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Panter S, Ayekoi A, Tesche J, Chen J, Illarionov B, Bacher A, Fischer M, Weber S. Shining a Spotlight on Methyl Groups: Photochemically Induced Dynamic Nuclear Polarization Spectroscopy of 5-Deazariboflavin and Its Nor Analogs. Int J Mol Sci 2024; 25:848. [PMID: 38255921 PMCID: PMC10815406 DOI: 10.3390/ijms25020848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/07/2024] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
5-Deazaflavins are analogs of naturally occurring flavin cofactors. They serve as substitutes for natural flavin cofactors to investigate and modify the reaction pathways of flavoproteins. Demethylated 5-deazaflavins are potential candidates for artificial cofactors, allowing us to fine-tune the reaction kinetics and absorption characteristics of flavoproteins. In this contribution, demethylated 5-deazariboflavin radicals are investigated (1) to assess the influence of the methyl groups on the electronic structure of the 5-deazaflavin radical and (2) to explore their photophysical properties with regard to their potential as artificial cofactors. We determined the proton hyperfine structure of demethylated 5-deazariboflavins using photochemically induced dynamic nuclear polarization (photo-CIDNP) spectroscopy, as well as density functional theory (DFT). To provide context, we compare our findings to a study of flavin mononucleotide (FMN) derivatives. We found a significant influence of the methylation pattern on the absorption properties, as well as on the proton hyperfine coupling ratios of the xylene moiety, which appears to be solvent-dependent. This effect is enhanced by the replacement of N5 by C5-H in 5-deazaflavin derivatives compared to their respective flavin counterparts.
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Affiliation(s)
- Sabrina Panter
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany; (S.P.); (A.A.)
| | - Audrey Ayekoi
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany; (S.P.); (A.A.)
| | - Jannis Tesche
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany; (S.P.); (A.A.)
| | - Jing Chen
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany; (S.P.); (A.A.)
| | - Boris Illarionov
- Institut für Lebensmittelchemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg, Germany; (B.I.); (M.F.)
| | - Adelbert Bacher
- TUM School of Natural Sciences, Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany;
| | - Markus Fischer
- Institut für Lebensmittelchemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg, Germany; (B.I.); (M.F.)
| | - Stefan Weber
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany; (S.P.); (A.A.)
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2
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Wörner J, Panter S, Illarionov B, Bacher A, Fischer M, Weber S. Expanding Reaction Horizons: Evidence of the 5-Deazaflavin Radical Through Photochemically Induced Dynamic Nuclear Polarization. Angew Chem Int Ed Engl 2023; 62:e202309334. [PMID: 37571931 DOI: 10.1002/anie.202309334] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/09/2023] [Accepted: 08/10/2023] [Indexed: 08/13/2023]
Abstract
Deazaflavins are important analogues of the naturally occurring flavins: riboflavin, flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD). The use of 5-deazaflavin as a replacement coenzyme in a number of flavoproteins has proven particularly valuable in unraveling and manipulating their reaction mechanisms. It was frequently reported that one-electron-transfer reactions in flavoproteins are impeded with 5-deazaflavin as the cofactor. Based on these findings, it was concluded that the 5-deazaflavin radical is significantly less stable compared to the respective flavin semiquinone and quickly re-oxidizes or undergoes disproportionation. The long-standing paradigm of 5-deazaflavin being solely a two-electron/hydride acceptor/donor-"a nicotinamide in flavin clothing"-needs to be re-evaluated now with the indirect observation of a one-electron-reduced (paramagnetic) species using photochemically induced dynamic nuclear polarization (photo-CIDNP) 1 H nuclear magnetic resonance (NMR) under biologically relevant conditions.
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Affiliation(s)
- Jakob Wörner
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104, Freiburg, Germany
| | - Sabrina Panter
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104, Freiburg, Germany
| | - Boris Illarionov
- Institut für Lebensmittelchemie, Universität Hamburg, Grindelallee 117, 20146, Hamburg, Germany
| | - Adelbert Bacher
- TUM School of Natural Sciences, Technische Universität München, Lichtenbergstraße 4, 85747, Garching, Germany
| | - Markus Fischer
- Institut für Lebensmittelchemie, Universität Hamburg, Grindelallee 117, 20146, Hamburg, Germany
| | - Stefan Weber
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104, Freiburg, Germany
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3
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Kurle-Tucholski P, Köhler L, Zhao Z, Link G, Wiebeler C, Matysik J. Stabilization of a flavoprotein for solid-state photo-CIDNP MAS NMR at room temperature by embedding in a glassy sugar matrix. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 353:107497. [PMID: 37295281 DOI: 10.1016/j.jmr.2023.107497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/26/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023]
Abstract
Hyperpolarization via the solid-state photochemically induced dynamic nuclear polarization (photo-CIDNP) effect can be detected in frozen solutions of electron transfer proteins generating a radical-pair upon illumination. The effect has been observed in various natural photosynthetic reaction centers and in light-oxygen-voltage (LOV) sensing domains incorporating a flavin mononucleotide (FMN) as chromophore. In LOV domains, where a highly conserved cysteine is mutated to a flavin to interrupt its natural photochemistry, a radical-pair is generated by electron transfer from a nearby tryptophan to the photoexcited triplet state of FMN. During the photocycle, both the LOV domain and the chromophore are photochemically degraded, e.g., by the formation of singlet oxygen. This limits the time for collection of hyperpolarized nuclear magnetic resonance (NMR) data. We show that embedding of the protein into a trehalose sugar glass matrix stabilizes the protein for 13C solid-state photo-CIDNP NMR experiments which can be conducted at room temperature in a powder sample. Additionally, this preparation allows for incorporation of high amounts of protein further boosting the intensity of the detected signals from FMN and tryptophan at natural abundance. Signal assignment is aided by quantum chemical calculations of absolute shieldings. The underlying mechanism for the surprising absorption-only signal pattern is not yet understood. Comparison to calculated isotropic hyperfine couplings imply that the enhancement is not due to the classical radical-pair mechanism (RPM). Analysis of the anisotropic hyperfine couplings associated with solid-state photo-CIDNP mechanisms also show no simple correlation, suggesting a more complex underlying mechanism.
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Affiliation(s)
- Patrick Kurle-Tucholski
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany
| | - Lisa Köhler
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany
| | - Ziyue Zhao
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany
| | - Gerhard Link
- Institut für Physikalische Chemie, Universität Freiburg, Albertstraße 21, D-79104 Freiburg, Germany
| | - Christian Wiebeler
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany; Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Linnéstraße 2, D-04103 Leipzig, Germany; Institut für Physik, Universität Augsburg, Universitätsstraße 1, D-86159 Augsburg, Germany
| | - Jörg Matysik
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany.
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4
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Eills J, Budker D, Cavagnero S, Chekmenev EY, Elliott SJ, Jannin S, Lesage A, Matysik J, Meersmann T, Prisner T, Reimer JA, Yang H, Koptyug IV. Spin Hyperpolarization in Modern Magnetic Resonance. Chem Rev 2023; 123:1417-1551. [PMID: 36701528 PMCID: PMC9951229 DOI: 10.1021/acs.chemrev.2c00534] [Citation(s) in RCA: 64] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Abstract] [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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5
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Li S, Yang H, Hofstetter H, Tonelli M, Cavagnero S. Magnetic-Field Dependence of LC-Photo-CIDNP in the Presence of Target Molecules Carrying a Quasi-Isolated Spin Pair. APPLIED MAGNETIC RESONANCE 2023; 54:59-75. [PMID: 37483563 PMCID: PMC10358788 DOI: 10.1007/s00723-022-01506-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/04/2022] [Accepted: 09/30/2022] [Indexed: 07/25/2023]
Abstract
NMR spectroscopy is well known for its superb resolution, especially at high applied magnetic field. However, the sensitivity of this technique is very low. Liquid-state low-concentration photo-chemically-induced dynamic nuclear polarization (LC-photo-CIDNP) is a promising emerging methodology capable of enhancing NMR sensitivity in solution. LC-photo-CIDNP works well on solvent-exposed Trp and Tyr residues, either in isolation or within proteins. This study explores the magnetic-field dependence of the LC-photo-CIDNP experienced by two tryptophan isotopologs in solution upon in situ LED-mediated optical irradiation. Out of the two uniformly 13C,15N-labeled Trp (Trp-U-13C,15N) and Trp-α-13C-β,β,2,4,5,6,7-d7 species employed here, only the latter bears a quasi-isolated 1Hα-13Cα spin pair. Computer simulations of the predicted polarization due to geminate recombination of both species display a roughly bell-shaped field dependence. However, while Trp-U-13C,15N is predicted to show a maximum at ca. 500 MHz (11.7 T) and a fairly weak field dependence, Trp-α-13C-β,β,2,4,5,6,7-d7 is expected to display a much sharper field dependence accompanied by a dramatic polarization increase at lower field (ca. 200 MHz, 4.7 T). Experimental LC-photo-CIDNP studies on both Trp isotopologs at 1μM concentration, performed at selected fields, are consistent with the theoretical predictions. In summary, this study highlights the prominent field-dependence of LC-photo-CIDNP enhancements (ε ) experienced by Trp isotopologs bearing a quasi-isolated spin pair.
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Affiliation(s)
- Siyu Li
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Ave., Madison, Wisconsin, 53706, USA
| | - Hanming Yang
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Ave., Madison, Wisconsin, 53706, USA
| | - Heike Hofstetter
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Ave., Madison, Wisconsin, 53706, USA
| | - Marco Tonelli
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, Wisconsin, 53706, USA
| | - Silvia Cavagnero
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Ave., Madison, Wisconsin, 53706, USA
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6
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Im J, Lee J, Lee JH. Surface Accessibility of an Intrinsically Disordered Protein Probed by 2D Time-Resolved Laser-Assisted NMR Spectroscopy. J Am Chem Soc 2022; 144:17010-17021. [PMID: 36083135 DOI: 10.1021/jacs.2c06309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Probing the protein surface accessibility of different residues is a powerful way of characterizing the overall conformation of intrinsically disordered proteins (IDPs). We present a two-dimensional (2D) time-resolved photo-CIDNP (TR-CIDNP) experiment suitable for IDP analysis. Pulse stretching of high-power laser pulses, band-selective decoupling of 13Cα, and simultaneous application of radiofrequency and laser pulses were implemented to quantitatively analyze the IDP surface at ultrahigh resolution. Comparative analysis with other methods that measure protein surface accessibility validated the newly developed method and emphasized the importance of dye charge in photo-CIDNP. Using the neutral riboflavin dye, surface accessibilities were measured to be nearly identical for the four Tyr residues of α-synuclein (α-Syn), whose 1Hα-13Cα correlations were well-resolved in the 2D TR-CIDNP spectrum. Having confirmed the similarity between the time-resolved and steady-state photo-CIDNP results for α-Syn, we used the more sensitive latter method to show that divalent cations induce compaction of the C-terminal region and release of the N-terminal region of α-Syn. The photo-CIDNP method presented herein can be used as an orthogonal and independent method for investigating important biological processes associated with changes in the overall IDP conformation.
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Affiliation(s)
- Jonghyuk Im
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
| | - Jongchan Lee
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
| | - Jung Ho Lee
- Department of Chemistry, Seoul National University, Seoul 08826, Korea.,Advanced Institutes of Convergence Technology, Suwon, Gyeonggi-do 16229, Korea
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7
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Yang H, Li S, Mickles CA, Guzman-Luna V, Sugisaki K, Thompson CM, Dang HH, Cavagnero S. Selective Isotope Labeling and LC-Photo-CIDNP Enable NMR Spectroscopy at Low-Nanomolar Concentration. J Am Chem Soc 2022; 144:11608-11619. [PMID: 35700317 DOI: 10.1021/jacs.2c01809] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
NMR spectroscopy is a powerful tool to investigate molecular structure and dynamics. The poor sensitivity of this technique, however, limits its ability to tackle questions requiring dilute samples. Low-concentration photochemically induced dynamic nuclear polarization (LC-photo-CIDNP) is an optically enhanced NMR technology capable of addressing the above challenge by increasing the detection limit of aromatic amino acids in solution up to 1000-fold, either in isolation or within proteins. Here, we show that the absence of NMR-active nuclei close to a magnetically active site of interest (e.g., the structurally diagnostic 1Hα-13Cα pair of amino acids) is expected to significantly increase LC-photo-CIDNP hyperpolarization. Then, we exploit the spin-diluted tryptophan isotopolog Trp-α-13C-β,β,2,4,5,6,7-d7 and take advantage of the above prediction to experimentally achieve a ca 4-fold enhancement in NMR sensitivity over regular LC-photo-CIDNP. This advance enables the rapid (within seconds) detection of 20 nM concentrations or the molecule of interest, corresponding to a remarkable 3 ng detection limit. Finally, the above Trp isotopolog is amenable to incorporation within proteins and is readily detectable at a 1 μM concentration in complex cell-like media, including Escherichia coli cell-free extracts.
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Affiliation(s)
- Hanming Yang
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Siyu Li
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Clayton A Mickles
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Valeria Guzman-Luna
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Kenji Sugisaki
- Department of Chemistry, Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.,JST PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Clayton M Thompson
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Hung H Dang
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Silvia Cavagnero
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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8
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Pompe N, Illarionov B, Fischer M, Bacher A, Weber S. Completing the Picture: Determination of 13C Hyperfine Coupling Constants of Flavin Semiquinone Radicals by Photochemically Induced Dynamic Nuclear Polarization Spectroscopy. J Phys Chem Lett 2022; 13:5160-5167. [PMID: 35658481 DOI: 10.1021/acs.jpclett.2c00919] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We investigate the electronic structure of flavin semiquinone radicals in terms of their 13C hyperfine coupling constants. Photochemically induced dynamic nuclear polarization (photo-CIDNP) spectroscopy was used to study both the neutral and anionic radical species of flavin mononucleotide (FMN) in bulk aqueous solution. Apart from universally 13C-labeled FMN, partially labeled isotopologues are used to increase sensitivity for nuclei exhibiting very small hyperfine couplings and to cope with spectral overlap. In addition, experimental findings are supported by quantum chemical calculations, and implications for the spin density distribution in free flavin radicals are discussed.
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Affiliation(s)
- Nils Pompe
- Institute of Physical Chemistry, University of Freiburg, 79104 Freiburg im Breisgau, Germany
| | - Boris Illarionov
- Hamburg School of Food Science, University of Hamburg, 20146 Hamburg, Germany
| | - Markus Fischer
- Hamburg School of Food Science, University of Hamburg, 20146 Hamburg, Germany
| | - Adelbert Bacher
- Department of Chemistry, Technical University of Munich, 85748 Garching, Germany
| | - Stefan Weber
- Institute of Physical Chemistry, University of Freiburg, 79104 Freiburg im Breisgau, Germany
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9
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Sheberstov KF, Chuchkova L, Hu Y, Zhukov IV, Kiryutin AS, Eshtukov AV, Cheshkov DA, Barskiy DA, Blanchard JW, Budker D, Ivanov KL, Yurkovskaya AV. Photochemically Induced Dynamic Nuclear Polarization of Heteronuclear Singlet Order. J Phys Chem Lett 2021; 12:4686-4691. [PMID: 33979166 DOI: 10.1021/acs.jpclett.1c00503] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Photochemically induced dynamic nuclear polarization (photo-CIDNP) is a method to hyperpolarize nuclear spins using light. In most cases, CIDNP experiments are performed in high magnetic fields and the sample is irradiated by light inside a nuclear magnetic resonance (NMR) spectrometer. Here we demonstrate photo-CIDNP hyperpolarization generated in the Earth's magnetic field and under zero- to ultralow-field (ZULF) conditions. Irradiating a sample containing tetraphenylporphyrin and para-benzoquinone for several seconds with light-emitting diodes produces strong hyperpolarization of 1H and 13C nuclear spins, enhancing the NMR signals more than 200 times. The hyperpolarized spin states at the Earth's field and in ZULF are different. In the latter case, the state corresponds to the singlet order between scalar-coupled 1H-13C nuclear spins. This state has a longer lifetime than the state hyperpolarized at Earth's field. The method is simple and cost-efficient and should be applicable to many molecular systems known to exhibit photo-CIDNP, including amino acids and nucleotides.
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Affiliation(s)
- Kirill F Sheberstov
- Institut für Physik, Johannes Gutenberg Universität-Mainz, 55128 Mainz, Germany
- GSI Helmholtzzentrum für Schwerionenforschung, Helmholtz-Institut Mainz, 55128 Mainz, Germany
| | - Liubov Chuchkova
- GSI Helmholtzzentrum für Schwerionenforschung, Helmholtz-Institut Mainz, 55128 Mainz, Germany
- Faculté des Sciences Mirande, Université de Bourgogne, Dijon 21078, France
| | - Yinan Hu
- Institut für Physik, Johannes Gutenberg Universität-Mainz, 55128 Mainz, Germany
- GSI Helmholtzzentrum für Schwerionenforschung, Helmholtz-Institut Mainz, 55128 Mainz, Germany
| | - Ivan V Zhukov
- International Tomography Center SB RAS, Novosibirsk 630090, Russia
- Novosibirsk State University, Novosibirsk 630090, Russia
| | - Alexey S Kiryutin
- International Tomography Center SB RAS, Novosibirsk 630090, Russia
- Novosibirsk State University, Novosibirsk 630090, Russia
| | - Artur V Eshtukov
- State Scientific Research Institute of Chemistry and Technology of Organoelement Compounds, Moscow 105118, Russia
| | - Dmitry A Cheshkov
- State Scientific Research Institute of Chemistry and Technology of Organoelement Compounds, Moscow 105118, Russia
| | - Danila A Barskiy
- Institut für Physik, Johannes Gutenberg Universität-Mainz, 55128 Mainz, Germany
- GSI Helmholtzzentrum für Schwerionenforschung, Helmholtz-Institut Mainz, 55128 Mainz, Germany
| | - John W Blanchard
- GSI Helmholtzzentrum für Schwerionenforschung, Helmholtz-Institut Mainz, 55128 Mainz, Germany
| | - Dmitry Budker
- Institut für Physik, Johannes Gutenberg Universität-Mainz, 55128 Mainz, Germany
- GSI Helmholtzzentrum für Schwerionenforschung, Helmholtz-Institut Mainz, 55128 Mainz, Germany
- University of California, Berkeley, California 94720-7300, United States
| | - Konstantin L Ivanov
- International Tomography Center SB RAS, Novosibirsk 630090, Russia
- Novosibirsk State University, Novosibirsk 630090, Russia
| | - Alexandra V Yurkovskaya
- International Tomography Center SB RAS, Novosibirsk 630090, Russia
- Novosibirsk State University, Novosibirsk 630090, Russia
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10
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Torres F, Sobol A, Greenwald J, Renn A, Morozova O, Yurkovskaya A, Riek R. Molecular features toward high photo-CIDNP hyperpolariztion explored through the oxidocyclization of tryptophan. Phys Chem Chem Phys 2021; 23:6641-6650. [PMID: 33710192 DOI: 10.1039/d0cp06068b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Photo-chemically induced dynamic nuclear polarization (photo-CIDNP) is a promising solution to the inherent lack of sensitivity in NMR spectroscopy. It is particularly interesting in biological systems since it operates in water, at room temperature, and it can be repeated if the bleaching of the system can be controlled. However, the photo-CIDNP signal enhancement is well below those of other hyperpolarization techniques. While DNP, PHIP, and SABRE reach polarization enhancements of 103 to 104-fold, photo-CIDNP enhancement is typically only one order of magnitude for 1H and two orders of magnitude for 13C in the amino-acids tryptophan and tyrosine. Here we report on a photo-oxidation product of tryptophan that is strongly photo-CIDNP active under continuous wave light irradiation. In conjunction with the dye Atto Thio 12, a 1H signal enhancement of 120-fold was observed on a 600 MHz spectrometer, while at 200 MHz the enhancement was 380-fold. These enhancements in signal to noise correspond to a reduction in measurement time of 14 400-fold and 144 400-fold, respectively. The enhancement for 13C is estimated to be over 1200-fold at 600 MHz which corresponds to an impressive measurement time reduction of 1 440 000-fold. This photo-CIDNP active oxidation product of tryptophan has been identified to be 3α-hydroxypyrroloindole. The reasons for its improved signal enhancement compared to tryptophan have been further investigated.
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Affiliation(s)
- Felix Torres
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland.
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11
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Ding Y, Kiryutin AS, Zhao Z, Xu QZ, Zhao KH, Kurle P, Bannister S, Kottke T, Sagdeev RZ, Ivanov KL, Yurkovskaya AV, Matysik J. Tailored flavoproteins acting as light-driven spin machines pump nuclear hyperpolarization. Sci Rep 2020; 10:18658. [PMID: 33122681 PMCID: PMC7596710 DOI: 10.1038/s41598-020-75627-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/15/2020] [Indexed: 11/24/2022] Open
Abstract
The solid-state photo-chemically induced dynamic nuclear polarization (photo-CIDNP) effect generates non-Boltzmann nuclear spin magnetization, referred to as hyperpolarization, allowing for high gain of sensitivity in nuclear magnetic resonance (NMR). Well known to occur in photosynthetic reaction centers, the effect was also observed in a light-oxygen-voltage (LOV) domain of the blue-light receptor phototropin, in which the functional cysteine was removed to prevent photo-chemical reactions with the cofactor, a flavin mononucleotide (FMN). Upon illumination, the FMN abstracts an electron from a tryptophan to form a transient spin-correlated radical pair (SCRP) generating the photo-CIDNP effect. Here, we report on designed molecular spin-machines producing nuclear hyperpolarization upon illumination: a LOV domain of aureochrome1a from Phaeodactylum tricornutum, and a LOV domain named 4511 from Methylobacterium radiotolerans (Mr4511) which lacks an otherwise conserved tryptophan in its wild-type form. Insertion of the tryptophan at canonical and novel positions in Mr4511 yields photo-CIDNP effects observed by 15N and 1H liquid-state high-resolution NMR with a characteristic magnetic-field dependence indicating an involvement of anisotropic magnetic interactions and a slow-motion regime in the transient paramagnetic state. The heuristic biomimetic design opens new categories of experiments to analyze and apply the photo-CIDNP effect.
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Affiliation(s)
- Yonghong Ding
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103, Leipzig, Germany
| | - Alexey S Kiryutin
- International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya, 3a, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 1, Novosibirsk, 630090, Russia
| | - Ziyue Zhao
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103, Leipzig, Germany
| | - Qian-Zhao Xu
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103, Leipzig, Germany
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Kai-Hong Zhao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Patrick Kurle
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103, Leipzig, Germany
| | - Saskia Bannister
- Physikalische und Biophysikalische Chemie, Universität Bielefeld, Universitätsstr. 25, 33615, Bielefeld, Germany
| | - Tilman Kottke
- Physikalische und Biophysikalische Chemie, Universität Bielefeld, Universitätsstr. 25, 33615, Bielefeld, Germany
| | - Renad Z Sagdeev
- International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya, 3a, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 1, Novosibirsk, 630090, Russia
| | - Konstantin L Ivanov
- International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya, 3a, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 1, Novosibirsk, 630090, Russia
| | - Alexandra V Yurkovskaya
- International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya, 3a, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 1, Novosibirsk, 630090, Russia
| | - Jörg Matysik
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103, Leipzig, Germany.
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12
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Pompe N, Chen J, Illarionov B, Panter S, Fischer M, Bacher A, Weber S. Methyl groups matter: Photo-CIDNP characterizations of the semiquinone radicals of FMN and demethylated FMN analogs. J Chem Phys 2019; 151:235103. [PMID: 31864274 DOI: 10.1063/1.5130557] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this contribution, the relative hyperfine couplings are determined for the 1H nuclei of the flavin mononucleotide (FMN) radical in an aqueous environment. In addition, three structural analogs with different methylation patterns are characterized and the influence of the substituents at the isoalloxazine moiety on the electronic structure of the radicals is explored. By exploiting nuclear hyperpolarization generated via the photo-CIDNP (chemically induced dynamic nuclear polarization) effect, it is possible to study the short-lived radical species generated by in situ light excitation. Experimental data are extracted by least-squares fitting and supported by quantum chemical calculations and published values from electron paramagnetic resonance and electron-nuclear double resonance. Furthermore, mechanistic details of the photoreaction of the investigated flavin analogs with l-tryptophan are derived from the photo-CIDNP spectra recorded at different pH values. Thereby, the neutral and anionic radicals of FMN and three structural analogs are, for the first time, characterized in terms of their electronic structure in an aqueous environment.
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Affiliation(s)
- Nils Pompe
- Institute of Physical Chemistry, University of Freiburg, 79104 Freiburg, Germany
| | - Jing Chen
- Institute of Physical Chemistry, University of Freiburg, 79104 Freiburg, Germany
| | - Boris Illarionov
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, 20146 Hamburg, Germany
| | - Sabrina Panter
- Institute of Physical Chemistry, University of Freiburg, 79104 Freiburg, Germany
| | - Markus Fischer
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, 20146 Hamburg, Germany
| | - Adelbert Bacher
- Department of Chemistry, Technical University of Munich, 85748 Garching, Germany
| | - Stefan Weber
- Institute of Physical Chemistry, University of Freiburg, 79104 Freiburg, Germany
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13
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Ding Y, Kiryutin AS, Yurkovskaya AV, Sosnovsky DV, Sagdeev RZ, Bannister S, Kottke T, Kar RK, Schapiro I, Ivanov KL, Matysik J. Nuclear spin-hyperpolarization generated in a flavoprotein under illumination: experimental field-dependence and theoretical level crossing analysis. Sci Rep 2019; 9:18436. [PMID: 31804538 PMCID: PMC6895156 DOI: 10.1038/s41598-019-54671-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 11/15/2019] [Indexed: 11/25/2022] Open
Abstract
The solid-state photo-chemically induced dynamic nuclear polarization (photo-CIDNP) effect generates non-equilibrium nuclear spin polarization in frozen electron-transfer proteins upon illumination and radical-pair formation. The effect can be observed in various natural photosynthetic reaction center proteins using magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, and in a flavin-binding light-oxygen-voltage (LOV) domain of the blue-light receptor phototropin. In the latter system, a functionally instrumental cysteine has been mutated to interrupt the natural cysteine-involving photochemistry allowing for an electron transfer from a more distant tryptophan to the excited flavin mononucleotide chromophore. We explored the solid-state photo-CIDNP effect and its mechanisms in phototropin-LOV1-C57S from the green alga Chlamydomonas reinhardtii by using field-cycling solution NMR. We observed the 13C and, to our knowledge, for the first time, 15N photo-CIDNP signals from phototropin-LOV1-C57S. Additionally, the 1H photo-CIDNP signals of residual water in the deuterated buffer of the protein were detected. The relative strengths of the photo-CIDNP effect from the three types of nuclei, 1H, 13C and 15N were measured in dependence of the magnetic field, showing their maximum polarizations at different magnetic fields. Theoretical level crossing analysis demonstrates that anisotropic mechanisms play the dominant role at high magnetic fields.
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Affiliation(s)
- Yonghong Ding
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103, Leipzig, Germany
| | - Alexey S Kiryutin
- International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya, 3а, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 1, Novosibirsk, 630090, Russia
| | - Alexandra V Yurkovskaya
- International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya, 3а, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 1, Novosibirsk, 630090, Russia
| | - Denis V Sosnovsky
- International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya, 3а, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 1, Novosibirsk, 630090, Russia
| | - Renad Z Sagdeev
- International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya, 3а, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 1, Novosibirsk, 630090, Russia
| | - Saskia Bannister
- Physical and Biophysical Chemistry, Bielefeld University, Universitätsstr. 25, 33615, Bielefeld, Germany
| | - Tilman Kottke
- Physical and Biophysical Chemistry, Bielefeld University, Universitätsstr. 25, 33615, Bielefeld, Germany
| | - Rajiv K Kar
- Fritz Haber Center for Molecular Dynamics Research, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Igor Schapiro
- Fritz Haber Center for Molecular Dynamics Research, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Konstantin L Ivanov
- International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya, 3а, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 1, Novosibirsk, 630090, Russia
| | - Jörg Matysik
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103, Leipzig, Germany.
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14
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Halse ME, Procacci B, Perutz RN, Duckett SB. Towards measuring reactivity on micro-to-millisecond timescales with laser pump, NMR probe spectroscopy. Faraday Discuss 2019; 220:28-44. [DOI: 10.1039/c9fd00039a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We present a quantitative analysis of the timescales of reactivity that are accessible to a laser pump, NMR probe spectroscopy method using para-hydrogen induced polarisation (PHIP) and identify three kinetic regimes: fast, intermediate and slow.
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Affiliation(s)
| | - Barbara Procacci
- Centre for Hyperpolarisation in Magnetic Resonance
- Department of Chemistry
- University of York
- York
- UK
| | | | - Simon B. Duckett
- Centre for Hyperpolarisation in Magnetic Resonance
- Department of Chemistry
- University of York
- York
- UK
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15
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Morozova OB, Ivanov KL. Time-Resolved Chemically Induced Dynamic Nuclear Polarization of Biologically Important Molecules. Chemphyschem 2018; 20:197-215. [DOI: 10.1002/cphc.201800566] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 10/11/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Olga B. Morozova
- International Tomography Center; Institutskaya 3a 630090 Novosibirsk Russia
- Novosibirsk State University; Pirogova 2 630090 Novosibirsk Russia
| | - Konstantin L. Ivanov
- International Tomography Center; Institutskaya 3a 630090 Novosibirsk Russia
- Novosibirsk State University; Pirogova 2 630090 Novosibirsk Russia
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16
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Okuno Y, Cavagnero S. Effect of heavy atoms on photochemically induced dynamic nuclear polarization in liquids. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 286:172-187. [PMID: 29274568 PMCID: PMC5767533 DOI: 10.1016/j.jmr.2017.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Revised: 11/18/2017] [Accepted: 12/02/2017] [Indexed: 06/07/2023]
Abstract
Given its short hyperpolarization time (∼10-6 s) and mostly non-perturbative nature, photo-chemically induced dynamic nuclear polarization (photo-CIDNP) is a powerful tool for sensitivity enhancement in nuclear magnetic resonance. In this study, we explore the extent of 1H-detected 13C nuclear hyperpolarization that can be gained via photo-CIDNP in the presence of small-molecule additives containing a heavy atom. The underlying rationale for this methodology is the well-known external-heavy-atom (EHA) effect, which leads to significant enhancements in the intersystem-crossing rate of selected photosensitizer dyes from photoexcited singlet to triplet. We exploited the EHA effect upon addition of moderate amounts of halogen-atom-containing cosolutes. The resulting increase in the transient triplet-state population of the photo-CIDNP sensitizer fluorescein resulted in a significant increase in the nuclear hyperpolarization achievable via photo-CIDNP in liquids. We also explored the internal-heavy-atom (IHA) effect, which is mediated by halogen atoms covalently incorporated into the photosensitizer dye. Widely different outcomes were achieved in the case of EHA and IHA, with EHA being largely preferable in terms of net hyperpolarization.
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Affiliation(s)
- Yusuke Okuno
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Ave., Madison, WI 53706, USA
| | - Silvia Cavagnero
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Ave., Madison, WI 53706, USA.
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17
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Morozova OB, Panov MS, Fishman NN, Yurkovskaya AV. Electron transfer vs. proton-coupled electron transfer as the mechanism of reaction between amino acids and triplet-excited benzophenones revealed by time-resolved CIDNP. Phys Chem Chem Phys 2018; 20:21127-21135. [DOI: 10.1039/c8cp03591a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We use proportionality between NMR signal enhancements in geminate products and hyperfine coupling constants in transient radicals to elucidate reaction mechanism in detail.
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Affiliation(s)
- Olga B. Morozova
- International Tomography Center
- 630090 Novosibirsk
- Russia
- Novosibirsk State University
- 630090 Novosibirsk
| | - Mikhail S. Panov
- International Tomography Center
- 630090 Novosibirsk
- Russia
- Novosibirsk State University
- 630090 Novosibirsk
| | - Natalya N. Fishman
- International Tomography Center
- 630090 Novosibirsk
- Russia
- Novosibirsk State University
- 630090 Novosibirsk
| | - Alexandra V. Yurkovskaya
- International Tomography Center
- 630090 Novosibirsk
- Russia
- Novosibirsk State University
- 630090 Novosibirsk
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18
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Paul S, Kiryutin AS, Guo J, Ivanov KL, Matysik J, Yurkovskaya AV, Wang X. Magnetic field effect in natural cryptochrome explored with model compound. Sci Rep 2017; 7:11892. [PMID: 28928466 PMCID: PMC5605708 DOI: 10.1038/s41598-017-10356-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 08/02/2017] [Indexed: 11/09/2022] Open
Abstract
Many animals sense the Earth's magnetic-field and use it for navigation. It is proposed that a light-dependent quantum effect in cryptochrome proteins, residing in the retina, allows for such an iron-free spin-chemical compass. The photochemical processes, spin-dynamics and its magnetic field dependence in natural cryptochrome are not fully understood by the in vivo and in vitro studies. For a deeper insight into these biophysical mechanisms in cryptochrome, we had introduced a flavin-tryptophan dyad (F10T). Here we present the magnetic field dependence of 1H photo-CIDNP NMR on F10T and a theoretical model for low-field photo-CIDNP of F10T. This model provides mixing mechanism of energy-levels and spin-dynamics at low magnetic fields. Photo-CIDNP has been observed even at Earth's magnetic field (~0.05 mT). These experiments prove F10T to be an excellent model compound establishing the key mechanism of avian-magnetoreception and provide insight into the optimal behaviour of cryptochrome at Earth's magnetic field.
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Affiliation(s)
- Shubhajit Paul
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr, 3, D-04103, Leipzig, Germany
| | - Alexey S Kiryutin
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Institutskaya 3a, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 2, Novosibirsk, 630090, Russia
| | - Jinping Guo
- Department of Chemistry and Biology, College of Science, National University of Defense Technology, 410073, Changsha, China
| | - Konstantin L Ivanov
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Institutskaya 3a, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 2, Novosibirsk, 630090, Russia
| | - Jörg Matysik
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr, 3, D-04103, Leipzig, Germany
| | - Alexandra V Yurkovskaya
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Institutskaya 3a, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 2, Novosibirsk, 630090, Russia
| | - Xiaojie Wang
- Department of Chemistry and Biology, College of Science, National University of Defense Technology, 410073, Changsha, China.
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19
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Morozova OB, Yurkovskaya AV, Vieth HM, Sosnovsky DV, Ivanov KL. Light-induced spin hyperpolarisation in condensed phase. Mol Phys 2017. [DOI: 10.1080/00268976.2017.1363923] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Olga B. Morozova
- Laboratory of Magnetic and Spin Phenomena, International Tomography Center SB RAS, Novosibirsk, 630090, Russia
- Laboratory of Magnetic Resonance in Chemistry, Biology and Medicine, Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Alexandra V. Yurkovskaya
- Laboratory of Magnetic and Spin Phenomena, International Tomography Center SB RAS, Novosibirsk, 630090, Russia
- Laboratory of Magnetic Resonance in Chemistry, Biology and Medicine, Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Hans-Martin Vieth
- Laboratory of Magnetic and Spin Phenomena, International Tomography Center SB RAS, Novosibirsk, 630090, Russia
- Department of Physics, Free University of Berlin, Berlin, 14195, Germany
| | - Denis V. Sosnovsky
- Laboratory of Magnetic and Spin Phenomena, International Tomography Center SB RAS, Novosibirsk, 630090, Russia
- Laboratory of Magnetic Resonance in Chemistry, Biology and Medicine, Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Konstantin L. Ivanov
- Laboratory of Magnetic and Spin Phenomena, International Tomography Center SB RAS, Novosibirsk, 630090, Russia
- Laboratory of Magnetic Resonance in Chemistry, Biology and Medicine, Novosibirsk State University, Novosibirsk, 630090, Russia
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20
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Halse ME, Procacci B, Henshaw SL, Perutz RN, Duckett SB. Coherent evolution of parahydrogen induced polarisation using laser pump, NMR probe spectroscopy: Theoretical framework and experimental observation. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 278:25-38. [PMID: 28347906 DOI: 10.1016/j.jmr.2017.03.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/07/2017] [Accepted: 03/08/2017] [Indexed: 06/06/2023]
Abstract
We recently reported a pump-probe method that uses a single laser pulse to introduce parahydrogen (p-H2) into a metal dihydride complex and then follows the time-evolution of the p-H2-derived nuclear spin states by NMR. We present here a theoretical framework to describe the oscillatory behaviour of the resultant hyperpolarised NMR signals using a product operator formalism. We consider the cases where the p-H2-derived protons form part of an AX, AXY, AXYZ or AA'XX' spin system in the product molecule. We use this framework to predict the patterns for 2D pump-probe NMR spectra, where the indirect dimension represents the evolution during the pump-probe delay and the positions of the cross-peaks depend on the difference in chemical shift of the p-H2-derived protons and the difference in their couplings to other nuclei. The evolution of the NMR signals of the p-H2-derived protons, as well as the transfer of hyperpolarisation to other NMR-active nuclei in the product, is described. The theoretical framework is tested experimentally for a set of ruthenium dihydride complexes representing the different spin systems. Theoretical predictions and experimental results agree to within experimental error for all features of the hyperpolarised 1H and 31P pump-probe NMR spectra. Thus we establish the laser pump, NMR probe approach as a robust way to directly observe and quantitatively analyse the coherent evolution of p-H2-derived spin order over micro-to-millisecond timescales.
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Affiliation(s)
- Meghan E Halse
- Centre for Hyperpolarisation in Magnetic Resonance, Department of Chemistry, York Science Park, University of York, Heslington, York YO10 5NY, UK; Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
| | - Barbara Procacci
- Centre for Hyperpolarisation in Magnetic Resonance, Department of Chemistry, York Science Park, University of York, Heslington, York YO10 5NY, UK; Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
| | - Sarah-Louise Henshaw
- Centre for Hyperpolarisation in Magnetic Resonance, Department of Chemistry, York Science Park, University of York, Heslington, York YO10 5NY, UK; Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
| | - Robin N Perutz
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
| | - Simon B Duckett
- Centre for Hyperpolarisation in Magnetic Resonance, Department of Chemistry, York Science Park, University of York, Heslington, York YO10 5NY, UK; Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
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21
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Amorati R, Valgimigli L, Viglianisi C, Schmallegger M, Neshchadin D, Gescheidt G. Proton-Coupled Electron Transfer from Hydrogen-Bonded Phenols to Benzophenone Triplets. Chemistry 2017; 23:5299-5306. [DOI: 10.1002/chem.201605931] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Indexed: 01/15/2023]
Affiliation(s)
- Riccardo Amorati
- University of Bologna; Department of Chemistry “G. Ciamician”; Via S. Giacomo 11 40126 Bologna Italy
| | - Luca Valgimigli
- University of Bologna; Department of Chemistry “G. Ciamician”; Via S. Giacomo 11 40126 Bologna Italy
| | - Caterina Viglianisi
- Department of Chemistry “Ugo Schiff”; University of Florence; Via della Lastruccia 3-13 50019 Sesto Fiorentino Italy
| | - Max Schmallegger
- Institute of Physical and Theoretical Chemistry; Graz University of Technology, NAWI Graz; Stremayrgasse 9 8010 Graz Austria
| | - Dmytro Neshchadin
- Institute of Physical and Theoretical Chemistry; Graz University of Technology, NAWI Graz; Stremayrgasse 9 8010 Graz Austria
| | - Georg Gescheidt
- Institute of Physical and Theoretical Chemistry; Graz University of Technology, NAWI Graz; Stremayrgasse 9 8010 Graz Austria
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22
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Procacci B, Aguiar PM, Halse ME, Perutz RN, Duckett SB. Photochemical pump and NMR probe to monitor the formation and kinetics of hyperpolarized metal dihydrides. Chem Sci 2016; 7:7087-7093. [PMID: 28451144 PMCID: PMC5363785 DOI: 10.1039/c6sc01956k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/03/2016] [Indexed: 12/22/2022] Open
Abstract
Pulsed-laser experiments validate photochemical pump-NMR probe spectroscopy for monitoring the rate of rapid H2 oxidative addition to a metal centre.
On reaction of IrI(CO)(PPh3)21 with para-hydrogen (p-H2), Ir(H)2I(CO)(PPh3)22 is formed which exhibits strongly enhanced 1H NMR signals for its hydride resonances. Complex 2 also shows similar enhancement of its NMR spectra when it is irradiated under p-H2. We report the use of this photochemical reactivity to measure the kinetics of H2 addition by laser-synchronized reactions in conjunction with NMR. The single laser pulse promotes the reductive elimination of H2 from Ir(H)2I(CO)(PPh3)22 in C6D6 solution to form the 16-electron precursor 1, back reaction with p-H2 then reforms 2 in a well-defined nuclear spin-state. The build up of this product can be followed by incrementing a precisely controlled delay (τ), in millisecond steps, between the laser and the NMR pulse. The resulting signal vs. time profile shows a dependence on p-H2 pressure. The plot of kobs against p-H2 pressure is linear and yields the second order rate constant, k2, for H2 addition to 1 of (3.26 ± 0.42) × 102 M–1 s–1. Validation was achieved by transient-UV-vis absorption spectroscopy which gives k2 of (3.06 ± 0.40) × 102 M–1 s–1. Furthermore, irradiation of a C6D6 solution of 2 with multiple laser shots, in conjunction with p-H2 derived hyperpolarization, allows the detection and characterisation of two minor reaction products, 2a and 3, which are produced in such low yields that they are not detected without hyperpolarization. Complex 2a is a configurational isomer of 2, while 3 is formed by substitution of CO by PPh3.
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Affiliation(s)
- Barbara Procacci
- Centre for Hyperpolarisation in Magnetic Resonance , Department of Chemistry , York Science Park , University of York , Heslington , York , YO10 5NY , UK . .,Department of Chemistry , University of York , Heslington , York YO10 5DD , UK .
| | - Pedro M Aguiar
- Department of Chemistry , University of York , Heslington , York YO10 5DD , UK .
| | - Meghan E Halse
- Centre for Hyperpolarisation in Magnetic Resonance , Department of Chemistry , York Science Park , University of York , Heslington , York , YO10 5NY , UK . .,Department of Chemistry , University of York , Heslington , York YO10 5DD , UK .
| | - Robin N Perutz
- Department of Chemistry , University of York , Heslington , York YO10 5DD , UK .
| | - Simon B Duckett
- Centre for Hyperpolarisation in Magnetic Resonance , Department of Chemistry , York Science Park , University of York , Heslington , York , YO10 5NY , UK . .,Department of Chemistry , University of York , Heslington , York YO10 5DD , UK .
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23
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Eisenreich W, Joshi M, Illarionov B, Kacprzak S, Lukaschek M, Kothe G, Budisa N, Fischer M, Bacher A, Weber S. Strategy for Enhancement of (13)C-Photo-CIDNP NMR Spectra by Exploiting Fractional (13)C-Labeling of Tryptophan. J Phys Chem B 2015; 119:13934-43. [PMID: 26244593 DOI: 10.1021/acs.jpcb.5b06668] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photo-CIDNP effect has proven to be useful to strongly enhance NMR signals of photochemically active proteins simply by irradiation with light. The evolving characteristic patterns of enhanced absorptive and emissive NMR lines can be exploited to elucidate the photochemistry and photophysics of light-driven protein reactions. In particular, by the assignment of (13)C NMR resonances, redox-active amino acids may be identified and thereby electron-transfer pathways unraveled, in favorable cases, even with (13)C at natural abundance. If signal enhancement is weak, uniform (13)C isotope labeling is traditionally applied to increase the signal strength of protein (13)C NMR. However, this typically leads to cross relaxation, which transfers light-induced nuclear-spin polarization to adjacent (13)C nuclei, thereby preventing an unambiguous analysis of the photo-CIDNP effect. In this contribution, two isotope labeling strategies are presented; one leads to specific but ubiquitous (13)C labeling in tryptophan, and the other is based on fractional isotope labeling affording sets of isotopologs with low probability of next-neighbor isotope accumulation within individual tryptophan molecules. Consequently, cross relaxation is largely avoided while the signal enhancement by (13)C enrichment is preserved. This results in significantly simplified polarization patterns that are easier to analyze with respect to the generation of light-generated nuclear-spin polarization.
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Affiliation(s)
- Wolfgang Eisenreich
- Technische Universität München , Lehrstuhl für Biochemie, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Monika Joshi
- Technische Universität München , Lehrstuhl für Biochemie, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Boris Illarionov
- Universität Hamburg , Institut für Lebensmittelchemie, Bundesstr. 45, 20146 Hamburg, Germany
| | - Sylwia Kacprzak
- Albert-Ludwigs-Universität Freiburg , Institut für Physikalische Chemie, Albertstr. 21, 79104 Freiburg, Germany
| | - Michail Lukaschek
- Albert-Ludwigs-Universität Freiburg , Institut für Physikalische Chemie, Albertstr. 21, 79104 Freiburg, Germany
| | - Gerd Kothe
- Albert-Ludwigs-Universität Freiburg , Institut für Physikalische Chemie, Albertstr. 21, 79104 Freiburg, Germany
| | - Nediljko Budisa
- Technische Universität Berlin , Institut für Chemie, Müller-Breslau-Str. 10, 10623 Berlin, Germany
| | - Markus Fischer
- Universität Hamburg , Institut für Lebensmittelchemie, Bundesstr. 45, 20146 Hamburg, Germany
| | - Adelbert Bacher
- Technische Universität München , Lehrstuhl für Biochemie, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Stefan Weber
- Albert-Ludwigs-Universität Freiburg , Institut für Physikalische Chemie, Albertstr. 21, 79104 Freiburg, Germany.,Freiburg Institute for Advanced Studies (FRIAS) , Albertstr. 19, 79104 Freiburg, Germany
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24
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Pravdivtsev AN, Yurkovskaya AV, Ivanov KL, Vieth HM. Importance of polarization transfer in reaction products for interpreting and analyzing CIDNP at low magnetic fields. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 254:35-47. [PMID: 25797825 DOI: 10.1016/j.jmr.2015.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 02/12/2015] [Accepted: 02/16/2015] [Indexed: 05/14/2023]
Abstract
The magnetic field dependence of Chemically Induced Dynamic Nuclear Polarization (CIDNP) was studied for the amino acids N-acetyl histidine, N-acetyl tryptophan and N-acetyl tyrosine. It is demonstrated that at low field CIDNP is strongly affected by polarization redistribution in the diamagnetic molecules. Such a polarization transfer is of coherent nature and is due to spin coherences formed together with non-equilibrium population of the spin states. These coherences clearly manifest themselves in an oscillatory time dependence of polarization. Polarization transfer effects are most pronounced at nuclear spin Level Anti-Crossings (LACs), which also result in sharp features in the CIDNP field dependence. Thus, polarization transfer is an important factor, which has to be taken into account in order to interpret low-field CIDNP data on both qualitative and quantitative level. Possible applications of polarization transfer phenomena are also discussed in the paper. In particular, the role of LACs in spin order transfer is highlighted: LACs provide a new tool for precise manipulation of spin hyperpolarization and NMR enhancement of selected target spins.
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Affiliation(s)
- Andrey N Pravdivtsev
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Institutskaya 3a, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogova 2, Novosibirsk 630090, Russia
| | - Alexandra V Yurkovskaya
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Institutskaya 3a, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogova 2, Novosibirsk 630090, Russia
| | - Konstantin L Ivanov
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Institutskaya 3a, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogova 2, Novosibirsk 630090, Russia.
| | - Hans-Martin Vieth
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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25
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Zhang Y, Berman GP, Kais S. Sensitivity and entanglement in the avian chemical compass. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:042707. [PMID: 25375523 DOI: 10.1103/physreve.90.042707] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Indexed: 06/04/2023]
Abstract
The radical pair mechanism can help to explain avian orientation and navigation. Some evidence indicates that the intensity of external magnetic fields plays an important role in avian navigation. In this paper, using a two-stage model, we demonstrate that birds could reasonably detect the directions of geomagnetic fields and gradients of these fields using a yield-based chemical compass that is sensitive enough for navigation. Also, we find that the lifetime of entanglement in this proposed compass is angle dependent and long enough to allow adequate electron transfer between molecules.
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Affiliation(s)
- Yiteng Zhang
- Department of Physics, Purdue University, West Lafayette, Indiana 47907, USA
| | - Gennady P Berman
- Theoretical Division, LANL, and New Mexico Consortium, Los Alamos, New Mexico 87545, USA
| | - Sabre Kais
- Department of Chemistry, Department of Physics, and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA and Qatar Environment and Energy Research Institute, Qatar Foundation, Doha 5825, Qatar
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26
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Torres O, Procacci B, Halse ME, Adams RW, Blazina D, Duckett SB, Eguillor B, Green RA, Perutz RN, Williamson DC. Photochemical Pump and NMR Probe: Chemically Created NMR Coherence on a Microsecond Time Scale. J Am Chem Soc 2014; 136:10124-31. [DOI: 10.1021/ja504732u] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Olga Torres
- Department
of Chemistry, University of York, Heslington, York YO10
5DD, U.K
| | - Barbara Procacci
- Department
of Chemistry, University of York, Heslington, York YO10
5DD, U.K
| | - Meghan E. Halse
- Department
of Chemistry, University of York, Heslington, York YO10
5DD, U.K
| | - Ralph W. Adams
- Department
of Chemistry, University of York, Heslington, York YO10
5DD, U.K
| | - Damir Blazina
- Department
of Chemistry, University of York, Heslington, York YO10
5DD, U.K
| | - Simon B. Duckett
- Department
of Chemistry, University of York, Heslington, York YO10
5DD, U.K
| | - Beatriz Eguillor
- Department
of Chemistry, University of York, Heslington, York YO10
5DD, U.K
| | - Richard A. Green
- Department
of Chemistry, University of York, Heslington, York YO10
5DD, U.K
| | - Robin N. Perutz
- Department
of Chemistry, University of York, Heslington, York YO10
5DD, U.K
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27
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Takahashi H, Iwama M, Akai N, Shibuya K, Kawai A. Pulsed EPR study on large dynamic electron polarisation created in the quenching of photo-excited xanthene dyes by nitroxide radicals in aqueous solutions. Mol Phys 2013. [DOI: 10.1080/00268976.2013.827255] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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28
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1H CIDNP study of the kinetics and mechanism of the reversible photoinduced oxidation of tryptophyl-tryptophan dipeptide in aqueous solutions. Russ Chem Bull 2012. [DOI: 10.1007/s11172-011-0396-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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29
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Goez M. Elucidating organic reaction mechanisms using photo-CIDNP spectroscopy. Top Curr Chem (Cham) 2012; 338:1-32. [PMID: 22911487 DOI: 10.1007/128_2012_348] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
CIDNP (chemically induced dynamic nuclear polarization) arises in radical pairs or biradicals but is detected in the diamagnetic reaction products. Hence, it can be used not only to identify and characterize both types of species but also to establish the pathways connecting precursors, paramagnetic intermediates and products, and to employ the polarizations as labels to individual nuclei. Recent applications of CIDNP to elucidate the mechanisms of photochemical reactions are reviewed, which illustrate all these facets.
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Affiliation(s)
- Martin Goez
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Str. 2, 06120, Halle/Saale, Germany,
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30
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Stoll S, Shafaat HS, Krzystek J, Ozarowski A, Tauber MJ, Kim JE, Britt RD. Hydrogen bonding of tryptophan radicals revealed by EPR at 700 GHz. J Am Chem Soc 2011; 133:18098-101. [PMID: 22007694 PMCID: PMC3251908 DOI: 10.1021/ja208462t] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Redox-active tryptophans are important in biological electron transfer and redox biochemistry. Proteins can tune the electron transfer kinetics and redox potentials of tryptophan via control of the protonation state and the hydrogen-bond strength. We examine the local environment of two neutral tryptophan radicals (Trp108 on the solvent-exposed surface and Trp48 buried in the hydrophobic core) in two azurin variants. Ultrahigh-field EPR spectroscopy at 700 GHz and 25 T allowed complete resolution of all of the principal components of the g tensors of the two radicals and revealed significant differences in the g tensor anisotropies. The spectra together with (2)H ENDOR spectra and supporting DFT calculations show that the g tensor anisotropy is directly diagnostic of the presence or absence as well as the strength of a hydrogen bond to the indole nitrogen. The approach is a powerful one for identifying and characterizing hydrogen bonds that are critical in the regulation of tryptophan-assisted electron transfer and tryptophan-mediated redox chemistry in proteins.
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Affiliation(s)
- Stefan Stoll
- Department of Chemistry, University of California Davis, Davis California 95616, United States
| | - Hannah S. Shafaat
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla California 92093, United States
| | - J. Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee Florida 32310, United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, Tallahassee Florida 32310, United States
| | - Michael J. Tauber
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla California 92093, United States
| | - Judy E. Kim
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla California 92093, United States
| | - R. David Britt
- Department of Chemistry, University of California Davis, Davis California 95616, United States
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31
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Maeda K, Neil SRT, Henbest KB, Weber S, Schleicher E, Hore PJ, Mackenzie SR, Timmel CR. Following Radical Pair Reactions in Solution: A Step Change in Sensitivity Using Cavity Ring-Down Detection. J Am Chem Soc 2011; 133:17807-15. [DOI: 10.1021/ja206783t] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kiminori Maeda
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford, OX1 3QR, U.K
- Centre for Advanced Electron Spin Resonance, University of Oxford, OX1 3QR, U.K
| | - Simon R. T. Neil
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford, OX1 3QZ, U.K
| | - Kevin B. Henbest
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford, OX1 3QR, U.K
- Centre for Advanced Electron Spin Resonance, University of Oxford, OX1 3QR, U.K
| | - Stefan Weber
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104 Freiburg, Germany
| | - Erik Schleicher
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104 Freiburg, Germany
| | - P. J. Hore
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford, OX1 3QZ, U.K
| | - Stuart R. Mackenzie
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford, OX1 3QZ, U.K
| | - Christiane R. Timmel
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford, OX1 3QR, U.K
- Centre for Advanced Electron Spin Resonance, University of Oxford, OX1 3QR, U.K
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32
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Lee JH, Sekhar A, Cavagnero S. 1H-Detected 13C photo-CIDNP as a sensitivity enhancement tool in solution NMR. J Am Chem Soc 2011; 133:8062-5. [PMID: 21548581 DOI: 10.1021/ja111613c] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
NMR is a powerful yet intrinsically insensitive technique. The applicability of NMR to chemical and biological systems would be substantially extended by new approaches going beyond current signal-to-noise capabilities. Here, we exploit the large enhancements arising from (13)C photochemically induced dynamic nuclear polarization ((13)C photo-CIDNP) in solution to improve biomolecular NMR sensitivity in the context of heteronuclear correlation spectroscopy. The (13)C-PRINT pulse sequence presented here involves an initial (13)C nuclear spin polarization via photo-CIDNP followed by conversion to anti-phase coherence and transfer to (1)H for detection. We observe substantial enhancements, up to ≫200-fold, relative to the dark (laser off) experiment. Resonances of both side-chain and backbone CH pairs are enhanced for the three aromatic residues Trp, His, and Tyr, the σ(32) peptide, and the drkN SH3 protein. The sensitivity of this experiment, defined as signal-to-noise per square root of unit time (S/N)(t), is unprecedented in the NMR polarization enhancement literature dealing with polypeptides in solution. Up to a 16-fold larger (S/N)(t) than for the (1)H-(13)C SE-HSQC reference sequence is achieved, for the σ(32) peptide. Data collection time is reduced up to 256-fold, highlighting the advantages of (1)H-detected (13)C photo-CIDNP in solution NMR.
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Affiliation(s)
- Jung Ho Lee
- Biophysics Graduate Program, University of Wisconsin, Madison, Wisconsin 53706, USA
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33
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Morozova OB, Ivanov KL, Kiryutin AS, Sagdeev RZ, Köchling T, Vieth HM, Yurkovskaya AV. Time-resolved CIDNP: an NMR way to determine the EPR parameters of elusive radicals. Phys Chem Chem Phys 2011; 13:6619-27. [DOI: 10.1039/c0cp02449j] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Neshchadin D, Levinn R, Gescheidt G, Batchelor SN. Probing the antioxidant activity of polyphenols by CIDNP: from model compounds to green tea and red wine. Chemistry 2010; 16:7008-16. [PMID: 20440723 DOI: 10.1002/chem.200903238] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Polyphenols occur naturally in a vast variety of plants. One of their predominant properties is their antioxidant activity. To provide a deeper understanding of the antioxidant mechanism, (1)H CIDNP spectroscopy (CIDNP=chemically induced dynamic nuclear polarization) is used to study model hydrogen abstraction reactions with four catechin-based polyphenols: catechin (CA), gallocatechin (GC), epigallocatechin (EGC), and epigallocatechin gallate (EGCG). The experiments involve photoinduced hydrogen-atom transfer to a hydrogen abstractor (e.g., excited isopropylthioxanthone) followed under steady-state conditions and in a time-resolved fashion (resolution 500 ns-1 ms). It is found that hydrogen abstraction is an essentially stochastic process with a slight preference for the B rings in the catechin-based polyphenols. Remarkably, analogous reactivity patterns could be followed in the "real systems", green tea and red wine. We also show that CIDNP can be used as a semiquantitative tool to assess chemical reactivity.
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Affiliation(s)
- Dmytro Neshchadin
- Institute of Physical and Theoretical Chemistry, Graz University of Technology, Technikerstrasse 4/I, 8010 Graz, Austria
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35
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Stoll S, NejatyJahromy Y, Woodward JJ, Ozarowski A, Marletta MA, Britt RD. Nitric oxide synthase stabilizes the tetrahydrobiopterin cofactor radical by controlling its protonation state. J Am Chem Soc 2010; 132:11812-23. [PMID: 20669954 DOI: 10.1021/ja105372s] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Nitric oxide synthase (NOS), a homodimeric enzyme with a flavin reductase domain and a P450-type heme-containing oxygenase domain, catalyzes the formation of NO from L-arginine, NADPH, and O(2) in a two-step reaction sequence. In the first step, a tetrahydrobiopterin (H(4)B) cofactor bound near one of the heme propionate groups acts as an electron donor to the P450-type heme active site, yielding a one-electron oxidized radical that is subsequently re-reduced. In solution, H(4)B undergoes two-electron oxidation, showing that the enzyme significantly alters the proton- and electron-transfer properties of the cofactor. Multifrequency EPR and ENDOR spectroscopy were used to determine magnetic parameters, and from them the (de)protonation state of the H(4)B radical in the oxygenase domain dimer of inducible NO synthase that was trapped by rapid freeze quench. From 9.5 and 330-416 GHz EPR and from 34 GHz (1)H ENDOR spectroscopy, the g tensor of the radical and the hyperfine tensors of several N and H nuclei in the radical were obtained. Density functional theory calculations at the PBE0/EPR-II level for H(4)B radical models predict different spin density distributions and g and hyperfine tensors for different protonation states. Comparison of the predicted and experimental values leads to the conclusion that the radical is cationic H(4)B(*+), suggesting that NOS stabilizes this protonated form to utilize the cofactor in a unique dual one-electron redox role, where it can deliver an electron to the active site for reductive oxygen activation and also remove an electron from the active site to generate NO and not NO(-). The protein environment also prevents further oxidation and subsequent loss of function of the cofactor, thus enabling the enzyme to perform the unusual catalytic one-electron chemistry.
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Affiliation(s)
- Stefan Stoll
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, USA
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36
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Maeda K, Robinson AJ, Henbest KB, Dell EJ, Timmel CR. Protein surface interactions probed by magnetic field effects on chemical reactions. J Am Chem Soc 2010; 132:1466-7. [PMID: 20085319 DOI: 10.1021/ja908988u] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Here we have employed the effects of weak static magnetic fields (not exceeding 46 mT) on radical recombination reactions to investigate protein-substrate interactions. Pulsed laser excitation of an aqueous solution of anthraquinone-2,6-disulfonate (AQDS(2-)) and either hen egg white lysozyme (HEWL) or bovine serum albumin (BSA) produces the triplet state of the radical pair (T)[AQDS(3-*) Trp(*)] by a photoinduced electron transfer reaction from tryptophan residues. Time-resolved absorption techniques were employed to study the recombination characteristics of these radical pairs at different static magnetic fields and ionic strengths. The experimental data in connection with the simulated curves unequivocally show that the radical pair has a lifetime of the order of microseconds in both systems (HEWL and BSA). However, the radical pair is embedded within a binding pocket of the BSA protein, while the (otherwise identical) radical pair, being subject to attractive Coulomb forces, resides on the protein surface in the HEWL system.
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Affiliation(s)
- Kiminori Maeda
- Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK.
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37
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Perrier S, Mugeniwabagara E, Kirsch-De Mesmaeker A, Hore PJ, Luhmer M. Exploring photoreactions between polyazaaromatic Ru(II) complexes and biomolecules by chemically induced dynamic nuclear polarization measurements. J Am Chem Soc 2009; 131:12458-65. [PMID: 19658383 DOI: 10.1021/ja9024287] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Steady-state (1)H photo-chemically induced dynamic nuclear polarization (CIDNP) experiments were conducted at 14.1 T on deoxygenated (buffered pH 7) aqueous solutions of [Ru(phen)(3)](2+), [Ru(tap)(2)(phen)](2+), and [Ru(tap)(3)](2+) (tap = 1,4,5,8-tetraazaphenanthrene; phen = 1,10-phenanthroline) in the presence of guanosine-5'-monophosphate or N-acetyltyrosine. For the first time, CIDNP arising from photo-oxidation by polyazaaromatic Ru(II) complexes is reported. In agreement with the occurrence of a photo-electron-transfer process, photo-CIDNP effects are observed with [Ru(tap)(3)](2+) and [Ru(tap)(2)(phen)](2+) but not with [Ru(phen)(3)](2+). With [Ru(tap)(2)(phen)](2+), no significant photo-CIDNP is observed for the (1)H nuclei of the phen ligand, consistent with the fact that the metal-to-ligand charge-transfer triplet excited states responsible for the photo-oxidation involve a tap ligand. Successive experiments with [Ru(tap)(3)](2+) highlight the accumulation of long-lived radical species in solution that cause (1)H NMR signal broadening and photo-CIDNP extinction. The (1)H photo-CIDNP observed for the biomolecules is rather weak, less than about 30% of the equilibrium magnetization. However, up to 60% polarization enhancement is observed for H-2 and H-7 of the tap ligands, which indicates high unpaired electron density in the vicinity of these atoms in the transient radical pair. This is consistent with the structure of known photoadducts formed, for instance, between the metallic compounds and the guanine base of mono- and polynucleotides. Indeed, in these adducts the covalent bond involves carbon C-2 or C-7 of a tap ligand. The occurrence of photo-CIDNP with polyazaaromatic Ru(II) complexes opens new perspectives for the study of this type of compound.
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Affiliation(s)
- Sandrine Perrier
- Laboratoire de Résonance Magnétique Nucléaire Haute Résolution, Université Libre de Bruxelles, 50 Av. F.D. Roosevelt, B-1050 Bruxelles, Belgium
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38
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Kiryutin AS, Ivanov KL, Morozova OB, Yurkovskaya AV, Vieth HM, Pirogov YA, Sagdeev RZ. TR-CIDNP as tool for quantitative analysis of hyperfine couplings in elusive radicals. DOKLADY PHYSICAL CHEMISTRY 2009. [DOI: 10.1134/s0012501609090061] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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39
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Tryptophan 13C nuclear-spin polarization generated by intraprotein electron transfer in a LOV2 domain of the blue-light receptor phototropin. Biochem Soc Trans 2009; 37:382-6. [PMID: 19290867 DOI: 10.1042/bst0370382] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
(13)C-NMR experiments were performed on photo-excited fully and partially (13)C-labelled LOV2 domains of the blue-light receptor phototropin. In the present paper, we report on nuclear-spin polarized tryptophan resonances that are generated by light-induced intraprotein electron transfer to the FMN cofactor. The spectra are discussed with respect to earlier data obtained from (13)C-NMR experiments on unlabelled LOV2 domains that have been reconstituted with FMN (13)C isotopologues.
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40
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Morozova OB, Korchak SE, Vieth HM, Yurkovskaya AV. Photo-CIDNP Study of Transient Radicals of Met-Gly and Gly-Met Peptides in Aqueous Solution at Variable pH. J Phys Chem B 2009; 113:7398-406. [DOI: 10.1021/jp8112182] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Olga B. Morozova
- International Tomography Center, Institutskaya 3a, 630090 Novosibirsk-90, Russia, Institute of Experimental Physics, Free University of Berlin, Arnimallee 14, D-14195, Germany
| | - Sergey E. Korchak
- International Tomography Center, Institutskaya 3a, 630090 Novosibirsk-90, Russia, Institute of Experimental Physics, Free University of Berlin, Arnimallee 14, D-14195, Germany
| | - Hans-Martin Vieth
- International Tomography Center, Institutskaya 3a, 630090 Novosibirsk-90, Russia, Institute of Experimental Physics, Free University of Berlin, Arnimallee 14, D-14195, Germany
| | - Alexandra V. Yurkovskaya
- International Tomography Center, Institutskaya 3a, 630090 Novosibirsk-90, Russia, Institute of Experimental Physics, Free University of Berlin, Arnimallee 14, D-14195, Germany
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41
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Duckett SB, Wood NJ. Parahydrogen-based NMR methods as a mechanistic probe in inorganic chemistry. Coord Chem Rev 2008. [DOI: 10.1016/j.ccr.2008.01.028] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Morozova OB, Yurkovskaya AV. Aminium Cation Radical of Glycylglycine and its Deprotonation to Aminyl Radical in Aqueous Solution. J Phys Chem B 2008; 112:12859-62. [DOI: 10.1021/jp807149a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Olga B. Morozova
- International Tomography Center of SB RAS, Institutskaya 3a, 630090 Novosibirsk, Russia, and Institute of Experimental Physics, Free University of Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Alexandra V. Yurkovskaya
- International Tomography Center of SB RAS, Institutskaya 3a, 630090 Novosibirsk, Russia, and Institute of Experimental Physics, Free University of Berlin, Arnimallee 14, 14195 Berlin, Germany
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Connor HD, Sturgeon BE, Mottley C, Sipe HJ, Mason RP. L-tryptophan radical cation electron spin resonance studies: connecting solution-derived hyperfine coupling constants with protein spectral interpretations. J Am Chem Soc 2008; 130:6381-7. [PMID: 18433127 DOI: 10.1021/ja0780277] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fast-flow electron spin resonance (ESR) spectroscopy has been used to detect a free radical formed from the reaction of l-tryptophan with Ce (4+) in an acidic aqueous environment. Computer simulations of the ESR spectra from l-tryptophan and several isotopically modified forms strongly support the conclusion that the l-tryptophan radical cation has been detected by ESR for the first time. The hyperfine coupling constants (HFCs) determined from the well-resolved isotropic ESR spectra support experimental and computational efforts to understand l-tryptophan's role in protein catalysis of oxidation-reduction processes. l-Tryptophan HFCs facilitated the simulation of fast-flow ESR spectra of free radicals from two related compounds, tryptamine and 3-methylindole. Analysis of these three compounds' beta-methylene hydrogen HFC data along with equivalent l-tyrosine data has led to a new computational method that can distinguish between these two amino acid free radicals in proteins without dependence on isotope labeling, electron-nuclear double resonance, or high-field ESR. This approach also produces geometric parameters (dihedral angles for the beta-methylene hydrogens) that should facilitate protein site assignment of observed l-tryptophan radicals as has been done for l-tyrosine radicals.
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Affiliation(s)
- Henry D Connor
- Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, P.O. Box 12233, Research Triangle Park, North Carolina 27709, USA
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Morozova OB, Kiryutin AS, Yurkovskaya AV. Electron transfer between guanosine radicals and amino acids in aqueous solution. II. Reduction of guanosine radicals by tryptophan. J Phys Chem B 2008; 112:2747-54. [PMID: 18266352 DOI: 10.1021/jp0752318] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The efficiency of the chemical pathway of DNA repair is studied by time-resolved chemically induced dynamic nuclear polarization (CIDNP) using the model system containing guanosyl base radicals, and tryptophan as the electron donor. Radicals were generated photochemically by pulsed laser irradiation of a solution containing the photosensitizer 2,2'-dipyridyl, guanosine-5'-monophosphate, and N-acetyl tryptophan. Depending on the pH of the aqueous solution, four protonation states of the guanosyl radical are formed via electron or hydrogen atom transfer to the triplet excited dye. The rate constants of electron transfer from the amino acid to the guanosyl radical were determined by quantitative analysis of the CIDNP kinetics, which is very sensitive to the efficiency of radical reactions in the bulk, and rate constants vary from (1.0 +/- 0.3) x 10(9) M(-1) s(-1) for the cation and dication radicals of the nucleotide to (1.2 +/- 0.3) x 10(7) M(-1) s(-1) for the radical in its anionic form. They were found to be higher than the corresponding values for electron transfer in the case of N-acetyl tyrosine as the reducing agent.
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Affiliation(s)
- Olga B Morozova
- International Tomography Center of SB RAS, Institutskaya 3a, 630090 Novosibirsk, Russia
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