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Efficient cross-effect dynamic nuclear polarization without depolarization in high-resolution MAS NMR

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 b...

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Autores principales: Mentink-Vigier, Frédéric, Mathies, Guinevere, Liu, Yangping, Barra, Anne-Laure, Caporini, Marc A., Lee, Daniel, Hediger, Sabine, G. Griffin, Robert, De Paëpe, Gaël
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Royal Society of Chemistry 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5861987/
https://www.ncbi.nlm.nih.gov/pubmed/29619170
http://dx.doi.org/10.1039/c7sc02199b
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author Mentink-Vigier, Frédéric
Mathies, Guinevere
Liu, Yangping
Barra, Anne-Laure
Caporini, Marc A.
Lee, Daniel
Hediger, Sabine
G. Griffin, Robert
De Paëpe, Gaël
author_facet Mentink-Vigier, Frédéric
Mathies, Guinevere
Liu, Yangping
Barra, Anne-Laure
Caporini, Marc A.
Lee, Daniel
Hediger, Sabine
G. Griffin, Robert
De Paëpe, Gaël
author_sort Mentink-Vigier, Frédéric
collection PubMed
description 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 (13)C–(13)C correlation spectrum at natural isotopic abundance at a magnetic field of 18.8 T.
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spelling pubmed-58619872018-04-04 Efficient cross-effect dynamic nuclear polarization without depolarization in high-resolution MAS NMR Mentink-Vigier, Frédéric Mathies, Guinevere Liu, Yangping Barra, Anne-Laure Caporini, Marc A. Lee, Daniel Hediger, Sabine G. Griffin, Robert De Paëpe, Gaël Chem Sci Chemistry 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 (13)C–(13)C correlation spectrum at natural isotopic abundance at a magnetic field of 18.8 T. Royal Society of Chemistry 2017-12-01 2017-10-02 /pmc/articles/PMC5861987/ /pubmed/29619170 http://dx.doi.org/10.1039/c7sc02199b Text en This journal is © The Royal Society of Chemistry 2017 http://creativecommons.org/licenses/by-nc/3.0/ This article is freely available. This article is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported Licence (CC BY-NC 3.0)
spellingShingle Chemistry
Mentink-Vigier, Frédéric
Mathies, Guinevere
Liu, Yangping
Barra, Anne-Laure
Caporini, Marc A.
Lee, Daniel
Hediger, Sabine
G. Griffin, Robert
De Paëpe, Gaël
Efficient cross-effect dynamic nuclear polarization without depolarization in high-resolution MAS NMR
title Efficient cross-effect dynamic nuclear polarization without depolarization in high-resolution MAS NMR
title_full Efficient cross-effect dynamic nuclear polarization without depolarization in high-resolution MAS NMR
title_fullStr Efficient cross-effect dynamic nuclear polarization without depolarization in high-resolution MAS NMR
title_full_unstemmed Efficient cross-effect dynamic nuclear polarization without depolarization in high-resolution MAS NMR
title_short Efficient cross-effect dynamic nuclear polarization without depolarization in high-resolution MAS NMR
title_sort efficient cross-effect dynamic nuclear polarization without depolarization in high-resolution mas nmr
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5861987/
https://www.ncbi.nlm.nih.gov/pubmed/29619170
http://dx.doi.org/10.1039/c7sc02199b
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