51
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Gunther W, Michaelis VK, Caporini MA, Griffin RG, Román-Leshkov Y. Dynamic nuclear polarization NMR enables the analysis of Sn-Beta zeolite prepared with natural abundance ¹¹⁹Sn precursors. J Am Chem Soc 2014; 136:6219-22. [PMID: 24697321 PMCID: PMC4017605 DOI: 10.1021/ja502113d] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Indexed: 02/07/2023]
Abstract
The catalytic activity of tin-containing zeolites, such as Sn-Beta, is critically dependent on the successful incorporation of the tin metal center into the zeolite framework. However, synchrotron-based techniques or solid-state nuclear magnetic resonance (ssNMR) of samples enriched with (119)Sn isotopes are the only reliable methods to verify framework incorporation. This work demonstrates, for the first time, the use of dynamic nuclear polarization (DNP) NMR for characterizing zeolites containing ~2 wt % of natural abundance Sn without the need for (119)Sn isotopic enrichment. The biradicals TOTAPOL, bTbK, bCTbK, and SPIROPOL functioned effectively as polarizing sources, and the solvent enabled proper transfer of spin polarization from the radical's unpaired electrons to the target nuclei. Using bCTbK led to an enhancement (ε) of 75, allowing the characterization of natural-abundance (119)Sn-Beta with excellent signal-to-noise ratios in <24 h. Without DNP, no (119)Sn resonances were detected after 10 days of continuous analysis.
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Affiliation(s)
- William
R. Gunther
- Department
of Chemical Engineering and Department of Chemistry and Francis
Bitter Magnet Laboratory, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Vladimir K. Michaelis
- Department
of Chemical Engineering and Department of Chemistry and Francis
Bitter Magnet Laboratory, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Marc A. Caporini
- Bruker BioSpin Corporation, Billerica, Massachusetts 01821, United States
| | - Robert G. Griffin
- Department
of Chemical Engineering and Department of Chemistry and Francis
Bitter Magnet Laboratory, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Yuriy Román-Leshkov
- Department
of Chemical Engineering and Department of Chemistry and Francis
Bitter Magnet Laboratory, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139, United States
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52
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Kiesewetter MK, Michaelis VK, Walish JJ, Griffin RG, Swager TM. High field dynamic nuclear polarization NMR with surfactant sheltered biradicals. J Phys Chem B 2014; 118:1825-30. [PMID: 24506193 PMCID: PMC3983347 DOI: 10.1021/jp410387e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 01/28/2014] [Indexed: 12/27/2022]
Abstract
We illustrate the ability to place a water-insoluble biradical, bTbk, into a glycerol/water matrix with the assistance of a surfactant, sodium octyl sulfate (SOS). This surfactant approach enables a previously water insoluble biradical, bTbk, with favorable electron-electron dipolar coupling to be used for dynamic nuclear polarization (DNP) nuclear magnetic resonance (NMR) experiments in frozen, glassy, aqueous media. Nuclear Overhauser enhancement (NOE) and paramagnetic relaxation enhancement (PRE) experiments are conducted to determine the distribution of urea and several biradicals within the SOS macromolecular assembly. We also demonstrate that SOS assemblies are an effective approach by which mixed biradicals are created through an assembly process.
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Affiliation(s)
- Matthew K Kiesewetter
- Department of Chemistry and ‡Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
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53
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Valentine K, Mathies G, Bédard S, Nucci NV, Dodevski I, Stetz MA, Can TV, Griffin RG, Wand AJ. Reverse micelles as a platform for dynamic nuclear polarization in solution NMR of proteins. J Am Chem Soc 2014; 136:2800-7. [PMID: 24456213 PMCID: PMC3955360 DOI: 10.1021/ja4107176] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Indexed: 02/06/2023]
Abstract
Despite tremendous advances in recent years, solution NMR remains fundamentally restricted due to its inherent insensitivity. Dynamic nuclear polarization (DNP) potentially offers significant improvements in this respect. The basic DNP strategy is to irradiate the EPR transitions of a stable radical and transfer this nonequilibrium polarization to the hydrogen spins of water, which will in turn transfer polarization to the hydrogens of the macromolecule. Unfortunately, these EPR transitions lie in the microwave range of the electromagnetic spectrum where bulk water absorbs strongly, often resulting in catastrophic heating. Furthermore, the residence times of water on the surface of the protein in bulk solution are generally too short for efficient transfer of polarization. Here we take advantage of the properties of solutions of encapsulated proteins dissolved in low viscosity solvents to implement DNP in liquids. Such samples are largely transparent to the microwave frequencies required and thereby avoid significant heating. Nitroxide radicals are introduced into the reverse micelle system in three ways: attached to the protein, embedded in the reverse micelle shell, and free in the aqueous core. Significant enhancements of the water resonance ranging up to ∼-93 at 0.35 T were observed. We also find that the hydration properties of encapsulated proteins allow for efficient polarization transfer from water to the protein. These and other observations suggest that merging reverse micelle encapsulation technology with DNP offers a route to a significant increase in the sensitivity of solution NMR spectroscopy of proteins and other biomolecules.
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Affiliation(s)
- Kathleen
G. Valentine
- Johnson
Research Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6059
| | - Guinevere Mathies
- Francis
Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Sabrina Bédard
- Johnson
Research Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6059
| | - Nathaniel V. Nucci
- Johnson
Research Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6059
| | - Igor Dodevski
- Johnson
Research Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6059
| | - Matthew A. Stetz
- Johnson
Research Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6059
| | - Thach V. Can
- Francis
Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Robert G. Griffin
- Francis
Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - A. Joshua Wand
- Johnson
Research Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6059
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54
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Michaelis VK, Ong TC, Kiesewetter MK, Frantz DK, Walish JJ, Ravera E, Luchinat C, Swager TM, Griffin RG. Topical Developments in High-Field Dynamic Nuclear Polarization. Isr J Chem 2014; 54:207-221. [PMID: 25977588 DOI: 10.1002/ijch.201300126] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We report our recent efforts directed at improving high-field DNP experiments. We investigated a series of thiourea nitroxide radicals and the associated DNP enhancements ranging from ε = 25 to 82 that demonstrate the impact of molecular structure on performance. We directly polarized low-gamma nuclei including 13C, 2H, and 17O using trityl via the cross effect. We discuss a variety of sample preparation techniques for DNP with emphasis on the benefit of methods that do not use a glass-forming cryoprotecting matrix. Lastly, we describe a corrugated waveguide for use in a 700 MHz / 460 GHz DNP system that improves microwave delivery and increases enhancements up to 50%.
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Affiliation(s)
- Vladimir K Michaelis
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.,Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Ta-Chung Ong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.,Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Matthew K Kiesewetter
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Derik K Frantz
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Joseph J Walish
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Enrico Ravera
- Department of Chemistry "Ugo Schiff" and Magnetic Resonance Center (CERM) University of Florence, 50019 Sesto Fiorentino (FI), Italy
| | - Claudio Luchinat
- Department of Chemistry "Ugo Schiff" and Magnetic Resonance Center (CERM) University of Florence, 50019 Sesto Fiorentino (FI), Italy
| | - Timothy M Swager
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Robert G Griffin
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.,Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
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55
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Ravera E, Corzilius B, Michaelis VK, Luchinat C, Griffin RG, Bertini I. DNP-enhanced MAS NMR of bovine serum albumin sediments and solutions. J Phys Chem B 2014; 118:2957-65. [PMID: 24460530 PMCID: PMC3983357 DOI: 10.1021/jp500016f] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
![]()
Protein
sedimentation sans cryoprotection is a new approach to
magic angle spinning (MAS) and dynamic nuclear polarization (DNP)
nuclear magnetic resonance (NMR) spectroscopy of proteins. It increases
the sensitivity of the experiments by a factor of ∼4.5 in comparison
to the conventional DNP sample preparation and circumvents intense
background signals from the cryoprotectant. In this paper, we investigate
sedimented samples and concentrated frozen solutions of natural abundance
bovine serum albumin (BSA) in the absence of a glycerol-based cryoprotectant.
We observe DNP signal enhancements of ε ∼ 66 at 140 GHz
in a BSA pellet sedimented from an aqueous solution containing the
biradical polarizing agent TOTAPOL and compare this with samples prepared
using the conventional protocol (i.e., dissolution of BSA in a glycerol/water
cryoprotecting mixture). The dependence of DNP parameters on the radical
concentration points to the presence of an interaction between TOTAPOL
and BSA, so much so that a frozen solution sans cryoprotectant still
gives ε ∼ 50. We have studied the interaction of BSA
with another biradical, SPIROPOL, that is more rigid than TOTAPOL
and has been reported to give higher enhancements. SPIROPOL was also
found to interact with BSA, and to give ε ∼ 26 close
to its maximum achievable concentration. Under the same conditions,
TOTAPOL gives ε ∼ 31, suggesting a lesser affinity of
BSA for SPIROPOL with respect to TOTAPOL. Altogether, these results
demonstrate that DNP is feasible in self-cryoprotecting samples.
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Affiliation(s)
- Enrico Ravera
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence , 50019 Sesto Fiorentino (FI), Italy
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56
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Takahashi H, Fernández-de-Alba C, Lee D, Maurel V, Gambarelli S, Bardet M, Hediger S, Barra AL, De Paëpe G. Optimization of an absolute sensitivity in a glassy matrix during DNP-enhanced multidimensional solid-state NMR experiments. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 239:91-99. [PMID: 24480716 DOI: 10.1016/j.jmr.2013.12.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 12/03/2013] [Accepted: 12/09/2013] [Indexed: 06/03/2023]
Abstract
Thanks to instrumental and theoretical development, notably the access to high-power and high-frequency microwave sources, high-field dynamic nuclear polarization (DNP) on solid-state NMR currently appears as a promising solution to enhance nuclear magnetization in many different types of systems. In magic-angle-spinning DNP experiments, systems of interest are usually dissolved or suspended in glass-forming matrices doped with polarizing agents and measured at low temperature (down to ∼100K). In this work, we discuss the influence of sample conditions (radical concentration, sample temperature, etc.) on DNP enhancements and various nuclear relaxation times which affect the absolute sensitivity of DNP spectra, especially in multidimensional experiments. Furthermore, DNP-enhanced solid-state NMR experiments performed at 9.4 T are complemented by high-field CW EPR measurements performed at the same magnetic field. Microwave absorption by the DNP glassy matrix is observed even below the glass transition temperature caused by softening of the glass. Shortening of electron relaxation times due to glass softening and its impact in terms of DNP sensitivity is discussed.
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Affiliation(s)
- Hiroki Takahashi
- Laboratoire de Chimie Inorganique et Biologique, UMR-E3 (CEA/UJF) and CNRS, Institut Nanosciences et Cryogénie, CEA, 38054 Grenoble, France
| | - Carlos Fernández-de-Alba
- Laboratoire de Chimie Inorganique et Biologique, UMR-E3 (CEA/UJF) and CNRS, Institut Nanosciences et Cryogénie, CEA, 38054 Grenoble, France
| | - Daniel Lee
- Laboratoire de Chimie Inorganique et Biologique, UMR-E3 (CEA/UJF) and CNRS, Institut Nanosciences et Cryogénie, CEA, 38054 Grenoble, France
| | - Vincent Maurel
- Laboratoire de Chimie Inorganique et Biologique, UMR-E3 (CEA/UJF) and CNRS, Institut Nanosciences et Cryogénie, CEA, 38054 Grenoble, France
| | - Serge Gambarelli
- Laboratoire de Chimie Inorganique et Biologique, UMR-E3 (CEA/UJF) and CNRS, Institut Nanosciences et Cryogénie, CEA, 38054 Grenoble, France
| | - Michel Bardet
- Laboratoire de Chimie Inorganique et Biologique, UMR-E3 (CEA/UJF) and CNRS, Institut Nanosciences et Cryogénie, CEA, 38054 Grenoble, France
| | - Sabine Hediger
- Laboratoire de Chimie Inorganique et Biologique, UMR-E3 (CEA/UJF) and CNRS, Institut Nanosciences et Cryogénie, CEA, 38054 Grenoble, France
| | - Anne-Laure Barra
- Laboratoire National des Champs Magnétiques Intenses, CNRS, F-38042 Grenoble, France
| | - Gaël De Paëpe
- Laboratoire de Chimie Inorganique et Biologique, UMR-E3 (CEA/UJF) and CNRS, Institut Nanosciences et Cryogénie, CEA, 38054 Grenoble, France.
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57
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Kirimli HE, Ovalioglu H. 19F Dynamic Nuclear Polarization and SEM in Suspensions Consisting of Fluorobenzene Derivatives and Asphaltene Extracted from MC-800 Liquid Asphalt. J DISPER SCI TECHNOL 2014. [DOI: 10.1080/01932691.2013.767208] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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58
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Debelouchina GT, Bayro MJ, Fitzpatrick AW, Ladizhansky V, Colvin MT, Caporini MA, Jaroniec CP, Bajaj VS, Rosay M, Macphee CE, Vendruscolo M, Maas WE, Dobson CM, Griffin RG. Higher order amyloid fibril structure by MAS NMR and DNP spectroscopy. J Am Chem Soc 2013; 135:19237-47. [PMID: 24304221 DOI: 10.1021/ja409050a] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Protein magic angle spinning (MAS) NMR spectroscopy has generated structural models of several amyloid fibril systems, thus providing valuable information regarding the forces and interactions that confer the extraordinary stability of the amyloid architecture. Despite these advances, however, obtaining atomic resolution information describing the higher levels of structural organization within the fibrils remains a significant challenge. Here, we detail MAS NMR experiments and sample labeling schemes designed specifically to probe such higher order amyloid structure, and we have applied them to the fibrils formed by an eleven-residue segment of the amyloidogenic protein transthyretin (TTR(105-115)). These experiments have allowed us to define unambiguously not only the arrangement of the peptide β-strands into β-sheets but also the β-sheet interfaces within each protofilament, and in addition to identify the nature of the protofilament-to-protofilament contacts that lead to the formation of the complete fibril. Our efforts have resulted in 111 quantitative distance and torsion angle restraints (10 per residue) that describe the various levels of structure organization. The experiments benefited extensively from the use of dynamic nuclear polarization (DNP), which in some cases allowed us to shorten the data acquisition time from days to hours and to improve significantly the signal-to-noise ratios of the spectra. The β-sheet interface and protofilament interactions identified here revealed local variations in the structure that result in multiple peaks for the exposed N- and C-termini of the peptide and in inhomogeneous line-broadening for the residues buried within the interior of the fibrils.
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Affiliation(s)
- Galia T Debelouchina
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
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59
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Ullrich SJ, Glaubitz C. Perspectives in enzymology of membrane proteins by solid-state NMR. Acc Chem Res 2013; 46:2164-71. [PMID: 23745719 DOI: 10.1021/ar4000289] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Membrane proteins catalyze reactions at the cell membrane and facilitate thetransport of molecules or signals across the membrane. Recently researchers have made great progress in understanding the structural biology of membrane proteins, mainly based on X-ray crystallography. In addition, the application of complementary spectroscopic techniques has allowed researchers to develop a functional understanding of these proteins. Solid-state NMR has become an indispensable tool for the structure-function analysis of insoluble proteins and protein complexes. It offers the possibility of investigating membrane proteins directly in their environment, which provides essential information about the intrinsic coupling of protein structure and functional dynamics within the lipid bilayer. However, to date, researchers have hardly explored the enzymology of mem-brane proteins. In this Account, we review the perspectives for investigating membrane-bound enzymes by solid-state NMR. Understanding enzyme mechanisms requires access to kinetic parameters, structural analysis of the catalytic center, knowledge of the 3D structure and methods to follow the structural dynamics of the enzyme during the catalytic cycle. In principle, solid-state NMR can address all of these issues. Researchers can characterize the enzyme kinetics by observing substrate turnover within the membrane or at the membrane interphase in a time-resolved fashion as shown for diacylglycerol kinase. Solid-state NMR has also provided a mechanistic understanding of soluble enzymes including triosephosphate isomerase (TIM) and different metal-binding proteins, which demonstrates a promising perspective also for membrane proteins. The increasing availability of high magnetic fields and the development of new experimental schemes and computational protocols have made it easier to determine 3D structure using solid-state NMR. Dynamic nuclear polarization, a key technique to boost sensitivity of solid-state NMR at low temperatures, can help with the analysis of thermally trapped catalytic intermediates, while methods to improve signal-to-noise per time unit enable the real-time measurement of kinetics of conformational changes during the catalytic cycle.
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Affiliation(s)
- Sandra J. Ullrich
- Institute for Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max von Laue Str. 9, 60438 Frankfurt am Main, Germany
| | - Clemens Glaubitz
- Institute for Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max von Laue Str. 9, 60438 Frankfurt am Main, Germany
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60
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Ni QZ, Daviso E, Can TV, Markhasin E, Jawla SK, Swager TM, Temkin RJ, Herzfeld J, Griffin RG. High frequency dynamic nuclear polarization. Acc Chem Res 2013; 46:1933-41. [PMID: 23597038 PMCID: PMC3778063 DOI: 10.1021/ar300348n] [Citation(s) in RCA: 390] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
During the three decades 1980-2010, magic angle spinning (MAS) NMR developed into the method of choice to examine many chemical, physical, and biological problems. In particular, a variety of dipolar recoupling methods to measure distances and torsion angles can now constrain molecular structures to high resolution. However, applications are often limited by the low sensitivity of the experiments, due in large part to the necessity of observing spectra of low-γ nuclei such as the I = 1/2 species (13)C or (15)N. The difficulty is still greater when quadrupolar nuclei, such as (17)O or (27)Al, are involved. This problem has stimulated efforts to increase the sensitivity of MAS experiments. A particularly powerful approach is dynamic nuclear polarization (DNP) which takes advantage of the higher equilibrium polarization of electrons (which conventionally manifests in the great sensitivity advantage of EPR over NMR). In DNP, the sample is doped with a stable paramagnetic polarizing agent and irradiated with microwaves to transfer the high polarization in the electron spin reservoir to the nuclei of interest. The idea was first explored by Overhauser and Slichter in 1953. However, these experiments were carried out on static samples, at magnetic fields that are low by current standards. To be implemented in contemporary MAS NMR experiments, DNP requires microwave sources operating in the subterahertz regime, roughly 150-660 GHz, and cryogenic MAS probes. In addition, improvements were required in the polarizing agents, because the high concentrations of conventional radicals that are required to produce significant enhancements compromise spectral resolution. In the last two decades, scientific and technical advances have addressed these problems and brought DNP to the point where it is achieving wide applicability. These advances include the development of high frequency gyrotron microwave sources operating in the subterahertz frequency range. In addition, low temperature MAS probes were developed that permit in situ microwave irradiation of the samples. And, finally, biradical polarizing agents were developed that increased the efficiency of DNP experiments by factors of ∼4 at considerably lower paramagnet concentrations. Collectively, these developments have made it possible to apply DNP on a routine basis to a number of different scientific endeavors, most prominently in the biological and material sciences. This Account reviews these developments, including the primary mechanisms used to transfer polarization in high frequency DNP, and the current choice of microwave sources and biradical polarizing agents. In addition, we illustrate the utility of the technique with a description of applications to membrane and amyloid proteins that emphasizes the unique structural information that is available in these two cases.
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Affiliation(s)
- Qing Zhe Ni
- Francis Bitter Magnet Laboratory, ‡Department of Chemistry, and §Plasma Science and Fusion Center, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
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61
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Ouari O, Phan T, Ziarelli F, Casano G, Aussenac F, Thureau P, Gigmes D, Tordo P, Viel S. Improved Structural Elucidation of Synthetic Polymers by Dynamic Nuclear Polarization Solid-State NMR Spectroscopy. ACS Macro Lett 2013; 2:715-719. [PMID: 35606957 DOI: 10.1021/mz4003003] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dynamic nuclear polarization (DNP) is shown to greatly improve the solid-state nuclear magnetic resonance (SSNMR) analysis of synthetic polymers by allowing structural assignment of intrinsically diluted NMR signals, which are typically not detected in conventional SSNMR. Specifically, SSNMR and DNP SSNMR were comparatively used to study functional polymers for which precise structural elucidation of chain ends is essential to control their reactivity and to eventually obtain advanced polymeric materials of complex architecture. Results show that the polymer chain-end signals, while hardly observable in conventional SSNMR, could be clearly identified in the DNP SSNMR spectrum owing to the increase in sensitivity afforded by the DNP setup (a factor ∼10 was achieved here), hence providing access to detailed structural characterization within realistic experimental times. This sizable gain in sensitivity opens new avenues for the characterization of "smart" functional polymeric materials and new analytical perspectives in polymer science.
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Affiliation(s)
- Olivier Ouari
- Aix-Marseille Université-CNRS, Institut de Chimie Radicalaire (UMR 7273), 13013 Marseille,
France
| | - Trang Phan
- Aix-Marseille Université-CNRS, Institut de Chimie Radicalaire (UMR 7273), 13013 Marseille,
France
| | - Fabio Ziarelli
- Aix-Marseille Université-CNRS, Fédération des Sciences Chimiques de Marseille (FR 1739), 13013 Marseille, France
| | - Gilles Casano
- Aix-Marseille Université-CNRS, Institut de Chimie Radicalaire (UMR 7273), 13013 Marseille,
France
| | | | - Pierre Thureau
- Aix-Marseille Université-CNRS, Institut de Chimie Radicalaire (UMR 7273), 13013 Marseille,
France
| | - Didier Gigmes
- Aix-Marseille Université-CNRS, Institut de Chimie Radicalaire (UMR 7273), 13013 Marseille,
France
| | - Paul Tordo
- Aix-Marseille Université-CNRS, Institut de Chimie Radicalaire (UMR 7273), 13013 Marseille,
France
| | - Stéphane Viel
- Aix-Marseille Université-CNRS, Institut de Chimie Radicalaire (UMR 7273), 13013 Marseille,
France
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62
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Sauvée C, Rosay M, Casano G, Aussenac F, Weber RT, Ouari O, Tordo P. Highly efficient, water-soluble polarizing agents for dynamic nuclear polarization at high frequency. Angew Chem Int Ed Engl 2013; 52:10858-61. [PMID: 23956072 DOI: 10.1002/anie.201304657] [Citation(s) in RCA: 327] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Indexed: 11/11/2022]
Affiliation(s)
- Claire Sauvée
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397 Marseille cedex 20 (France) http://sites.univ-provence.fr/srep/
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63
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Highly Efficient, Water-Soluble Polarizing Agents for Dynamic Nuclear Polarization at High Frequency. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201304657] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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64
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Markhasin E, Hu J, Su Y, Herzfeld J, Griffin RG. Efficient, balanced, transmission line RF circuits by back propagation of common impedance nodes. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 231:32-8. [PMID: 23567880 PMCID: PMC3739482 DOI: 10.1016/j.jmr.2013.02.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Revised: 02/22/2013] [Accepted: 02/28/2013] [Indexed: 05/05/2023]
Abstract
We present a new, efficient strategy for designing fully balanced transmission line RF circuits for solid state NMR probes based on back propagation of common impedance nodes (BPCIN). In this approach, the impedance node phenomenon is the sole means of achieving mutual RF isolation and balance in all RF channels. BPCIN is illustrated using a custom double resonance 3.2 mm MAS probe operating at 500 MHz ((1)H) and 125 MHz ((13)C). When fully optimized, the probe is capable of producing high homogeneity (810°/90° ratios of 86% and 89% for (1)H and (13)C, respectively) and high efficiency (γB1=100 kHz for (1)H and (13)C at 70 W and 180 W of RF input, respectively; up to 360 kHz for (1)H). The probe's performance is illustrated by 2D MAS correlation spectra of microcrystals of the tripeptide N-f-MLF-OH and hydrated amyloid fibrils of the protein PI3-SH3.
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Affiliation(s)
- Evgeny Markhasin
- Francis Bitter Magnet Laboratory, Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jianping Hu
- Department of Chemistry, Brandeis University, Waltham, MA 02454, USA
| | - Yongchao Su
- Francis Bitter Magnet Laboratory, Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Judith Herzfeld
- Department of Chemistry, Brandeis University, Waltham, MA 02454, USA
| | - Robert G. Griffin
- Francis Bitter Magnet Laboratory, Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Ong TC, Mak-Jurkauskas ML, Walish JJ, Michaelis VK, Corzilius B, Smith AA, Clausen AM, Cheetham JC, Swager TM, Griffin RG. Solvent-free dynamic nuclear polarization of amorphous and crystalline ortho-terphenyl. J Phys Chem B 2013; 117:3040-6. [PMID: 23421391 DOI: 10.1021/jp311237d] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dynamic nuclear polarization (DNP) of amorphous and crystalline ortho-terphenyl (OTP) in the absence of glass forming agents is presented in order to gauge the feasibility of applying DNP to pharmaceutical solid-state nuclear magnetic resonance experiments and to study the effect of intermolecular structure, or lack thereof, on the DNP enhancement. By way of (1)H-(13)C cross-polarization, we obtained a DNP enhancement (ε) of 58 for 95% deuterated OTP in the amorphous state using the biradical bis-TEMPO terephthalate (bTtereph) and ε of 36 in the crystalline state. Measurements of the (1)H T1 and electron paramagnetic resonance experiments showed the crystallization process led to phase separation of the polarization agent, creating an inhomogeneous distribution of radicals within the sample. Consequently, the effective radical concentration was decreased in the bulk OTP phase, and long-range (1)H-(1)H spin diffusion was the main polarization propagation mechanism. Preliminary DNP experiments with the glass-forming anti-inflammation drug, indomethacin, showed promising results, and further studies are underway to prepare DNP samples using pharmaceutical techniques.
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Affiliation(s)
- Ta-Chung Ong
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Serra SC, Rosso A, Tedoldi F. On the role of electron–nucleus contact and microwave saturation in thermal mixing DNP. Phys Chem Chem Phys 2013; 15:8416-28. [DOI: 10.1039/c3cp44667k] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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67
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Jawla S, Ni QZ, Barnes A, Guss W, Daviso E, Herzfeld J, Griffin R, Temkin R. Continuously Tunable 250 GHz Gyrotron with a Double Disk Window for DNP-NMR Spectroscopy. JOURNAL OF INFRARED, MILLIMETER AND TERAHERTZ WAVES 2013; 34:42-52. [PMID: 23539422 PMCID: PMC3607393 DOI: 10.1007/s10762-012-9947-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In this paper, we describe the design and experimental results from the rebuild of a 250 GHz gyrotron used for Dynamic Nuclear Polarization enhanced Nuclear Magnetic Resonance spectroscopy on a 380 MHz spectrometer. Tuning bandwidth of approximately 2 GHz is easily achieved at a fixed magnetic field of 9.24 T and a beam current of 95 mA producing an average output power of >10 W over the entire tuning band. This tube incorporates a double disk output sapphire window in order to maximize the transmission at 250.58 GHz. DNP Signal enhancement of >125 is achieved on a 13C-Urea sample using this gyrotron.
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Affiliation(s)
- Sudheer Jawla
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA-02139, USA
| | - Qing Zhe Ni
- Francis Bitter Magnet Lab and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA-02139, USA
| | - Alexander Barnes
- Francis Bitter Magnet Lab and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA-02139, USA
| | - William Guss
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA-02139, USA
| | - Eugenio Daviso
- Francis Bitter Magnet Lab and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA-02139, USA
- Department of Chemistry, Brandies University, Waltham, MA-02454, USA
| | - Judith Herzfeld
- Department of Chemistry, Brandies University, Waltham, MA-02454, USA
| | - Robert Griffin
- Francis Bitter Magnet Lab and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA-02139, USA
| | - Richard Temkin
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA-02139, USA
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