: 20573488 DOI: 10.1016/j.ssnmr.2010.04.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 04/30/2010] [Indexed: 05/14/2023]
Abstract
This article reviews the application of operator-based Floquet theory in solid-state NMR. Basic expressions for calculating effective Hamiltonians based on van Vleck perturbation theory are reviewed for problems with a single frequency or multiple incommensurate frequencies. Such a treatment allows calculation of effective Hamiltonians for resonant and non-resonant problems. Examples from literature are given for single-mode to triple-mode Floquet problems, covering a wide range of applications in solid-state NMR under magic-angle spinning and radio-frequency irradiation of a single nucleus or multiple nuclei.
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Affiliation(s)
- Ingo Scholz
- Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
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17
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Righi V, Andronesi O, Mintzopoulos D, Tzika AA. Molecular characterization and quantification using state of the art solid-state adiabatic TOBSY NMR in burn trauma. Int J Mol Med 2010; 24:749-57. [PMID: 19885614 PMCID: PMC3722686 DOI: 10.3892/ijmm_00000288] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We describe a novel solid-state nuclear magnetic resonance (NMR) method that maximizes the advantages of high-resolution magic-angle-spinning (HRMAS), relative conventional liquid-state NMR approaches, when applied to intact biopsies of skeletal muscle specimens collected from burn trauma patients. This novel method, termed optimized adiabatic TOtal through Bond correlation SpectroscopY (TOBSY) solid-state NMR pulse sequence for two-dimensional (2D)1H-1H homonuclear scalar-coupling longitudinal isotropic mixing, was demonstrated to provide a 40–60% improvement in signal-to-noise ratio (SNR) relative to its liquid-state analogue TOCSY (TOtal Correlation SpectroscopY). Using 1-and 2-dimensional HRMAS NMR experiments, we identified several metabolites in burned tissues. Quantification of metabolites in burned tissues showed increased levels of lipid compounds, intracellular metabolites (e.g., taurine and phosphocreatine) and substantially decreased water-soluble metabolites (e.g., glutathione, carnosine, glucose, glutamine/glutamate and alanine). These findings demonstrate that HRMAS NMR Spectroscopy using TOBSY is a feasible technique that reveals new insights into the pathophysiology of burn trauma. Moreover, this method has applications that facilitate the development of novel therapeutic strategies.
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Affiliation(s)
- Valeria Righi
- NMR Surgical Laboratory, Department of Surgery, Massachusetts General Hospital and Shriners Burn Institute, Harvard Medical School, Boston, MA 02114, USA
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18
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Herbst C, Herbst J, Leppert J, Ohlenschläger O, Görlach M, Ramachandran R. Numerical design of RN(n)(nu) symmetry-based RF pulse schemes for recoupling and decoupling of nuclear spin interactions at high MAS frequencies. JOURNAL OF BIOMOLECULAR NMR 2009; 44:235-244. [PMID: 19557520 DOI: 10.1007/s10858-009-9335-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 06/03/2009] [Indexed: 05/28/2023]
Abstract
An approach for the efficient implementation of RN(n)(nu) symmetry-based pulse schemes that are often employed for recoupling and decoupling of nuclear spin interactions in biological solid state NMR investigations is demonstrated at high magic-angle spinning frequencies. RF pulse sequences belonging to the RN(n)(nu) symmetry involve the repeated application of the pulse sandwich {R(phi)R(-phi)}, corresponding to a propagator U(RF) = exp(-i4phiI(z)), where phi = pinu/N and R is typically a pulse that rotates the nuclear spins through 180 degrees about the x-axis. In this study, broadband, phase-modulated 180 degrees pulses of constant amplitude were employed as the initial 'R' element and the phase-modulation profile of this 'R' element was numerically optimised for generating RN(n)(nu) symmetry-based pulse schemes with satisfactory magnetisation transfer characteristics. At representative MAS frequencies, RF pulse sequences were implemented for achieving 13C-13C double-quantum dipolar recoupling and through bond scalar coupling mediated chemical shift correlation and evaluated via numerical simulations and experimental measurements. The results from these investigations are presented here.
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Affiliation(s)
- Christian Herbst
- Research group Biomolecular NMR spectroscopy, Leibniz Institute for Age Research, Fritz Lipmann Institute, 07745 Jena, Germany
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Herbst C, Herbst J, Kirschstein A, Leppert J, Ohlenschläger O, Görlach M, Ramachandran R. Recoupling and decoupling of nuclear spin interactions at high MAS frequencies: numerical design of CN(n)(nu) symmetry-based RF pulse schemes. JOURNAL OF BIOMOLECULAR NMR 2009; 44:175-184. [PMID: 19548091 DOI: 10.1007/s10858-009-9334-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Accepted: 04/29/2009] [Indexed: 05/28/2023]
Abstract
The CN(n)(nu) class of RF pulse schemes, commonly employed for recoupling and decoupling of nuclear spin interactions in magic angle spinning solid state NMR studies of biological systems, involves the application of a basic "C" element corresponding to an RF cycle with unity propagator. In this study, the design of CN(n)(nu) symmetry-based RF pulse sequences for achieving 13C-13C double-quantum dipolar recoupling and through bond scalar coupling mediated 13C-13C chemical shift correlation has been examined at high MAS frequencies employing broadband, constant-amplitude, phase-modulated basic "C" elements. The basic elements were implemented as a sandwich of a small number of short pulses of equal duration with each pulse characterised by an RF phase value. The phase-modulation profile of the "C" element was optimised numerically so as to generate efficient RF pulse sequences. The performances of the sequences were evaluated via numerical simulations and experimental measurements and are presented here.
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Affiliation(s)
- Christian Herbst
- Research Group Biomolecular NMR Spectroscopy, Leibniz Institute for Age Research, Fritz Lipmann Institute, 07745 Jena, Germany
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20
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Herbst C, Herbst J, Kirschstein A, Leppert J, Ohlenschläger O, Görlach M, Ramachandran R. Design of high-power, broadband 180 degrees pulses and mixing sequences for fast MAS solid state chemical shift correlation NMR spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2009; 43:51-61. [PMID: 19018477 DOI: 10.1007/s10858-008-9292-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Accepted: 10/28/2008] [Indexed: 05/27/2023]
Abstract
An approach for the design of high-power, broadband 180 degrees pulses and mixing sequences for generating dipolar and scalar coupling mediated (13)C-(13)C chemical shift correlation spectra of isotopically labelled biological systems at fast magic-angle spinning frequencies without (1)H decoupling during mixing is presented. Considering RF field strengths in the range of 100-120 kHz, as typically available in MAS probes employed at high spinning speeds, and limited B (1) field inhomogeneities, the Fourier coefficients defining the phase modulation profile of the RF pulses were optimised numerically to obtain broadband inversion and refocussing pulses and mixing sequences. Experimental measurements were carried out to assess the performance characteristics of the mixing sequences reported here.
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Affiliation(s)
- Christian Herbst
- Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany
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Agarwal V, Reif B. Residual methyl protonation in perdeuterated proteins for multi-dimensional correlation experiments in MAS solid-state NMR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2008; 194:16-24. [PMID: 18571955 DOI: 10.1016/j.jmr.2008.05.021] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Accepted: 05/19/2008] [Indexed: 05/26/2023]
Abstract
NMR studies involving perdeuterated proteins focus in general on exchangeable amide protons. However, non-exchangeable sites contain as well a small amount of protons as the employed precursors for protein biosynthesis are not completely proton depleted. The degree of methyl group protonation is in the order of 9% for CD2H using >97% deuterium enriched glucose. We show in this manuscript that this small amount of residual protonation is sufficient to perform 2D and 3D MAS solid-state NMR experiments. In particular, we suggest a HCCH-TOBSY type experiment which we successfully employ to assign the methyl resonances in aliphatic side chains in a perdeuterated sample of the SH3 domain of chicken alpha-spectrin.
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Affiliation(s)
- Vipin Agarwal
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, Robert-Rössle-Strase 10, D-13125 Berlin, Germany
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Wasmer C, Soragni A, Sabaté R, Lange A, Riek R, Meier BH. Infectious and noninfectious amyloids of the HET-s(218-289) prion have different NMR spectra. Angew Chem Int Ed Engl 2008; 47:5839-41. [PMID: 18548467 DOI: 10.1002/anie.200704896] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Christian Wasmer
- Laboratorium für Physikalische Chemie, ETH Zurich, 8093 Zurich, Switzerland
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Andronesi OC, Mintzopoulos D, Struppe J, Black PM, Tzika AA. Solid-state NMR adiabatic TOBSY sequences provide enhanced sensitivity for multidimensional high-resolution magic-angle-spinning 1H MR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2008; 193:251-258. [PMID: 18556227 DOI: 10.1016/j.jmr.2008.05.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Revised: 05/12/2008] [Accepted: 05/12/2008] [Indexed: 05/26/2023]
Abstract
We propose a solid-state NMR method that maximizes the advantages of high-resolution magic-angle-spinning (HRMAS) applied to intact biopsies when compared to more conventional liquid-state NMR approaches. Theoretical treatment, numerical simulations and experimental results on intact human brain biopsies are presented. Experimentally, it is proven that an optimized adiabatic TOBSY (TOtal through Bond correlation SpectroscopY) solid-state NMR pulse sequence for two-dimensional 1H-1H homonuclear scalar-coupling longitudinal isotropic mixing provides a 20%-50% improvement in signal-to-noise ratio relative to its liquid-state analogue TOCSY (TOtal Correlation SpectroscopY). For this purpose we have refined the C9(15)1 symmetry-based 13C TOBSY pulse sequence for 1H MRS use and compared it to MLEV-16 TOCSY sequence. Both sequences were rotor-synchronized and implemented using WURST-8 adiabatic inversion pulses. As discussed theoretically and shown in simulations, the improved magnetization-transfer comes from actively removing residual dipolar couplings from the average Hamiltonian. Importantly, the solid-state NMR techniques are tailored to perform measurements at low temperatures where sample degradation is reduced. This is the first demonstration of such a concept for HRMAS metabolic profiling of disease processes, including cancer, from biopsies requiring reduced sample degradation for further genomic analysis.
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Affiliation(s)
- Ovidiu C Andronesi
- NMR Surgical Laboratory, Department of Surgery, Massachusetts General Hospital and Shriner's Burn Institute, Harvard Medical School, 51 Blossom Street, Room 261, Boston, MA 02114, USA.
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Wasmer C, Soragni A, Sabaté R, Lange A, Riek R, Meier B. Infektiöse und nichtinfektiöse Amyloide des HET‐s(218‐289)‐Prions haben unterschiedliche NMR‐Spektren. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200704896] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Kehlet C, Bjerring M, Sivertsen AC, Kristensen T, Enghild JJ, Glaser SJ, Khaneja N, Nielsen NC. Optimal control based NCO and NCA experiments for spectral assignment in biological solid-state NMR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 188:216-30. [PMID: 17681479 DOI: 10.1016/j.jmr.2007.06.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Revised: 06/02/2007] [Accepted: 06/07/2007] [Indexed: 05/16/2023]
Abstract
We present novel pulse sequences for magic-angle-spinning solid-state NMR structural studies of (13)C,(15)N-isotope labeled proteins. The pulse sequences have been designed numerically using optimal control procedures and demonstrate superior performance relative to previous methods with respect to sensitivity, robustness to instrumental errors, and band-selective excitation profiles for typical biological solid-state NMR applications. Our study addresses specifically (15)N to (13)C coherence transfers being important elements in spectral assignment protocols for solid-state NMR structural characterization of uniformly (13)C,(15)N-labeled proteins. The pulse sequences are analyzed in detail and their robustness towards spin system and external experimental parameters are illustrated numerically for typical (15)N-(13)C spin systems under high-field solid-state NMR conditions. Experimentally the methods are demonstrated by 1D (15)N-->(13)C coherence transfer experiments, as well as 2D and 3D (15)N,(13)C and (15)N,(13)C,(13)C chemical shift correlation experiments on uniformly (13)C,(15)N-labeled ubiquitin.
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Affiliation(s)
- Cindie Kehlet
- Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO), University of Aarhus, Langelandsgade 140, DK-8000, Aarhus C, Denmark
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26
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Cadars S, Sein J, Duma L, Lesage A, Pham TN, Baltisberger JH, Brown SP, Emsley L. The refocused INADEQUATE MAS NMR experiment in multiple spin-systems: interpreting observed correlation peaks and optimising lineshapes. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 188:24-34. [PMID: 17588789 DOI: 10.1016/j.jmr.2007.05.016] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Accepted: 05/18/2007] [Indexed: 05/12/2023]
Abstract
The robustness of the refocused INADEQUATE MAS NMR pulse sequence for probing through-bond connectivities has been demonstrated in a large range of solid-state applications. This pulse sequence nevertheless suffers from artifacts when applied to multispin systems, e.g. uniformly labeled (13)C solids, which distort the lineshapes and can potentially result in misleading correlation peaks. In this paper, we present a detailed account that combines product-operator analysis, numerical simulations and experiments of the behavior of a three-spin system during the refocused INADEQUATE pulse sequence. The origin of undesired anti-phase contributions to the spectral lineshapes are described, and we show that they do not interfere with the observation of long-range correlations (e.g. two-bond (13)C-(13)C correlations). The suppression of undesired contributions to the refocused INADEQUATE spectra is shown to require the removal of zero-quantum coherences within a z-filter. A method is proposed to eliminate zero-quantum coherences through dephasing by heteronuclear dipolar couplings, which leads to pure in-phase spectra.
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Affiliation(s)
- Sylvian Cadars
- Laboratoire de Chimie (UMR 5182 CNRS/ENS Lyon), Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07, France
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Mou Y, Chen PH, Lee HW, Chan JCC. Determination of chemical shift anisotropies of unresolved carbonyl sites by C-alpha detection under magic-angle spinning. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 187:352-6. [PMID: 17524685 DOI: 10.1016/j.jmr.2007.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Revised: 04/03/2007] [Accepted: 05/06/2007] [Indexed: 05/15/2023]
Abstract
We demonstrate that the static powder pattern line shape of chemical shift anisotropy (CSA) can be obtained for unresolved carbonyl sites of polypeptides under magic-angle spinning. The CSA interaction is first recoupled at the carbonyl site. The phase factors associated with the CSA recoupling are then transferred to the adjacent alpha carbon by an isotropic polarization transfer based on scalar spin-spin coupling. Because alpha carbons of polypeptides are usually better resolved, we can then obtain the CSA static powder pattern line shapes of the carbonyl sites after Fourier transformation in the second dimension. We validate our approach experimentally by measurements on [U-(13)C, (15)N]-l-alanine, [U-(13)C, (15)N]-l-valine and prion fibrils with uniform (13)C and (15)N labels on selected residues.
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Affiliation(s)
- Yun Mou
- Department of Chemistry, National Taiwan University, No. 1 Section 4 Roosevelt Road, Taipei, Taiwan
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28
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Riedel K, Herbst C, Leppert J, Ohlenschläger O, Görlach M, Ramachandran R. Broadband homonuclear chemical shift correlation at high MAS frequencies: a study of tanh/tan adiabatic RF pulse schemes without 1H decoupling during mixing. JOURNAL OF BIOMOLECULAR NMR 2007; 37:277-86. [PMID: 17288003 DOI: 10.1007/s10858-006-9137-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Accepted: 12/11/2006] [Indexed: 05/13/2023]
Abstract
At high magic angle spinning (MAS) frequencies the potential of tanh/tan adiabatic RF pulse schemes for 13C chemical shift correlation without 1H decoupling during mixing has been evaluated. It is shown via numerical simulations that a continuous train of adiabatic 13C inversion pulses applied at high RF field strengths leads to efficient broadband heteronuclear decoupling. It is demonstrated that this can be exploited effectively for generating through-bond and through-space, including double-quantum, correlation spectra of biological systems at high magnetic fields and spinning speeds with no 1H decoupling applied during the mixing period. Experiments carried out on a polycrystalline sample of histidine clearly suggest that an improved signal to noise ratio can be realised by eliminating 1H decoupling during mixing.
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Affiliation(s)
- Kerstin Riedel
- Research Group Molecular Biophysics/NMR Spectroscopy, Leibniz Institute for Age Research, Fritz Lipmann Institute, 07745 Jena, Germany
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29
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Mou Y, Tsai TWT, Chan JCC. Determination of the backbone torsion psi angle by tensor correlation of chemical shift anisotropy and heteronuclear dipole-dipole interaction. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2007; 31:72-81. [PMID: 17329083 DOI: 10.1016/j.ssnmr.2007.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Revised: 12/25/2006] [Accepted: 01/20/2007] [Indexed: 05/14/2023]
Abstract
We demonstrate that the backbone torsion psi angle of a uniformly labeled residue can be determined accurately by correlating the chemical shift anisotropy of the carbonyl carbon and the 13C-1H heteronuclear dipole-dipole interaction of the alpha carbon. To obtain the highest sensitivity for the psi angle determination, the following conditions are desired: (i) the recoupling pulse sequences for the CSA and the heteronuclear dipolar interactions are gamma encoded, in which the spatial parts of m=2 are selected; (ii) the homonuclear polarization transfer is based on the scalar spin-spin coupling. Experimental data were obtained for [U-13C, 15N]-alanine and N-acetyl-[U-13C, 15N]-d,l-valine under magic-angle spinning at 25kHz. Only three data points are required for the measurements and the dihedral angles determined are in excellent agreement with the diffraction data.
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Affiliation(s)
- Yun Mou
- Department of Chemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei, Taiwan
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30
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Marcotte I, van Beek JD, Meier BH. Molecular Disorder and Structure of Spider Dragline Silk Investigated by Two-Dimensional Solid-State NMR Spectroscopy. Macromolecules 2007. [DOI: 10.1021/ma062452n] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Beat H. Meier
- Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
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31
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Kervern G, Pintacuda G, Emsley L. Fast adiabatic pulses for solid-state NMR of paramagnetic systems. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2006.12.056] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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32
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Cadars S, Lesage A, Trierweiler M, Heux L, Emsley L. NMR measurements of scalar-coupling distributions in disordered solids. Phys Chem Chem Phys 2007; 9:92-103. [PMID: 17164890 DOI: 10.1039/b611096g] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The measurement of scalar (J) couplings by solid-state NMR is a field of great interest, since this interaction is a rich source of local structural information, complementary to dipolar and chemical shift interactions. Here, we first demonstrate that J-coupling distributions exist and can be observed in disordered solids, as illustrated with the observation of a pair-specific distribution of (2)J((31)P-N-(31)P) couplings in a bis-phosphino amine, and we investigate the potential effects of such distributions on the measurement of average J-coupling constants. Second, we show that the measurement of two-dimensional (2D) distributions of J-couplings provides a much richer probe of local structural disorder than one-dimensional distributions, and we introduce new methods that provide different (selective or non-selective) ways of measuring 2D J distributions in a wide range of disordered systems. These methods are finally applied to a slightly disordered polymorphic sample of fully (13)C-enriched cellulose, and then to the bis-phosphino amine sample, from which 2D (2)J(PP)-coupling distributions are clearly identified and interpreted.
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Affiliation(s)
- Sylvian Cadars
- Laboratoire de Chimie (UMR 5182 CNRS/ENS Lyon), Ecole Normale Supérieure de Lyon, Lyon, France
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33
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Siemer AB, Arnold AA, Ritter C, Westfeld T, Ernst M, Riek R, Meier BH. Observation of Highly Flexible Residues in Amyloid Fibrils of the HET-s Prion. J Am Chem Soc 2006; 128:13224-8. [PMID: 17017802 DOI: 10.1021/ja063639x] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the observation of undetected (until now) residues of the prion protein fragment HET-s(218-289) which give rise to well-resolved (13)C, (15)N, and (1)H NMR resonances under high-resolution magic-angle spinning (HRMAS) conditions. The observed signals belong to large polymeric units as shown by measuring the lateral diffusion constants. The amino acids identified in the spectra are compatible with their localization in the segments of the protein which could not be detected in earlier solid-state NMR experiments. The observed chemical shifts indicate that these residues are in a random-coil conformation. Complementary experiments which detect only dynamic or static residues, respectively, strongly suggest that they belong to different parts of the same molecule.
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Cadars S, Lesage A, Hedin N, Chmelka BF, Emsley L. Selective NMR Measurements of Homonuclear Scalar Couplings in Isotopically Enriched Solids. J Phys Chem B 2006; 110:16982-91. [PMID: 16927991 DOI: 10.1021/jp062920v] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Scalar (J) couplings in solid-state NMR spectroscopy are sensitive to covalent through-bond interactions that make them informative structural probes for a wide range of complex materials. Until now, however, they have been generally unsuitable for use in isotopically enriched solids, such as proteins or many inorganic solids, because of the complications presented by multiple coupled but nonisolated spins. Such difficulties are overcome by incorporating a z-filter that results in a robust method for measuring pure J-coupling modulations between selected pairs of nuclei in an isotopically enriched spin system. The reliability of the new experimental approach is established by using numerical simulations and tested on fully (13)C-labeled polycrystalline L-alanine. It is furthermore shown to be applicable to partially enriched systems, when used in combination with a selective double-quantum (DQ) filter, as demonstrated for the measurement of (2)J((29)Si-O-(29)Si) couplings in a 50% (29)Si-enriched surfactant-templated layered silicate lacking long-range 3D crystallinity. J-coupling constants are obtained with sufficient accuracy to distinguish between different (29)Si-O-(29)Si pairs, shedding insight on the local structure of the silicate framework. The new experiment is appropriate for fully or partially enriched liquid or solid samples.
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Affiliation(s)
- Sylvian Cadars
- Laboratoire de Chimie, UMR 5182 CNRS/ENS Lyon, Ecole Normale Supérieure de Lyon, Lyon, France
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35
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Herbst C, Riedel K, Leppert J, Ohlenschläger O, Görlach M, Ramachandran R. Solid state NMR at high magic angle spinning frequencies: dipolar chemical shift correlation with adiabatic inversion pulse based RF pulse schemes. JOURNAL OF BIOMOLECULAR NMR 2006; 35:241-8. [PMID: 16865414 DOI: 10.1007/s10858-006-9040-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2006] [Accepted: 05/30/2006] [Indexed: 05/11/2023]
Abstract
The efficacy of hetero- and homonuclear dipolar recoupling employing tanh/tan adiabatic inversion pulse based RF pulse schemes has been examined at high magic angle spinning (MAS) frequencies via numerical simulations and experimental measurements. An approach for minimising the recoupling RF power level is presented, taking into consideration the spinning speed, the range of resonance offsets and H(1) inhomogeneities and the available RF field strength. This involves the tailoring of the frequency and amplitude modulation profiles of the inversion pulses. The applicability of tanh/tan pulse based dipolar recoupling schemes to spinning speed regimes where the performance with conventional rectangular pulses may not be satisfactory is demonstrated.
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Affiliation(s)
- Christian Herbst
- Molecular Biophysics/NMR spectroscopy group, Leibniz Institute for Age Research, Fritz Lipmann Institute, D-07745, Jena, Germany
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36
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Mou Y, Chao JCH, Chan JCC. Efficient spin-spin scalar coupling mediated C-13 homonuclear polarization transfer in biological solids without proton decoupling. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2006; 29:278-82. [PMID: 16289520 DOI: 10.1016/j.ssnmr.2005.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Revised: 10/05/2005] [Indexed: 05/05/2023]
Abstract
We demonstrate that an efficient C' <--> C alpha polarization transfer based on J-coupling can be realized under fast magic-angle spinning (MAS) condition without 1H decoupling. Experimental results are presented for model crystalline compounds as well as a non-crystalline 17-residue polypeptide MB(i + 4)EK. Measurements on MB(i + 4)EK demonstrate that 53% of the initial C' polarization was transferred to the cross peaks at 7.05 T under 25 kHz MAS spinning.
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Affiliation(s)
- Yun Mou
- Department of Chemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei, Taiwan
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37
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38
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Bechinger B, Aisenbrey C, Bertani P. The alignment, structure and dynamics of membrane-associated polypeptides by solid-state NMR spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1666:190-204. [PMID: 15519315 DOI: 10.1016/j.bbamem.2004.08.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2004] [Accepted: 08/06/2004] [Indexed: 10/26/2022]
Abstract
Solid-state NMR spectroscopy is being developed at a fast pace for the structural investigation of immobilized and non-crystalline biomolecules. These include proteins and peptides associated with phospholipid bilayers. In contrast to solution NMR spectroscopy, where complete or almost complete averaging leads to isotropic values, the anisotropic character of nuclear interactions is apparent in solid-state NMR spectra. In static samples the orientation dependence of chemical shift, dipolar or quadrupolar interactions, therefore, provides angular constraints when the polypeptides have been reconstituted into oriented membranes. Furthermore, solid-state NMR spectroscopy of aligned samples offers distinct advantages in allowing access to dynamic processes such as topological equilibria or rotational diffusion in membrane environments. Alternatively, magic angle sample spinning (MAS) results in highly resolved NMR spectra, provided that the sample is sufficiently homogenous. MAS spinning solid-state NMR spectra allow to measure distances and dihedral angles with high accuracy. The technique has recently been developed to selectively establish through-space and through-bond correlations between nuclei, similar to the approaches well-established in solution-NMR spectroscopy.
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Affiliation(s)
- Burkhard Bechinger
- Faculté de chimie, Institut le Bel, 4, rue Blaise Pascal, 67000 Strasbourg, France.
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39
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Riedel K, Leppert J, Ohlenschläger O, Görlach M, Ramachandran R. TEDOR with adiabatic inversion pulses: Resonance assignments of 13C/15N labelled RNAs. JOURNAL OF BIOMOLECULAR NMR 2005; 31:49-57. [PMID: 15692738 DOI: 10.1007/s10858-004-6066-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/22/2004] [Indexed: 05/24/2023]
Abstract
We have examined via numerical simulations the performance characteristics of different 15N RF pulse schemes employed in the transferred echo double resonance (TEDOR) experimental protocol for generating 13C-15N dipolar chemical shift correlation spectra of isotopically labelled biological systems at moderate MAS frequencies (omega(r) approximately 10 kHz). With an 15N field strength of approximately 30-35 kHz that is typically available in 5 mm triple resonance MAS NMR probes, it is shown that a robust TEDOR sequence with significant tolerance to experimental imperfections sa as H1 inhomogeneity and resonance offsets can be effectively implemented using adiabatic heteronuclear dipolar recoupling pulse schemes. TEDOR-based 15N-13C and 15N-13C-13C chemical shift correlation experiments were carried out for obtaining 13C and 15N resonance assignments of an RNA composed of 97 (CUG) repeats which has been implicated in the neuromuscular disease myotonic dystrophy.
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Affiliation(s)
- Kerstin Riedel
- Abteilung Molekulare Biophysik/NMR-Spektroskopie, Institut für Molekulare Biotechnologie, 07745 Jena, Germany
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Riedel K, Leppert J, Häfner S, Ohlenschläger O, Görlach M, Ramachandran R. Homonuclear chemical shift correlation in rotating solids via RNnu n symmetry-based adiabatic RF pulse schemes. JOURNAL OF BIOMOLECULAR NMR 2004; 30:389-395. [PMID: 15630559 DOI: 10.1007/s10858-004-4056-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2004] [Accepted: 09/16/2004] [Indexed: 05/24/2023]
Abstract
The efficacy of RN(nu) (n) symmetry-based adiabatic Zero-Quantum (ZQ) dipolar recoupling schemes for obtaining chemical shift correlation data at moderate magic angle spinning frequencies has been evaluated. RN(nu) (n) sequences generally employ basic inversion elements that correspond to a net 180 degrees rotation about the rotating frame x-axis. It is shown here via numerical simulations and experimental measurements that it is also possible to achieve efficient ZQ dipolar recoupling via RN(nu) (n) schemes employing adiabatic pulses. Such an approach was successfully used for obtaining (13)C chemical shift correlation spectra of a uniformly labelled sample of (CUG)(97) - a triplet repeat expansion RNA that has been implicated in the neuromuscular disease myotonic dystrophy. An analysis of the (13)C sugar carbon chemical shifts suggests, in agreement with our recent (15)N MAS-NMR studies, that this RNA adopts an Alpha-helical conformation.
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Affiliation(s)
- Kerstin Riedel
- Abteilung Molekulare Biophysik/NMR-Spektroskopie, Institut für Molekulare Biotechnologie, 07745 Jena, Germany
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Riedel K, Leppert J, Ohlenschläger O, Görlach M, Ramachandran R. Heteronuclear decoupling in rotating solids via symmetry-based adiabatic RF pulse schemes. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.07.106] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Brinkmann A, Edén M. Second order average Hamiltonian theory of symmetry-based pulse schemes in the nuclear magnetic resonance of rotating solids: Application to triple-quantum dipolar recoupling. J Chem Phys 2004; 120:11726-45. [PMID: 15268208 DOI: 10.1063/1.1738102] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The average Hamiltonian theory (AHT) of several classes of symmetry-based radio-frequency pulse sequences is developed to second order, allowing quantitative analyses of a wide range of recoupling and decoupling applications in magic-angle-spinning solid state nuclear magnetic resonance. General closed analytical expressions are presented for a cross term between any two interactions recoupled to second order AHT. We classify them into different categories and show that some properties of the recoupling pulse sequence may be predicted directly from this classification. These results are applied to examine a novel homonuclear recoupling strategy, effecting a second order average dipolar Hamiltonian comprising trilinear triple quantum (3Q) spin operators. We discuss general features and design principles of such 3Q recoupling sequences and demonstrate by numerical simulations and experiments that they provide more efficient excitation of (13)C 3Q coherences compared to previous techniques. We passed up to 15% of the signal through a state of 3Q coherence in rotating powders of uniformly (13)C-labeled alanine and tyrosine. Second order recoupling-based (13)C homonuclear 3Q correlation spectroscopy is introduced and demonstrated on tyrosine.
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Affiliation(s)
- Andreas Brinkmann
- Physical Chemistry/Solid State NMR, NSRIM Center, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
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Mueller LJ, Elliott DW, Leskowitz GM, Struppe J, Olsen RA, Kim KC, Reed CA. Uniform-sign cross-peak double-quantum-filtered correlation spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2004; 168:327-335. [PMID: 15140444 DOI: 10.1016/j.jmr.2004.03.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2003] [Revised: 03/18/2004] [Indexed: 05/24/2023]
Abstract
We detail the uniform-sign cross-peak double-quantum-filtered correlation spectroscopy (UC2QF COSY) experiment, a new through-bond correlation method for disordered solids. This experiment is a refocused version of the popular double-quantum-filtered correlation spectroscopy experiment in liquids. Its key feature is that it provides in-phase and doubly absorptive line shapes, which renders it robust for chemical shift correlation in solids. Both theory and experiment point to distinct advantages of this protocol, which are illustrated by several experiments under challenging conditions, including fast magic-angle spinning (30kHz), anisotropic molecular motion, and (13)C correlation spectroscopy at the natural abundance isotope level.
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Affiliation(s)
- Leonard J Mueller
- Department of Chemistry, University of California, Riverside, CA 92521, USA.
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