1
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Levien M, Yang L, van der Ham A, Reinhard M, John M, Purea A, Ganz J, Marquardsen T, Tkach I, Orlando T, Bennati M. Overhauser enhanced liquid state nuclear magnetic resonance spectroscopy in one and two dimensions. Nat Commun 2024; 15:5904. [PMID: 39003303 PMCID: PMC11246421 DOI: 10.1038/s41467-024-50265-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 07/02/2024] [Indexed: 07/15/2024] Open
Abstract
Nuclear magnetic resonance (NMR) is fundamental in the natural sciences, from chemical analysis and structural biology, to medicine and physics. Despite its enormous achievements, one of its most severe limitations is the low sensitivity, which arises from the small population difference of nuclear spin states. Methods such as dissolution dynamic nuclear polarization and parahydrogen induced hyperpolarization can enhance the NMR signal by several orders of magnitude, however, their intrinsic limitations render multidimensional hyperpolarized liquid-state NMR a challenge. Here, we report an instrumental design for 9.4 Tesla liquid-state dynamic nuclear polarization that enabled enhanced high-resolution NMR spectra in one and two-dimensions for small molecules, including drugs and metabolites. Achieved enhancements of up to two orders of magnitude translate to signal acquisition gains up to a factor of 10,000. We show that hyperpolarization can be transferred between nuclei, allowing DNP-enhanced two-dimensional 13C-13C correlation experiments at 13C natural abundance. The enhanced sensitivity opens up perspectives for structural determination of natural products or characterization of drugs, available in small quantities. The results provide a starting point for a broader implementation of DNP in liquid-state NMR.
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Affiliation(s)
- Marcel Levien
- Electron-Spin Resonance Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
- Institute of Physical Chemistry, Department of Chemistry, Georg-August-University, Tammannstr. 6, 37077, Göttingen, Germany
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Luming Yang
- Electron-Spin Resonance Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Alex van der Ham
- Electron-Spin Resonance Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Maik Reinhard
- Electron-Spin Resonance Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
- Institute of Physical Chemistry, Department of Chemistry, Georg-August-University, Tammannstr. 6, 37077, Göttingen, Germany
| | - Michael John
- Institute of Organic and Biomolecular Chemistry, Department of Chemistry, Georg-August-University, Tammannstr. 2, 37077, Göttingen, Germany
| | - Armin Purea
- Bruker Biospin GmbH, Rudolf-Plank-Str. 23, 76275, Ettlingen, Germany
| | - Jürgen Ganz
- Bruker Biospin GmbH, Rudolf-Plank-Str. 23, 76275, Ettlingen, Germany
| | | | - Igor Tkach
- Electron-Spin Resonance Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Tomas Orlando
- Electron-Spin Resonance Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
- National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., 32310, Tallahassee, FL, USA
| | - Marina Bennati
- Electron-Spin Resonance Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany.
- Institute of Physical Chemistry, Department of Chemistry, Georg-August-University, Tammannstr. 6, 37077, Göttingen, Germany.
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2
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Sezer D. The solid effect of dynamic nuclear polarization in liquids. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2023; 4:153-174. [PMID: 37904804 PMCID: PMC10583289 DOI: 10.5194/mr-4-153-2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/23/2023] [Indexed: 11/01/2023]
Abstract
The solid-state effect of dynamic nuclear polarization (DNP) is operative also in viscous liquids where the dipolar interaction between the electronic and nuclear spins is partially averaged. The proper way to quantify the degree of averaging, and thus calculate the efficiency of the effect, should be based on the time-correlation function of the dipolar interaction. Here we use the stochastic Liouville equation formalism to develop a general theoretical description of the solid effect in liquids. The derived expressions can be used with different dipolar correlations functions depending on the assumed motional model. At high magnetic fields, the theory predicts DNP enhancements at small offsets, far from the classical solid-effect positions that are displaced by one nuclear Larmor frequency from the electronic resonance. The predictions are in quantitative agreement with such enhancement peaks observed at 9.4 T . These non-canonical peaks are not due to thermal mixing or the cross effect but exactly follow the dispersive component of the EPR line.
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Affiliation(s)
- Deniz Sezer
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt am Main, Germany
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3
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Eills J, Budker D, Cavagnero S, Chekmenev EY, Elliott SJ, Jannin S, Lesage A, Matysik J, Meersmann T, Prisner T, Reimer JA, Yang H, Koptyug IV. Spin Hyperpolarization in Modern Magnetic Resonance. Chem Rev 2023; 123:1417-1551. [PMID: 36701528 PMCID: PMC9951229 DOI: 10.1021/acs.chemrev.2c00534] [Citation(s) in RCA: 64] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Indexed: 01/27/2023]
Abstract
Magnetic resonance techniques are successfully utilized in a broad range of scientific disciplines and in various practical applications, with medical magnetic resonance imaging being the most widely known example. Currently, both fundamental and applied magnetic resonance are enjoying a major boost owing to the rapidly developing field of spin hyperpolarization. Hyperpolarization techniques are able to enhance signal intensities in magnetic resonance by several orders of magnitude, and thus to largely overcome its major disadvantage of relatively low sensitivity. This provides new impetus for existing applications of magnetic resonance and opens the gates to exciting new possibilities. In this review, we provide a unified picture of the many methods and techniques that fall under the umbrella term "hyperpolarization" but are currently seldom perceived as integral parts of the same field. Specifically, before delving into the individual techniques, we provide a detailed analysis of the underlying principles of spin hyperpolarization. We attempt to uncover and classify the origins of hyperpolarization, to establish its sources and the specific mechanisms that enable the flow of polarization from a source to the target spins. We then give a more detailed analysis of individual hyperpolarization techniques: the mechanisms by which they work, fundamental and technical requirements, characteristic applications, unresolved issues, and possible future directions. We are seeing a continuous growth of activity in the field of spin hyperpolarization, and we expect the field to flourish as new and improved hyperpolarization techniques are implemented. Some key areas for development are in prolonging polarization lifetimes, making hyperpolarization techniques more generally applicable to chemical/biological systems, reducing the technical and equipment requirements, and creating more efficient excitation and detection schemes. We hope this review will facilitate the sharing of knowledge between subfields within the broad topic of hyperpolarization, to help overcome existing challenges in magnetic resonance and enable novel applications.
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Affiliation(s)
- James Eills
- Institute
for Bioengineering of Catalonia, Barcelona
Institute of Science and Technology, 08028Barcelona, Spain
| | - Dmitry Budker
- Johannes
Gutenberg-Universität Mainz, 55128Mainz, Germany
- Helmholtz-Institut,
GSI Helmholtzzentrum für Schwerionenforschung, 55128Mainz, Germany
- Department
of Physics, UC Berkeley, Berkeley, California94720, United States
| | - Silvia Cavagnero
- Department
of Chemistry, University of Wisconsin, Madison, Madison, Wisconsin53706, United States
| | - Eduard Y. Chekmenev
- Department
of Chemistry, Integrative Biosciences (IBio), Karmanos Cancer Institute
(KCI), Wayne State University, Detroit, Michigan48202, United States
- Russian
Academy of Sciences, Moscow119991, Russia
| | - Stuart J. Elliott
- Molecular
Sciences Research Hub, Imperial College
London, LondonW12 0BZ, United Kingdom
| | - Sami Jannin
- Centre
de RMN à Hauts Champs de Lyon, Université
de Lyon, CNRS, ENS Lyon, Université Lyon 1, 69100Villeurbanne, France
| | - Anne Lesage
- Centre
de RMN à Hauts Champs de Lyon, Université
de Lyon, CNRS, ENS Lyon, Université Lyon 1, 69100Villeurbanne, France
| | - Jörg Matysik
- Institut
für Analytische Chemie, Universität
Leipzig, Linnéstr. 3, 04103Leipzig, Germany
| | - Thomas Meersmann
- Sir
Peter Mansfield Imaging Centre, University Park, School of Medicine, University of Nottingham, NottinghamNG7 2RD, United Kingdom
| | - Thomas Prisner
- Institute
of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic
Resonance, Goethe University Frankfurt, , 60438Frankfurt
am Main, Germany
| | - Jeffrey A. Reimer
- Department
of Chemical and Biomolecular Engineering, UC Berkeley, and Materials Science Division, Lawrence Berkeley National
Laboratory, Berkeley, California94720, United States
| | - Hanming Yang
- Department
of Chemistry, University of Wisconsin, Madison, Madison, Wisconsin53706, United States
| | - Igor V. Koptyug
- International Tomography Center, Siberian
Branch of the Russian Academy
of Sciences, 630090Novosibirsk, Russia
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4
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Tagami K, Thicklin R, Jain S, Equbal A, Li M, Zens T, Siaw A, Han S. Design of a cryogen-free high field dual EPR and DNP probe. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 347:107351. [PMID: 36599253 DOI: 10.1016/j.jmr.2022.107351] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
We present the design and construction of a cryogen free, dual electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) probe for novel dynamic nuclear polarization (DNP) experiments and concurrent "in situ" analysis of DNP mechanisms. We focus on the probe design that meets the balance between EPR, NMR, and low temperature performance, while maintaining a high degree of versatility: allowing multi-nuclear NMR detection as well as broadband DNP/EPR excitation/detection. To accomplish high NMR/EPR performance, we implement a novel inductively coupled double resonance NMR circuit (1H-13C) in a solid state probe operating at cryogenic temperatures. The components of the circuit were custom built to provide maximum NMR performance, and the physical layout of this circuit was numerically optimized via magnetic field simulations to allow maximum microwave transmission to the sample for optimal EPR performance. Furthermore this probe is based around a cryogen free gas exchange cryostat and has been designed to allow unlimited experiment times down to 8.5 Kelvin with minimal cost. The affordability of EPR/DNP experiment is an extremely important aspect for broader impact with magnetic resonance measurements. The purpose of this article is to provide as complete information as we have available for others with interest in building a dual DNP/EPR instrument based around a cryogen-free cryostat.
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Affiliation(s)
- Kan Tagami
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA 93106, United States
| | - Raymond Thicklin
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA 93106, United States
| | - Sheetal Jain
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA 93106, United States
| | - Asif Equbal
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA 93106, United States
| | - Miranda Li
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA 93106, United States
| | - Toby Zens
- JEOL USA, Inc., 11 Dearborn Road, Peabody, MA 01960, United States
| | - Anthony Siaw
- JEOL USA, Inc., 11 Dearborn Road, Peabody, MA 01960, United States
| | - Songi Han
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA 93106, United States; Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA 93106, United States.
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5
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Rao Y, Venkatesh A, Moutzouri P, Emsley L. 1H Hyperpolarization of Solutions by Overhauser Dynamic Nuclear Polarization with 13C- 1H Polarization Transfer. J Phys Chem Lett 2022; 13:7749-7755. [PMID: 35969266 PMCID: PMC9421900 DOI: 10.1021/acs.jpclett.2c01956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 08/09/2022] [Indexed: 06/15/2023]
Abstract
Dynamic nuclear polarization (DNP) is a method that can significantly increase the sensitivity of nuclear magnetic resonance. The only effective DNP mechanism for in situ hyperpolarization in solution is Overhauser DNP, which is inefficient for 1H at high magnetic fields. Here we demonstrate the possibility of generating significant 1H hyperpolarization in solution at room temperature. To counter the poor direct 1H Overhauser DNP, we implement steady-state 13C Overhauser DNP in solutions and then transfer the 13C hyperpolarization to 1H via a reverse insensitive nuclei enhanced by polarization transfer scheme. We demonstrate this approach using a 400 MHz gyrotron-equipped 3.2 mm magic angle spinning DNP system to obtain 1H DNP enhancement factors of 48, 8, and 6 for chloroform, tetrachloroethane, and phenylacetylene, respectively, at room temperature.
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6
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Chow WY, De Paëpe G, Hediger S. Biomolecular and Biological Applications of Solid-State NMR with Dynamic Nuclear Polarization Enhancement. Chem Rev 2022; 122:9795-9847. [PMID: 35446555 DOI: 10.1021/acs.chemrev.1c01043] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Solid-state NMR spectroscopy (ssNMR) with magic-angle spinning (MAS) enables the investigation of biological systems within their native context, such as lipid membranes, viral capsid assemblies, and cells. However, such ambitious investigations often suffer from low sensitivity due to the presence of significant amounts of other molecular species, which reduces the effective concentration of the biomolecule or interaction of interest. Certain investigations requiring the detection of very low concentration species remain unfeasible even with increasing experimental time for signal averaging. By applying dynamic nuclear polarization (DNP) to overcome the sensitivity challenge, the experimental time required can be reduced by orders of magnitude, broadening the feasible scope of applications for biological solid-state NMR. In this review, we outline strategies commonly adopted for biological applications of DNP, indicate ongoing challenges, and present a comprehensive overview of biological investigations where MAS-DNP has led to unique insights.
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Affiliation(s)
- Wing Ying Chow
- Univ. Grenoble Alpes, CEA, CNRS, Interdisciplinary Research Institute of Grenoble (IRIG), Modeling and Exploration of Materials Laboratory (MEM), 38054 Grenoble, France.,Univ. Grenoble Alpes, CEA, CNRS, Inst. Biol. Struct. IBS, 38044 Grenoble, France
| | - Gaël De Paëpe
- Univ. Grenoble Alpes, CEA, CNRS, Interdisciplinary Research Institute of Grenoble (IRIG), Modeling and Exploration of Materials Laboratory (MEM), 38054 Grenoble, France
| | - Sabine Hediger
- Univ. Grenoble Alpes, CEA, CNRS, Interdisciplinary Research Institute of Grenoble (IRIG), Modeling and Exploration of Materials Laboratory (MEM), 38054 Grenoble, France
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7
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Denysenkov V, Dai D, Prisner TF. A triple resonance (e, 1H, 13C) probehead for liquid-state DNP experiments at 9.4 Tesla. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 337:107185. [PMID: 35276481 DOI: 10.1016/j.jmr.2022.107185] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/24/2022] [Accepted: 02/27/2022] [Indexed: 06/14/2023]
Abstract
In DNP experiments, NMR signal intensity is increased by transferring the much larger electron spin polarization to nuclear spins via microwave irradiation. Here we describe the design and performance of a probehead that makes it possible to perform Overhauser DNP experiments at 1H and 13C in liquid samples with a volume of up to 100 nl. We demonstrate on a 13C-labeled sodium pyruvate sample in water that proton decoupling under DNP conditions is possible with this new triple-resonance DNP probehead. In addition, the heat dissipation from the sample has been greatly improved with our new probe design. This makes it possible to keep liquid samples at a constant temperature under irradiation with a high-frequency 263 GHz microwave gyrotron with a few watts of output power. This improved performance opens up the possibility to disentangle the role of sample temperature and applied microwave power for DNP efficiency in liquids and to obtain a quantitative determination of EPR saturation by observing the suppression of paramagnetic shift as a function of microwave power.
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Affiliation(s)
- Vasyl Denysenkov
- Institute for Physical Chemistry, and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max von Laue Str. 7, 60438 Frankfurt am Main, Germany
| | - Danhua Dai
- Institute for Physical Chemistry, and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max von Laue Str. 7, 60438 Frankfurt am Main, Germany
| | - Thomas F Prisner
- Institute for Physical Chemistry, and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max von Laue Str. 7, 60438 Frankfurt am Main, Germany.
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8
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Biedenbänder T, Aladin V, Saeidpour S, Corzilius B. Dynamic Nuclear Polarization for Sensitivity Enhancement in Biomolecular Solid-State NMR. Chem Rev 2022; 122:9738-9794. [PMID: 35099939 DOI: 10.1021/acs.chemrev.1c00776] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Solid-state NMR with magic-angle spinning (MAS) is an important method in structural biology. While NMR can provide invaluable information about local geometry on an atomic scale even for large biomolecular assemblies lacking long-range order, it is often limited by low sensitivity due to small nuclear spin polarization in thermal equilibrium. Dynamic nuclear polarization (DNP) has evolved during the last decades to become a powerful method capable of increasing this sensitivity by two to three orders of magnitude, thereby reducing the valuable experimental time from weeks or months to just hours or days; in many cases, this allows experiments that would be otherwise completely unfeasible. In this review, we give an overview of the developments that have opened the field for DNP-enhanced biomolecular solid-state NMR including state-of-the-art applications at fast MAS and high magnetic field. We present DNP mechanisms, polarizing agents, and sample constitution methods suitable for biomolecules. A wide field of biomolecular NMR applications is covered including membrane proteins, amyloid fibrils, large biomolecular assemblies, and biomaterials. Finally, we present perspectives and recent developments that may shape the field of biomolecular DNP in the future.
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Affiliation(s)
- Thomas Biedenbänder
- Institute of Chemistry, University of Rostock, Albert-Einstein-Straße 3a, 18059 Rostock, Germany.,Department Life, Light & Matter, University of Rostock, Albert-Einstein-Straße 25, 18059 Rostock, Germany
| | - Victoria Aladin
- Institute of Chemistry, University of Rostock, Albert-Einstein-Straße 3a, 18059 Rostock, Germany.,Department Life, Light & Matter, University of Rostock, Albert-Einstein-Straße 25, 18059 Rostock, Germany
| | - Siavash Saeidpour
- Institute of Chemistry, University of Rostock, Albert-Einstein-Straße 3a, 18059 Rostock, Germany.,Department Life, Light & Matter, University of Rostock, Albert-Einstein-Straße 25, 18059 Rostock, Germany
| | - Björn Corzilius
- Institute of Chemistry, University of Rostock, Albert-Einstein-Straße 3a, 18059 Rostock, Germany.,Department Life, Light & Matter, University of Rostock, Albert-Einstein-Straße 25, 18059 Rostock, Germany
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9
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Kuzhelev AA, Dai D, Denysenkov V, Prisner TF. Solid-like Dynamic Nuclear Polarization Observed in the Fluid Phase of Lipid Bilayers at 9.4 T. J Am Chem Soc 2022; 144:1164-1168. [PMID: 35029974 DOI: 10.1021/jacs.1c12837] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Dynamic nuclear polarization (DNP) is a powerful method to enhance NMR sensitivity. Much progress has been achieved recently to optimize DNP performance at high magnetic fields in solid-state samples, mostly by utilizing the solid or the cross effect. In liquids, only the Overhauser mechanism is active, which exhibits a DNP field profile matching the EPR line shape of the radical, distinguishable from other DNP mechanisms. Here, we observe DNP enhancements with a field profile indicative of the solid effect and thermal mixing at ∼320 K and a magnetic field of 9.4 T in the fluid phase of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayers doped with the radical BDPA (1,3-bis(diphenylene)-2-phenylallyl). This interesting observation might open up new perspectives for DNP applications in macromolecular systems at ambient temperatures.
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Affiliation(s)
- Andrei A Kuzhelev
- Goethe University Frankfurt am Main, Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Max von Laue Str. 7, 60438 Frankfurt am Main, Germany
| | - Danhua Dai
- Goethe University Frankfurt am Main, Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Max von Laue Str. 7, 60438 Frankfurt am Main, Germany
| | - Vasyl Denysenkov
- Goethe University Frankfurt am Main, Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Max von Laue Str. 7, 60438 Frankfurt am Main, Germany
| | - Thomas F Prisner
- Goethe University Frankfurt am Main, Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Max von Laue Str. 7, 60438 Frankfurt am Main, Germany
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10
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Dai D, Wang X, Liu Y, Yang XL, Glaubitz C, Denysenkov V, He X, Prisner T, Mao J. Room-temperature dynamic nuclear polarization enhanced NMR spectroscopy of small biological molecules in water. Nat Commun 2021; 12:6880. [PMID: 34824218 PMCID: PMC8616939 DOI: 10.1038/s41467-021-27067-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 11/01/2021] [Indexed: 11/15/2022] Open
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a powerful and popular technique for probing the molecular structures, dynamics and chemical properties. However the conventional NMR spectroscopy is bottlenecked by its low sensitivity. Dynamic nuclear polarization (DNP) boosts NMR sensitivity by orders of magnitude and resolves this limitation. In liquid-state this revolutionizing technique has been restricted to a few specific non-biological model molecules in organic solvents. Here we show that the carbon polarization in small biological molecules, including carbohydrates and amino acids, can be enhanced sizably by in situ Overhauser DNP (ODNP) in water at room temperature and at high magnetic field. An observed connection between ODNP 13C enhancement factor and paramagnetic 13C NMR shift has led to the exploration of biologically relevant heterocyclic compound indole. The QM/MM MD simulation underscores the dynamics of intermolecular hydrogen bonds as the driving force for the scalar ODNP in a long-living radical-substrate complex. Our work reconciles results obtained by DNP spectroscopy, paramagnetic NMR and computational chemistry and provides new mechanistic insights into the high-field scalar ODNP.
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Affiliation(s)
- Danhua Dai
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
- Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
| | - Xianwei Wang
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China
- College of Science, Zhejiang University of Technology, Hangzhou, Zhejiang, 310023, China
| | - Yiwei Liu
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China
| | - Xiao-Liang Yang
- Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Clemens Glaubitz
- Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
- Institute of Biophysical Chemistry, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
| | - Vasyl Denysenkov
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
- Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
| | - Xiao He
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China.
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, 200062, China.
| | - Thomas Prisner
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
- Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
| | - Jiafei Mao
- Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany.
- Institute of Biophysical Chemistry, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany.
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11
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Zhang Z, Jiang Y, Pi H, Chen H, Liu C, Feng J, Liu M. THz-enhanced dynamic nuclear polarized liquid spectrometer. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 330:107044. [PMID: 34352701 DOI: 10.1016/j.jmr.2021.107044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 06/13/2023]
Abstract
Dynamic nuclear polarization (DNP) technology can be utilized to dramatically enhance NMR signal. In this paper, we report on the development of a self-constructed 5 T DNP spectrometer for liquid samples and the 13C DNP enhancement achieved with this spectrometer. The DNP spectrometer is comprised of a wide-bore superconducting magnet, a home-made console, a dual resonance probe and a self-built 140 GHz microwave source for the spectrometer. Specifically, a microwave source of traveling wave tube (TWT) amplifier has been developed, which can provide a maximum power output of 4.4 W and a wide frequency tuning range of 1 GHz. The excellent performance of our built liquid-state DNP spectrometer is verified by the observation of more than 100-fold DNP enhancement of the 13C NMR signal for liquid 13CCl4 sample. Our result shows the superiority of DNP technology in the liquid-state high-field NMR spectrometer.
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Affiliation(s)
- Zhekai Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yi Jiang
- Institute of Applied Electronics of CAEP, Mianyang 621900, China
| | - Haiya Pi
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongbin Chen
- Institute of Applied Electronics of CAEP, Mianyang 621900, China.
| | - Chaoyang Liu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China; Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Jiwen Feng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Maili Liu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China; Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
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12
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Abhyankar N, Szalai V. Challenges and Advances in the Application of Dynamic Nuclear Polarization to Liquid-State NMR Spectroscopy. J Phys Chem B 2021; 125:5171-5190. [PMID: 33960784 PMCID: PMC9871957 DOI: 10.1021/acs.jpcb.0c10937] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a powerful method to study the molecular structure and dynamics of materials. The inherently low sensitivity of NMR spectroscopy is a consequence of low spin polarization. Hyperpolarization of a spin ensemble is defined as a population difference between spin states that far exceeds what is expected from the Boltzmann distribution for a given temperature. Dynamic nuclear polarization (DNP) can overcome the relatively low sensitivity of NMR spectroscopy by using a paramagnetic matrix to hyperpolarize a nuclear spin ensemble. Application of DNP to NMR can result in sensitivity gains of up to four orders of magnitude compared to NMR without DNP. Although DNP NMR is now more routinely utilized for solid-state (ss) NMR spectroscopy, it has not been exploited to the same degree for liquid-state samples. This Review will consider challenges and advances in the application of DNP NMR to liquid-state samples. The Review is organized into four sections: (i) mechanisms of DNP NMR relevant to hyperpolarization of liquid samples; (ii) applications of liquid-state DNP NMR; (iii) available detection schemes for liquid-state samples; and (iv) instrumental challenges and outlook for liquid-state DNP NMR.
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Affiliation(s)
- Nandita Abhyankar
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742, USA
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Veronika Szalai
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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13
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Deo T, Cheng Q, Paul S, Qiang W, Potapov A. Application of DNP-enhanced solid-state NMR to studies of amyloid-β peptide interaction with lipid membranes. Chem Phys Lipids 2021; 236:105071. [PMID: 33716023 DOI: 10.1016/j.chemphyslip.2021.105071] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 02/13/2021] [Accepted: 03/01/2021] [Indexed: 11/16/2022]
Abstract
The cellular membrane disruption induced by the aggregation of Aβ peptide has been proposed as a plausible cause of neuronal cell death during Alzheimer's disease. The molecular-level details of the Aβ interaction with cellular membranes were previously probed using solid state NMR (ssNMR), however, due to the limited sensitivity of the latter, studies were limited to samples with high Aβ-to-lipid ratio. The dynamic nuclear polarization (DNP) is a technique for increasing the sensitivity of NMR. In this work we demonstrate the feasibility of DNP-enhanced ssNMR studies of Aβ40 peptide interacting with various model liposomes: (1) a mixture of zwitterionic 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) and negatively charged 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (POPG); (2) a mixture of POPC, POPG, cholesterol, sphingomyelin and ganglioside GM1; (3) the synaptic plasma membrane vesicles (SPMVs) extracted from rat brain tissues. In addition, DNP-ssNMR was applied to capturing changes in Aβ40 conformation taking place upon the peptide insertion into POPG liposomes. The signal enhancements under conditions of DNP allow carrying out informative 2D ssNMR experiments with about 0.25 mg of Aβ40 peptides (i.e. reaching Aβ40-to-lipid ratio of 1:200). In the studied liposome models, the 13C NMR chemical shifts at many 13C-labelled sites of Aβ40 are characteristic of β-sheets. In addition, in POPG liposomes the peptide forms hydrophobic contacts F19-L34 and F19-I32. Both the chemical shifts and hydrophobic contacts of Aβ40 in POPG remain the same before and after 8 h of incubation. This suggests that conformation at the 13C-labelled sites of the peptide is similar before and after the insertion process. Overall, our results demonstrate that DNP helps to overcome the sensitivity limitation of ssNMR, and thereby expand the applicability of ssNMR for charactering the Aβ peptide interacting with lipids.
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Affiliation(s)
- Thomas Deo
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Qinghui Cheng
- Department of Chemistry, Binghamton University, the State University of New York, Binghamton, NY, 13902, USA
| | - Subhadip Paul
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Wei Qiang
- Department of Chemistry, Binghamton University, the State University of New York, Binghamton, NY, 13902, USA
| | - Alexey Potapov
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
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14
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Levien M, Reinhard M, Hiller M, Tkach I, Bennati M, Orlando T. Spin density localization and accessibility of organic radicals affect liquid-state DNP efficiency. Phys Chem Chem Phys 2021; 23:4480-4485. [PMID: 33599637 DOI: 10.1039/d0cp05796g] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We report a large variation in liquid DNP performance of up to a factor of about five in coupling factor among organic radicals commonly used as polarizing agents. A comparative study of 1H and 13C DNP in model systems shows the impact of the spin density distribution and accessibility of the radical site by the target molecule.
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Affiliation(s)
- Marcel Levien
- ESR Spectroscopy Group, Max Planck Institute for Biophysical Chemistry, Am Faßberg 11, Göttigen, Germany.
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15
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Nevzorov AA, Marek A, Milikisiyants S, Smirnov AI. Characterization of photonic band resonators for DNP NMR of thin film samples at 7 T magnetic field. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 323:106893. [PMID: 33418455 PMCID: PMC8362290 DOI: 10.1016/j.jmr.2020.106893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 12/09/2020] [Accepted: 12/10/2020] [Indexed: 06/12/2023]
Abstract
Polarization of nuclear spins via Dynamic Nuclear Polarization (DNP) relies on generating sufficiently high mm-wave B1e fields over the sample, which could be achieved by developing suitable resonance structures. Recently, we have introduced one-dimensional photonic band gap (1D PBG) resonators for DNP and reported on prototype devices operating at ca. 200 GHz electron resonance frequency. Here we systematically compare the performance of five (5) PBG resonators constructed from various alternating dielectric layers by monitoring the DNP effect on natural-abundance 13C spins in synthetic diamond microparticles embedded into a commercial polyester-based lapping film of just 3 mil (76 μm) thickness. An odd-numbered configuration of dielectric layers for 1D PBG resonator was introduced to achieve further B1e enhancements. Among the PBG configurations tested, combinations of high-ε perovskite LiTaO3 together with AlN as well as AlN with optical quartz wafers have resulted in ca. 40 to over 50- fold gains in the average mm-wave power over the sample vs. the mirror-only configuration. The results are rationalized in terms of the electromagnetic energy distribution inside the resonators obtained analytically and from COMSOL simulations. It was found that average of B1e2 over the sample strongly depends on the arrangement of the dielectric layers that are the closest to the sample, which favors odd-numbered PBG resonator configurations for their use in DNP.
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Affiliation(s)
- Alexander A Nevzorov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States.
| | - Antonin Marek
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States
| | - Sergey Milikisiyants
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States
| | - Alex I Smirnov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States.
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16
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Ravula T, Sahoo BR, Dai X, Ramamoorthy A. Natural-abundance 17O NMR spectroscopy of magnetically aligned lipid nanodiscs. Chem Commun (Camb) 2020; 56:9998-10001. [PMID: 32724998 PMCID: PMC7484029 DOI: 10.1039/d0cc04011h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Natural-abundance 17O NMR experiments are used to investigate the hydrated water in magnetically aligned synthetic polymer based lipid-nanodiscs. Residual quadrupole couplings (RQCs) measured from the observed five 17O (central and satellite) transitions, and molecular dynamics simulations, are used to probe the ordering of water molecules across the lipid bilayer.
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Affiliation(s)
- Thirupathi Ravula
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
| | - Bikash R Sahoo
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
| | - Xiaofeng Dai
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
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17
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Abstract
Dynamic nuclear polarization (DNP) is one of the most prominent methods of sensitivity enhancement in nuclear magnetic resonance (NMR). Even though solid-state DNP under magic-angle spinning (MAS) has left the proof-of-concept phase and has become an important tool for structural investigations of biomolecules as well as materials, it is still far from mainstream applicability because of the potentially overwhelming combination of unique instrumentation, complex sample preparation, and a multitude of different mechanisms and methods available. In this review, I introduce the diverse field and history of DNP, combining aspects of NMR and electron paramagnetic resonance. I then explain the general concepts and detailed mechanisms relevant at high magnetic field, including solution-state methods based on Overhauser DNP but with a greater focus on the more established MAS DNP methods. Finally, I review practical considerations and fields of application and discuss future developments.
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Affiliation(s)
- Björn Corzilius
- Institute of Chemistry and Department of Life, Light and Matter, University of Rostock, 18059 Rostock, Germany;
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18
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Salnikov ES, Aussenac F, Abel S, Purea A, Tordo P, Ouari O, Bechinger B. Dynamic Nuclear Polarization / solid-state NMR of membranes. Thermal effects and sample geometry. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2019; 100:70-76. [PMID: 30995597 DOI: 10.1016/j.ssnmr.2019.03.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 03/18/2019] [Accepted: 03/18/2019] [Indexed: 06/09/2023]
Abstract
Whereas specially designed dinitroxide biradicals, reconstitution protocols, oriented sample geometries and NMR probes have helped to much increase the DNP enhancement factors of membrane samples they still lag considerably behind those obtained from glasses made of protein solutions. Here we show that not only the MAS rotor material but also the distribution of the membrane samples within the NMR rotor have a pronounced effect on the DNP enhancement. These observations are rationalized with the cooling efficiency and the internal properties of the sample, monitored by their T1 relaxation, microwave ON versus OFF signal intensities and DNP effect. The data are suggestive that for membranes the speed of cooling has a pronounced effect on the membrane properties and concomitantly the distribution of biradicals within the sample.
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Affiliation(s)
| | | | - Sebastian Abel
- Aix-Marseille University, CNRS, UMR 7273, Institut de Chimie Radicalaire, 13013, Marseille, France
| | | | - Paul Tordo
- Aix-Marseille University, CNRS, UMR 7273, Institut de Chimie Radicalaire, 13013, Marseille, France
| | - Olivier Ouari
- Aix-Marseille University, CNRS, UMR 7273, Institut de Chimie Radicalaire, 13013, Marseille, France
| | - Burkhard Bechinger
- Institute of Chemistry, University of Strasbourg / CNRS, UMR7177, 67070, Strasbourg, France.
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19
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Brodrecht M, Herr K, Bothe S, de Oliveira M, Gutmann T, Buntkowsky G. Efficient Building Blocks for Solid-Phase Peptide Synthesis of Spin Labeled Peptides for Electron Paramagnetic Resonance and Dynamic Nuclear Polarization Applications. Chemphyschem 2019; 20:1475-1487. [PMID: 30950574 DOI: 10.1002/cphc.201900211] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 03/22/2019] [Indexed: 11/11/2022]
Abstract
Specific spin labeling allows the site-selective investigation of biomolecules by EPR and DNP enhanced NMR spectroscopy. A novel spin labeling strategy for commercially available Fmoc-amino acids is developed. In this approach, the PROXYL spin label is covalently attached to the hydroxyl side chain of three amino acids hydroxyproline (Hyp), serine (Ser) and tyrosine (Tyr) by a simple three-step synthesis route. The obtained PROXYL containing building-blocks are N-terminally protected by the Fmoc-protection group, which makes them applicable for the use in solid-phase peptide synthesis (SPPS). This approach allows the insertion of the spin label at any desired position during SPPS, which makes it more versatile than the widely used post synthetic spin labeling strategies. For the final building-blocks, the radical activity is proven by EPR. DNP enhanced solid-state NMR experiments employing these building-blocks in a TCE solution show enhancement factors of up to 26 for 1 H and 13 C (1 H→13 C cross-polarization). To proof the viability of the presented building-blocks for insertion of the spin label during SPPS the penta-peptide Acetyl-Gly-Ser(PROXYL)-Gly-Gly-Gly was synthesized employing the spin labeled Ser building-block. This peptide could successfully be isolated and the spin label activity proved by EPR and DNP NMR measurements, showing enhancement factors of 12.1±0.1 for 1 H and 13.9±0.5 for 13 C (direct polarization).
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Affiliation(s)
- Martin Brodrecht
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287, Darmstadt, Germany
| | - Kevin Herr
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287, Darmstadt, Germany
| | - Sarah Bothe
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287, Darmstadt, Germany
| | - Marcos de Oliveira
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287, Darmstadt, Germany
| | - Torsten Gutmann
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287, Darmstadt, Germany.,University Kassel, Institute for Chemistry, Heinrich-Plett-Straße 40, D-34132, Kassel
| | - Gerd Buntkowsky
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287, Darmstadt, Germany
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20
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Nevzorov AA, Milikisiyants S, Marek AN, Smirnov AI. Multi-resonant photonic band-gap/saddle coil DNP probehead for static solid state NMR of microliter volume samples. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 297:113-123. [PMID: 30380458 PMCID: PMC6894392 DOI: 10.1016/j.jmr.2018.10.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 10/18/2018] [Accepted: 10/20/2018] [Indexed: 05/04/2023]
Abstract
The most critical condition for performing Dynamic Nuclear Polarization (DNP) NMR experiments is achieving sufficiently high electronic B1e fields over the sample at the matched EPR frequencies, which for modern high-resolution NMR instruments fall into the millimeter wave (mmW) range. Typically, mmWs are generated by powerful gyrotrons and/or extended interaction klystrons (EIKs) sources and then focused onto the sample by dielectric lenses. However, further development of DNP methods including new DNP pulse sequences may require B1e fields higher than one could achieve with the current mmW technology. In order to address the challenge of significantly enhancing the mmW field at the sample, we have constructed and tested one-dimensional photonic band-gap (PBG) mmW resonator that was incorporated inside a double-tuned radiofrequency (rf) NMR saddle coil. The photonic crystal is formed by stacking ceramic discs with alternating high and low dielectric constants and thicknesses of λ/4 or 3λ/4, where λ is the wavelength of the incident mmW field in the corresponding dielectric material. When the mmW frequency is within the band gap of the photonic crystal, a defect created in the middle of the crystal confines the mmW energy, thus forming a resonant structure. An aluminum mirror in the middle of the defect has been used to substitute one-half of the structure with its mirror image in order to reduce the resonator size and simplify its tuning. The latter is achieved by adjusting the width of the defect by moving the aluminum mirror with respect to the dielectric stack using a gear mechanism. The 1D PBG resonator was the key element for constructing a multi-resonant integrated DNP/NMR probehead operating at 190-199 GHz EPR/300 MHz 1H/75.5 MHz 13C NMR frequencies. Initial tests of the multi-resonant DNP/NMR probehead were carried out using a quasioptical mmW bridge and a Bruker Biospin Avance II spectrometer equipped with a standard Bruker 7 T wide-bore 89 mm magnet parked at 300.13 MHz 1H NMR frequency. The mmW bridge built with all solid-state active components allows for the frequency tuning between ca. 190 and ca. 199 GHz with the output power up to 27 dBm (0.5 W) at 192 GHz and up to 23 dBm (0.2 W) at 197.5 GHz. Room temperature DNP experiments with a synthetic single crystal high-pressure high-temperature (HPHT) diamond (0.3 × 0.3 × 3.0 mm3) demonstrated dramatic 1500-fold enhancement of 13C natural abundance NMR signal at full incident mmW power. Significant 13C DNP enhancement (of about 90) have been obtained at incident mmW powers of as low as <100 μW. Further tests of the resonator performance have been carried out with a thin (ca. 100 μm thickness) composite polystyrene-microdiamond film by controlling the average mmW power at the optimal DNP conditions via a gated mode of operation. From these experiments, the PBG resonator with loaded Q ≃ 250 and finesse F≈75 provides up to 12-fold or 11 db gain in the average mmW power vs. the non-resonant probehead configuration employing only a reflective mirror.
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Affiliation(s)
- Alexander A Nevzorov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States.
| | - Sergey Milikisiyants
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States
| | - Antonin N Marek
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States
| | - Alex I Smirnov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States.
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21
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Milikisiyants S, Nevzorov AA, Smirnov AI. Photonic band-gap resonators for high-field/high-frequency EPR of microliter-volume liquid aqueous samples. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 296:152-164. [PMID: 30268940 PMCID: PMC6235713 DOI: 10.1016/j.jmr.2018.09.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 09/17/2018] [Accepted: 09/19/2018] [Indexed: 05/12/2023]
Abstract
High-field EPR provides significant advantages for studying structure and dynamics of molecular systems possessing an unpaired electronic spin. However, routine use of high-field EPR in biophysical research, especially for aqueous biological samples, is still facing substantial technical difficulties stemming from high dielectric millimeter wave (mmW) losses associated with non-resonant absorption by water and other polar molecules. The strong absorbance of mmW's by water also limits the penetration depth to just fractions of mm or even less, thus making fabrication of suitable sample containers rather challenging. Here we describe a radically new line of high Q-factor mmW resonators that are based on forming lattice defects in one-dimensional photonic band-gap (PBG) structures composed of low-loss ceramic discs of λ/4 in thickness and having alternating dielectric constants. A sample (either liquid or solid) is placed within the E = 0 node of the standing mm wave confined within the defect. A resonator prototype has been built and tested at 94.3 GHz. The resonator performance is enhanced by employing ceramic nanoporous membranes as flat sample holders of controllable thickness and tunable effective dielectric constant. The experimental Q-factor of an empty resonator was ≈ 420. The Q-factor decreased slightly to ≈ 370 when loaded with a water-containing nanoporous disc of 50 μm in thickness. The resonator has been tested with a number of liquid biological samples and demonstrated about tenfold gain in concentration sensitivity vs. a high-Q cylindrical TE012-type cavity. Detailed HFSS Ansys simulations have shown that the resonator structure could be further optimized by properly choosing the thickness of the aqueous sample and employing metallized surfaces. The PBG resonator design is readily scalable to higher mmW frequencies and is capable of accommodating significantly larger sample volumes than previously achieved with either Fabry-Perot or cylindrical resonators.
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Affiliation(s)
- Sergey Milikisiyants
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States
| | - Alexander A Nevzorov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States.
| | - Alex I Smirnov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States.
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22
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Salnikov ES, Abel S, Karthikeyan G, Karoui H, Aussenac F, Tordo P, Bechinger B, Ouari O. Dynamic Nuclear Polarization/Solid-State NMR Spectroscopy of Membrane Polypeptides: Free-Radical Optimization for Matrix-Free Lipid Bilayer Samples. Chemphyschem 2017; 18:2103-2113. [PMID: 28574169 DOI: 10.1002/cphc.201700389] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 05/24/2017] [Indexed: 01/07/2023]
Abstract
Dynamic nuclear polarization (DNP) boosts the sensitivity of NMR spectroscopy by orders of magnitude and makes investigations previously out of scope possible. For magic-angle-spinning (MAS) solid-state NMR spectroscopy studies, the samples are typically mixed with biradicals dissolved in a glass-forming solvent and are investigated at cryotemperatures. Herein, we present new biradical polarizing agents developed for matrix-free samples such as supported lipid bilayers, which are systems widely used for the investigation of membrane polypeptides of high biomedical importance. A series of 11 biradicals with different structures, geometries, and physicochemical properties were comprehensively tested for DNP performance in lipid bilayers, some of them developed specifically for DNP investigations of membranes. The membrane-anchored biradicals PyPol-C16, AMUPOL-cholesterol, and bTurea-C16 were found to exhibit improved g-tensor alignment, inter-radical distance, and dispersion. Consequently, these biradicals show the highest signal enhancement factors so far obtained for matrix-free membranes or other matrix-free samples and may potentially shorten NMR acquisition times by three orders of magnitude. Furthermore, the optimal biradical-to-lipid ratio, sample deuteration, and membrane lipid composition were determined under static and MAS conditions. To rationalize biradical performance better, DNP enhancement was measured by using the 13 C and 15 N signals of lipids and a peptide as a function of the biradical concentration, DNP build-up time, resonance line width, quenching effect, microwave power, and MAS frequency.
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Affiliation(s)
- Evgeniy S Salnikov
- Institut de chimie, UMR 7177, Université de Strasbourg/CNRS, 4, rue Blaise Pascal, 67070, Strasbourg, France
| | - Sébastien Abel
- Aix Marseille Univ, CNRS, ICR UMR 7273, 13013, Marseille, France
| | | | - Hakim Karoui
- Aix Marseille Univ, CNRS, ICR UMR 7273, 13013, Marseille, France
| | - Fabien Aussenac
- Bruker Biospin, 34, rue de l'industrie, 67166, Wissembourg, France
| | - Paul Tordo
- Aix Marseille Univ, CNRS, ICR UMR 7273, 13013, Marseille, France
| | - Burkhard Bechinger
- Institut de chimie, UMR 7177, Université de Strasbourg/CNRS, 4, rue Blaise Pascal, 67070, Strasbourg, France
| | - Olivier Ouari
- Aix Marseille Univ, CNRS, ICR UMR 7273, 13013, Marseille, France
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23
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Yamamoto K, Caporini MA, Im SC, Waskell L, Ramamoorthy A. Transmembrane Interactions of Full-length Mammalian Bitopic Cytochrome-P450-Cytochrome-b 5 Complex in Lipid Bilayers Revealed by Sensitivity-Enhanced Dynamic Nuclear Polarization Solid-state NMR Spectroscopy. Sci Rep 2017; 7:4116. [PMID: 28646173 PMCID: PMC5482851 DOI: 10.1038/s41598-017-04219-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 05/11/2017] [Indexed: 01/12/2023] Open
Abstract
The dynamic protein-protein and protein-ligand interactions of integral bitopic membrane proteins with a single membrane-spanning helix play a plethora of vital roles in the cellular processes associated with human health and diseases, including signaling and enzymatic catalysis. While an increasing number of high-resolution structural studies of membrane proteins have successfully manifested an in-depth understanding of their biological functions, intact membrane-bound bitopic protein-protein complexes pose tremendous challenges for structural studies by crystallography or solution NMR spectroscopy. Therefore, there is a growing interest in developing approaches to investigate the functional interactions of bitopic membrane proteins embedded in lipid bilayers at atomic-level. Here we demonstrate the feasibility of dynamic nuclear polarization (DNP) magic-angle-spinning NMR techniques, along with a judiciously designed stable isotope labeling scheme, to measure atomistic-resolution transmembrane-transmembrane interactions of full-length mammalian ~72-kDa cytochrome P450-cytochrome b5 complex in lipid bilayers. Additionally, the DNP sensitivity-enhanced two-dimensional 13C/13C chemical shift correlations via proton driven spin diffusion provided distance constraints to characterize protein-lipid interactions and revealed the transmembrane topology of cytochrome b5. The results reported in this study would pave ways for high-resolution structural and topological investigations of membrane-bound full-length bitopic protein complexes under physiological conditions.
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Affiliation(s)
- Kazutoshi Yamamoto
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109-1055, USA
| | - Marc A Caporini
- Bruker Biospin Corporation, 15 Fortune Drive, Billerica, MA, 01821, USA
| | - Sang-Choul Im
- Department of Anesthesiology, VA Medical Center, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Lucy Waskell
- Department of Anesthesiology, VA Medical Center, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109-1055, USA.
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24
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Syryamina VN, Dzuba SA. Dynamical Transitions at Low Temperatures in the Nearest Hydration Shell of Phospholipid Bilayers. J Phys Chem B 2017; 121:1026-1032. [DOI: 10.1021/acs.jpcb.6b10133] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- V. N. Syryamina
- Institute
of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation
- Physics
Department, Novosibirsk State University, Novosibirsk 630090, Russian Federation
| | - S. A. Dzuba
- Institute
of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation
- Physics
Department, Novosibirsk State University, Novosibirsk 630090, Russian Federation
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25
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Abstract
Abstract
Dynamic nuclear polarization (DNP) is a methodology to increase the sensitivity of nuclear magnetic resonance (NMR) spectroscopy. It relies on the transfer of the electron spin polarization from a radical to coupled nuclear spins, driven by microwave excitation resonant with the electron spin transitions. In this work we explore the potential of pulsed multi-frequency microwave excitation in liquids. Here, the relevant DNP mechanism is the Overhauser effect. The experiments were performed with TEMPOL radicals in aqueous solution at room temperature using a Q-band frequency (1.2 T) electron paramagnetic resonance (EPR) spectrometer combined with a Minispec NMR spectrometer. A fast arbitrary waveform generator (AWG) enabled the generation of multi-frequency pulses used to either sequentially or simultaneously excite all three 14N-hyperfine lines of the nitroxide radical. The multi-frequency excitation resulted in a doubling of the observed DNP enhancements compared to single-frequency microwave excitation. Q-band free induction decay (FID) signals of TEMPOL were measured as a function of the excitation pulse length allowing the efficiency of the electron spin manipulation by the microwave pulses to be extracted. Based on this knowledge we could quantitatively model our pulsed DNP enhancements at 1.2 T by numerical solution of the Bloch equations, including electron spin relaxation and experimental parameters. Our results are in good agreement with theoretical predictions. Whereas for a narrow and homogeneous single EPR line continuous wave excitation leads to more efficient DNP enhancements compared to pulsed excitation for the same amount of averaged microwave power. The situation is different for radicals with several hyperfine lines or in the presence of inhomogeneous line broadening. In such cases pulsed single/multi-frequency excitation can lead to larger DNP enhancements.
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Affiliation(s)
- Philipp Schöps
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Philipp E. Spindler
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Thomas F. Prisner
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
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26
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Akbey Ü, Oschkinat H. Structural biology applications of solid state MAS DNP NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 269:213-224. [PMID: 27095695 DOI: 10.1016/j.jmr.2016.04.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 04/05/2016] [Accepted: 04/05/2016] [Indexed: 06/05/2023]
Abstract
Dynamic Nuclear Polarization (DNP) has long been an aim for increasing sensitivity of nuclear magnetic resonance (NMR) spectroscopy, delivering spectra in shorter experiment times or of smaller sample amounts. In recent years, it has been applied in magic angle spinning (MAS) solid-state NMR to a large range of samples, including biological macromolecules and functional materials. New research directions in structural biology can be envisaged by DNP, facilitating investigations on very large complexes or very heterogeneous samples. Here we present a summary of state of the art DNP MAS NMR spectroscopy and its applications to structural biology, discussing the technical challenges and factors affecting DNP performance.
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Affiliation(s)
- Ümit Akbey
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Høegh-Guldbergs Gade 6B, 8000 Aarhus C, Denmark; Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.
| | - Hartmut Oschkinat
- Leibniz Institute für Molekulare Pharmakologie (FMP), NMR Supported Structural Biology, Robert Roessle Str. 10, 13125 Berlin, Germany.
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27
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Zhang R, Mroue KH, Ramamoorthy A. Hybridizing cross-polarization with NOE or refocused-INEPT enhances the sensitivity of MAS NMR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 266:59-66. [PMID: 27040936 PMCID: PMC4851575 DOI: 10.1016/j.jmr.2016.03.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Revised: 03/13/2016] [Accepted: 03/24/2016] [Indexed: 05/05/2023]
Abstract
Heteronuclear cross polarization (CP) has been commonly used to enhance the sensitivity of dilute low-γ nuclei in almost all solid-state NMR experiments. However, CP relies on heteronuclear dipolar couplings, and therefore the magnetization transfer efficiency becomes inefficient when the dipolar couplings are weak, as is often the case for mobile components in solids. Here, we demonstrate methods that combine CP with heteronuclear Overhauser effect (referred to as CP-NOE) or with refocused-INEPT (referred to as CP-RINEPT) to overcome the efficiency limitation of CP and enhance the signal-to-noise ratio (S/N) for mobile components. Our experimental results reveal that, compared to the conventional CP, significant S/N ratio enhancement can be achieved for resonances originating from mobile components, whereas the resonance signals associated with rigid groups are not significantly affected due to their long spin-lattice relaxation times. In fact, the S/N enhancement factor is also dependent on the temperature, CP contact time as well as on the system under investigation. Furthermore, we also demonstrate that CP-RINEPT experiment can be successfully employed to independently detect mobile and rigid signals in a single experiment without affecting the data collection time. However, the resolution of CP spectrum obtained from the CP-RINEPT experiment could be slightly compromised by the mandatory use of continuous wave (CW) decoupling during the acquisition of signals from rigid components. In addition, CP-RINEPT experiment can be used for spectral editing utilizing the difference in dynamics of different regions of a molecule and/or different components present in the sample, and could also be useful for the assignment of resonances from mobile components in poorly resolved spectra. Therefore, we believe that the proposed approaches are beneficial for the structural characterization of multiphase and heterogeneous systems, and could be used as a building block in multidimensional solid-state NMR experiments.
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Affiliation(s)
- Rongchun Zhang
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Kamal H Mroue
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
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28
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Ravera E, Luchinat C, Parigi G. Basic facts and perspectives of Overhauser DNP NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 264:78-87. [PMID: 26920833 DOI: 10.1016/j.jmr.2015.12.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 12/16/2015] [Accepted: 12/17/2015] [Indexed: 05/03/2023]
Abstract
After the first surprisingly large (1)H DNP enhancements of the water signal in aqueous solutions of nitroxide radicals observed at high magnetic fields, Overhauser DNP is gaining increasing attention for a number of applications now flourishing, showing the potentialities of this mechanism in solution and solid state NMR as well as in MRI. Unexpected Overhauser DNP enhancements in insulating solids were recently measured at 100K, with a magnitude which increases with the applied magnetic field. We recapitulate here the theoretical premises of Overhauser DNP in solution and analyze the effects of the various parameters on the efficacy of the mechanism, underlining the link between the DNP enhancements and the field dependent relaxation properties. Promisingly, more effective DNP enhancements are expected by exploiting the potentialities offered by (13)C detection and the use of supercritical fluids.
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Affiliation(s)
- Enrico Ravera
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Italy
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Italy.
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Prisner T, Denysenkov V, Sezer D. Liquid state DNP at high magnetic fields: Instrumentation, experimental results and atomistic modelling by molecular dynamics simulations. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 264:68-77. [PMID: 26920832 DOI: 10.1016/j.jmr.2015.11.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 11/11/2015] [Accepted: 11/12/2015] [Indexed: 05/14/2023]
Abstract
Dynamic nuclear polarization (DNP) at high magnetic fields has recently become one of the major research areas in magnetic resonance spectroscopy and imaging. Whereas much work has been devoted to experiments where the polarization transfer from the electron spin to the nuclear spin is performed in the solid state, only a few examples exist of experiments where the polarization transfer is performed in the liquid state. Here we describe such experiments at a magnetic field of 9.2 T, corresponding to a nuclear Larmor frequency of 400 MHz for proton spins and an excitation frequency of 263 GHz for the electron spins. The technical requirements to perform such experiments are discussed in the context of the double resonance structures that we have implemented. The experimental steps that allowed access to the enhancement factors for proton spins of several organic solvents with nitroxide radicals as polarizing agents are described. A computational scheme for calculating the coupling factors from molecular dynamics (MD) simulations is outlined and used to highlight the limitations of the classical models based on translational and rotational motion that are typically employed to quantify the observed coupling factors. The ability of MD simulations to predict enhancements for a variety of radicals and solvent molecules at any magnetic field strength should prove useful in optimizing experimental conditions for DNP in the liquid state.
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Affiliation(s)
- Thomas Prisner
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Germany.
| | - Vasyl Denysenkov
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Germany
| | - Deniz Sezer
- Faculty of Engineering and Natural Sciences, Sabancı University, Orhanlı-Tuzla, 34956 Istanbul, Turkey.
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van Bentum J, van Meerten B, Sharma M, Kentgens A. Perspectives on DNP-enhanced NMR spectroscopy in solutions. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 264:59-67. [PMID: 26920831 DOI: 10.1016/j.jmr.2016.01.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 01/12/2016] [Accepted: 01/13/2016] [Indexed: 05/03/2023]
Abstract
More than 60 years after the seminal work of Albert Overhauser on dynamic nuclear polarization by dynamic cross relaxation of coupled electron-nuclear spin systems, the quest for sensitivity enhancement in NMR spectroscopy is as pressing as ever. In this contribution we will review the status and perspectives for dynamic nuclear polarization in the liquid state. An appealing approach seems to be the use of supercritical solvents that may allow an extension of the Overhauser mechanism towards common high magnetic fields. A complementary approach is the use of solid state DNP on frozen solutions, followed by a rapid dissolution or in-situ melting step and NMR detection with substantially enhanced polarization levels in the liquid state. We will review recent developments in the field and discuss perspectives for the near future.
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31
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Salnikov ES, Aisenbrey C, Aussenac F, Ouari O, Sarrouj H, Reiter C, Tordo P, Engelke F, Bechinger B. Membrane topologies of the PGLa antimicrobial peptide and a transmembrane anchor sequence by Dynamic Nuclear Polarization/solid-state NMR spectroscopy. Sci Rep 2016; 6:20895. [PMID: 26876950 PMCID: PMC4753517 DOI: 10.1038/srep20895] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 01/11/2016] [Indexed: 12/23/2022] Open
Abstract
Dynamic Nuclear Polarization (DNP) has been introduced to overcome the sensitivity limitations of nuclear magnetic resonance (NMR) spectroscopy also of supported lipid bilayers. When investigated by solid-state NMR techniques the approach typically involves doping the samples with biradicals and their investigation at cryo-temperatures. Here we investigated the effects of temperature and membrane hydration on the topology of amphipathic and hydrophobic membrane polypeptides. Although the antimicrobial PGLa peptide in dimyristoyl phospholipids is particularly sensitive to topological alterations, the DNP conditions represent well its membrane alignment also found in bacterial lipids at ambient temperature. With a novel membrane-anchored biradical and purpose-built hardware a 17-fold enhancement in NMR signal intensity is obtained by DNP which is one of the best obtained for a truly static matrix-free system. Furthermore, a membrane anchor sequence encompassing 19 hydrophobic amino acid residues was investigated. Although at cryotemperatures the transmembrane domain adjusts it membrane tilt angle by about 10 degrees, the temperature dependence of two-dimensional separated field spectra show that freezing the motions can have beneficial effects for the structural analysis of this sequence.
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Affiliation(s)
| | - Christopher Aisenbrey
- University of Strasbourg/CNRS, UMR7177, Chemistry Institute, 67070 Strasbourg, France
| | - Fabien Aussenac
- Bruker BioSpin, 34, rue de l’Industrie, 67166 Wissembourg, France
| | - Olivier Ouari
- Aix-Marseille University, Institut de Chimie Radicalaire, UMR 7273, Faculté des Sciences, 13397 Marseille, Cédex 20, France
| | - Hiba Sarrouj
- University of Strasbourg/CNRS, UMR7177, Chemistry Institute, 67070 Strasbourg, France
- Bruker BioSpin, Silberstreifen, 76287 Rheinstetten, Germany
| | | | - Paul Tordo
- Aix-Marseille University, Institut de Chimie Radicalaire, UMR 7273, Faculté des Sciences, 13397 Marseille, Cédex 20, France
| | - Frank Engelke
- Bruker BioSpin, Silberstreifen, 76287 Rheinstetten, Germany
| | - Burkhard Bechinger
- University of Strasbourg/CNRS, UMR7177, Chemistry Institute, 67070 Strasbourg, France
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Syryamina VN, Maryasov AG, Bowman MK, Dzuba SA. Electron spin echo envelope modulation of molecular motions of deuterium nuclei. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 261:169-174. [PMID: 26583529 DOI: 10.1016/j.jmr.2015.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 10/10/2015] [Accepted: 10/12/2015] [Indexed: 06/05/2023]
Abstract
Electron Spin Echo Envelope Modulation (ESEEM) spectroscopy is a powerful technique for the study of hyperfine interactions between an unpaired electron and nearby nuclei in solids, and is employed in quantitative structural studies. Here, we describe the use of ESEEM to study the slow motion of deuterium nuclei using their nuclear quadrupole resonance (NQR) line shapes. Two ESEEM techniques were employed: the conventional three-pulse ESEEM experiment, π/2 - τ - π/2 - T- π/2 - τ - echo, and the four-pulse ESEEM, π/2 - τ - π/2 - T/2 - π - T/2 - π/2 - τ - echo, with the time variable T scanned in both cases. The nitroxide free radical 4-tert-butyliminomethyl-2,2,5,5-tetramethyl(d12)-3-imidazoline-1-oxyl with four deuterated methyl groups was investigated in a glassy ortho-terphenyl matrix over a wide temperature range. It was shown that four-pulse ESEEM allowed measurement of the nearly pure (2)H NQR line shape. Between 90K and 120K, the ESEEM spectra change drastically. At low temperatures, four-pulse ESEEM spectra show a Pake-like pattern, which evolves into a single line at higher temperatures, which is typical for NQR of rotating methyl CD3 groups. Comparison with literature data on NQR allows estimation of the reorientation rate, k. At ∼100K, where the spectral changes are most pronounced, k was found to be ∼10(5)s(-1). The spectral linewidths for the three-pulse ESEEM were found to decrease similarly with increasing temperature; so the three-pulse technique is also capable to detect motion of this type. The ESEEM approach, along with site-directed spin labeling, may be useful for detection of motional transitions near the spin labels in biological systems, when information on motion is required in a wide temperature range.
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Affiliation(s)
- V N Syryamina
- Voevodsky Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russia; Novosibirsk State University, 630090 Novosibirsk, Russia
| | - A G Maryasov
- Voevodsky Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - M K Bowman
- Department of Chemistry, The University of Alabama, Box 870336, Tuscaloosa, AL 35487-0336, USA
| | - S A Dzuba
- Voevodsky Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russia; Novosibirsk State University, 630090 Novosibirsk, Russia.
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33
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Lelli M, Chaudhari SR, Gajan D, Casano G, Rossini AJ, Ouari O, Tordo P, Lesage A, Emsley L. Solid-State Dynamic Nuclear Polarization at 9.4 and 18.8 T from 100 K to Room Temperature. J Am Chem Soc 2015; 137:14558-61. [PMID: 26555676 PMCID: PMC4671100 DOI: 10.1021/jacs.5b08423] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Efficient dynamic nuclear polarization
(DNP) in solids, which enables
very high sensitivity NMR experiments, is currently limited to temperatures
of around 100 K and below. Here we show how by choosing an adequate
solvent, 1H cross effect DNP enhancements of over 80 can
be obtained at 240 K. To achieve this we use the biradical TEKPol
dissolved in a glassy phase of ortho-terphenyl (OTP).
We study the solvent DNP enhancement of both TEKPol and BDPA in OTP
in the range from 100 to 300 K at 9.4 and 18.8 T. Surprisingly, we
find that the DNP enhancement decreases only relatively slowly for
temperatures below the glass transition of OTP (Tg = 243 K), and 1H enhancements around 15–20
at ambient temperature can be observed. We use this to monitor molecular
dynamic transitions in the pharmaceutically relevant solids Ambroxol
and Ibuprofen.
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Affiliation(s)
- Moreno Lelli
- Institut de Sciences Analytiques, Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1) , 69100 Villeurbanne, France
| | - Sachin R Chaudhari
- Institut de Sciences Analytiques, Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1) , 69100 Villeurbanne, France
| | - David Gajan
- Institut de Sciences Analytiques, Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1) , 69100 Villeurbanne, France
| | - Gilles Casano
- Aix-Marseille Université, CNRS, ICR UMR 7273 , 13397 Marseille, France
| | - Aaron J Rossini
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Olivier Ouari
- Aix-Marseille Université, CNRS, ICR UMR 7273 , 13397 Marseille, France
| | - Paul Tordo
- Aix-Marseille Université, CNRS, ICR UMR 7273 , 13397 Marseille, France
| | - Anne Lesage
- Institut de Sciences Analytiques, Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1) , 69100 Villeurbanne, France
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
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Salnikov ES, Sarrouj H, Reiter C, Aisenbrey C, Purea A, Aussenac F, Ouari O, Tordo P, Fedotenko I, Engelke F, Bechinger B. Solid-State NMR/Dynamic Nuclear Polarization of Polypeptides in Planar Supported Lipid Bilayers. J Phys Chem B 2015; 119:14574-83. [PMID: 26487390 DOI: 10.1021/acs.jpcb.5b07341] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Dynamic nuclear polarization has been developed to overcome the limitations of the inherently low signal intensity of NMR spectroscopy. This technique promises to be particularly useful for solid-state NMR spectroscopy where the signals are broadened over a larger frequency range and most investigations rely on recording low gamma nuclei. To extend the range of possible investigations, a triple-resonance flat-coil solid-state NMR probe is presented with microwave irradiation capacities allowing the investigation of static samples at temperatures of 100 K, including supported lipid bilayers. The probe performance allows for two-dimensional separated local field experiments with high-power Lee-Goldberg decoupling and cross-polarization under simultaneous irradiation from a gyrotron microwave generator. Efficient cooling of the sample turned out to be essential for best enhancements and line shape and necessitated the development of a dedicated cooling chamber. Furthermore, a new membrane-anchored biradical is presented, and the geometry of supported membranes was optimized not only for good membrane alignment, handling, stability, and filling factor of the coil but also for heat and microwave dissipation. Enhancement factors of 17-fold were obtained, and a two-dimensional PISEMA spectrum of a transmembrane helical peptide was obtained in less than 2 h.
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Affiliation(s)
- Evgeniy S Salnikov
- Institute of Chemistry, University of Strasbourg/CNRS, UMR7177 , 67070 Strasbourg, France
| | - Hiba Sarrouj
- Institute of Chemistry, University of Strasbourg/CNRS, UMR7177 , 67070 Strasbourg, France.,Bruker BioSpin, Silberstreifen, 76287 Rheinstetten, Germany
| | | | - Christopher Aisenbrey
- Institute of Chemistry, University of Strasbourg/CNRS, UMR7177 , 67070 Strasbourg, France
| | - Armin Purea
- Bruker BioSpin, Silberstreifen, 76287 Rheinstetten, Germany
| | - Fabien Aussenac
- Bruker BioSpin, 34, rue de l'Industrie, 67166 Wissembourg, France
| | - Olivier Ouari
- 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
| | - Illya Fedotenko
- Aix Marseille Université, CNRS , Institut de Chimie Radicalaire, UMR 7273, 13013 Marseille, France
| | - Frank Engelke
- Bruker BioSpin, Silberstreifen, 76287 Rheinstetten, Germany
| | - Burkhard Bechinger
- Institute of Chemistry, University of Strasbourg/CNRS, UMR7177 , 67070 Strasbourg, France
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35
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Bukhari SNA, Hwei NS, Jantan I. Recent Advances in Solid-State Analysis of Pharmaceuticals. ACTA ACUST UNITED AC 2015. [DOI: 10.2174/1874844901502010013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Current analytical techniques for characterizing solid-state pharmaceuticals include powder x-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, infrared spectroscopy, Raman spectroscopy, electron microscopy and nuclear magnetic resonance. Powder x-ray diffraction and differential scanning calorimetry are mainstream techniques but they lack spatial resolution. Scanning electron microscopy and micro-Raman spectroscopy provide good chemical and optical characterization but they are not capable of analysing very small nanoparticles. Transmission electron microscopy and nano-thermal analysis can provide explicit characterization of nanoparticles but they are invasive. Nuclear magnetic resonance offers good spatial resolution but its use is mainly limited by poor sensitivity and high costs. In view of the many challenges posed by existing methods, new and novel techniques are being continually researched and developed to cater to the growing number of solid formulations in the pipeline and in the market. Some of the recent advances attained in the solid-state analysis of pharmaceutical are summarized in this review article.
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36
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Opella SJ. Solid-state NMR and membrane proteins. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 253:129-37. [PMID: 25681966 PMCID: PMC4372479 DOI: 10.1016/j.jmr.2014.11.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 11/17/2014] [Accepted: 11/30/2014] [Indexed: 05/15/2023]
Abstract
The native environment for a membrane protein is a phospholipid bilayer. Because the protein is immobilized on NMR timescales by the interactions within a bilayer membrane, solid-state NMR methods are essential to obtain high-resolution spectra. Approaches have been developed for both unoriented and oriented samples, however, they all rest on the foundation of the most fundamental aspects of solid-state NMR, and the chemical shift and homo- and hetero-nuclear dipole-dipole interactions. Solid-state NMR has advanced sufficiently to enable the structures of membrane proteins to be determined under near-native conditions in phospholipid bilayers.
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Affiliation(s)
- Stanley J Opella
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA.
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37
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Lee DK, Bhunia A, Kotler SA, Ramamoorthy A. Detergent-type membrane fragmentation by MSI-78, MSI-367, MSI-594, and MSI-843 antimicrobial peptides and inhibition by cholesterol: a solid-state nuclear magnetic resonance study. Biochemistry 2015; 54:1897-907. [PMID: 25715195 DOI: 10.1021/bi501418m] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Multidrug resistance against the existing antibiotics is becoming a global threat, and any potential drug that can be designed using cationic antimicrobial peptides (AMP) could be an alternate solution to alleviate this existing problem. The mechanism of action of killing bacteria by an AMP differs drastically in comparison to that of small molecule antibiotics. The main target of AMPs is to interact with the lipid bilayer of the cell membrane and disrupt it to kill bacteria. Consequently, the modes of membrane interaction that lead to the selectivity of an AMP are very important to understand. Here, we have used different membrane compositions, such as negatively charged, zwitterionic, or mixed large unilamellar vesicles (LUVs), to study the interaction of four different synthetically designed cationic, linear antimicrobial peptides: MSI-78 (commercially known as pexiganan), MSI-367, MSI-594, and MSI-843. Our solid-state nuclear magnetic resonance (NMR) experiments confirmed that the MSI peptides fragmented LUVs through a detergent-like carpet mechanism depending on the amino acid sequence of the MSI peptide and/or the membrane composition of LUVs. Interestingly, the fragmented lipid aggregates such as SUVs or micelles are sufficiently small to produce an isotropic peak in the (31)P NMR spectrum. These fragmented lipid aggregates contain only MSI peptides bestowed with lipid molecules as confirmed by NMR in conjunction with circular dichroism spectroscopy. Our results also demonstrate that cholesterol, which is present only in the eukaryotic cell membrane, inhibits the MSI-induced fragmentation of LUVs, suggesting that the MSI peptides can discriminate the bacteria and the eukaryotic cell membranes, and this selectivity could be used for further development of novel antibiotics.
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Affiliation(s)
- Dong-Kuk Lee
- †Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Anirban Bhunia
- †Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States.,§Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VII(M), Kolkata 700054, India
| | - Samuel A Kotler
- †Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Ayyalusamy Ramamoorthy
- †Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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Yamamoto K, Pearcy P, Lee DK, Yu C, Im SC, Waskell L, Ramamoorthy A. Temperature-resistant bicelles for structural studies by solid-state NMR spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:1496-1504. [PMID: 25565453 DOI: 10.1021/la5043876] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Three-dimensional structure determination of membrane proteins is important to fully understand their biological functions. However, obtaining a high-resolution structure has been a major challenge mainly due to the difficulties in retaining the native folding and function of membrane proteins outside of the cellular membrane environment. These challenges are acute if the protein contains a large soluble domain, as it needs bulk water unlike the transmembrane domains of an integral membrane protein. For structural studies on such proteins either by nuclear magnetic resonance (NMR) spectroscopy or X-ray crystallography, bicelles have been demonstrated to be superior to conventional micelles, yet their temperature restrictions attributed to their thermal instabilities are a major disadvantage. Here, we report an approach to overcome this drawback through searching for an optimum combination of bicellar compositions. We demonstrate that bicelles composed of 1,2-didecanoyl-sn-glycero-3-phosphocholine (DDPC) and 1,2-diheptanoyl-sn-glycero-3-phosphocholin (DHepPC), without utilizing additional stabilizing chemicals, are quite stable and are resistant to temperature variations. These temperature-resistant bicelles have a robust bicellar phase and magnetic alignment over a broad range of temperatures, between -15 and 80 °C, retain the native structure of a membrane protein, and increase the sensitivity of solid-state NMR experiments performed at low temperatures. Advantages of two-dimensional separated-local field (SLF) solid-state NMR experiments at a low temperature are demonstrated on magnetically aligned bicelles containing an electron carrier membrane protein, cytochrome b5. Morphological information on different DDPC-based bicellar compositions, varying q ratio/size, and hydration levels obtained from (31)P NMR experiments in this study is also beneficial for a variety of biophysical and spectroscopic techniques, including solution NMR and magic-angle-spinning (MAS) NMR for a wide range of temperatures.
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Affiliation(s)
- Kazutoshi Yamamoto
- Department of Chemistry and Biophysics, University of Michigan , 930 N. University Ave., Ann Arbor, Michigan 48109-1055, United States
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