1
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Li S, Bhattacharya S, Chou CY, Chu M, Chou SC, Tonelli M, Goger M, Yang H, Palmer AG, Cavagnero S. LC-Photo-CIDNP hyperpolarization of biomolecules bearing a quasi-isolated spin pair: Magnetic-Field dependence via a rapid-shuttling device. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2024; 359:107616. [PMID: 38271744 PMCID: PMC10922348 DOI: 10.1016/j.jmr.2023.107616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 12/27/2023] [Accepted: 12/28/2023] [Indexed: 01/27/2024]
Abstract
Liquid-state low-concentration photochemically induced dynamic nuclear polarization (LC-photo-CIDNP) is an emerging technology tailored to enhance the sensitivity of NMR spectroscopy via LED- or laser-mediated optical irradiation. LC-photo-CIDNP is particularly useful to detect solvent-exposed aromatic residues (Trp, Tyr), either in isolation or within polypeptides and proteins. This study investigates the magnetic-field dependence of the LC-photo-CIDNP of Trp-α-13C-β,β,2,4,5,6,7-d7, a Trp isotopolog bearing a quasi-isolated 1Hα-13Cαspin pair (QISP). We employed a new rapid-shuttling side-illumination field-cycling device that enables ultra-fast (90-120 ms) vertical movements of NMR samples within the bore of a superconducting magnet. Thus, LC-photo-CIDNP hyperpolarization occurs at low field, while hyperpolarized signals are detected at high field (700 MHz). Resonance lineshapes were excellent, and the effect of several fields (1.18-7.08 T range) on hyperpolarization efficiency could be readily explored. Remarkably, unprecedented LC-photo-CIDNP enhancements ε ≅ 1,200 were obtained at 50 MHz (1.18 T), suggesting exciting avenues to hypersensitive LED-enhanced NMR in liquids at low field.
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Affiliation(s)
- Siyu Li
- Dept. of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
| | | | - Ching-Yu Chou
- Field Cycling Technology LTD., New Taipei City 23444, Taiwan, ROC
| | - Minglee Chu
- Institute of Physics, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
| | - Shu-Cheng Chou
- Field Cycling Technology LTD., New Taipei City 23444, Taiwan, ROC
| | - Marco Tonelli
- Dept. of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Michael Goger
- New York Structural Biology Center, New York, NY 10027, United States
| | - Hanming Yang
- Dept. of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Arthur G Palmer
- New York Structural Biology Center, New York, NY 10027, United States; Dept. of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, United States
| | - Silvia Cavagnero
- Dept. of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States.
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2
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Eills J, Budker D, Cavagnero S, Chekmenev EY, Elliott SJ, Jannin S, Lesage A, Matysik J, Meersmann T, Prisner T, Reimer JA, Yang H, Koptyug IV. Spin Hyperpolarization in Modern Magnetic Resonance. Chem Rev 2023; 123:1417-1551. [PMID: 36701528 PMCID: PMC9951229 DOI: 10.1021/acs.chemrev.2c00534] [Citation(s) in RCA: 64] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Indexed: 01/27/2023]
Abstract
Magnetic resonance techniques are successfully utilized in a broad range of scientific disciplines and in various practical applications, with medical magnetic resonance imaging being the most widely known example. Currently, both fundamental and applied magnetic resonance are enjoying a major boost owing to the rapidly developing field of spin hyperpolarization. Hyperpolarization techniques are able to enhance signal intensities in magnetic resonance by several orders of magnitude, and thus to largely overcome its major disadvantage of relatively low sensitivity. This provides new impetus for existing applications of magnetic resonance and opens the gates to exciting new possibilities. In this review, we provide a unified picture of the many methods and techniques that fall under the umbrella term "hyperpolarization" but are currently seldom perceived as integral parts of the same field. Specifically, before delving into the individual techniques, we provide a detailed analysis of the underlying principles of spin hyperpolarization. We attempt to uncover and classify the origins of hyperpolarization, to establish its sources and the specific mechanisms that enable the flow of polarization from a source to the target spins. We then give a more detailed analysis of individual hyperpolarization techniques: the mechanisms by which they work, fundamental and technical requirements, characteristic applications, unresolved issues, and possible future directions. We are seeing a continuous growth of activity in the field of spin hyperpolarization, and we expect the field to flourish as new and improved hyperpolarization techniques are implemented. Some key areas for development are in prolonging polarization lifetimes, making hyperpolarization techniques more generally applicable to chemical/biological systems, reducing the technical and equipment requirements, and creating more efficient excitation and detection schemes. We hope this review will facilitate the sharing of knowledge between subfields within the broad topic of hyperpolarization, to help overcome existing challenges in magnetic resonance and enable novel applications.
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Affiliation(s)
- James Eills
- Institute
for Bioengineering of Catalonia, Barcelona
Institute of Science and Technology, 08028Barcelona, Spain
| | - Dmitry Budker
- Johannes
Gutenberg-Universität Mainz, 55128Mainz, Germany
- Helmholtz-Institut,
GSI Helmholtzzentrum für Schwerionenforschung, 55128Mainz, Germany
- Department
of Physics, UC Berkeley, Berkeley, California94720, United States
| | - Silvia Cavagnero
- Department
of Chemistry, University of Wisconsin, Madison, Madison, Wisconsin53706, United States
| | - Eduard Y. Chekmenev
- Department
of Chemistry, Integrative Biosciences (IBio), Karmanos Cancer Institute
(KCI), Wayne State University, Detroit, Michigan48202, United States
- Russian
Academy of Sciences, Moscow119991, Russia
| | - Stuart J. Elliott
- Molecular
Sciences Research Hub, Imperial College
London, LondonW12 0BZ, United Kingdom
| | - Sami Jannin
- Centre
de RMN à Hauts Champs de Lyon, Université
de Lyon, CNRS, ENS Lyon, Université Lyon 1, 69100Villeurbanne, France
| | - Anne Lesage
- Centre
de RMN à Hauts Champs de Lyon, Université
de Lyon, CNRS, ENS Lyon, Université Lyon 1, 69100Villeurbanne, France
| | - Jörg Matysik
- Institut
für Analytische Chemie, Universität
Leipzig, Linnéstr. 3, 04103Leipzig, Germany
| | - Thomas Meersmann
- Sir
Peter Mansfield Imaging Centre, University Park, School of Medicine, University of Nottingham, NottinghamNG7 2RD, United Kingdom
| | - Thomas Prisner
- Institute
of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic
Resonance, Goethe University Frankfurt, , 60438Frankfurt
am Main, Germany
| | - Jeffrey A. Reimer
- Department
of Chemical and Biomolecular Engineering, UC Berkeley, and Materials Science Division, Lawrence Berkeley National
Laboratory, Berkeley, California94720, United States
| | - Hanming Yang
- Department
of Chemistry, University of Wisconsin, Madison, Madison, Wisconsin53706, United States
| | - Igor V. Koptyug
- International Tomography Center, Siberian
Branch of the Russian Academy
of Sciences, 630090Novosibirsk, Russia
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3
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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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4
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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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5
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Sample illumination device facilitates in situ light-coupled NMR spectroscopy without fibre optics. Commun Chem 2022; 5:90. [PMID: 36697806 PMCID: PMC9814378 DOI: 10.1038/s42004-022-00704-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 07/13/2022] [Indexed: 01/28/2023] Open
Abstract
In situ illumination of liquid-state nuclear magnetic resonance (NMR) samples makes it possible for a wide range of light-dependent chemical and biological phenomena to be studied by the powerful analytical technique. However, the position of an NMR sample deep within the bore of the spectrometer magnet renders such illumination challenging. Here, we demonstrate the working principles of a sample illumination device (NMRtorch) where a lighthead containing an LED array is positioned directly at the top of an NMRtorch tube which is inserted into the NMR spectrometer. The wall of the tube itself acts as a light guide, illuminating the sample from the outside. We explore how this new setup performs in a number of photo-NMR applications, including photoisomerisation and photo-chemically induced dynamic nuclear polarisation (photo-CIDNP), and demonstrate the potential for ultraviolet (UV) degradation studies with continuous online NMR assessment. This setup enables users of any typical liquid-state spectrometer to easily perform in situ photo-NMR experiments, using a wide range of wavelengths.
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6
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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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7
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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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8
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Yang H, Mecha MF, Goebel CP, Cavagnero S. Enhanced nuclear-spin hyperpolarization of amino acids and proteins via reductive radical quenchers. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 324:106912. [PMID: 33524671 PMCID: PMC7925436 DOI: 10.1016/j.jmr.2021.106912] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 06/12/2023]
Abstract
Low-concentration photochemically induced dynamic nuclear polarization (LC-photo-CIDNP) has recently emerged as an effective tool for the hyperpolarization of aromatic amino acids in solution, either in isolation or within proteins. One factor limiting the maximum achievable signal-to-noise ratio in LC-photo-CIDNP is the progressive degradation of the target molecule and photosensitizer upon long-term optical irradiation. Fortunately, this effect does not cause spectral distortions but leads to a progressively smaller signal buildup upon long-term data-collection (e.g. 500 nM tryptophan on a 600 MHz spectrometer after ca. 200 scans). Given that it is generally desirable to minimize the extent of photodamage, we report that low-μM amounts of the reductive radical quenchers vitamin C (VC, i.e., ascorbic acid) or 2-mercaptoethylamine (MEA) enable LC-photo-CIDNP data to be acquired for significantly longer time than ever possible before. This approach increases the sensitivity of LC-photo-CIDNP by more than 100%, with larger enhancement factors achieved in experiments involving more transients. Our results are consistent with VC and MEA acting primarily by reducing transient free radicals of the NMR molecule of interest, thus attenuating the extent of photodamage. The benefits of this reductive radical-quencher approach are highlighted by the ability to collect long-term high-resolution 2D 1H-13C LC-photo-CIDNP data on a dilute sample of the drkN SH3 protein (5 μM).
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Affiliation(s)
- Hanming Yang
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Ave, Madison, WI 53706, USA
| | - Miranda F Mecha
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Ave, Madison, WI 53706, USA
| | - Collin P Goebel
- 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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9
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Cheney DJ, Wedge CJ. Optically-generated Overhauser dynamic nuclear polarization: A numerical analysis. J Chem Phys 2020; 152:034202. [DOI: 10.1063/1.5133408] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Daniel J. Cheney
- Department of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield, United Kingdom
| | - Christopher J. Wedge
- Department of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield, United Kingdom
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10
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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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11
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Yang H, Hofstetter H, Cavagnero S. Fast-pulsing LED-enhanced NMR: A convenient and inexpensive approach to increase NMR sensitivity. J Chem Phys 2019; 151:245102. [PMID: 31893873 DOI: 10.1063/1.5131452] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Low-concentration photochemically induced dynamic nuclear polarization (LC-photo-CIDNP) has recently emerged as a powerful technology for the detection of aromatic amino acids and proteins in solution in the low-micromolar to nanomolar concentration range. LC-photo-CIDNP is typically carried out in the presence of high-power lasers, which are costly and maintenance-heavy. Here, we show that LC-photo-CIDNP can be performed with light-emitting diodes (LEDs), which are inexpensive and much less cumbersome than lasers, laser diodes, flash lamps, or other light sources. When nuclear magnetic resonance (NMR) sample concentration is within the low-micromolar to nanomolar range, as in LC-photo-CIDNP, replacement of lasers with LEDs leads to no losses in sensitivity. We also investigate the effect of optical-fiber thickness and compare excitation rate constants of an Ar ion laser (488 nm) and a 466 nm LED, taking LED emission bandwidths into account. In addition, importantly, we develop a novel pulse sequence (13C RASPRINT) to perform ultrarapid LC-photo-CIDNP data collection. Remarkably, 13C RASPRINT leads to 4-fold savings in data collection time. The latter advance relies on the fact that photo-CID nuclear hyperpolarization does not suffer from the longitudinal-relaxation recovery requirements of conventional NMR. Finally, we combine both the above improvements, resulting in facile and rapid (≈16 s-2.5 min) collection of 1 and 2D NMR data on aromatic amino acids and proteins in solution at nanomolar to low micromolar concentration.
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Affiliation(s)
- 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
| | - Silvia Cavagnero
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, USA
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12
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Sobol A, Torres F, Aicher A, Renn A, Riek R. Atto Thio 12 as a promising dye for photo-CIDNP. J Chem Phys 2019; 151:234201. [DOI: 10.1063/1.5128575] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Alexander Sobol
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
| | - Felix Torres
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
| | - Anatol Aicher
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
| | - Alois Renn
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
| | - Roland Riek
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
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13
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Yang H, Cavagnero S. Improved sensitivity of laser-enhanced 1H α- 13C α-correlation via suppression of C α-C' scalar-coupling evolution. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 307:106572. [PMID: 31445479 PMCID: PMC7416423 DOI: 10.1016/j.jmr.2019.106572] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 08/06/2019] [Accepted: 08/12/2019] [Indexed: 06/10/2023]
Abstract
Low-concentration photochemically induced dynamic polarization (LC-photo-CIDNP) enables the spectroscopic analysis of biomolecules containing the amino acids Trp and Tyr at sub-micromolar concentration in solution. Typical LC-photo-CIDNP pulse sequences involving 1H-13C correlation, however, perform well in the case of aromatic resonances but display a relatively poor signal-to-noise ratio for 13Cα and 13Cβ resonances. Here, we develop a novel pulse sequence denoted as 13C perturbation-recovered selective-pulse photo-CINDP enhanced reverse INEPT, or 13C PRESPRINT, tailored to the LC-photo-CIDNP analysis of 1H-13Cα pairs. Our method, which is based on full suppression of 1-bond Cα-C' scalar-coupling evolution during the constant-time delay, results into a sensitivity improvement by a factor of 2. The enhanced performance of this pulse sequence enabled us to improve the analysis of LC-photo-CIDNP laser-power dependence at very low (200 nM) sample concentration. An improved theoretical model, developed to quantitatively describe this laser-power dependence, shows excellent agreement with our 13C PRESPRINT experimental data.
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Affiliation(s)
- Hanming Yang
- 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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Laser- and cryogenic probe-assisted NMR enables hypersensitive analysis of biomolecules at submicromolar concentration. Proc Natl Acad Sci U S A 2019; 116:11602-11611. [PMID: 31142651 DOI: 10.1073/pnas.1820573116] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Solution-state NMR typically requires 100 μM to 1 mM samples. This limitation prevents applications to mass-limited and aggregation-prone target molecules. Photochemically induced dynamic nuclear polarization was adapted to data collection on low-concentration samples by radiofrequency gating, enabling rapid 1D NMR spectral acquisition on aromatic amino acids and proteins bearing aromatic residues at nanomolar concentration, i.e., a full order of magnitude below other hyperpolarization techniques in liquids. Both backbone H1-C13 and side-chain resonances were enhanced, enabling secondary and tertiary structure analysis of proteins with remarkable spectral editing, via the 13C PREPRINT pulse sequence. Laser-enhanced 2D NMR spectra of 5 μM proteins at 600 MHz display 30-fold better S/N than conventional 2D data collected at 900 MHz. Sensitivity enhancements achieved with this technology, denoted as low-concentration photo-CIDNP (LC-photo-CIDNP), depend only weakly on laser intensity, highlighting the opportunity of safer and more cost-effective hypersensitive NMR applications employing low-power laser sources.
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Mompeán M, Sánchez-Donoso RM, de la Hoz A, Saggiomo V, Velders AH, Gomez MV. Pushing nuclear magnetic resonance sensitivity limits with microfluidics and photo-chemically induced dynamic nuclear polarization. Nat Commun 2018; 9:108. [PMID: 29317665 PMCID: PMC5760532 DOI: 10.1038/s41467-017-02575-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 12/11/2017] [Indexed: 12/03/2022] Open
Abstract
Among the methods to enhance the sensitivity of nuclear magnetic resonance (NMR) spectroscopy, small-diameter NMR coils (microcoils) are promising tools to tackle the study of mass-limited samples. Alternatively, hyperpolarization schemes based on dynamic nuclear polarization techniques provide strong signal enhancements of the NMR target samples. Here we present a method to effortlessly perform photo-chemically induced dynamic nuclear polarization in microcoil setups to boost NMR signal detection down to sub-picomole detection limits in a 9.4T system (400 MHz 1H Larmor frequency). This setup is unaffected by current major drawbacks such as the use of high-power light sources to attempt uniform irradiation of the sample, and accumulation of degraded photosensitizer in the detection region. The latter is overcome with flow conditions, which in turn open avenues for complex applications requiring rapid and efficient mixing that are not easily achievable on an NMR tube without resorting to complex hardware. Nuclear magnetic resonance (NMR) spectroscopy is a powerful technique with an inherently low sensitivity. Here, the authors present a combination of microcoils with photo-chemically induced dynamic nuclear polarization to boost NMR sensitivity down to sub-picomole detection limits.
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Affiliation(s)
- Miguel Mompeán
- Instituto Regional de Investigación Científica Aplicada (UCLM), Avda Camilo José Cela s/n, 13071, Ciudad Real, Spain
| | - Rosa M Sánchez-Donoso
- Instituto Regional de Investigación Científica Aplicada (UCLM), Avda Camilo José Cela s/n, 13071, Ciudad Real, Spain.,Laboratory of BioNanoTechnology, Wageningen University, PO Box 8038, 6700, EK Wageningen, The Netherlands
| | - Antonio de la Hoz
- Instituto Regional de Investigación Científica Aplicada (UCLM), Avda Camilo José Cela s/n, 13071, Ciudad Real, Spain
| | - Vittorio Saggiomo
- Laboratory of BioNanoTechnology, Wageningen University, PO Box 8038, 6700, EK Wageningen, The Netherlands
| | - Aldrik H Velders
- Instituto Regional de Investigación Científica Aplicada (UCLM), Avda Camilo José Cela s/n, 13071, Ciudad Real, Spain. .,Laboratory of BioNanoTechnology, Wageningen University, PO Box 8038, 6700, EK Wageningen, The Netherlands. .,MAGNEtic resonance research FacilitY-MAGNEFY, Wageningen University & Research, PO Box 8038, 6700, EK Wageningen, The Netherlands.
| | - M Victoria Gomez
- Instituto Regional de Investigación Científica Aplicada (UCLM), Avda Camilo José Cela s/n, 13071, Ciudad Real, Spain
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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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Okuno Y, Cavagnero S. Fluorescein: A Photo-CIDNP Sensitizer Enabling Hypersensitive NMR Data Collection in Liquids at Low Micromolar Concentration. J Phys Chem B 2016; 120:715-23. [PMID: 26744790 PMCID: PMC4879942 DOI: 10.1021/acs.jpcb.5b12339] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Photochemically induced dynamic nuclear polarization (photo-CIDNP) is a powerful approach for sensitivity enhancement in NMR spectroscopy. In liquids, intermolecular photo-CIDNP depends on the transient bimolecular reaction between photoexcited dye and sample of interest. Hence the extent of polarization is sample-concentration dependent. This study introduces fluorescein (FL) as a photo-CIDNP dye whose performance is exquisitely tailored to data collection at extremely low sample concentrations. The photo-CIDNP resonance intensities of tryptophan in the presence of either FL or FMN (i.e., the routinely employed flavin mononucleotide photosensitizer) in the liquid state show that FL yields superior sensitivity and enables rapid data collection down to an unprecedented 1 μM concentration. This result was achieved on a conventional spectrometer operating at 14.1 T and equipped with a room-temperature probe (i.e., noncryogenic). Kinetic simulations show that the excellent behavior of FL arises from its long excited-state triplet lifetime and superior photostability relative to conventional photo-CIDNP sensitizers.
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Affiliation(s)
- Yusuke Okuno
- 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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18
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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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Lee JH, Okuno Y, Cavagnero S. Sensitivity enhancement in solution NMR: emerging ideas and new frontiers. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 241:18-31. [PMID: 24656077 PMCID: PMC3967054 DOI: 10.1016/j.jmr.2014.01.005] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/14/2014] [Accepted: 01/17/2014] [Indexed: 05/05/2023]
Abstract
Modern NMR spectroscopy has reached an unprecedented level of sophistication in the determination of biomolecular structure and dynamics at atomic resolution in liquids. However, the sensitivity of this technique is still too low to solve a variety of cutting-edge biological problems in solution, especially those that involve viscous samples, very large biomolecules or aggregation-prone systems that need to be kept at low concentration. Despite the challenges, a variety of efforts have been carried out over the years to increase sensitivity of NMR spectroscopy in liquids. This review discusses basic concepts, recent developments and future opportunities in this exciting area of research.
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Affiliation(s)
- Jung Ho Lee
- Department of Chemistry and Biophysics Program, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1322, USA
| | - Yusuke Okuno
- Department of Chemistry and Biophysics Program, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1322, USA
| | - Silvia Cavagnero
- Department of Chemistry and Biophysics Program, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1322, USA.
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Abstract
Photo-chemically induced dynamic nuclear polarization (CIDNP) is a nuclear magnetic resonance (NMR) phenomenon which, among other things, is exploited to extract information on biomolecular structure via probing solvent-accessibilities of tryptophan (Trp), tyrosine (Tyr), and histidine (His) amino acid side chains both in polypeptides and proteins in solution. The effect, normally triggered by a (laser) light-induced photochemical reaction in situ, yields both positive and/or negative signal enhancements in the resulting NMR spectra which reflect the solvent exposure of these residues both in equilibrium and during structural transformations in "real time". As such, the method can offer - qualitatively and, to a certain extent, quantitatively - residue-specific structural and kinetic information on both the native and, in particular, the non-native states of proteins which, often, is not readily available from more routine NMR techniques. In this review, basic experimental procedures of the photo-CIDNP technique as applied to amino acids and proteins are discussed, recent improvements to the method highlighted, and future perspectives presented. First, the basic principles of the phenomenon based on the theory of the radical pair mechanism (RPM) are outlined. Second, a description of standard photo-CIDNP applications is given and it is shown how the effect can be exploited to extract residue-specific structural information on the conformational space sampled by unfolded or partially folded proteins on their "path" to the natively folded form. Last, recent methodological advances in the field are highlighted, modern applications of photo-CIDNP in the context of biological NMR evaluated, and an outlook into future perspectives of the method is given.
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Affiliation(s)
- Lars T Kuhn
- DFG Research Center Molecular Physiology of the Brain (CMPB), European Neuroscience Institute Göttingen (ENI-G) and EXC 171 Microscopy at the Nanometer Range, Göttingen, Germany,
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