1
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Eggeling A, Ngendahimana T, Jeschke G, Eaton GR, Eaton SS. Exploring tunneling ESEEM beyond methyl groups in nitroxides at low temperatures. Phys Chem Chem Phys 2024; 26:15240-15254. [PMID: 38751211 PMCID: PMC11135458 DOI: 10.1039/d4cp01212g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 05/04/2024] [Indexed: 05/30/2024]
Abstract
Tunneling of methyl rotors coupled to an electron spin causes magnetic field independent electron spin echo envelope modulation (ESEEM) at low temperatures. For nitroxides containing alkyl substituents, we observe this effect as a contribution at the beginning of the Hahn echo decay signal occurring on a faster time scale than the matrix-induced decoherence. The tunneling ESEEM contribution includes information on the local environment of the methyl rotors, which manifests as a distribution of rotation barriers P(V3) when measuring the paramagnetic species in a glassy matrix. Here, we investigate the differences in tunneling behaviour of geminal methyl and ethyl group rotors in nitroxides while exploring different levels of theory in our previously introduced methyl quantum rotor (MQR) model. Moreover, we extend the MQR model to analyze the tunneling ESEEM originating from two different rotor types coupled to the same electron spin. We find that ethyl groups in nitroxides give rise to stronger tunneling ESEEM contributions than methyl groups because the difference between hyperfine couplings of their methyl protons better matches the tunneling frequency. The methyl rotors of both ethyl and propyl groups exhibit distributions at lower rotation barriers compared to geminal methyl groups. This is in good agreement with density functional theory (DFT) calculations of their rotation barriers and showcases that conformational flexibility impacts the hindrance of rotation. Using Monte-Carlo based fitting in combination with an identifiability analysis of the MQR model parameter space, we extract rotation barrier distributions for the individual rotor types in mixed-rotor nitroxides as well as identify which rotors dominate the observed tunneling contribution in the Hahn echo decay signal.
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Affiliation(s)
- Andrea Eggeling
- ETH Zurich, Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland.
| | - Thacien Ngendahimana
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, USA.
| | - Gunnar Jeschke
- ETH Zurich, Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland.
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, USA.
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, USA.
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2
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Qiu Y, Eckvahl HJ, Equbal A, Krzyaniak MD, Wasielewski MR. Enhancing Coherence Times of Chromophore-Radical Molecular Qubits and Qudits by Rational Design. J Am Chem Soc 2023; 145:25903-25909. [PMID: 37963349 DOI: 10.1021/jacs.3c10772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
An important criterion for quantum operations is long qubit coherence times. To elucidate the influence of molecular structure on the coherence times of molecular spin qubits and qudits, a series of molecules featuring perylenediimide (PDI) chromophores covalently linked to stable nitroxide radicals were synthesized and investigated by pulse electron paramagnetic resonance spectroscopy. Photoexcitation of PDI in these systems creates an excited quartet state (Q) followed by a spin-polarized doublet ground state (D0), which hold promise as spin qudits and qubits, respectively. By tailoring the molecular structure of these spin qudit/qubit candidates by selective deuteration and eliminating intramolecular motion, coherence times of Tm = 9.1 ± 0.3 and 4.2 ± 0.3 μs at 85 K for D0 and Q, respectively, are achieved. These coherence times represent a nearly 3-fold enhancement compared to those of the initial molecular design. This approach offers a rational structural design protocol for effectively extending coherence times in molecular spin qudits/qubits.
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Affiliation(s)
- Yunfan Qiu
- Department of Chemistry, Center for Molecular Quantum Transduction, and Paula M. Trienens Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3313, United States
| | - Hannah J Eckvahl
- Department of Chemistry, Center for Molecular Quantum Transduction, and Paula M. Trienens Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3313, United States
| | - Asif Equbal
- Department of Chemistry, Center for Molecular Quantum Transduction, and Paula M. Trienens Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3313, United States
| | - Matthew D Krzyaniak
- Department of Chemistry, Center for Molecular Quantum Transduction, and Paula M. Trienens Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3313, United States
| | - Michael R Wasielewski
- Department of Chemistry, Center for Molecular Quantum Transduction, and Paula M. Trienens Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3313, United States
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3
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Yang Z, Stein RA, Pink M, Madzelan P, Ngendahimana T, Rajca S, Wilson MA, Eaton SS, Eaton GR, Mchaourab HS, Rajca A. Cucurbit[7]uril Enhances Distance Measurements of Spin-Labeled Proteins. J Am Chem Soc 2023; 145:25726-25736. [PMID: 37963181 PMCID: PMC10961179 DOI: 10.1021/jacs.3c09184] [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] [Indexed: 11/16/2023]
Abstract
We report complex formation between the chloroacetamide 2,6-diazaadamantane nitroxide radical (ClA-DZD) and cucurbit[7]uril (CB-7), for which the association constant in water, Ka = 1.9 × 106 M-1, is at least 1 order of magnitude higher than the previously studied organic radicals. The radical is highly immobilized by CB-7, as indicated by the increase in the rotational correlation time, τrot, by a factor of 36, relative to that in the buffer solution. The X-ray structure of ClA-DZD@CB-7 shows the encapsulated DZD guest inside the undistorted CB-7 host, with the pendant group protruding outside. Upon addition of CB-7 to T4 Lysozyme (T4L) doubly spin-labeled with the iodoacetamide derivative of DZD, we observe the increase in τrot and electron spin coherence time, Tm, along with the narrowing of interspin distance distributions. Sensitivity of the DEER measurements at 83 K increases by a factor 4-9, compared to the common spin label such as MTSL, which is not affected by CB-7. Interspin distances of 3 nm could be reliably measured in water/glycerol up to temperatures near the glass transition/melting temperature of the matrix at 200 K, thus bringing us closer to the goal of supramolecular recognition-enabled long-distance DEER measurements at near physiological temperatures. The X-ray structure of DZD-T4L 65 at 1.12 Å resolution allows for unambiguous modeling of the DZD label (0.88 occupancy), indicating an undisturbed structure and conformation of the protein.
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Affiliation(s)
- Zhimin Yang
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Richard A. Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Maren Pink
- IUMSC, Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
| | - Peter Madzelan
- Department of Biochemistry and Redox Biology Center, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Thacien Ngendahimana
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Suchada Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Mark A. Wilson
- Department of Biochemistry and Redox Biology Center, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Sandra S. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Gareth R. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Hassane S. Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
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4
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Shu C, Yang Z, Rajca A. From Stable Radicals to Thermally Robust High-Spin Diradicals and Triradicals. Chem Rev 2023; 123:11954-12003. [PMID: 37831948 DOI: 10.1021/acs.chemrev.3c00406] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2023]
Abstract
Stable radicals and thermally robust high-spin di- and triradicals have emerged as important organic materials due to their promising applications in diverse fields. New fundamental properties, such as SOMO/HOMO inversion of orbital energies, are explored for the design of new stable radicals, including highly luminescent ones with good photostability. A relation with the singlet-triplet energy gap in the corresponding diradicals is proposed. Thermally robust high-spin di- and triradicals, with energy gaps that are comparable to or greater than a thermal energy at room temperature, are more challenging to synthesize but more rewarding. We summarize a number of high-spin di- and triradicals, based on nitronyl nitroxides that provide a relation between the experimental pairwise exchange coupling constant J/k in the high-spin species vs experimental hyperfine coupling constants in the corresponding monoradicals. This relation allows us to identify outliers, which may correspond to radicals where J/k is not measured with sufficient accuracy. Double helical high-spin diradicals, in which spin density is delocalized over the chiral π-system, have been barely explored, with the sole example of such high-spin diradical possessing alternant π-system with Kekulé resonance form. Finally, we discuss a high-spin diradical with electrical conductivity and derivatives of triangulene diradicals.
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Affiliation(s)
- Chan Shu
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Zhimin Yang
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
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5
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Schäfter D, Wischnat J, Tesi L, De Sousa JA, Little E, McGuire J, Mas-Torrent M, Rovira C, Veciana J, Tuna F, Crivillers N, van Slageren J. Molecular One- and Two-Qubit Systems with Very Long Coherence Times. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2302114. [PMID: 37289574 DOI: 10.1002/adma.202302114] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 06/06/2023] [Indexed: 06/10/2023]
Abstract
General-purpose quantum computation and quantum simulation require multi-qubit architectures with precisely defined, robust interqubit interactions, coupled with local addressability. This is an unsolved challenge, primarily due to scalability issues. These issues often derive from poor control over interqubit interactions. Molecular systems are promising materials for the realization of large-scale quantum architectures, due to their high degree of positionability and the possibility to precisely tailor interqubit interactions. The simplest quantum architecture is the two-qubit system, with which quantum gate operations can be implemented. To be viable, a two-qubit system must possess long coherence times, the interqubit interaction must be well defined and the two qubits must also be addressable individually within the same quantum manipulation sequence. Here results are presented on the investigation of the spin dynamics of chlorinated triphenylmethyl organic radicals, in particular the perchlorotriphenylmethyl (PTM) radical, a mono-functionalized PTM, and a biradical PTM dimer. Extraordinarily long ensemble coherence times up to 148 µs are found at all temperatures below 100 K. Two-qubit and, importantly, individual qubit addressability in the biradical system are demonstrated. These results underline the potential of molecular materials for the development of quantum architectures.
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Affiliation(s)
- Dennis Schäfter
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Jonathan Wischnat
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Lorenzo Tesi
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - J Alejandro De Sousa
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Networking Research Center on Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, Bellaterra, 08193, Spain
- Laboratorio de Electroquímica, Departamento de Química, Facultad de Ciencias, Universidad de los Andes, Mérida, 5101, Venezuela
| | - Edmund Little
- Department of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Jake McGuire
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Marta Mas-Torrent
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Networking Research Center on Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, Bellaterra, 08193, Spain
| | - Concepció Rovira
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Networking Research Center on Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, Bellaterra, 08193, Spain
| | - Jaume Veciana
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Networking Research Center on Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, Bellaterra, 08193, Spain
| | - Floriana Tuna
- Department of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Núria Crivillers
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Networking Research Center on Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, Bellaterra, 08193, Spain
| | - Joris van Slageren
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
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6
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Yang Z, Stein RA, Pink M, Madzelan P, Ngendahimana T, Rajca S, Wilson MA, Eaton SS, Eaton GR, Mchaourab HS, Rajca A. Cucurbit[7]uril Enhances Distance Measurements of Spin-Labeled Proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.22.554361. [PMID: 37662277 PMCID: PMC10473685 DOI: 10.1101/2023.08.22.554361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
We report complex formation between the chloroacetamide 2,6-diazaadamantane nitroxide radical (ClA-DZD) and cucurbit[7]uril (CB-7), for which the association constant in water, Ka = 1.9 × 106 M-1, is at least one order of magnitude higher than the previously studied organic radicals. The radical is highly immobilized by CB-7, as indicated by the increase of the rotational correlation time, τrot, by a factor of 36, relative to that in the buffer solution. The X-ray structure of ClA-DZD@CB-7 shows the encapsulated DZD guest inside the undistorted CB-7 host, with the pendant group protruding outside. Upon addition of CB-7 to T4 Lysozyme (T4L) doubly spin-labeled with the iodoacetamide derivative of DZD, we observe the increase in τrot and electron spin coherence time, Tm, along with the narrowing of inter-spin distance distributions. Sensitivity of the DEER measurements at 83 K increases by a factor 4 - 9, compared to the common spin label such as MTSL, which is not affected by CB-7. Inter-spin distances of 3-nm could be reliably measured in water/glycerol up to temperatures near the glass transition/melting temperature of the matrix at 200 K, thus bringing us closer to the goal of supramolecular recognition-enabled long-distance DEER measurements at near physiological temperatures. The X-ray structure of DZD-T4L 65 at 1.12 Å resolution allows for unambiguous modeling of the DZD label (0.88 occupancy), indicating undisturbed structure and conformation of the protein.
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Affiliation(s)
- Zhimin Yang
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Richard A. Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Maren Pink
- IUMSC, Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
| | - Peter Madzelan
- Department of Biochemistry and Redox Biology Center, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Thacien Ngendahimana
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Suchada Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Mark A. Wilson
- Department of Biochemistry and Redox Biology Center, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Sandra S. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Gareth R. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Hassane S. Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
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7
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Khoroshunova YV, Morozov DA, Kuznetsov DA, Rybalova TV, Glazachev YI, Bagryanskaya EG, Kirilyuk IA. Synthesis and Properties of (1 R( S),5 R( S),7 R( S),8 R( S))-1,8-Bis(hydroxymethyl)-6-azadispiro[4.1.4.2]tridecane-6-oxyl: Reduction-Resistant Spin Labels with High Spin Relaxation Times. Int J Mol Sci 2023; 24:11498. [PMID: 37511257 PMCID: PMC10380268 DOI: 10.3390/ijms241411498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Site-directed spin labeling followed by investigation using Electron Paramagnetic Resonance spectroscopy is a rapidly expanding powerful biophysical technique to study structure, local dynamics and functions of biomolecules using pulsed EPR techniques and nitroxides are the most widely used spin labels. Modern trends of this method include measurements directly inside a living cell, as well as measurements without deep freezing (below 70 K), which provide information that is more consistent with the behavior of the molecules under study in natural conditions. Such studies require nitroxides, which are resistant to the action of biogenic reductants and have high spin relaxation (dephasing) times, Tm. (1R(S),5R(S),7R(S),8R(S))-1,8-bis(hydroxymethyl)-6-azadispiro[4.1.4.2]tridecane-6-oxyl is a unique nitroxide that combines these features. We have developed a convenient method for the synthesis of this radical and studied the ways of its functionalization. Promising spin labels have been obtained, the parameters of their spin relaxation T1 and Tm have been measured, and the kinetics of reduction with ascorbate have been studied.
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Affiliation(s)
- Yulia V Khoroshunova
- N.N. Vorozhtsov Institute of Organic Chemistry SB RAS, Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia
- Department of Physics, Novosibirsk State University, Pirogova Str. 1, 630090 Novosibirsk, Russia
| | - Denis A Morozov
- N.N. Vorozhtsov Institute of Organic Chemistry SB RAS, Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia
| | - Danil A Kuznetsov
- Department of Physics, Novosibirsk State University, Pirogova Str. 1, 630090 Novosibirsk, Russia
| | - Tatyana V Rybalova
- N.N. Vorozhtsov Institute of Organic Chemistry SB RAS, Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia
| | - Yurii I Glazachev
- Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Institutskaya 3, 630090 Novosibirsk, Russia
| | - Elena G Bagryanskaya
- N.N. Vorozhtsov Institute of Organic Chemistry SB RAS, Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia
| | - Igor A Kirilyuk
- N.N. Vorozhtsov Institute of Organic Chemistry SB RAS, Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia
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8
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Sowiński MP, Gahlawat S, Lund BA, Warnke AL, Hopmann KH, Lovett JE, Haugland MM. Conformational tuning improves the stability of spirocyclic nitroxides with long paramagnetic relaxation times. Commun Chem 2023; 6:111. [PMID: 37277501 DOI: 10.1038/s42004-023-00912-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 05/24/2023] [Indexed: 06/07/2023] Open
Abstract
Nitroxides are widely used as probes and polarization transfer agents in spectroscopy and imaging. These applications require high stability towards reducing biological environments, as well as beneficial relaxation properties. While the latter is provided by spirocyclic groups on the nitroxide scaffold, such systems are not in themselves robust under reducing conditions. In this work, we introduce a strategy for stability enhancement through conformational tuning, where incorporating additional substituents on the nitroxide ring effects a shift towards highly stable closed spirocyclic conformations, as indicated by X-ray crystallography and density functional theory (DFT) calculations. Closed spirocyclohexyl nitroxides exhibit dramatically improved stability towards reduction by ascorbate, while maintaining long relaxation times in electron paramagnetic resonance (EPR) spectroscopy. These findings have important implications for the future design of new nitroxide-based spin labels and imaging agents.
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Affiliation(s)
- Mateusz P Sowiński
- Department of Chemistry, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Sahil Gahlawat
- Department of Chemistry, UiT The Arctic University of Norway, 9037, Tromsø, Norway
- Hylleraas Center for Quantum Molecular Sciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Bjarte A Lund
- Department of Chemistry, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Anna-Luisa Warnke
- Department of Chemistry, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Kathrin H Hopmann
- Department of Chemistry, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Janet E Lovett
- SUPA, School of Physics and Astronomy and BSRC, University of St Andrews, North Haugh, St Andrews, KY16 9SS, UK
| | - Marius M Haugland
- Department of Chemistry, UiT The Arctic University of Norway, 9037, Tromsø, Norway.
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9
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Asanbaeva NB, Gurskaya LY, Polienko YF, Rybalova TV, Kazantsev MS, Dmitriev AA, Gritsan NP, Haro-Mares N, Gutmann T, Buntkowsky G, Tretyakov EV, Bagryanskaya EG. Effects of Spiro-Cyclohexane Substitution of Nitroxyl Biradicals on Dynamic Nuclear Polarization. Molecules 2022; 27:3252. [PMID: 35630726 PMCID: PMC9143461 DOI: 10.3390/molecules27103252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 05/17/2022] [Accepted: 05/17/2022] [Indexed: 11/20/2022] Open
Abstract
Spiro-substituted nitroxyl biradicals are widely used as reagents for dynamic nuclear polarization (DNP), which is especially important for biopolymer research. The main criterion for their applicability as polarizing agents is the value of the spin-spin exchange interaction parameter (J), which can vary considerably when different couplers are employed that link the radical moieties. This paper describes a study on biradicals, with a ferrocene-1,1'-diyl-substituted 1,3-diazetidine-2,4-diimine coupler, that have never been used before as DNP agents. We observed a substantial difference in the temperature dependence between Electron Paramagnetic Resonance (EPR) spectra of biradicals carrying either methyl or spirocyclohexane substituents and explain the difference using Density Functional Theory (DFT) calculation results. It was shown that the replacement of methyl groups by spirocycles near the N-O group leads to an increase in the contribution of conformers having J ≈ 0. The DNP gain observed for the biradicals with methyl substituents is three times higher than that for the spiro-substituted nitroxyl biradicals and is inversely proportional to the contribution of biradicals manifesting the negligible exchange interaction. The effects of nucleophiles and substituents in the nitroxide biradicals on the ring-opening reaction of 1,3-diazetidine and the influence of the ring opening on the exchange interaction were also investigated. It was found that in contrast to the methyl-substituted nitroxide biradical (where we observed the ring-opening reaction upon the addition of amines), the ring opening does not occur in the spiro-substituted biradical owing to a steric barrier created by the bulky cyclohexyl substituents.
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Affiliation(s)
- Nargiz B. Asanbaeva
- N.N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), 9 Acad. Lavrentiev Avenue, Novosibirsk 630090, Russia; (N.B.A.); (L.Y.G.); (Y.F.P.); (T.V.R.); (M.S.K.)
| | - Larisa Yu. Gurskaya
- N.N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), 9 Acad. Lavrentiev Avenue, Novosibirsk 630090, Russia; (N.B.A.); (L.Y.G.); (Y.F.P.); (T.V.R.); (M.S.K.)
| | - Yuliya F. Polienko
- N.N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), 9 Acad. Lavrentiev Avenue, Novosibirsk 630090, Russia; (N.B.A.); (L.Y.G.); (Y.F.P.); (T.V.R.); (M.S.K.)
| | - Tatyana V. Rybalova
- N.N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), 9 Acad. Lavrentiev Avenue, Novosibirsk 630090, Russia; (N.B.A.); (L.Y.G.); (Y.F.P.); (T.V.R.); (M.S.K.)
| | - Maxim S. Kazantsev
- N.N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), 9 Acad. Lavrentiev Avenue, Novosibirsk 630090, Russia; (N.B.A.); (L.Y.G.); (Y.F.P.); (T.V.R.); (M.S.K.)
| | - Alexey A. Dmitriev
- V.V. Voevodsky Institute of Chemical Kinetics and Combustion, SB RAS, 3 Institutskaya Str., Novosibirsk 630090, Russia; (A.A.D.); (N.P.G.)
| | - Nina P. Gritsan
- V.V. Voevodsky Institute of Chemical Kinetics and Combustion, SB RAS, 3 Institutskaya Str., Novosibirsk 630090, Russia; (A.A.D.); (N.P.G.)
| | - Nadia Haro-Mares
- TU Darmstadt, Eduard-Zintl-Institute for Inorganic and Physical Chemistry, Alarich-Weiss-Straße 8, 64287 Darmstadt, Germany; (N.H.-M.); (T.G.); (G.B.)
| | - Torsten Gutmann
- TU Darmstadt, Eduard-Zintl-Institute for Inorganic and Physical Chemistry, Alarich-Weiss-Straße 8, 64287 Darmstadt, Germany; (N.H.-M.); (T.G.); (G.B.)
| | - Gerd Buntkowsky
- TU Darmstadt, Eduard-Zintl-Institute for Inorganic and Physical Chemistry, Alarich-Weiss-Straße 8, 64287 Darmstadt, Germany; (N.H.-M.); (T.G.); (G.B.)
| | - Evgeny V. Tretyakov
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky Prosp., Moscow 119991, Russia;
| | - Elena G. Bagryanskaya
- N.N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), 9 Acad. Lavrentiev Avenue, Novosibirsk 630090, Russia; (N.B.A.); (L.Y.G.); (Y.F.P.); (T.V.R.); (M.S.K.)
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10
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Peek Inside the Water Mixtures of Ionic Liquids at Molecular Level: Microscopic Properties Probed by EPR Spectroscopy. Int J Mol Sci 2021; 22:ijms222111900. [PMID: 34769336 PMCID: PMC8584414 DOI: 10.3390/ijms222111900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 01/06/2023] Open
Abstract
Many ionic liquids (ILs) can be mixed with water, forming either true solutions or emulsions. This favors their applications in many respects, but at the same time might strongly alter their physicochemical properties. A number of methods exist for studying the macroscopic properties of such mixtures, whereas understanding their characteristics at micro/nanoscale is rather challenging. In this work we investigate microscopic properties, such as viscosity and local structuring, in binary water mixtures of IL [Bmim]BF4 in liquid and glassy states. For this sake, we use continuous wave and pulse electron paramagnetic resonance (EPR) spectroscopy with dedicated spin probes, located preferably in IL-rich domains or distributed in IL- and water-rich domains. We demonstrate that the glassy-state nanostructuring of IL-rich domains is very similar to that in neat ILs. At the same time, in liquid state the residual water makes local viscosity in IL-rich domains noticeably different compared to neat ILs, even though the overwhelming amount of water is contained in water-rich domains. These results have to be taken into account in various applications of IL-water mixtures, especially in those cases demanding the combinations of optimum micro- and macroscopic characteristics.
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11
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Moore W, Yao R, Liu Y, Eaton SS, Eaton GR. Spin-spin interaction and relaxation in two trityl-nitroxide diradicals. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 332:107078. [PMID: 34649176 PMCID: PMC8592039 DOI: 10.1016/j.jmr.2021.107078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/24/2021] [Accepted: 08/30/2021] [Indexed: 05/11/2023]
Abstract
Trityl-nitroxides show substantial promise as polarizing agents in solid state dynamic nuclear polarization. To optimize performance it is important to understand the impact of spin-spin interactions on relaxation times of the diradicals. CW spectra and electron spin relaxation were measured for two trityl-nitroxides that differ in the substituents on the amide linker and have different strengths of the exchange interaction J. Analysis of the EPR spectra in terms of overlapping AB spin-spin splitting patterns explains the impact of J on various regions of the spectra. Even modest values of J are large relative to the separation between trityl and nitroxide resonances for some nitrogen nuclear spin state. Two conformations for each diradical were observed in CW spectra in fluid solution at X-band and Q-band. For one diradical J = 15 G (83%) and 5 G (17%) at 293 K, and J = 27 G (67%) and 3 G (33%) with interspin distances of 16 Å and 12 Å, respectively, at 80 K. For the second diradical the exchange interaction is stronger: the two conformations in fluid solution at 293 K had J = 113 G (67%) and 59 G (33%) and at 80 K the value of J was 43 G and there were two conformations with interspin distances of 13 and 11.5 Å. The observation of two conformations for each diradical, with different values of J, demonstrates the dependence of their exchange interactions on through-bond orbital interactions. X-band values of spin relaxation rates 1/T1 and 1/Tm at 80 to 120 K for the trityl-nitroxides are similar to values for nitroxide mono-radicals, and faster than for trityl radicals. These observations show that even for a relatively small value of J, the nitroxide is very effective in enhancing the relaxation of the more slowly relaxing trityl.
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Affiliation(s)
- Whylder Moore
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80210, United States
| | - Ru Yao
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, PR China
| | - Yangping Liu
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, PR China.
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80210, United States
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80210, United States.
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12
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Huang S, Pink M, Ngendahimana T, Rajca S, Eaton GR, Eaton SS, Rajca A. Bis-Spiro-Oxetane and Bis-Spiro-Tetrahydrofuran Pyrroline Nitroxide Radicals: Synthesis and Electron Spin Relaxation Studies. J Org Chem 2021; 86:13636-13643. [PMID: 34546727 PMCID: PMC10441184 DOI: 10.1021/acs.joc.1c01670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Synthesis of bis-spiro-oxetane and bis-spiro-tetrahydrofuran pyrroline nitroxide radicals relies on the Mitsunobu reaction-mediated double cyclizations of N-Boc protected pyrroline tetraols. Structures of the nitroxide radicals are supported by X-ray crystallography. In a trehalose/sucrose matrix at room temperature, the bis-spiro-oxetane nitroxide radical possesses electron spin coherence time, Tm ≈ 0.7 μs. The observed enhanced Tm is most likely associated with strong hydrogen bonding of oxetane moieties to the trehalose/sucrose matrix.
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Affiliation(s)
- Shengdian Huang
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304
| | - Maren Pink
- IUMSC, Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102
| | - Thacien Ngendahimana
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208-2436
| | - Suchada Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304
| | - Gareth R. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208-2436
| | - Sandra S. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208-2436
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304
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13
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Ivanov MY, Prikhod’ko SA, Bakulina OD, Kiryutin AS, Adonin NY, Fedin MV. Validation of Structural Grounds for Anomalous Molecular Mobility in Ionic Liquid Glasses. Molecules 2021; 26:5828. [PMID: 34641371 PMCID: PMC8510339 DOI: 10.3390/molecules26195828] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 11/25/2022] Open
Abstract
Ionic liquid (IL) glasses have recently drawn much interest as unusual media with unique physicochemical properties. In particular, anomalous suppression of molecular mobility in imidazolium IL glasses vs. increasing temperature was evidenced by pulse Electron Paramagnetic Resonance (EPR) spectroscopy. Although such behavior has been proven to originate from dynamics of alkyl chains of IL cations, the role of electron spin relaxation induced by surrounding protons still remains unclear. In this work we synthesized two deuterated imidazolium-based ILs to reduce electron-nuclear couplings between radical probe and alkyl chains of IL, and investigated molecular mobility in these glasses. The obtained trends were found closely similar for deuterated and protonated analogs, thus excluding the relaxation-induced artifacts and reliably demonstrating structural grounds of the observed anomalies in heterogeneous IL glasses.
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Affiliation(s)
- Mikhail Yu. Ivanov
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia; (O.D.B.); (A.S.K.)
| | - Sergey A. Prikhod’ko
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia; (S.A.P.); (N.Y.A.)
| | - Olga D. Bakulina
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia; (O.D.B.); (A.S.K.)
| | - Alexey S. Kiryutin
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia; (O.D.B.); (A.S.K.)
| | - Nicolay Yu. Adonin
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia; (S.A.P.); (N.Y.A.)
| | - Matvey V. Fedin
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia; (O.D.B.); (A.S.K.)
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14
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Zaytseva EV, Mazhukin DG. Spirocyclic Nitroxides as Versatile Tools in Modern Natural Sciences: From Synthesis to Applications. Part I. Old and New Synthetic Approaches to Spirocyclic Nitroxyl Radicals. Molecules 2021; 26:677. [PMID: 33525514 PMCID: PMC7865516 DOI: 10.3390/molecules26030677] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/19/2021] [Accepted: 01/25/2021] [Indexed: 12/19/2022] Open
Abstract
Spirocyclic nitroxyl radicals (SNRs) are stable paramagnetics bearing spiro-junction at a-, b-, or g-carbon atom of the nitroxide fragment, which is part of the heterocyclic system. Despite the fact that the first representatives of SNRs were obtained about 50 years ago, the methodology of their synthesis and their usage in chemistry and biochemical applications have begun to develop rapidly only in the last two decades. Due to the presence of spiro-function in the SNRs molecules, the latter have increased stability to various reducing agents (including biogenic ones), while the structures of the biradicals (SNBRs) comprises a rigid spiro-fused core that fixes mutual position and orientation of nitroxide moieties that favors their use in dynamic nuclear polarization (DNP) experiments. This first review on SNRs will give a glance at various strategies for the synthesis of spiro-substituted, mono-, and bis-nitroxides on the base of six-membered (piperidine, 1,2,3,4-tetrahydroquinoline, 9,9'(10H,10H')-spirobiacridine, piperazine, and morpholine) or five-membered (2,5-dihydro-1H-pyrrole, pyrrolidine, 2,5-dihydro-1H-imidazole, 4,5-dihydro-1H-imidazole, imidazolidine, and oxazolidine) heterocyclic cores.
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Affiliation(s)
| | - Dmitrii G. Mazhukin
- Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia;
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15
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Yang Z, Stein RA, Ngendahimana T, Pink M, Rajca S, Jeschke G, Eaton SS, Eaton GR, Mchaourab HS, Rajca A. Supramolecular Approach to Electron Paramagnetic Resonance Distance Measurement of Spin-Labeled Proteins. J Phys Chem B 2020; 124:3291-3299. [PMID: 32227839 DOI: 10.1021/acs.jpcb.0c00743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We demonstrate a host-guest molecular recognition approach to advance double electron-electron resonance (DEER) distance measurements of spin-labeled proteins. We synthesized an iodoacetamide derivative of 2,6-diazaadamantane nitroxide (DZD) spin label that could be doubly incorporated into T4 Lysozyme (T4L) by site-directed spin labeling with efficiency up to 50% per cysteine. The rigidity of the fused ring structure and absence of mobile methyl groups increase the spin echo dephasing time (Tm) at temperatures above 80 K. This enables DEER measurements of distances >4 nm in DZD-labeled T4L in glycerol/water at temperatures up to 150 K with increased sensitivity compared to that of a common spin label such as MTSL. Addition of β-cyclodextrin reduces the rotational correlation time of the label, slightly increases Tm, and most importantly, narrows (and slightly lengthens) the interspin distance distributions. The distance distributions are in good agreement with simulated distance distributions obtained by rotamer libraries. These results provide a foundation for developing supramolecular recognition to facilitate long-distance DEER measurements at near physiological temperatures.
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Affiliation(s)
- Zhimin Yang
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Richard A Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Thacien Ngendahimana
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Maren Pink
- IUMSC, Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
| | - Suchada Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Gunnar Jeschke
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
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16
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K A, Kathirvelu V. Electron spin relaxation time of Ni(II) ion in hexapyrazole zinc(II) dinitrate at 300 K. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:329-333. [PMID: 32017195 DOI: 10.1002/mrc.5007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/27/2020] [Accepted: 02/01/2020] [Indexed: 06/10/2023]
Abstract
Understanding the electron spin relaxation properties of paramagnetic species is a fundamental requirement to use them as a probe to measure distances between sites in biomolecules by electron paramagnetic resonance (EPR) spectroscopy. Even though Ni(II) ion is an essential trace element for many species, relaxation properties are not well understood. Herein, the polycrystalline sample of Ni(II) ion magnetically diluted in Zn(Pyrazole)6 (NO3 )2 (Ni/ZPN) has been studied in detail by EPR spectroscopy to explore the electron spin relaxation time. Progressive continuous-wave (CW) EPR power saturation study on Ni/ZPN at 300 K yielded 907 mW as the P1/2 value. The cavity constant (KQ ) has been calculated using tempol in PVA-BA glass matrix and the product of electron spin-lattice relaxation time (T1 ) and spin-spin relaxation time (T2 ) for Ni/ZPN at 300 K has been reported for the first time.
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Affiliation(s)
- Amrutha K
- Department of Applied Sciences, National Institute of Technology Goa, Ponda, India
| | - Velavan Kathirvelu
- Department of Applied Sciences, National Institute of Technology Goa, Ponda, India
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17
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Dobrynin SA, Kirilyuk IA, Gatilov YV, Kuzhelev AA, Krumkacheva OA, Fedin MV, Bowman MK, Bagryanskaya EG. Unexpected one-pot formation of the 1 H-6a,8a-epiminotricyclopenta[ a, c, e][8]annulene system from cyclopentanone, ammonia and dimethyl fumarate. Synthesis of highly strained polycyclic nitroxide and EPR study. Beilstein J Org Chem 2019; 15:2664-2670. [PMID: 31807201 PMCID: PMC6880831 DOI: 10.3762/bjoc.15.259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 10/16/2019] [Indexed: 11/28/2022] Open
Abstract
The unexpected formation of a highly strained polycyclic amine was observed in a one-pot synthesis from cyclopentanone, dimethyl fumarate and ammonium acetate. This multistep reaction includes 1,3-dipolar cycloaddition of dimethyl fumarate to the cyclic azomethine ylide formed in situ from cyclopentanone and ammonia. The polycyclic amine product was easily converted into a sterically shielded polycyclic nitroxide. The EPR spectra and spin relaxation behavior of the nitroxide were studied in solution. The spin relaxation seems well suited for the use as a biological spin label and are comparable with those of cyclic nitroxides with two spirocyclic moieties adjacent to the N–O· group.
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Affiliation(s)
- Sergey A Dobrynin
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk, 630090, Russia.,Novosibirsk State University, Pirogova Str. 2, Novosibirsk, 630090, Russia
| | - Igor A Kirilyuk
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk, 630090, Russia.,Novosibirsk State University, Pirogova Str. 2, Novosibirsk, 630090, Russia
| | - Yuri V Gatilov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk, 630090, Russia
| | - Andrey A Kuzhelev
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk, 630090, Russia.,Novosibirsk State University, Pirogova Str. 2, Novosibirsk, 630090, Russia
| | - Olesya A Krumkacheva
- Novosibirsk State University, Pirogova Str. 2, Novosibirsk, 630090, Russia.,International Tomography Center SB RAS, Institutskaya Str. 3a, Novosibirsk, 630090, Russia
| | - Matvey V Fedin
- Novosibirsk State University, Pirogova Str. 2, Novosibirsk, 630090, Russia.,International Tomography Center SB RAS, Institutskaya Str. 3a, Novosibirsk, 630090, Russia
| | - Michael K Bowman
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk, 630090, Russia.,University of Alabama, Tuscaloosa, Alabama 35487-0336, United States
| | - Elena G Bagryanskaya
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk, 630090, Russia.,Novosibirsk State University, Pirogova Str. 2, Novosibirsk, 630090, Russia
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18
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Bonucci A, Ouari O, Guigliarelli B, Belle V, Mileo E. In‐Cell EPR: Progress towards Structural Studies Inside Cells. Chembiochem 2019; 21:451-460. [DOI: 10.1002/cbic.201900291] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Alessio Bonucci
- Magnetic Resonance CenterCERMUniversity of Florence 50019 Sesto Fiorentino Italy
| | - Olivier Ouari
- Aix Marseille UnivCNRSICRInstitut de Chimie Radicalaire 13013 Marseille France
| | - Bruno Guigliarelli
- Aix Marseille UnivCNRSBIPBioénergétique et Ingénierie des ProtéinesIMM 13009 Marseille France
| | - Valérie Belle
- Aix Marseille UnivCNRSBIPBioénergétique et Ingénierie des ProtéinesIMM 13009 Marseille France
| | - Elisabetta Mileo
- Aix Marseille UnivCNRSBIPBioénergétique et Ingénierie des ProtéinesIMM 13009 Marseille France
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19
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Krumkacheva OA, Timofeev IO, Politanskaya LV, Polienko YF, Tretyakov EV, Rogozhnikova OY, Trukhin DV, Tormyshev VM, Chubarov AS, Bagryanskaya EG, Fedin MV. Triplet Fullerenes as Prospective Spin Labels for Nanoscale Distance Measurements by Pulsed Dipolar EPR Spectroscopy. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201904152] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Olesya A. Krumkacheva
- International Tomography Center SB RAS Novosibirsk 630090 Russia
- Novosibirsk State University Novosibirsk 630090 Russia
| | - Ivan O. Timofeev
- International Tomography Center SB RAS Novosibirsk 630090 Russia
- Novosibirsk State University Novosibirsk 630090 Russia
| | - Larisa V. Politanskaya
- N.N.Vorozhtsov Institute of Organic Chemistry SB RAS Novosibirsk 630090 Russia
- Novosibirsk State University Novosibirsk 630090 Russia
| | - Yuliya F. Polienko
- N.N.Vorozhtsov Institute of Organic Chemistry SB RAS Novosibirsk 630090 Russia
- Novosibirsk State University Novosibirsk 630090 Russia
| | - Evgeny V. Tretyakov
- N.N.Vorozhtsov Institute of Organic Chemistry SB RAS Novosibirsk 630090 Russia
- Novosibirsk State University Novosibirsk 630090 Russia
| | - Olga Yu. Rogozhnikova
- N.N.Vorozhtsov Institute of Organic Chemistry SB RAS Novosibirsk 630090 Russia
- Novosibirsk State University Novosibirsk 630090 Russia
| | - Dmitry V. Trukhin
- N.N.Vorozhtsov Institute of Organic Chemistry SB RAS Novosibirsk 630090 Russia
- Novosibirsk State University Novosibirsk 630090 Russia
| | - Victor M. Tormyshev
- N.N.Vorozhtsov Institute of Organic Chemistry SB RAS Novosibirsk 630090 Russia
- Novosibirsk State University Novosibirsk 630090 Russia
| | - Alexey S. Chubarov
- Institute of Chemical Biology and Fundamental Medicine SB RAS Novosibirsk 630090 Russia
- Novosibirsk State University Novosibirsk 630090 Russia
| | - Elena G. Bagryanskaya
- N.N.Vorozhtsov Institute of Organic Chemistry SB RAS Novosibirsk 630090 Russia
- Novosibirsk State University Novosibirsk 630090 Russia
| | - Matvey V. Fedin
- International Tomography Center SB RAS Novosibirsk 630090 Russia
- Novosibirsk State University Novosibirsk 630090 Russia
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20
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Krumkacheva OA, Timofeev IO, Politanskaya LV, Polienko YF, Tretyakov EV, Rogozhnikova OY, Trukhin DV, Tormyshev VM, Chubarov AS, Bagryanskaya EG, Fedin MV. Triplet Fullerenes as Prospective Spin Labels for Nanoscale Distance Measurements by Pulsed Dipolar EPR Spectroscopy. Angew Chem Int Ed Engl 2019; 58:13271-13275. [PMID: 31322814 DOI: 10.1002/anie.201904152] [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] [Received: 04/04/2019] [Revised: 07/11/2019] [Indexed: 11/11/2022]
Abstract
Precise nanoscale distance measurements by pulsed electron paramagnetic resonance (EPR) spectroscopy play a crucial role in structural studies of biomolecules. The properties of the spin labels used in this approach determine the sensitivity limits, attainable distances, and proximity to biological conditions. Herein, we propose and validate the use of photoexcited fullerenes as spin labels for pulsed dipolar (PD) EPR distance measurements. Hyperpolarization and the narrower spectrum of fullerenes compared to other triplets (e.g., porphyrins) boost the sensitivity, and superior relaxation properties allow PD EPR measurements up to a near-room temperature. This approach is demonstrated using fullerene-nitroxide and fullerene-triarylmethyl pairs, as well as a supramolecular complex of fullerene with nitroxide-labeled protein. Photoexcited triplet fullerenes can be considered as new spin labels with outstanding spectroscopic properties for future structural studies of biomolecules.
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Affiliation(s)
- Olesya A Krumkacheva
- International Tomography Center SB RAS, Novosibirsk, 630090, Russia.,Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Ivan O Timofeev
- International Tomography Center SB RAS, Novosibirsk, 630090, Russia.,Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Larisa V Politanskaya
- N.N.Vorozhtsov Institute of Organic Chemistry SB RAS, Novosibirsk, 630090, Russia.,Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Yuliya F Polienko
- N.N.Vorozhtsov Institute of Organic Chemistry SB RAS, Novosibirsk, 630090, Russia.,Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Evgeny V Tretyakov
- N.N.Vorozhtsov Institute of Organic Chemistry SB RAS, Novosibirsk, 630090, Russia.,Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Olga Yu Rogozhnikova
- N.N.Vorozhtsov Institute of Organic Chemistry SB RAS, Novosibirsk, 630090, Russia.,Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Dmitry V Trukhin
- N.N.Vorozhtsov Institute of Organic Chemistry SB RAS, Novosibirsk, 630090, Russia.,Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Victor M Tormyshev
- N.N.Vorozhtsov Institute of Organic Chemistry SB RAS, Novosibirsk, 630090, Russia.,Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Alexey S Chubarov
- Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk, 630090, Russia.,Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Elena G Bagryanskaya
- N.N.Vorozhtsov Institute of Organic Chemistry SB RAS, Novosibirsk, 630090, Russia.,Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Matvey V Fedin
- International Tomography Center SB RAS, Novosibirsk, 630090, Russia.,Novosibirsk State University, Novosibirsk, 630090, Russia
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21
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McPeak JE, Quine RW, Eaton SS, Eaton GR. An x-band continuous wave saturation recovery electron paramagnetic resonance spectrometer based on an arbitrary waveform generator. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:024102. [PMID: 30831717 PMCID: PMC6364795 DOI: 10.1063/1.5043316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 12/20/2018] [Indexed: 05/29/2023]
Abstract
An X-band (ca. 9-10 GHz) continuous wave saturation recovery spectrometer to measure electron spin-lattice relaxation (T1) was designed around an arbitrary waveform generator (AWG). The AWG is the microwave source and is used for timing of microwave pulses, generation of control signals, and digitizer triggering. Use of the AWG substantially simplifies the hardware in the bridge relative to that in conventional spectrometers and decreases the footprint. The bridge includes selectable paths with different power amplifications to permit experiments requiring hundreds of milliwatts to fractions of nanowatts for the pump and observe periods. The signal is detected with either a single or quadrature-output double balanced mixer. The system can operate with reflection or crossed-loop resonators. The source noise from the AWG was decreased by addition of a Wenzel high-stability clock. The source is sufficiently stable that automatic frequency control is not needed. The spectrometer was tested with samples that contained 1 × 1015 to 8 × 1017 spins and have T1 between a few hundred ns and hundreds of μs. Excellent signal-to-noise ratio was obtained with acquisition times of 2-90 s. Signal-to-noise performance is similar to that of a conventional saturation recovery spectrometer with a solid-state source. The stability and data reproducibility are better than with conventional sources. With replacement of frequency-sensitive components, this spectrometer can be used to perform saturation recovery measurements at any frequency within the range of the AWG.
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Affiliation(s)
- Joseph E. McPeak
- Department of Chemistry and Biochemistry,
University of Denver, Denver, Colorado 80210, USA
| | - Richard W. Quine
- Ritchie School of Engineering and Computer
Science, University of Denver, Denver, Colorado 80210,
USA
| | - Sandra S. Eaton
- Department of Chemistry and Biochemistry,
University of Denver, Denver, Colorado 80210, USA
| | - Gareth R. Eaton
- Department of Chemistry and Biochemistry,
University of Denver, Denver, Colorado 80210, USA
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22
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Gränz M, Erlenbach N, Spindler P, Gophane DB, Stelzl LS, Sigurdsson ST, Prisner TF. Dynamics of Nucleic Acids at Room Temperature Revealed by Pulsed EPR Spectroscopy. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201803682] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Markus Gränz
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic ResonanceGoethe University Frankfurt Max-von-Laue-Straße 7 60438 Frankfurt am Main Germany
| | - Nicole Erlenbach
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic ResonanceGoethe University Frankfurt Max-von-Laue-Straße 7 60438 Frankfurt am Main Germany
| | - Philipp Spindler
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic ResonanceGoethe University Frankfurt Max-von-Laue-Straße 7 60438 Frankfurt am Main Germany
| | - Dnyaneshwar B. Gophane
- Department of ChemistryScience InstituteUniversity of Iceland Dunhaga 3 107 Reykjavík Iceland
| | - Lukas S. Stelzl
- Department of Theoretical BiophysicsMax Planck Institute of Biophysics Max-von-Laue-Straße 3 60438 Frankfurt am Main Germany
| | - Snorri Th. Sigurdsson
- Department of ChemistryScience InstituteUniversity of Iceland Dunhaga 3 107 Reykjavík Iceland
| | - Thomas F. Prisner
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic ResonanceGoethe University Frankfurt Max-von-Laue-Straße 7 60438 Frankfurt am Main Germany
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23
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Gränz M, Erlenbach N, Spindler P, Gophane DB, Stelzl LS, Sigurdsson ST, Prisner TF. Dynamics of Nucleic Acids at Room Temperature Revealed by Pulsed EPR Spectroscopy. Angew Chem Int Ed Engl 2018; 57:10540-10543. [PMID: 29858557 DOI: 10.1002/anie.201803682] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/06/2018] [Indexed: 12/16/2022]
Abstract
The investigation of the structure and conformational dynamics of biomolecules under physiological conditions is challenging for structural biology. Although pulsed electron paramagnetic resonance (like PELDOR) techniques provide long-range distance and orientation information with high accuracy, such studies are usually performed at cryogenic temperatures. At room temperature (RT) PELDOR studies are seemingly impossible due to short electronic relaxation times and loss of dipolar interactions through rotational averaging. We incorporated the rigid nitroxide spin label Ç into a DNA duplex and immobilized the sample on a solid support to overcome this limitation. This enabled orientation-selective PELDOR measurements at RT. A comparison with data recorded at 50 K revealed averaging of internal dynamics, which occur on the ns time range at RT. Thus, our approach adds a new method to study structural and dynamical processes at physiological temperature in the <10 μs time range with atomistic resolution.
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Affiliation(s)
- Markus Gränz
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438, Frankfurt am Main, Germany
| | - Nicole Erlenbach
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438, Frankfurt am Main, Germany
| | - Philipp Spindler
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438, Frankfurt am Main, Germany
| | - Dnyaneshwar B Gophane
- Department of Chemistry, Science Institute, University of Iceland, Dunhaga 3, 107, Reykjavík, Iceland
| | - Lukas S Stelzl
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438, Frankfurt am Main, Germany
| | - Snorri Th Sigurdsson
- Department of Chemistry, Science Institute, University of Iceland, Dunhaga 3, 107, Reykjavík, Iceland
| | - Thomas F Prisner
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438, Frankfurt am Main, Germany
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24
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Jassoy JJ, Meyer A, Spicher S, Wuebben C, Schiemann O. Synthesis of Nanometer Sized Bis- and Tris-trityl Model Compounds with Different Extent of Spin-Spin Coupling. Molecules 2018; 23:E682. [PMID: 29562622 PMCID: PMC6017437 DOI: 10.3390/molecules23030682] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 03/12/2018] [Accepted: 03/16/2018] [Indexed: 12/29/2022] Open
Abstract
Tris(2,3,5,6-tetrathiaaryl)methyl radicals, so-called trityl radicals, are emerging as spin labels for distance measurements in biological systems based on Electron Paramagnetic Resonance (EPR). Here, the synthesis and characterization of rigid model systems carrying either two or three trityl moieties is reported. The monofunctionalized trityl radicals are connected to the molecular bridging scaffold via an esterification reaction employing the Mukaiyama reagent 2-chloro-methylpyridinium iodide. The bis- and tris-trityl compounds exhibit different inter-spin distances, strength of electron-electron exchange and dipolar coupling and can give rise to multi-spin effects. They are to serve as benchmark systems in comparing EPR distance measurement methods.
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Affiliation(s)
- J Jacques Jassoy
- Institute of Physical and Theoretical Chemistry, University of Bonn, 53115 Bonn, Germany.
| | - Andreas Meyer
- Institute of Physical and Theoretical Chemistry, University of Bonn, 53115 Bonn, Germany.
| | - Sebastian Spicher
- Institute of Physical and Theoretical Chemistry, University of Bonn, 53115 Bonn, Germany.
| | - Christine Wuebben
- Institute of Physical and Theoretical Chemistry, University of Bonn, 53115 Bonn, Germany.
| | - Olav Schiemann
- Institute of Physical and Theoretical Chemistry, University of Bonn, 53115 Bonn, Germany.
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25
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Bleve V, Franchi P, Gualandi L, Romano F, Mezzina E, Lucarini M. Synthesis and characterization of a doubly spin-labelled electrochemically driven molecular shuttle. Org Chem Front 2018. [DOI: 10.1039/c8qo00187a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The EPR properties of novel nitroxide-spin-labelled rotaxanes containing a tetrathiafulvalene (TTF) unit and a cyclobis(paraquat-p-phenylene) ring are described.
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Affiliation(s)
- Valentina Bleve
- Department of Chemistry “G. Ciamician” – Alma Mater Studiorum-University of Bologna
- Bologna
- Italy
| | - Paola Franchi
- Department of Chemistry “G. Ciamician” – Alma Mater Studiorum-University of Bologna
- Bologna
- Italy
| | - Lorenzo Gualandi
- Department of Chemistry “G. Ciamician” – Alma Mater Studiorum-University of Bologna
- Bologna
- Italy
| | - Francesco Romano
- Department of Chemistry “G. Ciamician” – Alma Mater Studiorum-University of Bologna
- Bologna
- Italy
| | - Elisabetta Mezzina
- Department of Chemistry “G. Ciamician” – Alma Mater Studiorum-University of Bologna
- Bologna
- Italy
| | - Marco Lucarini
- Department of Chemistry “G. Ciamician” – Alma Mater Studiorum-University of Bologna
- Bologna
- Italy
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26
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Meyer A, Jassoy JJ, Spicher S, Berndhäuser A, Schiemann O. Performance of PELDOR, RIDME, SIFTER, and DQC in measuring distances in trityl based bi- and triradicals: exchange coupling, pseudosecular coupling and multi-spin effects. Phys Chem Chem Phys 2018; 20:13858-13869. [DOI: 10.1039/c8cp01276h] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The performance of pulsed EPR methods for distance measurements is evaluated on three different trityl model systems.
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Affiliation(s)
- Andreas Meyer
- Institute of Physical and Theoretical Chemistry
- Rheinische Friedrich-Wilhelms-University Bonn
- 53115 Bonn
- Germany
| | - Jean Jacques Jassoy
- Institute of Physical and Theoretical Chemistry
- Rheinische Friedrich-Wilhelms-University Bonn
- 53115 Bonn
- Germany
| | - Sebastian Spicher
- Institute of Physical and Theoretical Chemistry
- Rheinische Friedrich-Wilhelms-University Bonn
- 53115 Bonn
- Germany
| | - Andreas Berndhäuser
- Institute of Physical and Theoretical Chemistry
- Rheinische Friedrich-Wilhelms-University Bonn
- 53115 Bonn
- Germany
| | - Olav Schiemann
- Institute of Physical and Theoretical Chemistry
- Rheinische Friedrich-Wilhelms-University Bonn
- 53115 Bonn
- Germany
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27
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Eaton SS, Rajca A, Yang Z, Eaton GR. Azaadamantyl nitroxide spin label: complexation with β-cyclodextrin and electron spin relaxation. Free Radic Res 2017; 52:319-326. [PMID: 28946790 DOI: 10.1080/10715762.2017.1384954] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
An iodoacetamide azaadamantyl spin label was studied in fluid solution and in 9:1 trehalose:sucrose glass. In 9:1 toluene:CH2Cl2 solution at 293 K, the isotropic nitrogen hyperfine coupling is 19.2 G, T1 is 0.37 µs and T2 is 0.30-0.35 µs. Between about 80 and 150 K 1/Tm in 9:1 trehalose:sucrose is approximately independent of temperature demonstrating that the absence of methyl groups decreases 1/Tm relative to that which is observed in spin labels with methyl groups on the alpha carbons. Spin lattice relaxation rates between about 80 and 293 K in 9:1 trehalose:sucrose are similar to those observed for other nitroxide spin labels, consistent with the expectation that relaxation is dominated by Raman and local mode processes. Although complexation of the azaadamantyl spin label with β-cyclodextrin slows tumbling in aqueous solution by about a factor of 10, it has little impact on 1/T1 or 1/Tm in 9:1 trehalose:sucrose between 80 and 293 K.
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Affiliation(s)
- Sandra S Eaton
- a Department of Chemistry and Biochemistry , University of Denver , Denver , CO , USA
| | - Andrzej Rajca
- b Department of Chemistry , University of Nebraska , Lincoln , NE , USA
| | - Zhimin Yang
- b Department of Chemistry , University of Nebraska , Lincoln , NE , USA
| | - Gareth R Eaton
- a Department of Chemistry and Biochemistry , University of Denver , Denver , CO , USA
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28
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Krumkacheva O, Bagryanskaya E. EPR-based distance measurements at ambient temperature. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 280:117-126. [PMID: 28579097 DOI: 10.1016/j.jmr.2017.02.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 02/23/2017] [Accepted: 02/24/2017] [Indexed: 05/24/2023]
Abstract
Pulsed dipolar (PD) EPR spectroscopy is a powerful technique allowing for distance measurements between spin labels in the range of 2.5-10.0nm. It was proposed more than 30years ago, and nowadays is widely used in biophysics and materials science. Until recently, PD EPR experiments were limited to cryogenic temperatures (T<80K). Recently, application of spin labels with long electron spin dephasing time at room temperature such as triarylmethyl radicals and nitroxides with bulky substituents at a position close to radical centers enabled measurements at room temperature and even at physiologically relevant temperatures by PD EPR as well as other approaches based on EPR (e.g., relaxation enhancement; RE). In this paper, we review the features of PD EPR and RE at ambient temperatures, in particular, requirements on electron spin phase memory time, ways of immobilization of biomolecules, the influence of a linker between the spin probe and biomolecule, and future opportunities.
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Affiliation(s)
- Olesya Krumkacheva
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Pr. Lavrentjeva 9, Novosibirsk 630090, Russian Federation; Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russian Federation; International Tomography Center SB RAS, Institutskaya 3A, Novosibirsk 630090, Russian Federation.
| | - Elena Bagryanskaya
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Pr. Lavrentjeva 9, Novosibirsk 630090, Russian Federation; Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russian Federation.
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29
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Konnert L, Lamaty F, Martinez J, Colacino E. Recent Advances in the Synthesis of Hydantoins: The State of the Art of a Valuable Scaffold. Chem Rev 2017. [PMID: 28644621 DOI: 10.1021/acs.chemrev.7b00067] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The review highlights the hydantoin syntheses presented from the point of view of the preparation methods. Novel synthetic routes to various hydantoin structures, the advances brought to the classical methods in the aim of producing more sustainable and environmentally friendly procedures for the preparation of these biomolecules, and a critical comparison of the different synthetic approaches developed in the last twelve years are also described. The review is composed of 95 schemes, 8 figures and 528 references for the last 12 years and includes the description of the hydantoin-based marketed drugs and clinical candidates.
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Affiliation(s)
- Laure Konnert
- Université de Montpellier, Institut des Biomolécules Max Mousseron UMR 5247 CNRS - Universités Montpellier - ENSCM , Place E. Bataillon, Campus Triolet, cc 1703, 34095 Montpellier, France
| | - Frédéric Lamaty
- Université de Montpellier, Institut des Biomolécules Max Mousseron UMR 5247 CNRS - Universités Montpellier - ENSCM , Place E. Bataillon, Campus Triolet, cc 1703, 34095 Montpellier, France
| | - Jean Martinez
- Université de Montpellier, Institut des Biomolécules Max Mousseron UMR 5247 CNRS - Universités Montpellier - ENSCM , Place E. Bataillon, Campus Triolet, cc 1703, 34095 Montpellier, France
| | - Evelina Colacino
- Université de Montpellier, Institut des Biomolécules Max Mousseron UMR 5247 CNRS - Universités Montpellier - ENSCM , Place E. Bataillon, Campus Triolet, cc 1703, 34095 Montpellier, France
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30
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Huang S, Paletta JT, Elajaili H, Huber K, Pink M, Rajca S, Eaton GR, Eaton SS, Rajca A. Synthesis and Electron Spin Relaxation of Tetracarboxylate Pyrroline Nitroxides. J Org Chem 2017; 82:1538-1544. [PMID: 28032758 PMCID: PMC5478179 DOI: 10.1021/acs.joc.6b02737] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
![]()
We report the design,
synthesis, and electron spin relaxation properties
of hydrophilic tetracarboxylate ester pyrroline nitroxides 1 and 2, which serve as models in the search for new
spin labels for DEER distance measurement at room temperature. The
nitroxides are designed to have the methyl groups further away from
the N–O spin site to decrease the inequivalent couplings of
the unpaired electron to the methyl protons that shorten Tm at T > 70 K in currently used labels.
The key step in the synthesis of 1 and 2 is the reaction of the dianion of pyrrole-1,2,5-tricarboxylic acid tert-butyl ester dimethyl ester with electrophiles such
as methyl chloroformate and methyl bromoacetate. Structures of 1 and 2 are confirmed by X-ray crystallography.
Studies of electron spin relaxation rates in rigid trehalose/sucrose
matrices reveal approximately temperature independent values of 1/Tm for 1 and 2 up to
about 160 K and modest temperature dependence up to 295 K, demonstrating
that increasing the distance between the nitroxide moiety and methyl
groups is effective in lengthening Tm at T > 70 K.
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Affiliation(s)
- Shengdian Huang
- Department of Chemistry, University of Nebraska , Lincoln, Nebraska 68588-0304, United States
| | - Joseph T Paletta
- Department of Chemistry, University of Nebraska , Lincoln, Nebraska 68588-0304, United States
| | - Hanan Elajaili
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208-2436, United States
| | - Kirby Huber
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208-2436, United States
| | - Maren Pink
- IUMSC, Department of Chemistry, Indiana University , Bloomington, Indiana 47405-7102, United States
| | - Suchada Rajca
- Department of Chemistry, University of Nebraska , Lincoln, Nebraska 68588-0304, United States
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208-2436, United States
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208-2436, United States
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska , Lincoln, Nebraska 68588-0304, United States
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31
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Kadtsyn E, Anikeenko A, Medvedev N. Molecular dynamics simulation of a DNA duplex labeled with triarylmethyl spin radicals. J Mol Liq 2016. [DOI: 10.1016/j.molliq.2016.06.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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32
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Kuzhelev AA, Strizhakov RK, Krumkacheva OA, Polienko YF, Morozov DA, Shevelev GY, Pyshnyi DV, Kirilyuk IA, Fedin MV, Bagryanskaya EG. Room-temperature electron spin relaxation of nitroxides immobilized in trehalose: Effect of substituents adjacent to NO-group. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 266:1-7. [PMID: 26987109 DOI: 10.1016/j.jmr.2016.02.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 02/04/2016] [Accepted: 02/29/2016] [Indexed: 05/24/2023]
Abstract
Trehalose has been recently promoted as efficient immobilizer of biomolecules for room-temperature EPR studies, including distance measurements between attached nitroxide spin labels. Generally, the structure of nitroxide influences the electron spin relaxation times, being crucial parameters for room-temperature pulse EPR measurements. Therefore, in this work we investigated a series of nitroxides with different substituents adjacent to NO-moiety including spirocyclohexane, spirocyclopentane, tetraethyl and tetramethyl groups. Electron spin relaxation times (T1, Tm) of these radicals immobilized in trehalose were measured at room temperature at X- and Q-bands (9/34GHz). In addition, a comparison was made with the corresponding relaxation times in nitroxide-labeled DNA immobilized in trehalose. In all cases phase memory times Tm were close to 700ns and did not essentially depend on structure of substituents. Comparison of temperature dependences of Tm at T=80-300K shows that the benefit of spirocyclohexane substituents well-known at medium temperatures (∼100-180K) becomes negligible at 300K. Therefore, unless there are specific interactions between spin labels and biomolecules, the room-temperature value of Tm in trehalose is weakly dependent on the structure of substituents adjacent to NO-moiety of nitroxide. The issues of specific interactions and stability of nitroxide labels in biological media might be more important for room temperature pulsed dipolar EPR than differences in intrinsic spin relaxation of radicals.
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Affiliation(s)
- Andrey A Kuzhelev
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev ave. 9, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogova str. 2, Novosibirsk 630090, Russia
| | - Rodion K Strizhakov
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev ave. 9, Novosibirsk 630090, Russia; International Tomography Center SB RAS, Institutskaya str. 3a, Novosibirsk 630090, Russia
| | - Olesya A Krumkacheva
- International Tomography Center SB RAS, Institutskaya str. 3a, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogova str. 2, Novosibirsk 630090, Russia
| | - Yuliya F Polienko
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev ave. 9, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogova str. 2, Novosibirsk 630090, Russia
| | - Denis A Morozov
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev ave. 9, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogova str. 2, Novosibirsk 630090, Russia
| | - Georgiy Yu Shevelev
- Novosibirsk State University, Pirogova str. 2, Novosibirsk 630090, Russia; Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk 630090, Russia
| | - Dmitrii V Pyshnyi
- Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk 630090, Russia
| | - Igor A Kirilyuk
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev ave. 9, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogova str. 2, Novosibirsk 630090, Russia
| | - Matvey V Fedin
- International Tomography Center SB RAS, Institutskaya str. 3a, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogova str. 2, Novosibirsk 630090, Russia.
| | - Elena G Bagryanskaya
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev ave. 9, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogova str. 2, Novosibirsk 630090, Russia.
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33
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Sauvée C, Casano G, Abel S, Rockenbauer A, Akhmetzyanov D, Karoui H, Siri D, Aussenac F, Maas W, Weber RT, Prisner T, Rosay M, Tordo P, Ouari O. Tailoring of Polarizing Agents in the bTurea Series for Cross-Effect Dynamic Nuclear Polarization in Aqueous Media. Chemistry 2016; 22:5598-606. [PMID: 26992052 DOI: 10.1002/chem.201504693] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Indexed: 11/10/2022]
Abstract
A series of 18 nitroxide biradicals derived from bTurea has been prepared, and their enhancement factors ɛ ((1)H) in cross-effect dynamic nuclear polarization (CE DNP) NMR experiments at 9.4 and 14.1 T and 100 K in a DNP-optimized glycerol/water matrix ("DNP juice") have been studied. We observe that ɛ ((1)H) is strongly correlated with the substituents on the polarizing agents, and its trend is discussed in terms of different molecular parameters: solubility, average e-e distance, relative orientation of the nitroxide moieties, and electron spin relaxation times. We show that too short an e-e distance or too long a T1e can dramatically limit ɛ ((1)H). Our study also shows that the molecular structure of AMUPol is not optimal and its ɛ ((1)H) could be further improved through stronger interaction with the glassy matrix and a better orientation of the TEMPO moieties. A new AMUPol derivative introduced here provides a better ɛ ((1)H) than AMUPol itself (by a factor of ca. 1.2).
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Affiliation(s)
- Claire Sauvée
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397, Marseille cedex 20, France
| | - Gilles Casano
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397, Marseille cedex 20, France
| | - Sébastien Abel
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397, Marseille cedex 20, France
| | - Antal Rockenbauer
- Institute of Materials and Environmental Chemistry, Hungarian Academy of Sciences, Department of Physics, Budapest University of Technology and Economics and MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111, Budapest, Hungary
| | - Dimitry Akhmetzyanov
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue Str. 7, 60438, Frankfurt-am-Main, Germany
| | - Hakim Karoui
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397, Marseille cedex 20, France
| | - Didier Siri
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397, Marseille cedex 20, France
| | - Fabien Aussenac
- Bruker BioSpin S.A.S., 34 rue de l'industrie, 67166, Wissembourg, France
| | - Werner Maas
- Bruker BioSpin Corporation, 15 Fortune Drive, Billerica, Massachusetts, 01821, USA
| | - Ralph T Weber
- Bruker BioSpin Corporation, 15 Fortune Drive, Billerica, Massachusetts, 01821, USA
| | - Thomas Prisner
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue Str. 7, 60438, Frankfurt-am-Main, Germany
| | - Mélanie Rosay
- Bruker BioSpin Corporation, 15 Fortune Drive, Billerica, Massachusetts, 01821, USA
| | - Paul Tordo
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397, Marseille cedex 20, France.
| | - Olivier Ouari
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397, Marseille cedex 20, France.
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34
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Meyer V, Swanson MA, Clouston LJ, Boratyński PJ, Stein RA, Mchaourab HS, Rajca A, Eaton SS, Eaton GR. Room-temperature distance measurements of immobilized spin-labeled protein by DEER/PELDOR. Biophys J 2016; 108:1213-9. [PMID: 25762332 DOI: 10.1016/j.bpj.2015.01.015] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 12/17/2014] [Accepted: 01/14/2015] [Indexed: 11/18/2022] Open
Abstract
Nitroxide spin labels are used for double electron-electron resonance (DEER) measurements of distances between sites in biomolecules. Rotation of gem-dimethyls in commonly used nitroxides causes spin echo dephasing times (Tm) to be too short to perform DEER measurements at temperatures between ∼80 and 295 K, even in immobilized samples. A spirocyclohexyl spin label has been prepared that has longer Tm between 80 and 295 K in immobilized samples than conventional labels. Two of the spirocyclohexyl labels were attached to sites on T4 lysozyme introduced by site-directed spin labeling. Interspin distances up to ∼4 nm were measured by DEER at temperatures up to 160 K in water/glycerol glasses. In a glassy trehalose matrix the Tm for the doubly labeled T4 lysozyme was long enough to measure an interspin distance of 3.2 nm at 295 K, which could not be measured for the same protein labeled with the conventional 1-oxyl-2,2,5,5-tetramethyl-3-pyrroline-3-(methyl)methanethio-sulfonate label.
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Affiliation(s)
- Virginia Meyer
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado
| | - Michael A Swanson
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado
| | - Laura J Clouston
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska
| | | | - Richard A Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado.
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35
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Geiger MA, Orwick-Rydmark M, Märker K, Franks WT, Akhmetzyanov D, Stöppler D, Zinke M, Specker E, Nazaré M, Diehl A, van Rossum BJ, Aussenac F, Prisner T, Akbey Ü, Oschkinat H. Temperature dependence of cross-effect dynamic nuclear polarization in rotating solids: advantages of elevated temperatures. Phys Chem Chem Phys 2016; 18:30696-30704. [DOI: 10.1039/c6cp06154k] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
DNP on proteins at 200 K.
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36
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Roser P, Schmidt MJ, Drescher M, Summerer D. Site-directed spin labeling of proteins for distance measurements in vitro and in cells. Org Biomol Chem 2016; 14:5468-76. [DOI: 10.1039/c6ob00473c] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We here review strategies for site-directed spin labeling (SDSL) of proteins and discuss their potential for EPR distance measurements to study protein function in vitro and in cells.
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Affiliation(s)
- P. Roser
- Department of Chemistry
- Zukunftskolleg
- and Konstanz Research School Chemical Biology
- University of Konstanz
- 78457 Konstanz
| | - M. J. Schmidt
- Department of Chemistry
- Zukunftskolleg
- and Konstanz Research School Chemical Biology
- University of Konstanz
- 78457 Konstanz
| | - M. Drescher
- Department of Chemistry
- Zukunftskolleg
- and Konstanz Research School Chemical Biology
- University of Konstanz
- 78457 Konstanz
| | - D. Summerer
- Department of Chemistry and Chemical Biology
- Technical University of Dortmund
- 44227 Dortmund
- Germany
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37
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Babaylova ES, Ivanov AV, Malygin AA, Vorobjeva MA, Venyaminova AG, Polienko YF, Kirilyuk IA, Krumkacheva OA, Fedin MV, Karpova GG, Bagryanskaya EG. A versatile approach for site-directed spin labeling and structural EPR studies of RNAs. Org Biomol Chem 2015; 12:3129-36. [PMID: 24714823 DOI: 10.1039/c3ob42154f] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Site-directed spin labeling (SDSL) is widely applied for structural studies of biopolymers by electron paramagnetic resonance (EPR). However, SDSL of long RNA sequences still remains a challenging task. Here, we propose a novel SDSL approach potentially suitable for long natural RNAs, which is based on the attachment of a linker containing an aliphatic amino group to the target nucleotide residue followed by selective coupling of a spin label to this amino group. Such a linker can be attached to the desired RNA residue via a sequence-specific reaction with the derivatives of oligodeoxyribonucleotides. To verify this approach, we applied it to model RNA duplex with known structure and expected distance between corresponding residues. A new 2,5-bis(spirocyclohexane)-substituted spin label with advanced stability and relaxation properties has been used, and the distance distribution measured using Q-band (34 GHz) pulsed double electron-electron resonance corresponds well to the expected one. We have additionally validated the obtained results by studying a similar RNA duplex, where the linker with the aliphatic amino group was introduced via solid-phase synthesis. Although this novel SDSL approach does not provide an advantage in precision of molecular distance measurements, we believe that its applicability to long RNAs is a crucial benefit for future structural studies using pulse EPR.
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Affiliation(s)
- Elena S Babaylova
- Institute of Chemical Biology and Fundamental Medicine SB RAS, pr. Lavrentjeva 8, Novosibirsk, 630090, Russia
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38
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Bagryanskaya EG, Krumkacheva OA, Fedin MV, Marque SR. Development and Application of Spin Traps, Spin Probes, and Spin Labels. Methods Enzymol 2015; 563:365-96. [DOI: 10.1016/bs.mie.2015.06.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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39
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40
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El Mkami H, Ward R, Bowman A, Owen-Hughes T, Norman DG. The spatial effect of protein deuteration on nitroxide spin-label relaxation: implications for EPR distance measurement. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 248:36-41. [PMID: 25310878 PMCID: PMC4245719 DOI: 10.1016/j.jmr.2014.09.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 09/11/2014] [Accepted: 09/12/2014] [Indexed: 05/27/2023]
Abstract
Pulsed electron-electron double resonance (PELDOR) coupled with site-directed spin labeling is a powerful technique for the elucidation of protein or nucleic acid, macromolecular structure and interactions. The intrinsic high sensitivity of electron paramagnetic resonance enables measurement on small quantities of bio-macromolecules, however short relaxation times impose a limit on the sensitivity and size of distances that can be measured using this technique. The persistence of the electron spin-echo, in the PELDOR experiment, is one of the most crucial limitations to distance measurement. At a temperature of around 50 K one of the predominant factors affecting persistence of an echo, and as such, the sensitivity and measurable distance between spin labels, is the electron spin echo dephasing time (Tm). It has become normal practice to use deuterated solvents to extend Tm and recently it has been demonstrated that deuteration of the underlying protein significantly extends Tm. Here we examine the spatial effect of segmental deuteration of the underlying protein, and also explore the concentration and temperature dependence of highly deuterated systems.
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Affiliation(s)
- Hassane El Mkami
- School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, UK
| | - Richard Ward
- Nucleic Acids Structure Research Group, University of Dundee, Dundee DD1 5EH, UK
| | - Andrew Bowman
- Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, UK
| | - Tom Owen-Hughes
- Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, UK
| | - David G Norman
- Nucleic Acids Structure Research Group, University of Dundee, Dundee DD1 5EH, UK.
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41
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New developments in spin labels for pulsed dipolar EPR. Molecules 2014; 19:16998-7025. [PMID: 25342554 PMCID: PMC6271499 DOI: 10.3390/molecules191016998] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/07/2014] [Accepted: 10/13/2014] [Indexed: 11/17/2022] Open
Abstract
Spin labelling is a chemical technique that enables the integration of a molecule containing an unpaired electron into another framework for study. Given the need to understand the structure, dynamics, and conformational changes of biomacromolecules, spin labelling provides a relatively non-intrusive technique and has certain advantages over X-ray crystallography; which requires high quality crystals. The technique relies on the design of binding probes that target a functional group, for example, the thiol group of a cysteine residue within a protein. The unpaired electron is typically supplied through a nitroxide radical and sterically shielded to preserve stability. Pulsed electron paramagnetic resonance (EPR) techniques allow small magnetic couplings to be measured (e.g., <50 MHz) providing information on single label probes or the dipolar coupling between multiple labels. In particular, distances between spin labels pairs can be derived which has led to many protein/enzymes and nucleotides being studied. Here, we summarise recent examples of spin labels used for pulse EPR that serve to illustrate the contribution of chemistry to advancing discoveries in this field.
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42
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Yu Z, Quine RW, Rinard GA, Tseitlin M, Elajaili H, Kathirvelu V, Clouston LJ, Boratyński PJ, Rajca A, Stein R, Mchaourab H, Eaton SS, Eaton GR. Rapid-scan EPR of immobilized nitroxides. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 247:67-71. [PMID: 25240151 PMCID: PMC4247172 DOI: 10.1016/j.jmr.2014.08.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 08/13/2014] [Accepted: 08/14/2014] [Indexed: 05/05/2023]
Abstract
X-band electron paramagnetic resonance spectra of immobilized nitroxides were obtained by rapid scan at 293 K. Scan widths were 155 G with 13.4 kHz scan frequency for (14)N-perdeuterated tempone and for T4 lysozyme doubly spin labeled with an iodoacetamide spirocyclohexyl nitroxide and 100 G with 20.9 kHz scan frequency for (15)N-perdeuterated tempone. These wide scans were made possible by modifications to our rapid-scan driver, scan coils made of Litz wire, and the placement of highly conducting aluminum plates on the poles of a Bruker 10″ magnet to reduce resistive losses in the magnet pole faces. For the same data acquisition time, the signal-to-noise for the rapid-scan absorption spectra was about an order of magnitude higher than for continuous wave first-derivative spectra recorded with modulation amplitudes that do not broaden the lineshapes.
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Affiliation(s)
- Zhelin Yu
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, USA
| | - Richard W Quine
- School of Engineering and Computer Science, University of Denver, Denver, CO 80208, USA
| | - George A Rinard
- School of Engineering and Computer Science, University of Denver, Denver, CO 80208, USA
| | - Mark Tseitlin
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, USA
| | - Hanan Elajaili
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, USA
| | - Velavan Kathirvelu
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, USA
| | - Laura J Clouston
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, USA
| | | | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, USA
| | - Richard Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Hassane Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, USA
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, USA.
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43
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Wang Y, Paletta JT, Berg K, Reinhart E, Rajca S, Rajca A. Synthesis of unnatural amino acids functionalized with sterically shielded pyrroline nitroxides. Org Lett 2014; 16:5298-300. [PMID: 25324010 PMCID: PMC4201325 DOI: 10.1021/ol502449r] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
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A series
of unnatural amino acids functionalized with sterically
shielded pyrroline nitroxides were synthesized. Their reduction by
ascorbate/glutathione indicates that l-cysteine functionalized
with gem-diethylpyrroline nitroxide is reduced at
the slowest rate and is comparable to that measured for the most resistant
to reduction pyrroline and pyrrolidine nitroxides.
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Affiliation(s)
- Ying Wang
- Department of Chemistry, University of Nebraska , Lincoln, Nebraska 68588-0304, United States
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44
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Shevelev GY, Krumkacheva OA, Lomzov AA, Kuzhelev AA, Rogozhnikova OY, Trukhin DV, Troitskaya TI, Tormyshev VM, Fedin MV, Pyshnyi DV, Bagryanskaya EG. Physiological-temperature distance measurement in nucleic acid using triarylmethyl-based spin labels and pulsed dipolar EPR spectroscopy. J Am Chem Soc 2014; 136:9874-7. [PMID: 24963806 DOI: 10.1021/ja505122n] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Resolving the nanometer-scale structure of biomolecules in natural conditions still remains a challenging task. We report the first distance measurement in nucleic acid at physiological temperature using electron paramagnetic resonance (EPR). The model 10-mer DNA duplex has been labeled with reactive forms of triarylmethyl radicals and then immobilized on a sorbent in water solution and investigated by double quantum coherence EPR. We succeeded in development of optimal triarylmethyl-based labels, approach for site-directed spin labeling and efficient immobilization procedure that, working together, allowed us to measure as long distances as ~4.6 nm with high accuracy at 310 K (37 °C).
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Affiliation(s)
- Georgiy Yu Shevelev
- Institute of Chemical Biology and Fundamental Medicine, §International Tomography Center, and #N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of the Sciences (SB RAS) , Novosibirsk 630090, Russia
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45
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Manoni R, Romano F, Casati C, Franchi P, Mezzina E, Lucarini M. Synthesis and characterization of spin-labelled [2]rotaxanes containing tetrathiafulvalene and 1,5-dioxynaphthalene molecular stations. Org Chem Front 2014. [DOI: 10.1039/c4qo00065j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Zagdoun A, Casano G, Ouari O, Schwarzwälder M, Rossini AJ, Aussenac F, Yulikov M, Jeschke G, Copéret C, Lesage A, Tordo P, Emsley L. Large molecular weight nitroxide biradicals providing efficient dynamic nuclear polarization at temperatures up to 200 K. J Am Chem Soc 2013; 135:12790-7. [PMID: 23961876 DOI: 10.1021/ja405813t] [Citation(s) in RCA: 273] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A series of seven functionalized nitroxide biradicals (the bTbK biradical and six derivatives) are investigated as exogenous polarization sources for dynamic nuclear polarization (DNP) solid-state NMR at 9.4 T and with ca. 100 K sample temperatures. The impact of electron relaxation times on the DNP enhancement (ε) is examined, and we observe that longer inversion recovery and phase memory relaxation times provide larger ε. All radicals are tested in both bulk 1,1,2,2-tetrachloroethane solutions and in mesoporous materials, and the difference in ε between the two cases is discussed. The impact of the sample temperature and magic angle spinning frequency on ε is investigated for several radicals each characterized by a range of electron relaxation times. In particular, TEKPol, a bulky derivative of bTbK with a molecular weight of 905 g·mol(-1), is presented. Its high-saturation factor makes it a very efficient polarizing agent for DNP, yielding unprecedented proton enhancements of over 200 in both bulk and materials samples at 9.4 T and 100 K. TEKPol also yields encouraging enhancements of 33 at 180 K and 12 at 200 K, suggesting that with the continued improvement of radicals large ε may be obtained at higher temperatures.
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Affiliation(s)
- Alexandre Zagdoun
- Centre de RMN à Très Hauts Champs, Institut de Sciences Analytiques, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1), 69100 Villeurbanne, France
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47
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Sauvée C, Rosay M, Casano G, Aussenac F, Weber RT, Ouari O, Tordo P. Highly efficient, water-soluble polarizing agents for dynamic nuclear polarization at high frequency. Angew Chem Int Ed Engl 2013; 52:10858-61. [PMID: 23956072 DOI: 10.1002/anie.201304657] [Citation(s) in RCA: 327] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Indexed: 11/11/2022]
Affiliation(s)
- Claire Sauvée
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397 Marseille cedex 20 (France) http://sites.univ-provence.fr/srep/
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48
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Highly Efficient, Water-Soluble Polarizing Agents for Dynamic Nuclear Polarization at High Frequency. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201304657] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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49
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Morozov DA, Kirilyuk IA, Komarov DA, Goti A, Bagryanskaya IY, Kuratieva NV, Grigor’ev IA. Synthesis of a Chiral C2-Symmetric Sterically Hindered Pyrrolidine Nitroxide Radical via Combined Iterative Nucleophilic Additions and Intramolecular 1,3-Dipolar Cycloadditions to Cyclic Nitrones. J Org Chem 2012; 77:10688-98. [DOI: 10.1021/jo3019158] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Denis A. Morozov
- Novosibirsk Institute of Organic Chemistry, Novosibirsk 630090, Russia
- Novosibirsk State University, Novosibirsk
630090, Russia
| | - Igor A. Kirilyuk
- Novosibirsk Institute of Organic Chemistry, Novosibirsk 630090, Russia
| | - Denis A. Komarov
- Novosibirsk Institute of Organic Chemistry, Novosibirsk 630090, Russia
| | - Andrea Goti
- Dipartimento
di Chimica “Ugo Schiff”, Universitá degli Studi di Firenze, Sesto Fiorentino, Firenze I-50019,
Italy
| | | | | | - Igor A. Grigor’ev
- Novosibirsk Institute of Organic Chemistry, Novosibirsk 630090, Russia
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50
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Collauto A, Barbon A, Brustolon M. First determination of the spin relaxation properties of a nitronyl nitroxide in solution by electron spin echoes at X-band: a comparison with Tempone. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 223:180-186. [PMID: 22975247 DOI: 10.1016/j.jmr.2012.07.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 07/12/2012] [Accepted: 07/13/2012] [Indexed: 06/01/2023]
Abstract
We studied by electron spin echo pulse methods the spin relaxation properties of a phenyl nitronyl nitroxide radical (2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide, PTIO) at X-band in fluid toluene solution in a wide temperature range, and in a water/glycerol 1:1 mixture near room temperature. The relaxation properties of PTIO have been compared with that of Tempone, as a widely used nitroxide. By a new procedure, based on experimental results on the temperature dependences of the relaxation times T(1) and T(2), and on the approximation of an isotropic brownian rotational diffusion, we separated non-secular, spin rotational and residual terms from the transverse relaxation rate to isolate secular and pseudosecular contributions. By comparing the results for the two radicals we found the differences in the magnetic properties that give rise to slower transverse (T(2)) and longitudinal (T(1)) electron spin relaxation for PTIO in the whole temperature range explored in this work.
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Affiliation(s)
- A Collauto
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, I-35131 Padova, Italy
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