1
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Scott FJ, Dubroca T, Schurko RW, Hill S, Long JR, Mentink-Vigier F. Characterization of dielectric properties and their impact on MAS-DNP NMR applications. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2024; 365:107742. [PMID: 39116460 DOI: 10.1016/j.jmr.2024.107742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 06/17/2024] [Accepted: 07/13/2024] [Indexed: 08/10/2024]
Abstract
The dielectric properties of materials play a crucial role in the propagation and absorption of microwave beams employed in Magic Angle Spinning - Dynamic Nuclear Polarization (MAS-DNP) NMR experiments. Despite ongoing optimization efforts in sample preparation, routine MAS-DNP NMR applications often fall short of theoretical sensitivity limits. Offering a different perspective, we report the refractive indices and extinction coefficients of diverse materials used in MAS-DNP NMR experiments, spanning a frequency range from 70 to 960 GHz. Knowledge of their dielectric properties enables the accurate simulation of electron nutation frequencies, thereby guiding the design of more efficient hardware and sample preparation of biological or material samples. This is illustrated experimentally for four different rotor materials (sapphire, yttria-stabilized zirconia (YSZ), aluminum nitride (AlN), and SiAlON ceramics) used for DNP at 395 GHz/1H 600 MHz. Finally, electromagnetic simulations and state-of-the-art MAS-DNP numerical simulations provide a rational explanation for the observed magnetic field dependence of the enhancement when using nitroxide biradicals, offering insights that will improve MAS-DNP NMR at high magnetic fields.
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Affiliation(s)
- Faith J Scott
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr., Tallahassee, FL 32310, USA
| | - Thierry Dubroca
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr., Tallahassee, FL 32310, USA
| | - Robert W Schurko
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr., Tallahassee, FL 32310, USA; Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
| | - Stephen Hill
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr., Tallahassee, FL 32310, USA; Department of Physics, Florida State University, Tallahassee, FL 32306, USA
| | - Joanna R Long
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr., Tallahassee, FL 32310, USA; Department of Biochemistry and Molecular Biology, University of Florida, PO Box 100245, Gainesville, FL 32610, USA.
| | - Frédéric Mentink-Vigier
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr., Tallahassee, FL 32310, USA.
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2
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Chatterjee S, Venkatesh A, Sigurdsson ST, Mentink-Vigier F. Role of Protons in and around Strongly Coupled Nitroxide Biradicals for Cross-Effect Dynamic Nuclear Polarization. J Phys Chem Lett 2024; 15:2160-2168. [PMID: 38364262 DOI: 10.1021/acs.jpclett.3c03472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2024]
Abstract
In magic angle spinning dynamic nuclear polarization (DNP), biradicals such as bis-nitroxides are used to hyperpolarize protons under microwave irradiation through the cross-effect mechanism. This mechanism relies on electron-electron spin interactions (dipolar coupling and exchange interaction) and electron-nuclear spin interactions (hyperfine coupling) to hyperpolarize the protons surrounding the biradical. This hyperpolarization is then transferred to the bulk sample via nuclear spin diffusion. However, the involvement of the protons in the biradical in the cross-effect DNP process has been under debate. In this work, we address this question by exploring the hyperpolarization pathways in and around bis-nitroxides. We demonstrate that for biradicals with strong electron-electron interactions, as in the case of the AsymPols, the protons on the biradical may not be necessary to quickly generate hyperpolarization. Instead, such biradicals can efficiently, and directly, polarize the surrounding protons of the solvent. The findings should impact the design of the next generation of biradicals.
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Affiliation(s)
- Satyaki Chatterjee
- University of Iceland, Department of Chemistry, Science Institute, Dunhaga 3, 107 Reykjavik, Iceland
| | - Amrit Venkatesh
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Snorri Th Sigurdsson
- University of Iceland, Department of Chemistry, Science Institute, Dunhaga 3, 107 Reykjavik, Iceland
| | - Frédéric Mentink-Vigier
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
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3
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Venkatesh A, Casano G, Wei R, Rao Y, Lingua H, Karoui H, Yulikov M, Ouari O, Emsley L. Rational Design of Dinitroxide Polarizing Agents for Dynamic Nuclear Polarization to Enhance Overall NMR Sensitivity. Angew Chem Int Ed Engl 2024; 63:e202317337. [PMID: 38193258 DOI: 10.1002/anie.202317337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/03/2024] [Accepted: 01/08/2024] [Indexed: 01/10/2024]
Abstract
We evaluate the overall sensitivity gains provided by a series of eighteen nitroxide biradicals for dynamic nuclear polarization (DNP) solid-state NMR at 9.4 T and 100 K, including eight new biradicals. We find that in the best performing group the factors contributing to the overall sensitivity gains, namely the DNP enhancement, the build-up time, and the contribution factor, often compete with each other leading to very similar overall sensitivity across a range of biradicals. NaphPol and HydroPol are found to provide the best overall sensitivity factors, in organic and aqueous solvents respectively. One of the new biradicals, AMUPolCbm, provides high sensitivity for all three solvent formulations measured here, and can be considered to be a "universal" polarizing agent.
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Affiliation(s)
- Amrit Venkatesh
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
- Current address: National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Gilles Casano
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, 13013, Marseille, France
| | - Ran Wei
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Yu Rao
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Hugo Lingua
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, 13013, Marseille, France
| | - Hakim Karoui
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, 13013, Marseille, France
| | - Maxim Yulikov
- Laboratory of Physical Chemistry, Department of Chemistry, ETH Zürich, 8093, Zürich, Switzerland
| | - Olivier Ouari
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, 13013, Marseille, France
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
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4
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Zhao Y, El Mkami H, Hunter RI, Casano G, Ouari O, Smith GM. Large cross-effect dynamic nuclear polarisation enhancements with kilowatt inverting chirped pulses at 94 GHz. Commun Chem 2023; 6:171. [PMID: 37607991 PMCID: PMC10444895 DOI: 10.1038/s42004-023-00963-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 07/25/2023] [Indexed: 08/24/2023] Open
Abstract
Dynamic nuclear polarisation (DNP) is a process that transfers electron spin polarisation to nuclei by applying resonant microwave radiation, and has been widely used to improve the sensitivity of nuclear magnetic resonance (NMR). Here we demonstrate new levels of performance for static cross-effect proton DNP using high peak power chirped inversion pulses at 94 GHz to create a strong polarisation gradient across the inhomogeneously broadened line of the mono-radical 4-amino TEMPO. Enhancements of up to 340 are achieved at an average power of a few hundred mW, with fast build-up times (3 s). Experiments are performed using a home-built wideband kW pulsed electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz, integrated with an NMR detection system. Simultaneous DNP and EPR characterisation of other mono-radicals and biradicals, as a function of temperature, leads to additional insights into limiting relaxation mechanisms and give further motivation for the development of wideband pulsed amplifiers for DNP at higher frequencies.
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Affiliation(s)
- Yujie Zhao
- School of Physics and Astronomy, University of St Andrews, KY16 9SS, Fife, Scotland
| | - Hassane El Mkami
- School of Physics and Astronomy, University of St Andrews, KY16 9SS, Fife, Scotland
| | - Robert I Hunter
- School of Physics and Astronomy, University of St Andrews, KY16 9SS, Fife, Scotland
| | - Gilles Casano
- Aix Marseille University, CNRS, ICR, UMR 7273, F-13013, Marseille, France
| | - Olivier Ouari
- Aix Marseille University, CNRS, ICR, UMR 7273, F-13013, Marseille, France
| | - Graham M Smith
- School of Physics and Astronomy, University of St Andrews, KY16 9SS, Fife, Scotland.
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5
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Menzildjian G, Schlagnitweit J, Casano G, Ouari O, Gajan D, Lesage A. Polarizing agents for efficient high field DNP solid-state NMR spectroscopy under magic-angle spinning: from design principles to formulation strategies. Chem Sci 2023; 14:6120-6148. [PMID: 37325158 PMCID: PMC10266460 DOI: 10.1039/d3sc01079a] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 05/09/2023] [Indexed: 06/17/2023] Open
Abstract
Dynamic Nuclear Polarization (DNP) has recently emerged as a cornerstone approach to enhance the sensitivity of solid-state NMR spectroscopy under Magic Angle Spinning (MAS), opening unprecedented analytical opportunities in chemistry and biology. DNP relies on a polarization transfer from unpaired electrons (present in endogenous or exogenous polarizing agents) to nearby nuclei. Developing and designing new polarizing sources for DNP solid-state NMR spectroscopy is currently an extremely active research field per se, that has recently led to significant breakthroughs and key achievements, in particular at high magnetic fields. This review describes recent developments in this area, highlighting key design principles that have been established over time and led to the introduction of increasingly more efficient polarizing sources. After a short introduction, Section 2 presents a brief history of solid-state DNP, highlighting the main polarization transfer schemes. The third section is devoted to the development of dinitroxide radicals, discussing the guidelines that were progressively established to design the fine-tuned molecular structures in use today. In Section 4, we describe recent efforts in developing hybrid radicals composed of a narrow EPR line radical covalently linked to a nitroxide, highlighting the parameters that modulate the DNP efficiency of these mixed structures. Section 5 reviews recent advances in the design of metal complexes suitable for DNP MAS NMR as exogenous electron sources. In parallel, current strategies that exploit metal ions as endogenous polarization sources are discussed. Section 6 briefly describes the recent introduction of mixed-valence radicals. In the last part, experimental aspects regarding sample formulation are reviewed to make best use of these polarizing agents in a broad panel of application fields.
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Affiliation(s)
- Georges Menzildjian
- Centre de RMN à, Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1) 5 Rue de la doua 69100 Villeurbanne France
| | - Judith Schlagnitweit
- Centre de RMN à, Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1) 5 Rue de la doua 69100 Villeurbanne France
| | - Gilles Casano
- Aix Marseille Univ., CNRS, Institut de Chimie Radicalaire, UMR 7273 Marseille France
| | - Olivier Ouari
- Aix Marseille Univ., CNRS, Institut de Chimie Radicalaire, UMR 7273 Marseille France
| | - David Gajan
- Centre de RMN à, Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1) 5 Rue de la doua 69100 Villeurbanne France
| | - Anne Lesage
- Centre de RMN à, Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1) 5 Rue de la doua 69100 Villeurbanne France
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6
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An EPR Study on Highly Stable Nitroxyl-Nitroxyl Biradicals for Dynamic Nuclear Polarization Applications at High Magnetic Fields. Molecules 2023; 28:molecules28041926. [PMID: 36838912 PMCID: PMC9958542 DOI: 10.3390/molecules28041926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 02/13/2023] [Accepted: 02/15/2023] [Indexed: 02/22/2023] Open
Abstract
Nitroxide biradicals are efficient polarizing agents in dynamic nuclear polarization (DNP) solid-state nuclear magnetic resonance. Many recently reported radicals possess substantial DNP efficiency in organic solvents but have poor solubility in water media which is unfavorable for biological applications. In this paper, we report DNP efficiency at a high magnetic field for two water-soluble biradicals resistant to reducing media. Water solubility was achieved by obtaining the radicals in the form of quaternary ammonium salts. Parameters of hyperfine interaction and exchange interaction were quantified by EPR spectroscopy, and their influence on the DNP effect was determined. The resistance of the biradicals to strongly reducing media was characterized. High stability was achieved using tetraethyl substituents and pyrrolidine moieties.
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7
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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: 63] [Impact Index Per Article: 63.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [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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8
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Michaelis VK, Keeler EG, Bahri S, Ong TC, Daviso E, Colvin MT, Griffin RG. Biradical Polarizing Agents at High Fields. J Phys Chem B 2022; 126:7847-7856. [PMID: 36194539 PMCID: PMC9886493 DOI: 10.1021/acs.jpcb.2c03985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The sensitivity enhancements available from dynamic nuclear polarization (DNP) are rapidly reshaping the research landscape and expanding the field of nuclear magnetic resonance (NMR) spectroscopy as a tool for solving complex chemical and structural problems. The past decade has seen considerable advances in this burgeoning method, while efforts to further improve its capabilities continue along many avenues. In this report, we examine the influence of static magnetic field strength and temperature on the reported 1H DNP enhancements from three conventional organic biradicals: TOTAPOL, AMUPol, and SPIROPOL. In contrast to the conventional wisdom, our findings show that at liquid nitrogen temperatures and 700 MHz/460.5 GHz, these three bisnitroxides all provide similar 1H DNP enhancements, ε ≈ 60. Furthermore, we investigate the influence of temperature, microwave power, magnetic field strength, and protein sample deuteration on the NMR experimental results.
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Affiliation(s)
- Vladimir K. Michaelis
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139 Massachusetts, United States; Department of Chemistry, University of Alberta, Edmonton T6G 2G2 Alberta, Canada
| | - Eric G. Keeler
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139 Massachusetts, United States; New York Structural Biology Center, New York 10027, New York, United States
| | - Salima Bahri
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139 Massachusetts, United States; Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht 3584CH, The Netherlands
| | - Ta-Chung Ong
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139 Massachusetts, United States; Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles 90095 California, United States
| | - Eugenio Daviso
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139 Massachusetts, United States; Department of Scientific Support and Applications Development, Covaris LLC, Woburn 01801 Massachusetts, United States
| | - Michael T. Colvin
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139 Massachusetts, United States; Ortho Clinical Diagnostics, Rochester 14626 New York, United States
| | - Robert G. Griffin
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139 Massachusetts, United States
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9
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Yau WM, Blake Wilson C, Jeon J, Tycko R. Nitroxide-based triradical dopants for efficient low-temperature dynamic nuclear polarization in aqueous solutions over a broad pH range. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 342:107284. [PMID: 35986970 PMCID: PMC9463097 DOI: 10.1016/j.jmr.2022.107284] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 08/05/2022] [Accepted: 08/09/2022] [Indexed: 05/31/2023]
Abstract
Dynamic nuclear polarization (DNP) can provide substantial sensitivity enhancements in solid state nuclear magnetic resonance (ssNMR) measurements on frozen solutions, thereby enabling experiments that would otherwise be impractical. Previous work has shown that nitroxide-based triradical compounds are particularly effective as dopants in DNP-enhanced measurements at moderate magic-angle spinning frequencies and moderate magnetic field strengths, generally leading to a more rapid build-up of nuclear spin polarizations under microwave irradiation than the more common biradical dopants at the same electron spin concentrations. Here we report the synthesis and DNP performance at 25 K and 9.41 T for two new triradical compounds, sulfoacetyl-DOTOPA and PEG12-DOTOPA. Under our experimental conditions, these compounds exhibit ssNMR signal enhancements and DNP build-up times that are nearly identical to those of previously described triradical dopants. Moreover, these compounds have high solubility in aqueous buffers and water/glycerol mixtures at both acidic and basic pH values, making them useful in a wide variety of experiments on biomolecular systems.
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Affiliation(s)
- Wai-Ming Yau
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, United States
| | - C Blake Wilson
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, United States
| | - Jaekyun Jeon
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, United States
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, United States.
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10
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Asanbaeva NB, Gurskaya LY, Polienko YF, Rybalova TV, Kazantsev MS, Dmitriev AA, Gritsan NP, Haro-Mares N, Gutmann T, Buntkowsky G, Tretyakov EV, Bagryanskaya EG. Effects of Spiro-Cyclohexane Substitution of Nitroxyl Biradicals on Dynamic Nuclear Polarization. Molecules 2022; 27:3252. [PMID: 35630726 PMCID: PMC9143461 DOI: 10.3390/molecules27103252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 05/17/2022] [Accepted: 05/17/2022] [Indexed: 11/20/2022] Open
Abstract
Spiro-substituted nitroxyl biradicals are widely used as reagents for dynamic nuclear polarization (DNP), which is especially important for biopolymer research. The main criterion for their applicability as polarizing agents is the value of the spin-spin exchange interaction parameter (J), which can vary considerably when different couplers are employed that link the radical moieties. This paper describes a study on biradicals, with a ferrocene-1,1'-diyl-substituted 1,3-diazetidine-2,4-diimine coupler, that have never been used before as DNP agents. We observed a substantial difference in the temperature dependence between Electron Paramagnetic Resonance (EPR) spectra of biradicals carrying either methyl or spirocyclohexane substituents and explain the difference using Density Functional Theory (DFT) calculation results. It was shown that the replacement of methyl groups by spirocycles near the N-O group leads to an increase in the contribution of conformers having J ≈ 0. The DNP gain observed for the biradicals with methyl substituents is three times higher than that for the spiro-substituted nitroxyl biradicals and is inversely proportional to the contribution of biradicals manifesting the negligible exchange interaction. The effects of nucleophiles and substituents in the nitroxide biradicals on the ring-opening reaction of 1,3-diazetidine and the influence of the ring opening on the exchange interaction were also investigated. It was found that in contrast to the methyl-substituted nitroxide biradical (where we observed the ring-opening reaction upon the addition of amines), the ring opening does not occur in the spiro-substituted biradical owing to a steric barrier created by the bulky cyclohexyl substituents.
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Affiliation(s)
- Nargiz B. Asanbaeva
- N.N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), 9 Acad. Lavrentiev Avenue, Novosibirsk 630090, Russia; (N.B.A.); (L.Y.G.); (Y.F.P.); (T.V.R.); (M.S.K.)
| | - Larisa Yu. Gurskaya
- N.N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), 9 Acad. Lavrentiev Avenue, Novosibirsk 630090, Russia; (N.B.A.); (L.Y.G.); (Y.F.P.); (T.V.R.); (M.S.K.)
| | - Yuliya F. Polienko
- N.N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), 9 Acad. Lavrentiev Avenue, Novosibirsk 630090, Russia; (N.B.A.); (L.Y.G.); (Y.F.P.); (T.V.R.); (M.S.K.)
| | - Tatyana V. Rybalova
- N.N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), 9 Acad. Lavrentiev Avenue, Novosibirsk 630090, Russia; (N.B.A.); (L.Y.G.); (Y.F.P.); (T.V.R.); (M.S.K.)
| | - Maxim S. Kazantsev
- N.N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), 9 Acad. Lavrentiev Avenue, Novosibirsk 630090, Russia; (N.B.A.); (L.Y.G.); (Y.F.P.); (T.V.R.); (M.S.K.)
| | - Alexey A. Dmitriev
- V.V. Voevodsky Institute of Chemical Kinetics and Combustion, SB RAS, 3 Institutskaya Str., Novosibirsk 630090, Russia; (A.A.D.); (N.P.G.)
| | - Nina P. Gritsan
- V.V. Voevodsky Institute of Chemical Kinetics and Combustion, SB RAS, 3 Institutskaya Str., Novosibirsk 630090, Russia; (A.A.D.); (N.P.G.)
| | - Nadia Haro-Mares
- TU Darmstadt, Eduard-Zintl-Institute for Inorganic and Physical Chemistry, Alarich-Weiss-Straße 8, 64287 Darmstadt, Germany; (N.H.-M.); (T.G.); (G.B.)
| | - Torsten Gutmann
- TU Darmstadt, Eduard-Zintl-Institute for Inorganic and Physical Chemistry, Alarich-Weiss-Straße 8, 64287 Darmstadt, Germany; (N.H.-M.); (T.G.); (G.B.)
| | - Gerd Buntkowsky
- TU Darmstadt, Eduard-Zintl-Institute for Inorganic and Physical Chemistry, Alarich-Weiss-Straße 8, 64287 Darmstadt, Germany; (N.H.-M.); (T.G.); (G.B.)
| | - Evgeny V. Tretyakov
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky Prosp., Moscow 119991, Russia;
| | - Elena G. Bagryanskaya
- N.N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), 9 Acad. Lavrentiev Avenue, Novosibirsk 630090, Russia; (N.B.A.); (L.Y.G.); (Y.F.P.); (T.V.R.); (M.S.K.)
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11
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Kundu K, Dubroca T, Rane V, Mentink-Vigier F. Spinning-Driven Dynamic Nuclear Polarization with Optical Pumping. J Phys Chem A 2022; 126:2600-2608. [PMID: 35417169 PMCID: PMC9121629 DOI: 10.1021/acs.jpca.2c01559] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We propose a new, more efficient, and potentially cost effective, solid-state nuclear spin hyperpolarization method combining the cross-effect mechanism and electron spin optical hyperpolarization in rotating solids. We first demonstrate optical hyperpolarization in the solid state at low temperatures and low field and then investigate its field dependence to obtain the optimal condition for high-field electron spin hyperpolarization. The results are then incorporated into advanced magic-angle spinning dynamic nuclear polarization (MAS-DNP) numerical simulations that show that optically pumped MAS-DNP could yield breakthrough enhancements at very high magnetic fields. Based on these investigations, enhancements greater than the ratio of electron to nucleus magnetic moments (>658 for 1H) are possible without microwave irradiation. This could solve at once the MAS-DNP performance decrease with increasing field and the high cost of MAS-DNP instruments at very high fields.
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Affiliation(s)
- Krishnendu Kundu
- National High Magnetic Field Laboratory, Florida State University, 1800 E Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Thierry Dubroca
- National High Magnetic Field Laboratory, Florida State University, 1800 E Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Vinayak Rane
- Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Frederic Mentink-Vigier
- National High Magnetic Field Laboratory, Florida State University, 1800 E Paul Dirac Drive, Tallahassee, Florida 32310, United States
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12
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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: 28] [Impact Index Per Article: 14.0] [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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13
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Wi S, Dwivedi N, Dubey R, Mentink-Vigier F, Sinha N. Dynamic nuclear polarization-enhanced, double-quantum filtered 13C- 13C dipolar correlation spectroscopy of natural 13C abundant bone-tissue biomaterial. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 335:107144. [PMID: 35085899 PMCID: PMC8823282 DOI: 10.1016/j.jmr.2022.107144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 01/07/2022] [Accepted: 01/08/2022] [Indexed: 05/03/2023]
Abstract
Here, we describe a method for obtaining a dynamic nuclear polarization (DNP)-enhanced double-quantum filtered (DQF) two-dimensional (2D) dipolar 13C-13C correlation spectra of bone-tissue material at natural 13C abundance. DNP-enhanced DQF 2D dipolar 13C-13C spectra were obtained using a few different mixing times of the dipolar-assisted rotational resonance (DARR) scheme and these spectra were compared to a conventional 2D through-space double-quantum (DQ)-single-quantum (SQ) correlation spectrum. While this scheme can only be used for an assignment purpose to reveal the carbon-carbon connectivity within a residue, the DQF 13C-13C dipolar correlation scheme introduced here can be used to obtain longer distance carbon-carbon constraints. A DQF pulse block is placed before the DARR mixing scheme for removing dominant 13C single-quantum (SQ) signals because these SQ 13C signals are overwhelmingly large compared to those 13C-13C dipolar cross-peaks generated and therefore saturate the dynamic range of the NMR detection. This approach exhibits strong enough 2D cross-peaks in a dipolar 13C-13C correlation spectrum and potentially provides pairwise 13C-13C dipolar constraints because the dipolar truncation effect as well as multi-step signal propagations involving a spin cluster that contains more than two spins can be ignored probabilistically. To obtain fast signal averaging, AsymPolPOK was used to provide a short 1H DNP signal build-up time (1.3 s) and to expedite our MAS DNP NMR acquisitions while still maintaining a satisfactory DNP enhancement factor (ε = 50). Under long DARR mixing, a t1-noise-like artifact was observed at a site that possesses a large chemical shift anisotropy (CSA) and a few different strategies to address this problem were discussed.
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Affiliation(s)
- Sungsool Wi
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32304, USA.
| | - Navneet Dwivedi
- Department of Advanced Spectroscopy and Imaging, Centre of Biomedical Research, SGPGIMS Campus, Raebarelly Road, Lucknow 226014, India; Department of Physics, Integral University, Lucknow 226026, India
| | - Richa Dubey
- Department of Advanced Spectroscopy and Imaging, Centre of Biomedical Research, SGPGIMS Campus, Raebarelly Road, Lucknow 226014, India
| | - Frederic Mentink-Vigier
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32304, USA
| | - Neeraj Sinha
- Department of Advanced Spectroscopy and Imaging, Centre of Biomedical Research, SGPGIMS Campus, Raebarelly Road, Lucknow 226014, India
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14
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Menzildjian G, Lund A, Yulikov M, Gajan D, Niccoli L, Karthikeyan G, Casano G, Jeschke G, Ouari O, Lelli M, Lesage A. Efficient Dynamic Nuclear Polarization up to 230 K with Hybrid BDPA-Nitroxide Radicals at a High Magnetic Field. J Phys Chem B 2021; 125:13329-13338. [PMID: 34818009 DOI: 10.1021/acs.jpcb.1c07307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pairing the spectral resolution provided by high magnetic fields at ambient temperature with the enhanced sensitivity offered by dynamic nuclear polarization (DNP) is a major goal of modern solid-state NMR spectroscopy, which will allow one to unlock ever-challenging applications. This study demonstrates that, by combining HyTEK2, a hybrid BDPA-nitroxide biradical polarizing agent, with ortho-terphenyl (OTP), a rigid DNP matrix, enhancement factors as high as 65 can be obtained at 230 K, 40 kHz magic angle spinning (MAS), and 18.8 T. The temperature dependence of the DNP enhancement and its behavior around the glass transition temperature (Tg) of the matrix is investigated by variable-temperature EPR measurements of the electron relaxation properties and numerical simulations. A correlation is suggested between the decrease in enhancement at the passage of the Tg and the concomitant drop of both transverse electron relaxation times in the biradical.
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Affiliation(s)
- Georges Menzildjian
- Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCBL), 69100 Villeurbanne, France
| | - Alicia Lund
- Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCBL), 69100 Villeurbanne, France
| | - Maxim Yulikov
- Department of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland
| | - David Gajan
- Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCBL), 69100 Villeurbanne, France
| | - Lorenzo Niccoli
- Center of Magnetic Resonance (CERM), University of Florence, 50019 Sesto Fiorentino, Italy
| | - Ganesan Karthikeyan
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire, 13013 Marseille, France
| | - Gilles Casano
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire, 13013 Marseille, France
| | - Gunnar Jeschke
- Department of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland
| | - Olivier Ouari
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire, 13013 Marseille, France
| | - Moreno Lelli
- Center of Magnetic Resonance (CERM), University of Florence, 50019 Sesto Fiorentino, Italy
| | - Anne Lesage
- Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCBL), 69100 Villeurbanne, France
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15
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Ghassemi N, Poulhazan A, Deligey F, Mentink-Vigier F, Marcotte I, Wang T. Solid-State NMR Investigations of Extracellular Matrixes and Cell Walls of Algae, Bacteria, Fungi, and Plants. Chem Rev 2021; 122:10036-10086. [PMID: 34878762 DOI: 10.1021/acs.chemrev.1c00669] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Extracellular matrixes (ECMs), such as the cell walls and biofilms, are important for supporting cell integrity and function and regulating intercellular communication. These biomaterials are also of significant interest to the production of biofuels and the development of antimicrobial treatment. Solid-state nuclear magnetic resonance (ssNMR) and magic-angle spinning-dynamic nuclear polarization (MAS-DNP) are uniquely powerful for understanding the conformational structure, dynamical characteristics, and supramolecular assemblies of carbohydrates and other biomolecules in ECMs. This review highlights the recent high-resolution investigations of intact ECMs and native cells in many organisms spanning across plants, bacteria, fungi, and algae. We spotlight the structural principles identified in ECMs, discuss the current technical limitation and underexplored biochemical topics, and point out the promising opportunities enabled by the recent advances of the rapidly evolving ssNMR technology.
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Affiliation(s)
- Nader Ghassemi
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Alexandre Poulhazan
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States.,Department of Chemistry, Université du Québec à Montréal, Montreal H2X 2J6, Canada
| | - Fabien Deligey
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | | | - Isabelle Marcotte
- Department of Chemistry, Université du Québec à Montréal, Montreal H2X 2J6, Canada
| | - Tuo Wang
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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16
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Mentink-Vigier F, Dubroca T, Van Tol J, Sigurdsson ST. The distance between g-tensors of nitroxide biradicals governs MAS-DNP performance: The case of the bTurea family. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 329:107026. [PMID: 34246883 PMCID: PMC8316413 DOI: 10.1016/j.jmr.2021.107026] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 05/20/2023]
Abstract
Bis-nitroxide radicals are common polarizing agents (PA), used to enhance the sensitivity of solid-state NMR experiments via Magic Angle Spinning Dynamic Nuclear Polarization (MAS-DNP). These biradicals can increase the proton spin polarization through the Cross-Effect (CE) mechanism, which requires PAs with at least two unpaired electrons. The relative orientation of the bis-nitroxide moieties is critical to ensure efficient polarization transfer. Recently, we have defined a new quantity, the distance between g-tensors, that correlates the relative orientation of the nitroxides with the ability to polarize the surrounding nuclei. Here we analyse experimentally and theoretically a series of biradicals belonging to the bTurea family, namely bcTol, AMUPol and bcTol-M. They differ by the degree of substitution on the urea bridge that connects the two nitroxides. Using quantitative simulations developed for moderate MAS frequencies, we show that these modifications mostly affect the relative orientations of the nitroxide, i.e. the length and distribution of the distance between the g-tensors, that in turn impacts both the steady state nuclear polarization/depolarization as well as the build-up times. The doubly substituted urea bridge favours a large distance between the g-tensors, which enables bcTol-M to provide ∊on/off>200 at 14.1 T/600 MHz/395 GHz with build-up times of 3.8 s using a standard homogenous solution. The methodology described herein was used to show how the conformation of the spirocyclic rings flanking the nitroxide function in the recently described c- and o-HydrOPol affects the distance between the g-tensors and thereby polarization performance.
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Affiliation(s)
- Frédéric Mentink-Vigier
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr, Tallahassee, FL 32310, United States.
| | - Thierry Dubroca
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr, Tallahassee, FL 32310, United States
| | - Johan Van Tol
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr, Tallahassee, FL 32310, United States
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17
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Cai X, Lucini Paioni A, Adler A, Yao R, Zhang W, Beriashvili D, Safeer A, Gurinov A, Rockenbauer A, Song Y, Baldus M, Liu Y. Highly Efficient Trityl-Nitroxide Biradicals for Biomolecular High-Field Dynamic Nuclear Polarization. Chemistry 2021; 27:12758-12762. [PMID: 34181286 DOI: 10.1002/chem.202102253] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Indexed: 12/22/2022]
Abstract
Dynamic nuclear polarization (DNP) is a powerful method to enhance the sensitivity of solid-state magnetic nuclear resonance (ssNMR) spectroscopy. However, its biomolecular applications at high magnetic fields (preferably>14 T) have so far been limited by the intrinsically low efficiency of polarizing agents and sample preparation aspects. Herein, we report a new class of trityl-nitroxide biradicals, dubbed SNAPols that combine high DNP efficiency with greatly enhanced hydrophilicity. SNAPol-1, the best compound in the series, shows DNP enhancement factors at 18.8 T of more than 100 in small molecules and globular proteins and also exhibits strong DNP enhancements in membrane proteins and cellular preparations. By integrating optimal sensitivity and high resolution, we expect widespread applications of this new polarizing agent in high-field DNP/ssNMR spectroscopy, especially for complex biomolecules.
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Affiliation(s)
- Xinyi Cai
- The province and ministry co-sponsored collaborative innovation center for medical epigenetics Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P. R. China
| | - Alessandra Lucini Paioni
- NMR Spectroscopy group Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Agnes Adler
- NMR Spectroscopy group Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Ru Yao
- The province and ministry co-sponsored collaborative innovation center for medical epigenetics Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P. R. China
| | - Wenxiao Zhang
- The province and ministry co-sponsored collaborative innovation center for medical epigenetics Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P. R. China
| | - David Beriashvili
- NMR Spectroscopy group Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Adil Safeer
- NMR Spectroscopy group Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Andrei Gurinov
- NMR Spectroscopy group Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Antal Rockenbauer
- Institute of Materials and Environmental Chemistry Hungarian Academy of Sciences and Department of Physics, Budapest University of Technology and Economics Budafoki ut 8, 1111, Budapest, Hungary
| | - Yuguang Song
- The province and ministry co-sponsored collaborative innovation center for medical epigenetics Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P. R. China
| | - Marc Baldus
- NMR Spectroscopy group Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Yangping Liu
- The province and ministry co-sponsored collaborative innovation center for medical epigenetics Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P. R. China
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18
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Pell AJ. A method to calculate the NMR spectra of paramagnetic species using thermalized electronic relaxation. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 326:106939. [PMID: 33744830 DOI: 10.1016/j.jmr.2021.106939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 06/12/2023]
Abstract
For paramagnetic species, it has been long understood that the hyperfine interaction between the unpaired electrons and the nucleus results in a nuclear magnetic resonance (NMR) peak that is shifted by a paramagnetic shift, rather than split by the coupling, due to an averaging of the electronic magnetic moment caused by electronic relaxation that is fast in comparison to the hyperfine coupling constant. However, although this feature of paramagnetic NMR has formed the basis of all theories of the paramagnetic shift, the precise theory and mechanism of the electronic relaxation required to predict this result has never been discussed, nor has the assertion been tested. In this paper, we show that the standard semi-classical Redfield theory of relaxation fails to predict a paramagnetic shift, as does any attempt to correct for the semi-classical theory using modifications such as the inhomogeneous master equation or Levitt-di Bari thermalization. In fact, only the recently-introduced Lindbladian theory of relaxation in magnetic resonance [J.Magn.Reson., 310, 106645 (2019)] is able to correctly predict the paramagnetic shift tensor and relaxation-induced linewidth in pNMR. Furthermore, this new formalism is able to predict the NMR spectra of paramagnetic species outside the high-temperature and weak-order limits, and is therefore also applicable to dynamic nuclear polarization. The formalism is tested by simulations of five case studies, which include Fermi-contact and spin-dipolar hyperfine couplings, g-anisotropy, zero-field splitting, high and low temperatures, and fast and slow electronic relaxation.
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Affiliation(s)
- Andrew J Pell
- Department of Materials and Environmental Chemistry, Stockholm University, Svänte Arrhenius väg 16 C, 106 91 Stockholm, Sweden; Centre de RMN Trés Hauts Champs de Lyon (UMR5082 CNRS/ENS-Lyon/Université Claude Bernard Lyon 1), Université de Lyon, 5 rue de la Doua, 69100 Villeurbanne, France.
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19
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Gauto D, Dakhlaoui O, Marin-Montesinos I, Hediger S, De Paëpe G. Targeted DNP for biomolecular solid-state NMR. Chem Sci 2021; 12:6223-6237. [PMID: 34084422 PMCID: PMC8115112 DOI: 10.1039/d0sc06959k] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/18/2021] [Indexed: 12/23/2022] Open
Abstract
High-field dynamic nuclear polarization is revolutionizing the scope of solid-state NMR with new applications in surface chemistry, materials science and structural biology. In this perspective article, we focus on a specific DNP approach, called targeted DNP, in which the paramagnets introduced to polarize are not uniformly distributed in the sample but site-specifically located on the biomolecular system. After reviewing the various targeting strategies reported to date, including a bio-orthogonal chemistry-based approach, we discuss the potential of targeted DNP to improve the overall NMR sensitivity while avoiding the use of glass-forming DNP matrix. This is especially relevant to the study of diluted biomolecular systems such as, for instance, membrane proteins within their lipidic environment. We also discuss routes towards extracting structural information from paramagnetic relaxation enhancement (PRE) induced by targeted DNP at cryogenic temperature, and the possibility to recover site-specific information in the vicinity of the paramagnetic moieties using high-resolution selective DNP spectra. Finally, we review the potential of targeted DNP for in-cell NMR studies and how it can be used to extract a given protein NMR signal from a complex cellular background.
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Affiliation(s)
- Diego Gauto
- Univ. Grenoble Alpes, CEA, CNRS, IRIG-MEM Grenoble France
| | - Ons Dakhlaoui
- Univ. Grenoble Alpes, CEA, CNRS, IRIG-MEM Grenoble France
- Univ. Grenoble Alpes, CNRS, CERMAV Grenoble France
| | - Ildefonso Marin-Montesinos
- Univ. Grenoble Alpes, CEA, CNRS, IRIG-MEM Grenoble France
- University of Aveiro, CICECO Chem. Dept. Aveiro Portugal
| | - Sabine Hediger
- Univ. Grenoble Alpes, CEA, CNRS, IRIG-MEM Grenoble France
| | - Gaël De Paëpe
- Univ. Grenoble Alpes, CEA, CNRS, IRIG-MEM Grenoble France
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20
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Gurská M, Brezová V, Šalitroš I, Švorc Ľ, Špánik I, Moncoľ J, Pavlik J, Szolcsányi P. Polyradical PROXYL/TEMPO Conjugates Connected by Ester/Amide Bridges: Synthesis, Physicochemical Studies, and DFT Calculations. Chempluschem 2021; 86:396-405. [PMID: 33645915 DOI: 10.1002/cplu.202000803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/11/2021] [Indexed: 12/16/2022]
Abstract
A series of di-/trinitroxide esters and amides featuring PROXYL and/or TEMPO radicals connected with alicyclic bridges were prepared in 61-92 % yields and their properties were analysed by using multiple experimental techniques. The examination of EPR spectra of radicals in organic solvents augmented with DFT calculations brought valuable information on the conformational dynamics and spin exchange mechanisms. Cyclic voltammetry investigations revealed (quasi)reversible electrochemical behaviour of studied nitroxides with their half-wave potentials ranging from -51 to -17 mV. SQUID measurements of selected radicals revealed that the magnetism of di- and trinitroxides is significantly different, since antiferromagnetic coupling in biradicals is notably larger than in triradicals. The single-crystal X-ray analysis of selected biradicals revealed the existence of 3D supramolecular networks of molecules linked through hydrogen-bonding interactions. These polynitroxide radicals can serve as promising bridging or chelating ligands in the synthesis of transition-metal-based molecular magnets.
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Affiliation(s)
- Mária Gurská
- Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37, Bratislava, Slovak Republic.,Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 41, Bratislava, Slovak Republic
| | - Vlasta Brezová
- Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37, Bratislava, Slovak Republic
| | - Ivan Šalitroš
- Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37, Bratislava, Slovak Republic.,Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 771 46, Olomouc, Czech Republic.,Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200, Brno, Czech Republic
| | - Ľubomír Švorc
- Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37, Bratislava, Slovak Republic.,Department of Chemistry, Faculty of Natural Sciences, Matej Bel University, Tajovského 40, SK-974 00, Banská Bystrica, Slovak Republic
| | - Ivan Špánik
- Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37, Bratislava, Slovak Republic
| | - Ján Moncoľ
- Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37, Bratislava, Slovak Republic
| | - Ján Pavlik
- Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37, Bratislava, Slovak Republic
| | - Peter Szolcsányi
- Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37, Bratislava, Slovak Republic
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21
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Zaytseva EV, Mazhukin DG. Spirocyclic Nitroxides as Versatile Tools in Modern Natural Sciences: From Synthesis to Applications. Part I. Old and New Synthetic Approaches to Spirocyclic Nitroxyl Radicals. Molecules 2021; 26:677. [PMID: 33525514 PMCID: PMC7865516 DOI: 10.3390/molecules26030677] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/19/2021] [Accepted: 01/25/2021] [Indexed: 12/19/2022] Open
Abstract
Spirocyclic nitroxyl radicals (SNRs) are stable paramagnetics bearing spiro-junction at a-, b-, or g-carbon atom of the nitroxide fragment, which is part of the heterocyclic system. Despite the fact that the first representatives of SNRs were obtained about 50 years ago, the methodology of their synthesis and their usage in chemistry and biochemical applications have begun to develop rapidly only in the last two decades. Due to the presence of spiro-function in the SNRs molecules, the latter have increased stability to various reducing agents (including biogenic ones), while the structures of the biradicals (SNBRs) comprises a rigid spiro-fused core that fixes mutual position and orientation of nitroxide moieties that favors their use in dynamic nuclear polarization (DNP) experiments. This first review on SNRs will give a glance at various strategies for the synthesis of spiro-substituted, mono-, and bis-nitroxides on the base of six-membered (piperidine, 1,2,3,4-tetrahydroquinoline, 9,9'(10H,10H')-spirobiacridine, piperazine, and morpholine) or five-membered (2,5-dihydro-1H-pyrrole, pyrrolidine, 2,5-dihydro-1H-imidazole, 4,5-dihydro-1H-imidazole, imidazolidine, and oxazolidine) heterocyclic cores.
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Affiliation(s)
| | - Dmitrii G. Mazhukin
- Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia;
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22
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Zhai W, Lucini Paioni A, Cai X, Narasimhan S, Medeiros-Silva J, Zhang W, Rockenbauer A, Weingarth M, Song Y, Baldus M, Liu Y. Postmodification via Thiol-Click Chemistry Yields Hydrophilic Trityl-Nitroxide Biradicals for Biomolecular High-Field Dynamic Nuclear Polarization. J Phys Chem B 2020; 124:9047-9060. [PMID: 32961049 DOI: 10.1021/acs.jpcb.0c08321] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Dynamic nuclear polarization (DNP) is a powerful method to enhance nuclear magnetic resonance (NMR) signal intensities, enabling unprecedented applications in life and material science. An ultimate goal is to expand the use of DNP-enhanced solid-state NMR to ultrahigh magnetic fields where optimal spectral resolution and sensitivity are integrated. Trityl-nitroxide (TN) biradicals have attracted significant interest in high-field DNP, but their application to complex (bio)molecules has so far been limited. Here we report a novel postmodification strategy for synthesis of hydrophilic TN biradicals in order to improve their use in biomolecular applications. Initially, three TN biradicals (referred to as NATriPols 1-3) with amino-acid linkers were synthesized. EPR studies showed that the α-position of the amino-acid linkers is an ideal modification site for these biradicals since their electron-electron magnetic interactions are marginally affected by the substituents at this position. On the basis of this finding, we synthesized NATriPol-4 with pyridine disulfide appended at the α-position. Postmodification of NATriPol-4 via thiol-click chemistry resulted in various TN biradicals including hydrophilic NATriPol-5 in a quantitative manner. Interestingly, DNP enhancements at 18.8 T of NATriPols for 13C,15N-proline in a glycerol/water matrix are inversely correlated with their hydrophobicity. Importantly, applications of hydrophilic NATriPol-5 and NATriPol-3 to biomolecules including a globular soluble protein and a membrane targeting peptide reveal significantly improved performance compared to TEMTriPol-1 and AMUPol. Our work provides an efficient approach for one-step synthesis of new polarizing agents with tunable physicochemical properties, thus expediting optimization of new biradicals for biomolecular applications at ultrahigh magnetic fields.
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Affiliation(s)
- Weixiang Zhai
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Alessandra Lucini Paioni
- NMR Spectroscopy, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Xinyi Cai
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Siddarth Narasimhan
- NMR Spectroscopy, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - João Medeiros-Silva
- NMR Spectroscopy, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Wenxiao Zhang
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Antal Rockenbauer
- Institute of Materials and Environmental Chemistry, Hungarian Academy of Sciences, and Department of Physics, Budapest University of Technology and Economics, Budafokiut 8, 1111 Budapest, Hungary
| | - Markus Weingarth
- NMR Spectroscopy, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Yuguang Song
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Marc Baldus
- NMR Spectroscopy, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Yangping Liu
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
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23
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Stevanato G, Casano G, Kubicki DJ, Rao Y, Esteban Hofer L, Menzildjian G, Karoui H, Siri D, Cordova M, Yulikov M, Jeschke G, Lelli M, Lesage A, Ouari O, Emsley L. Open and Closed Radicals: Local Geometry around Unpaired Electrons Governs Magic-Angle Spinning Dynamic Nuclear Polarization Performance. J Am Chem Soc 2020; 142:16587-16599. [PMID: 32806886 DOI: 10.1021/jacs.0c04911] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The development of magic-angle spinning dynamic nuclear polarization (MAS DNP) has allowed atomic-level characterization of materials for which conventional solid-state NMR is impractical due to the lack of sensitivity. The rapid progress of MAS DNP has been largely enabled through the understanding of rational design concepts for more efficient polarizing agents (PAs). Here, we identify a new design principle which has so far been overlooked. We find that the local geometry around the unpaired electron can change the DNP enhancement by an order of magnitude for two otherwise identical conformers. We present a set of 13 new stable mono- and dinitroxide PAs for MAS DNP NMR where this principle is demonstrated. The radicals are divided into two groups of isomers, named open (O-) and closed (C-), based on the ring conformations in the vicinity of the N-O bond. In all cases, the open conformers exhibit dramatically improved DNP performance as compared to the closed counterparts. In particular, a new urea-based biradical named HydrOPol and a mononitroxide O-MbPyTol yield enhancements of 330 ± 60 and 119 ± 25, respectively, at 9.4 T and 100 K, which are the highest enhancements reported so far in the aqueous solvents used here. We find that while the conformational changes do not significantly affect electron spin-spin distances, they do affect the distribution of the exchange couplings in these biradicals. Electron spin echo envelope modulation (ESEEM) experiments suggest that the improved performance of the open conformers is correlated with higher solvent accessibility.
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Affiliation(s)
- Gabriele Stevanato
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Gilles Casano
- Aix Marseille Université, CNRS, ICR UMR 7273, 13013 Marseille, France
| | - Dominik J Kubicki
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Yu Rao
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Laura Esteban Hofer
- Department of Chemistry, Laboratory of Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Georges Menzildjian
- Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS de Lyon/UCB-Lyon 1), 69100 Villeurbanne, France
| | - Hakim Karoui
- Aix Marseille Université, CNRS, ICR UMR 7273, 13013 Marseille, France
| | - Didier Siri
- Aix Marseille Université, CNRS, ICR UMR 7273, 13013 Marseille, France
| | - Manuel Cordova
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Maxim Yulikov
- Department of Chemistry, Laboratory of Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Gunnar Jeschke
- Department of Chemistry, Laboratory of Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Moreno Lelli
- Magnetic Resonance Center (CERM/CIRMMP), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
| | - Anne Lesage
- Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS de Lyon/UCB-Lyon 1), 69100 Villeurbanne, France
| | - Olivier Ouari
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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24
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Tran NT, Mentink-Vigier F, Long JR. Dynamic Nuclear Polarization of Biomembrane Assemblies. Biomolecules 2020; 10:E1246. [PMID: 32867275 PMCID: PMC7565305 DOI: 10.3390/biom10091246] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/10/2020] [Accepted: 08/11/2020] [Indexed: 01/02/2023] Open
Abstract
While atomic scale structural and dynamic information are hallmarks of nuclear magnetic resonance (NMR) methodologies, sensitivity is a fundamental limitation in NMR studies. Fully exploiting NMR capabilities to study membrane proteins is further hampered by their dilution within biological membranes. Recent developments in dynamic nuclear polarization (DNP), which can transfer the relatively high polarization of unpaired electrons to nuclear spins, show promise for overcoming the sensitivity bottleneck and enabling NMR characterization of membrane proteins under native-like conditions. Here we discuss fundamental aspects of DNP-enhanced solid-state NMR spectroscopy, experimental details relevant to the study of lipid assemblies and incorporated proteins, and sensitivity gains which can be realized in biomembrane-based samples. We also present unique insights which can be gained from DNP measurements and prospects for further development of the technique for elucidating structures and orientations of membrane proteins in native lipid environments.
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Affiliation(s)
- Nhi T. Tran
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA;
| | - Frédéric Mentink-Vigier
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA;
| | - Joanna R. Long
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA;
- Department of Biochemistry & Molecular Biology and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
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25
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Lund A, Casano G, Menzildjian G, Kaushik M, Stevanato G, Yulikov M, Jabbour R, Wisser D, Renom-Carrasco M, Thieuleux C, Bernada F, Karoui H, Siri D, Rosay M, Sergeyev IV, Gajan D, Lelli M, Emsley L, Ouari O, Lesage A. TinyPols: a family of water-soluble binitroxides tailored for dynamic nuclear polarization enhanced NMR spectroscopy at 18.8 and 21.1 T. Chem Sci 2020; 11:2810-2818. [PMID: 34084341 PMCID: PMC8157490 DOI: 10.1039/c9sc05384k] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 01/31/2020] [Indexed: 11/21/2022] Open
Abstract
Dynamic Nuclear Polarization (DNP) has recently emerged as a key method to increase the sensitivity of solid-state NMR spectroscopy under Magic Angle Spinning (MAS). While efficient binitroxide polarizing agents such as AMUPol have been developed for MAS DNP NMR at magnetic fields up to 9.4 T, their performance drops rapidly at higher fields due to the unfavorable field dependence of the cross-effect (CE) mechanism and AMUPol-like radicals were so far disregarded in the context of the development of polarizing agents for very high-field DNP. Here, we introduce a new family of water-soluble binitroxides, dubbed TinyPols, which have a three-bond non-conjugated flexible amine linker allowing sizable couplings between the two unpaired electrons. We show that this adjustment of the linker is crucial and leads to unexpectedly high DNP enhancement factors at 18.8 T and 21.1 T: an improvement of about a factor 2 compared to AMUPol is reported for spinning frequencies ranging from 5 to 40 kHz, with ε H of up to 90 at 18.8 T and 38 at 21.1 T for the best radical in this series, which are the highest MAS DNP enhancements measured so far in aqueous solutions at these magnetic fields. This work not only breathes a new momentum into the design of binitroxides tailored towards high magnetic fields, but also is expected to push the application frontiers of high-resolution DNP MAS NMR, as demonstrated here on a hybrid mesostructured silica material.
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Affiliation(s)
- Alicia Lund
- Centre de RMN à; Très Hauts Champs, Université; de Lyon (CNRS/ENS Lyon/UCB Lyon 1) 69100 Villeurbanne France
| | | | - Georges Menzildjian
- Centre de RMN à; Très Hauts Champs, Université; de Lyon (CNRS/ENS Lyon/UCB Lyon 1) 69100 Villeurbanne France
| | - Monu Kaushik
- Centre de RMN à; Très Hauts Champs, Université; de Lyon (CNRS/ENS Lyon/UCB Lyon 1) 69100 Villeurbanne France
| | - Gabriele Stevanato
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) CH-1015 Lausanne Switzerland
| | - Maxim Yulikov
- Department of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule Zürich CH-8093 Zürich Switzerland
| | - Ribal Jabbour
- Centre de RMN à; Très Hauts Champs, Université; de Lyon (CNRS/ENS Lyon/UCB Lyon 1) 69100 Villeurbanne France
| | - Dorothea Wisser
- Centre de RMN à; Très Hauts Champs, Université; de Lyon (CNRS/ENS Lyon/UCB Lyon 1) 69100 Villeurbanne France
| | - Marc Renom-Carrasco
- Institute of Chemistry of Lyon, Laboratory C2P2 UMR 5265-CNRS-University Lyon 1-CPE Lyon, University of Lyon 43 Bd du 11 Novembre 1918 69616 Villeurbanne France
| | - Chloé Thieuleux
- Institute of Chemistry of Lyon, Laboratory C2P2 UMR 5265-CNRS-University Lyon 1-CPE Lyon, University of Lyon 43 Bd du 11 Novembre 1918 69616 Villeurbanne France
| | | | | | - Didier Siri
- Aix Marseille Univ, CNRS, ICR Marseille France
| | - Melanie Rosay
- Bruker Biospin Corporation 15 Fortune Drive Billerica Massachusetts 01821 USA
| | - Ivan V Sergeyev
- Bruker Biospin Corporation 15 Fortune Drive Billerica Massachusetts 01821 USA
| | - David Gajan
- Centre de RMN à; Très Hauts Champs, Université; de Lyon (CNRS/ENS Lyon/UCB Lyon 1) 69100 Villeurbanne France
| | - Moreno Lelli
- Center of Magnetic Resonance (CERM), University of Florence Via Luigi Sacconi 6 50019 Sesto Fiorentino Italy
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) CH-1015 Lausanne Switzerland
| | | | - Anne Lesage
- Centre de RMN à; Très Hauts Champs, Université; de Lyon (CNRS/ENS Lyon/UCB Lyon 1) 69100 Villeurbanne France
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26
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Yau WM, Jeon J, Tycko R. Succinyl-DOTOPA: An effective triradical dopant for low-temperature dynamic nuclear polarization with high solubility in aqueous solvent mixtures at neutral pH. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 311:106672. [PMID: 31887554 PMCID: PMC6964257 DOI: 10.1016/j.jmr.2019.106672] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 12/10/2019] [Accepted: 12/18/2019] [Indexed: 05/05/2023]
Abstract
We report the synthesis of the nitroxide-based triradical compound succinyl-DOTOPA and the characterization of its performance as a dopant for dynamic nuclear polarization (DNP) experiments in frozen solutions at low temperatures. Compared with previously described DOTOPA derivatives, succinyl-DOTOPA has substantially greater solubility in glycerol/water mixtures with pH > 4 and therefore has wider applicability. Solid state nuclear magnetic resonance (ssNMR) measurements at 9.39 T and 25 K, with magic-angle spinning at 7.00 kHz, show that build-up times of DNP-enhanced, cross-polarized 13C ssNMR signals are shorter and that signal amplitudes are larger for glycerol/water solutions of L-proline containing succinyl-DOTOPA than for solutions containing the biradical AMUPol, with electron spin concentrations of 15 mM or 30 mM, resulting in greater net sensitivity gains from DNP. In similar measurements at 90 K, AMUPol yields greater net sensitivity, apparently due to its longer electron spin-lattice and spin-spin relaxation times. One- and two-dimensional 13C ssNMR measurements at 25 K on the complex of the 27-residue peptide M13 with the calcium-sensing protein calmodulin, in glycerol/water with 10 mM succinyl-DOTOPA, demonstrate the utility of this compound in DNP-enhanced ssNMR studies of biomolecular systems.
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Affiliation(s)
- Wai-Ming Yau
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | - Jaekyun Jeon
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA.
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27
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Mentink-Vigier F. Optimizing nitroxide biradicals for cross-effect MAS-DNP: the role of g-tensors' distance. Phys Chem Chem Phys 2020; 22:3643-3652. [PMID: 31998899 DOI: 10.1039/c9cp06201g] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nitroxide biradicals are common polarizing agents used to enhance the sensitivity of solid-state NMR experiments via Magic Angle Spinning Dynamic Nuclear Polarization (MAS-DNP). These biradicals are used to increase the polarization of protons through the cross-effect mechanism, which requires two unpaired electrons with a Larmor frequency difference greater than that of the protons. From their early conception, the relative orientation of the nitroxide rings has been identified as a critical factor determining their MAS-DNP performance. However, the MAS leads to a complex DNP mechanism with time dependent energy level anti-crossings making it difficult to pinpoint the role of relative g-tensor orientation. In this article, a single parameter called "g-tensors' distance" is introduced to characterize the relative orientation's impact on the MAS-DNP field profiles. It is demonstrated for the first time how the g-tensors' distance determines the nuclear hyperpolarization and depolarization properties of a given biradical. This provides a new critical parameter that paves the way for more efficient bis-nitroxides for MAS-DNP.
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Affiliation(s)
- Frédéric Mentink-Vigier
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr, Tallahassee, FL 32310, USA.
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28
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Kocman V, Di Mauro GM, Veglia G, Ramamoorthy A. Use of paramagnetic systems to speed-up NMR data acquisition and for structural and dynamic studies. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2019; 102:36-46. [PMID: 31325686 PMCID: PMC6698407 DOI: 10.1016/j.ssnmr.2019.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/10/2019] [Accepted: 07/11/2019] [Indexed: 05/05/2023]
Abstract
NMR spectroscopy is a powerful experimental technique to study biological systems at the atomic resolution. However, its intrinsic low sensitivity results in long acquisition times that in extreme cases lasts for days (or even weeks) often exceeding the lifetime of the sample under investigation. Different paramagnetic agents have been used in an effort to decrease the spin-lattice (T1) relaxation times of the studied nuclei, which are the main cause for long acquisition times necessary for signal averaging to enhance the signal-to-noise ratio of NMR spectra. Consequently, most of the experimental time is "wasted" in waiting for the magnetization to recover between successive scans. In this review, we discuss how to set up an optimal paramagnetic relaxation enhancement (PRE) system to effectively reduce the T1 relaxation times avoiding significant broadening of NMR signals. Additionally, we describe how PRE-agents can be used to provide structural and dynamic information and can even be used to follow the intermediates of chemical reactions and to speed-up data acquisition. We also describe the unique challenges and benefits associated with the application of PRE to solid-state NMR spectroscopy, explaining how the use of PREs is more complex for membrane mimetic systems as PREs can also be exploited to change the alignment of oriented membrane systems. Functionalization of membrane mimetics, such as bicelles, can provide a controlled region of paramagnetic effect that has the potential, together with the desired alignment, to provide crucial biologically relevant structural information. And finally, we discuss how paramagnetic metals can be utilized to further increase the dynamic nuclear polarization (DNP) effects and how to preserve the enhancements when dissolution DNP is implemented.
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Affiliation(s)
- Vojč Kocman
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA; Biophysics, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI, USA
| | | | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA; Biophysics, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI, USA.
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29
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Tagami K, Equbal A, Kaminker I, Kirtman B, Han S. Biradical rotamer states tune electron J coupling and MAS dynamic nuclear polarization enhancement. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2019; 101:12-20. [PMID: 31075525 DOI: 10.1016/j.ssnmr.2019.04.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/30/2019] [Accepted: 04/09/2019] [Indexed: 05/13/2023]
Abstract
Cross Effect (CE) Dynamic Nuclear Polarization (DNP) relies on the dipolar (D) and exchange (J) coupling interaction between two electron spins. Until recently only the electron spin D coupling was explicitly included in quantifying the DNP mechanism. Recent literature discusses the potential role of J coupling in DNP, but does not provide an account of the distribution and source of electron spin J coupling of commonly used biradicals in DNP. In this study, we quantified the distribution of electron spin J coupling in AMUPol and TOTAPol biradicals using a combination of continuous wave (CW) X-band electron paramagnetic resonance (EPR) lineshape analysis in a series of solvents and at variable temperatures in solution - a state to be vitrified for DNP. We found that both radicals show a temperature dependent distribution of J couplings, and the source of this distribution to be conformational dynamics. To qualify this conformational dependence of J coupling in both molecules we carry out Broken Symmetry DFT calculations which show that the biradical rotamer distribution can account for a large distribution of J couplings, with the magnitude of J coupling directly depending on the relative orientation of the electron spin pair. We demonstrate that the electron spin J couplings in both AMUPol and TOTAPol span a much wider distribution than suggested in the literature. We affirm the importance of electron spin J coupling for DNP with density matrix simulations of DNP in Liouville space and under magic angle spinning, showcasing that a rotamer with high J coupling and optimum relative g-tensor orientation can significantly boost the DNP performance compared to random orientations of the electron spin pair. We conclude that moderate electron spin J coupling above a threshold value can facilitate DNP enhancements.
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Affiliation(s)
- Kan Tagami
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, United States
| | - Asif Equbal
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, United States
| | - Ilia Kaminker
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, United States
| | - Bernard Kirtman
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, United States
| | - Songi Han
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, United States; Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, United States.
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30
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Ha M, Thiessen AN, Sergeyev IV, Veinot JGC, Michaelis VK. Endogenous dynamic nuclear polarization NMR of hydride-terminated silicon nanoparticles. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2019; 100:77-84. [PMID: 31015058 DOI: 10.1016/j.ssnmr.2019.04.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 04/09/2019] [Accepted: 04/09/2019] [Indexed: 06/09/2023]
Abstract
Silicon nanoparticles (SiNPs) are intriguing materials and their properties fascinate the broader scientific community; they are also attractive to the biological and materials science sub-disciplines because of their established biological and environmental compatibility, as well as their far-reaching practical applications. While characterization of the particle nanostructure can be performed using 29Si solid-state nuclear magnetic resonance (NMR) spectroscopy, poor sensitivity due to low Boltzmann population and long acquisition times hinder in-depth studies of these potentially game-changing materials. In this study, we compare two dynamic nuclear polarization (DNP) NMR protocols to boost 29Si sensitivity in hydride-terminated SiNPs. First, we assess a traditional indirect DNP approach, where a nitroxide biradical (AMUPol or bCTbk) is incorporated into a glassing agent and transferred through protons (e- → 1H → 29Si) to enhance the silicon. In this mode, electron paramagnetic resonance (EPR) spectroscopy demonstrated that the hydride-terminated surface was highly reactive with the exogenous biradicals, thus decomposing the radicals within hours and resulting in an enhancement factor, ε, of 3 (TB = 15 s) for the 64 nm SiNP, revealing the surface components. Secondly, direct DNP NMR methods were used to enhance the silicon without the addition of an exogenous radical (i.e., use of dangling bonds as an endogenous radical source). With radical concentrations <1 mM, 29Si enhancements were obtained for the series of SiNPs ranging from 3 to 64 nm. The ability to use direct 29Si DNP transfer (e- → 29Si) shows promise for DNP studies of these inorganic nanomaterials (ε = 6 (TB = 79 min) for 64 nm SiNPs) with highly reactive surfaces, showing the sub-surface and core features. These preliminary findings lay a foundation for future endogenous radical development through tailoring the surface chemistry, targeting further sensitivity gains.
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Affiliation(s)
- Michelle Ha
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | | | - Ivan V Sergeyev
- Bruker-Biospin Corporation, 15 Fortune Drive, Billerica, MA, 01821, USA
| | - Jonathan G C Veinot
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada.
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31
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Wang X, Caulkins BG, Riviere G, Mueller LJ, Mentink-Vigier F, Long JR. Direct dynamic nuclear polarization of 15N and 13C spins at 14.1 T using a trityl radical and magic angle spinning. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2019; 100:85-91. [PMID: 31026722 PMCID: PMC6604067 DOI: 10.1016/j.ssnmr.2019.03.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/27/2019] [Accepted: 03/28/2019] [Indexed: 05/05/2023]
Abstract
We investigate solid-state dynamic nuclear polarization of 13C and 15N nuclei using monoradical trityl OX063 as a polarizing agent in a magnetic field of 14.1 T with magic angle spinning at ∼100 K. We monitored the field dependence of direct 13C and 15N polarization for frozen [13C, 15N] urea and achieved maximum absolute enhancement factors of 240 and 470, respectively. The field profiles are consistent with polarization of 15N spins via either the solid effect or the cross effect, and polarization of 13C spins via a combination of cross effect and solid effect. For microcrystalline, 15N-enriched tryptophan synthase sample containing trityl radical, a 1500-fold increase in 15N signal was observed under microwave irradiation. These results show the promise of trityl radicals and their derivatives for direct polarization of low gamma, spin-½ nuclei at high magnetic fields and suggest a novel approach for selectively polarizing specific moieties or for polarizing systems which have low levels of protonation.
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Affiliation(s)
- Xiaoling Wang
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA
| | - Bethany G Caulkins
- Department of Chemistry, University of California Riverside, Riverside, CA, 92521, USA
| | - Gwladys Riviere
- Department of Biochemistry and Molecular Biology, McKnight Brain Institute and National High Magnetic Field Laboratory, University of Florida, Gainesville, FL, 32610-0245, USA
| | - Leonard J Mueller
- Department of Chemistry, University of California Riverside, Riverside, CA, 92521, USA
| | - Frederic Mentink-Vigier
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA
| | - Joanna R Long
- Department of Biochemistry and Molecular Biology, McKnight Brain Institute and National High Magnetic Field Laboratory, University of Florida, Gainesville, FL, 32610-0245, USA.
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32
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Pell AJ, Pintacuda G, Grey CP. Paramagnetic NMR in solution and the solid state. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 111:1-271. [PMID: 31146806 DOI: 10.1016/j.pnmrs.2018.05.001] [Citation(s) in RCA: 215] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 05/11/2018] [Accepted: 05/12/2018] [Indexed: 05/22/2023]
Abstract
The field of paramagnetic NMR has expanded considerably in recent years. This review addresses both the theoretical description of paramagnetic NMR, and the way in which it is currently practised. We provide a review of the theory of the NMR parameters of systems in both solution and the solid state. Here we unify the different languages used by the NMR, EPR, quantum chemistry/DFT, and magnetism communities to provide a comprehensive and coherent theoretical description. We cover the theory of the paramagnetic shift and shift anisotropy in solution both in the traditional formalism in terms of the magnetic susceptibility tensor, and using a more modern formalism employing the relevant EPR parameters, such as are used in first-principles calculations. In addition we examine the theory first in the simple non-relativistic picture, and then in the presence of spin-orbit coupling. These ideas are then extended to a description of the paramagnetic shift in periodic solids, where it is necessary to include the bulk magnetic properties, such as magnetic ordering at low temperatures. The description of the paramagnetic shift is completed by describing the current understanding of such shifts due to lanthanide and actinide ions. We then examine the paramagnetic relaxation enhancement, using a simple model employing a phenomenological picture of the electronic relaxation, and again using a more complex state-of-the-art theory which incorporates electronic relaxation explicitly. An additional important consideration in the solid state is the impact of bulk magnetic susceptibility effects on the form of the spectrum, where we include some ideas from the field of classical electrodynamics. We then continue by describing in detail the solution and solid-state NMR methods that have been deployed in the study of paramagnetic systems in chemistry, biology, and the materials sciences. Finally we describe a number of case studies in paramagnetic NMR that have been specifically chosen to highlight how the theory in part one, and the methods in part two, can be used in practice. The systems chosen include small organometallic complexes in solution, solid battery electrode materials, metalloproteins in both solution and the solid state, systems containing lanthanide ions, and multi-component materials used in pharmaceutical controlled-release formulations that have been doped with paramagnetic species to measure the component domain sizes.
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Affiliation(s)
- Andrew J Pell
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Svante Arrhenius väg 16 C, SE-106 91 Stockholm, Sweden.
| | - Guido Pintacuda
- Institut des Sciences Analytiques (CNRS UMR 5280, ENS de Lyon, UCB Lyon 1), Université de Lyon, 5 rue de la Doua, 69100 Villeurbanne, France
| | - Clare P Grey
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
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33
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Combes S, Tran KT, Ayhan MM, Karoui H, Rockenbauer A, Tonetto A, Monnier V, Charles L, Rosas R, Viel S, Siri D, Tordo P, Clair S, Wang R, Bardelang D, Ouari O. Triangular Regulation of Cucurbit[8]uril 1:1 Complexes. J Am Chem Soc 2019; 141:5897-5907. [PMID: 30808163 DOI: 10.1021/jacs.9b00150] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Triangular shapes have inspired scientists over time and are common in nature, such as the flower petals of oxalis triangularis, the triangular faces of tetrahedrite crystals, and the icosahedron faces of virus capsids. Supramolecular chemistry has enabled the construction of triangular assemblies, many of which possess functional features. Among these structures, cucurbiturils have been used to build supramolecular triangles, and we recently reported paramagnetic cucurbit[8]uril (CB[8]) triangles, but the reasons for their formation remain unclear. Several parameters have now been identified to explain their formation. At first sight, the radical nature of the guest was of prime importance in obtaining the triangles, and we focused on extending this concept to biradicals to get supramolecular hexaradicals. Two sodium ions were systematically observed by ESI-MS in trimer structures, and the presence of Na+ triggered or strengthened the triangulation of CB[8]/guest 1:1 complexes in solution. X-ray crystallography and molecular modeling have allowed the proposal of two plausible sites of residence for the two sodium cations. We then found that a diamagnetic guest with an H-bond acceptor function is equally good at forming CB[8] triangles. Hence, a guest molecule containing a ketone function has been precisely triangulated thanks to CB[8] and sodium cations as determined by DOSY-NMR and DLS. A binding constant for the triangulation of 1:1 to 3:3 complexes is proposed. This concept has finally been extended to the triangulation of ditopic guests toward network formation by the reticulation of CB[8] triangles using dinitroxide biradicals.
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Affiliation(s)
- Sébastien Combes
- Aix Marseille Univ , CNRS, ICR , Marseille , France.,Centre de Recherche en Cancérologie de Marseille (CRCM), CNRS UMR7258, Inserm U1068, Institut Paoli-Calmettes , Aix Marseille Univ, UM105 , 13009 Marseille , France
| | | | - Mehmet Menaf Ayhan
- Aix Marseille Univ , CNRS, ICR , Marseille , France.,Department of Chemistry , Gebze Technical University , P.K.141 , 41400 Gebze , Kocaeli , Turkey
| | - Hakim Karoui
- Aix Marseille Univ , CNRS, ICR , Marseille , France
| | - Antal Rockenbauer
- Institute of Materials and Environmental Chemistry , Hungarian Academy of Sciences , P.O. Box. 286, 1519 Budapest , Hungary.,Department of Physics , Budapest University of Technology and Economics , 1111 Budapest , Hungary
| | - Alain Tonetto
- Aix Marseille Univ , CNRS, Centrale Marseille, FSCM (FR1739), PRATIM , F-13397 Marseille , France
| | - Valérie Monnier
- Aix Marseille Univ , CNRS, Centrale Marseille, FSCM, Spectropole , Marseille , France
| | | | - Roselyne Rosas
- Aix Marseille Univ , CNRS, Centrale Marseille, FSCM, Spectropole , Marseille , France
| | - Stéphane Viel
- Aix Marseille Univ , CNRS, ICR , Marseille , France.,Institut Universitaire de France , F-75005 Paris , France
| | - Didier Siri
- Aix Marseille Univ , CNRS, ICR , Marseille , France
| | - Paul Tordo
- Aix Marseille Univ , CNRS, ICR , Marseille , France
| | - Sylvain Clair
- Aix Marseille Univ, University of Toulon , CNRS, IM2NP, Marseille , France
| | - Ruibing Wang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences , University of Macau , Taipa , Macau , China
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34
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Equbal A, Leavesley A, Jain SK, Han S. Cross-Effect Dynamic Nuclear Polarization Explained: Polarization, Depolarization, and Oversaturation. J Phys Chem Lett 2019; 10:548-558. [PMID: 30645130 DOI: 10.1021/acs.jpclett.8b02834] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The scope of this Perspective is to analytically describe NMR hyperpolarization by the three-spin cross effect (CE) dynamic nuclear polarization (DNP) using an effective Hamiltonian concept. We apply, for the first time, the bimodal operator-based Floquet theory in the Zeeman-interaction frame for two and three coupled spins to derive the known interaction Hamiltonian for CE-DNP. With a unified understanding of CE-DNP, and supported by empirical observation of the state of electron spin polarization under the given experimental conditions, we explain diverse manifestations of CE from oversaturation, enhanced hyperpolarization by broad-band saturation, to nuclear spin depolarization under magic-angle spinning.
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Affiliation(s)
- Asif Equbal
- Department of Chemistry and Biochemistry , University of California, Santa Barbara , Santa Barbara , California 93106 , United States
| | - Alisa Leavesley
- Department of Chemistry and Biochemistry , University of California, Santa Barbara , Santa Barbara , California 93106 , United States
| | - Sheetal Kumar Jain
- Department of Chemistry and Biochemistry , University of California, Santa Barbara , Santa Barbara , California 93106 , United States
| | - Songi Han
- Department of Chemistry and Biochemistry , University of California, Santa Barbara , Santa Barbara , California 93106 , United States
- Department of Chemical Engineering , University of California, Santa Barbara , Santa Barbara , California 93106 , United States
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35
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Lacabanne D, Fogeron ML, Wiegand T, Cadalbert R, Meier BH, Böckmann A. Protein sample preparation for solid-state NMR investigations. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 110:20-33. [PMID: 30803692 DOI: 10.1016/j.pnmrs.2019.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/11/2019] [Accepted: 01/12/2019] [Indexed: 06/09/2023]
Abstract
Preparation of a protein sample for solid-state NMR is in many aspects similar to solution-state NMR approaches, mainly with respect to the need for stable isotope labeling. But the possibility of using solid-state NMR to investigate membrane proteins in (native) lipids adds the important requirement of adapted membrane-reconstitution schemes. Also, dynamic nuclear polarization and paramagnetic NMR in solids need specific schemes using metal ions and radicals. Sample sedimentation has enabled structural investigations of objects inaccessible to other structural techniques, but rotor filling using sedimentation has become increasingly complex with smaller and smaller rotors, as needed for higher and higher magic-angle spinning (MAS) frequencies. Furthermore, solid-state NMR can investigate very large proteins and their complexes without the concomitant increase in line widths, motivating the use of selective labeling and unlabeling strategies, as well as segmental labeling, to decongest spectra. The possibility of investigating sub-milligram amounts of protein today using advanced fast MAS techniques enables alternative protein synthesis schemes such as cell-free expression. Here we review these specific aspects of solid-state NMR sample preparation.
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Affiliation(s)
- Denis Lacabanne
- Molecular Microbiology and Structural Biochemistry, Labex Ecofect, UMR 5086 CNRS/Université de Lyon, 69367 Lyon, France; Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Marie-Laure Fogeron
- Molecular Microbiology and Structural Biochemistry, Labex Ecofect, UMR 5086 CNRS/Université de Lyon, 69367 Lyon, France
| | - Thomas Wiegand
- Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | | | - Beat H Meier
- Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland.
| | - Anja Böckmann
- Molecular Microbiology and Structural Biochemistry, Labex Ecofect, UMR 5086 CNRS/Université de Lyon, 69367 Lyon, France.
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36
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Mentink-Vigier F, Barra AL, van Tol J, Hediger S, Lee D, De Paëpe G. De novo prediction of cross-effect efficiency for magic angle spinning dynamic nuclear polarization. Phys Chem Chem Phys 2019; 21:2166-2176. [PMID: 30644474 DOI: 10.1039/c8cp06819d] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Magic angle spinning dynamic nuclear polarization (MAS-DNP) has become a key approach to boost the intrinsic low sensitivity of NMR in solids. This method relies on the use of both stable radicals as polarizing agents (PAs) and suitable high frequency microwave irradiation to hyperpolarize nuclei of interest. Relating PA chemical structure to DNP efficiency has been, and is still, a long-standing problem. The complexity of the polarization transfer mechanism has so far limited the impact of analytical derivation. However, recent numerical approaches have profoundly improved the basic understanding of the phenomenon and have now evolved to a point where they can be used to help design new PAs. In this work, the potential of advanced MAS-DNP simulations combined with DFT calculations and high-field EPR to qualitatively and quantitatively predict hyperpolarization efficiency of particular PAs is analyzed. This approach is demonstrated on AMUPol and TEKPol, two widely-used bis-nitroxide PAs. The results notably highlight how the PA structure and EPR characteristics affect the detailed shape of the DNP field profile. We also show that refined simulations of this profile using the orientation dependency of the electron spin-lattice relaxation times can be used to estimate the microwave B1 field experienced by the sample. Finally, we show how modelling the nuclear spin-lattice relaxation times of close and bulk nuclei while accounting for PA concentration allows for a prediction of DNP enhancement factors and hyperpolarization build-up times.
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37
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Kiryutin AS, Rodin BA, Yurkovskaya AV, Ivanov KL, Kurzbach D, Jannin S, Guarin D, Abergel D, Bodenhausen G. Transport of hyperpolarized samples in dissolution-DNP experiments. Phys Chem Chem Phys 2019; 21:13696-13705. [DOI: 10.1039/c9cp02600b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The magnetic field strength during sample transfer in dissolution dynamic nuclear polarization influences the resulting spectra.
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Affiliation(s)
- Alexey S. Kiryutin
- International Tomography Center SB RAS
- Institutskaya 3A
- Novosibirsk
- Russia
- Novosibirsk State University
| | - Bogdan A. Rodin
- International Tomography Center SB RAS
- Institutskaya 3A
- Novosibirsk
- Russia
- Novosibirsk State University
| | - Alexandra V. Yurkovskaya
- International Tomography Center SB RAS
- Institutskaya 3A
- Novosibirsk
- Russia
- Novosibirsk State University
| | - Konstantin L. Ivanov
- International Tomography Center SB RAS
- Institutskaya 3A
- Novosibirsk
- Russia
- Novosibirsk State University
| | - Dennis Kurzbach
- University Vienna
- Faculty of Chemistry
- Institute of Biological Chemistry
- Währinger Straße 38
- 1090 Vienna
| | - Sami Jannin
- Université de Lyon
- Centre de RMN à Très Hauts Champs (FRE2034 CNRS/UCBL/ENS Lyon)
- 5 rue de la Doua
- 69100 Villeurbanne
- France
| | - David Guarin
- Laboratoire des biomolécules
- LBM, Département de chimie, École normale supérieure
- PSL University
- Sorbonne Université
- CNRS
| | - Daniel Abergel
- Laboratoire des biomolécules
- LBM, Département de chimie, École normale supérieure
- PSL University
- Sorbonne Université
- CNRS
| | - Geoffrey Bodenhausen
- Laboratoire des biomolécules
- LBM, Département de chimie, École normale supérieure
- PSL University
- Sorbonne Université
- CNRS
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38
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Leavesley A, Jain S, Kamniker I, Zhang H, Rajca S, Rajca A, Han S. Maximizing NMR signal per unit time by facilitating the e-e-n cross effect DNP rate. Phys Chem Chem Phys 2018; 20:27646-27657. [PMID: 30375593 PMCID: PMC6370975 DOI: 10.1039/c8cp04909b] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dynamic nuclear polarization (DNP) efficiency is critically dependent on the properties of the radical, solvent, and solute constituting the sample system. In this study, we focused on the three spin e-e-n cross effect (CE)'s influence on the nuclear longitudinal relaxation time constant T1n, the build-up time constants of nuclear magnetic resonance (NMR) signal, TDNP and DNP-enhancement of NMR signal. The dipolar interaction strength between the electron spins driving the e-e-n process was systematically modulated using mono-, di-, tri-, and dendritic-nitroxide radicals, while maintaining a constant global electron spin concentration of 10 mM. Experimental results showed that an increase in electron spin clustering led to an increased electron spin depolarization, as mapped by electron double resonance (ELDOR), and a dramatically shortened T1n and TDNP time constants under static and magic angle spinning (MAS) conditions. A theoretical analysis reveals that strong e-e interactions, caused by electron spin clustering, increase the CE rate. The three spin e-e-n CE is a hitherto little recognized mechanism for shortening T1n and TDNP in solid-state NMR experiments at cryogenic temperatures, and offers a design principle to enhance the effective CE DNP enhancement per unit time. Fast CE rates will benefit DNP at liquid helium temperatures, or at higher magnetic fields and pulsed DNP, where slow e-e-n polarization transfer rate is a key bottleneck to achieving maximal DNP performance.
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Affiliation(s)
- Alisa Leavesley
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA
| | - Sheetal Jain
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA
| | - Ilia Kamniker
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA
| | - Hui Zhang
- Department of Chemistry, University of Nebraska, Lincoln, NE
| | - Suchada Rajca
- Department of Chemistry, University of Nebraska, Lincoln, NE
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, NE
| | - Songi Han
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA
- Department of Chemical Engineering, University of California, Santa Barbara, CA
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39
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Perras FA, Pruski M. Large-scale ab initio simulations of MAS DNP enhancements using a Monte Carlo optimization strategy. J Chem Phys 2018; 149:154202. [PMID: 30342444 DOI: 10.1063/1.5042651] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Magic-angle-spinning (MAS) dynamic nuclear polarization (DNP) has recently emerged as a powerful technology enabling otherwise unrealistic solid-state NMR experiments. The simulation of DNP processes which might, for example, aid in refining the experimental conditions or the design of better performing polarizing agents, is, however, plagued with significant challenges, often limiting the system size to only 3 spins. Here, we present the first approach to fully ab initio large-scale simulations of MAS DNP enhancements. The Landau-Zener equation is used to treat all interactions concerning electron spins, and the low-order correlations in the Liouville space method is used to accurately treat the spin diffusion, as well as its MAS speed dependence. As the propagator cannot be stored, a Monte Carlo optimization method is used to determine the steady-state enhancement factors. This new software is employed to investigate the MAS speed dependence of the enhancement factors in large spin systems where spin diffusion is of importance, as well as to investigate the impacts of solvent and polarizing agent deuteration on the performance of MAS DNP.
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40
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Soetbeer J, Gast P, Walish JJ, Zhao Y, George C, Yang C, Swager TM, Griffin RG, Mathies G. Conformation of bis-nitroxide polarizing agents by multi-frequency EPR spectroscopy. Phys Chem Chem Phys 2018; 20:25506-25517. [PMID: 30277229 PMCID: PMC7256712 DOI: 10.1039/c8cp05236k] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The chemical structure of polarizing agents critically determines the efficiency of dynamic nuclear polarization (DNP). For cross-effect DNP, biradicals are the polarizing agents of choice and the interaction and relative orientation of the two unpaired electrons should be optimal. Both parameters are affected by the molecular structure of the biradical in the frozen glassy matrix that is typically used for DNP/MAS NMR and likely differs from the structure observed with X-ray crystallography. We have determined the conformations of six bis-nitroxide polarizing agents, including the highly efficient AMUPol, in their DNP matrix with EPR spectroscopy at 9.7 GHz, 140 GHz, and 275 GHz. The multi-frequency approach in combination with an advanced fitting routine allows us to reliably extract the interaction and relative orientation of the nitroxide moieties. We compare the structures of six bis-nitroxides to their DNP performance at 500 MHz/330 GHz.
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Affiliation(s)
- Janne Soetbeer
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Peter Gast
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden, The Netherlands
| | - Joseph J Walish
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yanchuan Zhao
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Christy George
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Chen Yang
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Timothy M Swager
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert G Griffin
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Guinevere Mathies
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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41
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Jaudzems K, Polenova T, Pintacuda G, Oschkinat H, Lesage A. DNP NMR of biomolecular assemblies. J Struct Biol 2018; 206:90-98. [PMID: 30273657 DOI: 10.1016/j.jsb.2018.09.011] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 09/13/2018] [Accepted: 09/27/2018] [Indexed: 11/30/2022]
Abstract
Dynamic Nuclear Polarization (DNP) is an effective approach to alleviate the inherently low sensitivity of solid-state NMR (ssNMR) under magic angle spinning (MAS) towards large-sized multi-domain complexes and assemblies. DNP relies on a polarization transfer at cryogenic temperatures from unpaired electrons to adjacent nuclei upon continuous microwave irradiation. This is usually made possible via the addition in the sample of a polarizing agent. The first pioneering experiments on biomolecular assemblies were reported in the early 2000s on bacteriophages and membrane proteins. Since then, DNP has experienced tremendous advances, with the development of extremely efficient polarizing agents or with the introduction of new microwaves sources, suitable for NMR experiments at very high magnetic fields (currently up to 900 MHz). After a brief introduction, several experimental aspects of DNP enhanced NMR spectroscopy applied to biomolecular assemblies are discussed. Recent demonstration experiments of the method on viral capsids, the type III and IV bacterial secretion systems, ribosome and membrane proteins are then described.
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Affiliation(s)
- Kristaps Jaudzems
- Centre de RMN à Très Hauts Champs, Institut des Sciences Analytiques (UMR 5280 - CNRS, ENS Lyon, UCB Lyon 1), Université de Lyon, 5 rue de la Doua, 69100 Villeurbanne, France
| | - Tatyana Polenova
- Department of Chemistry and Biochemistry, University of Delaware, 163 The Green, DE 19716, USA
| | - Guido Pintacuda
- Centre de RMN à Très Hauts Champs, Institut des Sciences Analytiques (UMR 5280 - CNRS, ENS Lyon, UCB Lyon 1), Université de Lyon, 5 rue de la Doua, 69100 Villeurbanne, France
| | - Hartmut Oschkinat
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie im Forschungsverbund Berlin e.V. (FMP), Campus Berlin-Buch Robert-Roessle-Str. 10 13125 Berlin, Germany
| | - Anne Lesage
- Centre de RMN à Très Hauts Champs, Institut des Sciences Analytiques (UMR 5280 - CNRS, ENS Lyon, UCB Lyon 1), Université de Lyon, 5 rue de la Doua, 69100 Villeurbanne, France
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42
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Wisser D, Karthikeyan G, Lund A, Casano G, Karoui H, Yulikov M, Menzildjian G, Pinon AC, Purea A, Engelke F, Chaudhari SR, Kubicki D, Rossini AJ, Moroz IB, Gajan D, Copéret C, Jeschke G, Lelli M, Emsley L, Lesage A, Ouari O. BDPA-Nitroxide Biradicals Tailored for Efficient Dynamic Nuclear Polarization Enhanced Solid-State NMR at Magnetic Fields up to 21.1 T. J Am Chem Soc 2018; 140:13340-13349. [DOI: 10.1021/jacs.8b08081] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dorothea Wisser
- Institut de Sciences Analytiques, Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1), 69100 Villeurbanne, France
| | | | - Alicia Lund
- 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
- AixMarseille Univ, CNRS, ICR, 13013 Marseille, France
| | - Hakim Karoui
- AixMarseille Univ, CNRS, ICR, 13013 Marseille, France
| | - Maxim Yulikov
- Department of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland
| | - Georges Menzildjian
- Institut de Sciences Analytiques, Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1), 69100 Villeurbanne, France
| | - Arthur C. Pinon
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | | | | | - 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
| | - Dominik Kubicki
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Aaron J. Rossini
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Ilia B. Moroz
- Department of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland
| | - 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
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland
| | - Gunnar Jeschke
- Department of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland
| | - Moreno Lelli
- Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - 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
| | - Olivier Ouari
- AixMarseille Univ, CNRS, ICR, 13013 Marseille, France
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43
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Mentink-Vigier F, Marin-Montesinos I, Jagtap AP, Halbritter T, van Tol J, Hediger S, Lee D, Sigurdsson ST, De Paëpe G. Computationally Assisted Design of Polarizing Agents for Dynamic Nuclear Polarization Enhanced NMR: The AsymPol Family. J Am Chem Soc 2018; 140:11013-11019. [PMID: 30095255 PMCID: PMC6145599 DOI: 10.1021/jacs.8b04911] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Indexed: 12/11/2022]
Abstract
We introduce a new family of highly efficient polarizing agents for dynamic nuclear polarization (DNP)-enhanced nuclear magnetic resonance (NMR) applications, composed of asymmetric bis-nitroxides, in which a piperidine-based radical and a pyrrolinoxyl or a proxyl radical are linked together. The design of the AsymPol family was guided by the use of advanced simulations that allow computation of the impact of the radical structure on DNP efficiency. These simulations suggested the use of a relatively short linker with the intention to generate a sizable intramolecular electron dipolar coupling/ J-exchange interaction, while avoiding parallel nitroxide orientations. The characteristics of AsymPol were further tuned, for instance with the addition of a conjugated carbon-carbon double bond in the 5-membered ring to improve the rigidity and provide a favorable relative orientation, the replacement of methyls by spirocyclohexanolyl groups to slow the electron spin relaxation, and the introduction of phosphate groups to yield highly water-soluble dopants. An in-depth experimental and theoretical study for two members of the family, AsymPol and AsymPolPOK, is presented here. We report substantial sensitivity gains at both 9.4 and 18.8 T. The robust efficiency of this new family is further demonstrated through high-resolution surface characterization of an important industrial catalyst using fast sample spinning at 18.8 T. This work highlights a new direction for polarizing agent design and the critical importance of computations in this process.
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Affiliation(s)
- Frédéric Mentink-Vigier
- Univ.
Grenoble Alpes, CEA, CNRS, INAC-MEM, F-38000 Grenoble, France
- CIMAR/NMR
National High Magnetic Field Laboratory, 1800 E. Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | | | - Anil P. Jagtap
- Department
of Chemistry, University of Iceland, Science
Institute, Dunhaga 3, 107 Reykjavik, Iceland
| | - Thomas Halbritter
- Department
of Chemistry, University of Iceland, Science
Institute, Dunhaga 3, 107 Reykjavik, Iceland
| | - Johan van Tol
- EMR
National High Magnetic Field Laboratory, 1800 E. Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Sabine Hediger
- Univ.
Grenoble Alpes, CEA, CNRS, INAC-MEM, F-38000 Grenoble, France
| | - Daniel Lee
- Univ.
Grenoble Alpes, CEA, CNRS, INAC-MEM, F-38000 Grenoble, France
| | - Snorri Th. Sigurdsson
- Department
of Chemistry, University of Iceland, Science
Institute, Dunhaga 3, 107 Reykjavik, Iceland
| | - Gaël De Paëpe
- Univ.
Grenoble Alpes, CEA, CNRS, INAC-MEM, F-38000 Grenoble, France
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44
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Geiger MA, Jagtap AP, Kaushik M, Sun H, Stöppler D, Sigurdsson ST, Corzilius B, Oschkinat H. Efficiency of Water-Soluble Nitroxide Biradicals for Dynamic Nuclear Polarization in Rotating Solids at 9.4 T: bcTol-M and cyolyl-TOTAPOL as New Polarizing Agents. Chemistry 2018; 24:13485-13494. [PMID: 29741214 DOI: 10.1002/chem.201801251] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 05/01/2018] [Indexed: 12/24/2022]
Abstract
Nitroxide biradicals are very efficient polarizing agents in magic angle spinning (MAS) cross effect (CE) dynamic nuclear polarization (DNP) nuclear magnetic resonance (NMR). Many recently synthesized, new radicals show superior DNP-efficiency in organic solvents but suffer from insufficient solubility in water or glycerol/water for biological applications. We report DNP efficiencies for two new radicals, the water-soluble bcTol-M and cyolyl-TOTAPOL, and include a comparison with three known biradicals, TOTAPOL, bcTol, and AMUPol. They differ by linker groups, featuring either a 3-aminopropane-1,2-diol or a urea tether, or by the structure of the alkyl substituents that flank the nitroxide groups. For evaluating their performances, we measured both signal enhancements ϵ and DNP-enhanced sensitivity κ, and compared the results to electron spin relaxation data recorded at the same magnetic field strength (9.4 T). In our study, differences in DNP efficiency correlate with changes in the nuclear polarization dynamics rather than electron relaxation. The ratios of their individual ϵ and κ differ by up to 20 %, which is explained by starkly different nuclear polarization build-up rates. For the radicals compared here empirically, using proline standard solutions, the new radical bcTol-M performs best while being most soluble in water/glycerol mixtures.
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Affiliation(s)
- Michel-Andreas Geiger
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert Roessle-Str. 10, 13125, Berlin, Germany
| | - Anil P Jagtap
- Department of Chemistry, Science Institute, University of Iceland, Dunhaga 3, 107, Reykjavik, Iceland
| | - Monu Kaushik
- Institut für Physikalische und Theoretische Chemie, Institut für Biophysikalische Chemie, und Biomolekulares Magnetresonanzzentrum (BMRZ), Goethe-Universität Frankfurt, Max-van-Laue-Str.7-9, 60438, Frankfurt am Main, Germany
| | - Han Sun
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert Roessle-Str. 10, 13125, Berlin, Germany
| | - Daniel Stöppler
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert Roessle-Str. 10, 13125, Berlin, Germany
| | - Snorri T Sigurdsson
- Department of Chemistry, Science Institute, University of Iceland, Dunhaga 3, 107, Reykjavik, Iceland
| | - Björn Corzilius
- Institut für Physikalische und Theoretische Chemie, Institut für Biophysikalische Chemie, und Biomolekulares Magnetresonanzzentrum (BMRZ), Goethe-Universität Frankfurt, Max-van-Laue-Str.7-9, 60438, Frankfurt am Main, Germany
| | - Hartmut Oschkinat
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert Roessle-Str. 10, 13125, Berlin, Germany
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45
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Kovtunov KV, Pokochueva EV, Salnikov OG, Cousin S, Kurzbach D, Vuichoud B, Jannin S, Chekmenev EY, Goodson BM, Barskiy DA, Koptyug IV. Hyperpolarized NMR Spectroscopy: d-DNP, PHIP, and SABRE Techniques. Chem Asian J 2018; 13:10.1002/asia.201800551. [PMID: 29790649 PMCID: PMC6251772 DOI: 10.1002/asia.201800551] [Citation(s) in RCA: 156] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Indexed: 11/10/2022]
Abstract
The intensity of NMR signals can be enhanced by several orders of magnitude by using various techniques for the hyperpolarization of different molecules. Such approaches can overcome the main sensitivity challenges facing modern NMR/magnetic resonance imaging (MRI) techniques, whilst hyperpolarized fluids can also be used in a variety of applications in material science and biomedicine. This Focus Review considers the fundamentals of the preparation of hyperpolarized liquids and gases by using dissolution dynamic nuclear polarization (d-DNP) and parahydrogen-based techniques, such as signal amplification by reversible exchange (SABRE) and parahydrogen-induced polarization (PHIP), in both heterogeneous and homogeneous processes. The various new aspects in the formation and utilization of hyperpolarized fluids, along with the possibility of observing NMR signal enhancement, are described.
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Affiliation(s)
- Kirill V. Kovtunov
- Laboratory of Magnetic Resonance Microimaging, International Tomography Center, SB RAS, 3A Institutskaya St., Novosibirsk 630090 (Russia)
- Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090 (Russia)
| | - Ekaterina V. Pokochueva
- Laboratory of Magnetic Resonance Microimaging, International Tomography Center, SB RAS, 3A Institutskaya St., Novosibirsk 630090 (Russia)
- Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090 (Russia)
| | - Oleg G. Salnikov
- Laboratory of Magnetic Resonance Microimaging, International Tomography Center, SB RAS, 3A Institutskaya St., Novosibirsk 630090 (Russia)
- Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090 (Russia)
| | - Samuel Cousin
- Univ Lyon, CNRS, Université Claude Bernard Lyon 1, ENS de Lyon, Institut des Sciences Analytiques, UMR 5280, 5 rue de la Doua, 69100 Villeurbanne, France
| | - Dennis Kurzbach
- Laboratoire des biomolécules, LBM, Département de chimie, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Basile Vuichoud
- Univ Lyon, CNRS, Université Claude Bernard Lyon 1, ENS de Lyon, Institut des Sciences Analytiques, UMR 5280, 5 rue de la Doua, 69100 Villeurbanne, France
| | - Sami Jannin
- Univ Lyon, CNRS, Université Claude Bernard Lyon 1, ENS de Lyon, Institut des Sciences Analytiques, UMR 5280, 5 rue de la Doua, 69100 Villeurbanne, France
| | - Eduard Y. Chekmenev
- Department of Chemistry & Karmanos Cancer Center, Wayne State University, Detroit, 48202, MI, United States
- Russian Academy of Sciences, Moscow, 119991, Russia
| | - Boyd M. Goodson
- Southern Illinois University, Carbondale, IL 62901, United States
| | - Danila A. Barskiy
- Department of Chemistry, University of California at Berkeley, Berkeley, California 94720-3220, United States
| | - Igor V. Koptyug
- Laboratory of Magnetic Resonance Microimaging, International Tomography Center, SB RAS, 3A Institutskaya St., Novosibirsk 630090 (Russia)
- Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090 (Russia)
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46
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Zhai W, Feng Y, Liu H, Rockenbauer A, Mance D, Li S, Song Y, Baldus M, Liu Y. Diastereoisomers of l-proline-linked trityl-nitroxide biradicals: synthesis and effect of chiral configurations on exchange interactions. Chem Sci 2018; 9:4381-4391. [PMID: 29896379 PMCID: PMC5958346 DOI: 10.1039/c8sc00969d] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 04/05/2018] [Indexed: 01/08/2023] Open
Abstract
The chiral configuration of the two radical parts is a crucial factor controlling the exchange interactions and DNP properties of trityl-nitroxide biradicals.
The exchange (J) interaction of organic biradicals is a crucial factor controlling their physiochemical properties and potential applications and can be modulated by changing the nature of the linker. In the present work, we for the first time demonstrate the effect of chiral configurations of radical parts on the J values of trityl-nitroxide (TN) biradicals. Four diastereoisomers (TNT1, TNT2, TNL1 and TNL2) of TN biradicals were synthesized and purified by the conjugation of a racemic (R/S) nitroxide with the racemic (M/P) trityl radical vial-proline. The absolute configurations of these diastereoisomers were assigned by comparing experimental and calculated electronic circular dichroism (ECD) spectra as (M, S, S) for TNT1, (P, S, S) for TNT2, (M, S, R) for TNL1 and (P, S, R) for TNL2. Electron paramagnetic resonance (EPR) results showed that the configuration of the nitroxide part instead of the trityl part is dominant in controlling the exchange interactions and the order of the J values at room temperature is TNT1 (252 G) > TNT2 (127 G) ≫ TNL2 (33 G) > TNL1 (14 G). Moreover, the J values of TNL1/TNL2 with the S configuration in the nitroxide part vary with temperature and the polarity of solvents due to their flexible linker, whereas the J values of TNT1/TNT2 are almost insensitive to these two factors due to the rigidity of their linkers. The distinct exchange interactions between TNT1,2 and TNL1,2 in the frozen state led to strongly different high-field dynamic nuclear polarization (DNP) enhancements with ε = 7 for TNT1,2 and 40 for TNL1,2 under 800 MHz DNP conditions.
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Affiliation(s)
- Weixiang Zhai
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics , School of Pharmacy , Tianjin Medical University , Tianjin 300070 , P. R. China . ;
| | - Yalan Feng
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics , School of Pharmacy , Tianjin Medical University , Tianjin 300070 , P. R. China . ;
| | - Huiqiang Liu
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics , School of Pharmacy , Tianjin Medical University , Tianjin 300070 , P. R. China . ;
| | - Antal Rockenbauer
- Institute of Materials and Environmental Chemistry , Hungarian Academy of Sciences , Department of Physics , Budapest University of Technology and Economics , Budafoki ut 8 , 1111 Budapest , Hungary .
| | - Deni Mance
- NMR Spectroscopy , Bijvoet Center for Biomolecular Research , Utrecht University , 3584 CH Utrecht , The Netherlands
| | - Shaoyong Li
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics , School of Pharmacy , Tianjin Medical University , Tianjin 300070 , P. R. China . ;
| | - Yuguang Song
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics , School of Pharmacy , Tianjin Medical University , Tianjin 300070 , P. R. China . ;
| | - Marc Baldus
- NMR Spectroscopy , Bijvoet Center for Biomolecular Research , Utrecht University , 3584 CH Utrecht , The Netherlands
| | - Yangping Liu
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics , School of Pharmacy , Tianjin Medical University , Tianjin 300070 , P. R. China . ;
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47
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Plainchont B, Berruyer P, Dumez JN, Jannin S, Giraudeau P. Dynamic Nuclear Polarization Opens New Perspectives for NMR Spectroscopy in Analytical Chemistry. Anal Chem 2018; 90:3639-3650. [PMID: 29481058 DOI: 10.1021/acs.analchem.7b05236] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Dynamic nuclear polarization (DNP) can boost sensitivity in nuclear magnetic resonance (NMR) experiments by several orders of magnitude. This Feature illustrates how the coupling of DNP with both liquid- and solid-state NMR spectroscopy has the potential to considerably extend the range of applications of NMR in analytical chemistry.
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Affiliation(s)
- Bertrand Plainchont
- Université de Nantes , CNRS, CEISAM UMR 6230 , 44322 Nantes Cedex 03 , France
| | - Pierrick Berruyer
- Université Claude Bernard Lyon 1, CNRS, ENS de Lyon , Institut des Sciences Analytiques, UMR 5280 , 5 Rue de la Doua , 69100 Villeurbanne , France
| | - Jean-Nicolas Dumez
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301 , Univ. Paris Sud, Université Paris-Saclay , 91190 Gif-sur Yvette , France
| | - Sami Jannin
- Université Claude Bernard Lyon 1, CNRS, ENS de Lyon , Institut des Sciences Analytiques, UMR 5280 , 5 Rue de la Doua , 69100 Villeurbanne , France
| | - Patrick Giraudeau
- Université de Nantes , CNRS, CEISAM UMR 6230 , 44322 Nantes Cedex 03 , France.,Institut Universitaire de France , 75005 Paris , France
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48
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Eaton SS, Woodcock LB, Eaton GR. Continuous wave electron paramagnetic resonance of nitroxide biradicals in fluid solution. CONCEPTS IN MAGNETIC RESONANCE. PART A, BRIDGING EDUCATION AND RESEARCH 2018; 47A:e21426. [PMID: 31548835 PMCID: PMC6756774 DOI: 10.1002/cmr.a.21426] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Nitroxide biradicals have been prepared with electron-electron spin-spin exchange interaction, J, ranging from weak to very strong. EPR spectra of these biradicals in fluid solution depend on the ratio of J to the nitrogen hyperfine coupling, AN, and the rates of interconversion between conformations with different values of J. For relatively rigid biradicals EPR spectra can be simulated as the superposition of AB splitting patterns arising from different combinations of nitrogen nuclear spin states. For more flexible biradicals spectra can be simulated with a Liouville representation of the dynamics that interconvert conformations with different values of J on the EPR timescale. Analysis of spectra, factors that impact J, and examples of applications to chemical and biophysical problems are discussed.
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Affiliation(s)
- Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver CO 80210 USA
| | - Lukas B Woodcock
- Department of Chemistry and Biochemistry, University of Denver, Denver CO 80210 USA
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver CO 80210 USA
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49
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Mentink-Vigier F, Vega S, De Paëpe G. Fast and accurate MAS-DNP simulations of large spin ensembles. Phys Chem Chem Phys 2018; 19:3506-3522. [PMID: 28093594 DOI: 10.1039/c6cp07881h] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A deeper understanding of parameters affecting Magic Angle Spinning Dynamic Nuclear Polarization (MAS-DNP), an emerging nuclear magnetic resonance hyperpolarization method, is crucial for the development of new polarizing agents and the successful implementation of the technique at higher magnetic fields (>10 T). Such progress is currently impeded by computational limitation which prevents the simulation of large spin ensembles (electron as well as nuclear spins) and to accurately describe the interplay between all the multiple key parameters at play. In this work, we present an alternative approach to existing cross-effect and solid-effect MAS-DNP codes that yields fast and accurate simulations. More specifically we describe the model, the associated Liouville-based formalism (Bloch-type derivation and/or Landau-Zener approximations) and the linear time algorithm that allows computing MAS-DNP mechanisms with unprecedented time savings. As a result, one can easily scan through multiple parameters and disentangle their mutual influences. In addition, the simulation code is able to handle multiple electrons and protons, which allows probing the effect of (hyper)polarizing agents concentration, as well as fully revealing the interplay between the polarizing agent structure and the hyperfine couplings, nuclear dipolar couplings, nuclear relaxation times, both in terms of depolarization effect, but also of polarization gain and buildup times.
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Affiliation(s)
- Frédéric Mentink-Vigier
- Univ. Grenoble Alpes, INAC, MEM, F-38000 Grenoble, France and CEA, INAC, MEM, F-38000 Grenoble, France.
| | - Shimon Vega
- Weizmann institute of Science, Rehovot, Israel
| | - Gaël De Paëpe
- Univ. Grenoble Alpes, INAC, MEM, F-38000 Grenoble, France and CEA, INAC, MEM, F-38000 Grenoble, France.
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50
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Mentink-Vigier F, Mathies G, Liu Y, Barra AL, Caporini MA, Lee D, Hediger S, G Griffin R, De Paëpe G. Efficient cross-effect dynamic nuclear polarization without depolarization in high-resolution MAS NMR. Chem Sci 2017; 8:8150-8163. [PMID: 29619170 PMCID: PMC5861987 DOI: 10.1039/c7sc02199b] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 10/01/2017] [Indexed: 11/21/2022] Open
Abstract
Dynamic nuclear polarization (DNP) has the potential to enhance the sensitivity of magic-angle spinning (MAS) NMR by many orders of magnitude and therefore to revolutionize atomic resolution structural analysis. Currently, the most widely used approach to DNP for studies of chemical, material, and biological systems involves the cross-effect (CE) mechanism, which relies on biradicals as polarizing agents. However, at high magnetic fields (≥5 T), the best biradicals used for CE MAS-DNP are still far from optimal, primarily because of the nuclear depolarization effects they induce. In the presence of bisnitroxide biradicals, magic-angle rotation results in a reverse CE that can deplete the initial proton Boltzmann polarization by more than a factor of 2. In this paper we show that these depolarization losses can be avoided by using a polarizing agent composed of a narrow-line trityl radical tethered to a broad-line TEMPO. Consequently, we show that a biocompatible trityl-nitroxide biradical, TEMTriPol-1, provides the highest MAS NMR sensitivity at ≥10 T, and its relative efficiency increases with the magnetic field strength. We use numerical simulations to explain the absence of depolarization for TEMTriPol-1 and its high efficiency, paving the way for the next generation of polarizing agents for DNP. We demonstrate the superior sensitivity enhancement using TEMTriPol-1 by recording the first solid-state 2D 13C-13C correlation spectrum at natural isotopic abundance at a magnetic field of 18.8 T.
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Affiliation(s)
| | - Guinevere Mathies
- Francis Bitter Magnet Laboratory , Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA
| | - Yangping Liu
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics , School of Pharmacy , Tianjin Medical University , Tianjin 300070 , China
| | - Anne-Laure Barra
- Laboratoire National des Champs Magnétiques Intenses - CNRS , Univ. Grenoble Alpes , F-38042 Grenoble , France
| | - Marc A Caporini
- Bruker BioSpin Corporation , 15 Fortune Drive , Billerica , MA 01821 , USA
| | - Daniel Lee
- Univ. Grenoble Alpes , CEA , CNRS , INAC-MEM , F-38000 Grenoble , France .
| | - Sabine Hediger
- Univ. Grenoble Alpes , CEA , CNRS , INAC-MEM , F-38000 Grenoble , France .
| | - Robert G Griffin
- Francis Bitter Magnet Laboratory , Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA
| | - Gaël De Paëpe
- Univ. Grenoble Alpes , CEA , CNRS , INAC-MEM , F-38000 Grenoble , France .
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