1
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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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2
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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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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. 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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4
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Velayutham M, Poncelet M, Perini JA, Kupec JT, Dietz MJ, Driesschaert B, Khramtsov VV. EPR Viscometric Measurements Using a 13C-Labeled Triarylmethyl Radical in Protein-based Biotherapeutics and Human Synovial Fluids. APPLIED MAGNETIC RESONANCE 2023; 54:779-791. [PMID: 38707765 PMCID: PMC11068027 DOI: 10.1007/s00723-023-01556-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/22/2023] [Accepted: 06/22/2023] [Indexed: 05/07/2024]
Abstract
The viscosity measurements are of clinical significance for evaluation of the potential pathological conditions of biological lubricants such as synovial fluids of joints, and for formulation and characterization of peptide- and protein-based biotherapeutics. Due to inherent potential therapeutic activity, protein drugs have proven to be one of the most efficient therapeutic agents in treatment of several life-threatening disorders, such as diabetes and autoimmune diseases. However, home-use applications for treating chronic inflammatory diseases, such as diabetes and rheumatoid arthritis, necessitate the development of high-concentration insulin and monoclonal antibodies formulations for patient self-administration. High protein concentrations can affect viscosity of the corresponding drug solutions complicating their manufacture and administration. The measurements of the viscosity of new insulin analogs and monoclonal antibodies solutions under development is of practical importance to avoid unwanted highly viscous, and therefore, painful for injection drug formulations. Recently, we have demonstrated capability of the electron paramagnetic resonance (EPR) viscometry using viscosity-sensitive 13C-labeled trityl spin probe (13C1-dFT) to report the viscosity of human blood, and interstitial fluids measured in various organs in mice ex-vivo and in anesthetized mice, in vivo. In the present work, we demonstrate utility of the EPR viscometry using 13C1-dFT to measure microviscosity of commercial insulin samples, antibodies solution, and human synovial fluids using small microliter volume samples (5-50 μL). This viscometry analysis approach provides useful tool to control formulations and administration of new biopharmaceuticals, and for evaluation of the state of synovial fluids of importance for clinical applications.
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Affiliation(s)
- Murugesan Velayutham
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center
- Department of Biochemistry and Molecular Medicine
| | - Martin Poncelet
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center
- Department of Pharmaceutical Sciences
| | | | | | | | - Benoit Driesschaert
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center
- Department of Pharmaceutical Sciences
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506, USA
| | - Valery V. Khramtsov
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center
- Department of Biochemistry and Molecular Medicine
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5
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Kuzhelev AA, Denysenkov V, Ahmad IM, Rogozhnikova OY, Trukhin DV, Bagryanskaya EG, Tormyshev VM, Sigurdsson ST, Prisner TF. Solid-Effect Dynamic Nuclear Polarization in Viscous Liquids at 9.4 T Using Narrow-Line Polarizing Agents. J Am Chem Soc 2023; 145:10268-10274. [PMID: 37104685 DOI: 10.1021/jacs.3c01358] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Dynamic nuclear polarization (DNP) is a hyperpolarization method that is widely used for increasing the sensitivity of nuclear magnetic resonance (NMR) experiments. DNP is efficient in solid-state and liquid-state NMR, but its implementation in the intermediate state, namely, viscous media, is still less explored. Here, we show that a 1H DNP enhancement of over 50 can be obtained in viscous liquids at a magnetic field of 9.4 T and a temperature of 315 K. This was accomplished by using narrow-line polarizing agents in glycerol, both the water-soluble α,γ-bisdiphenylen-β-phenylallyl (BDPA) and triarylmethyl radicals, and a microwave/RF double-resonance probehead. We observed DNP enhancements with a field profile indicative of the solid effect and investigated the influence of microwave power, temperature, and concentration on the 1H NMR results. To demonstrate potential applications of this new DNP approach for chemistry and biology, we show hyperpolarized 1H NMR spectra of tripeptides, triglycine, and glypromate, in glycerol-d8.
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Affiliation(s)
- Andrei A Kuzhelev
- Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max von Laue Straße 7, 60438 Frankfurt am Main, Germany
| | - Vasyl Denysenkov
- Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max von Laue Straße 7, 60438 Frankfurt am Main, Germany
| | - Iram M Ahmad
- Department of Chemistry, Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavik, Iceland
| | - Olga Yu Rogozhnikova
- N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Acad. Lavrentiev Avenue 9, 630090 Novosibirsk, Russia
| | - Dmitry V Trukhin
- N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Acad. Lavrentiev Avenue 9, 630090 Novosibirsk, Russia
| | - Elena G Bagryanskaya
- N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Acad. Lavrentiev Avenue 9, 630090 Novosibirsk, Russia
| | - Victor M Tormyshev
- N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Acad. Lavrentiev Avenue 9, 630090 Novosibirsk, Russia
| | - Snorri Th Sigurdsson
- Department of Chemistry, Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavik, Iceland
| | - Thomas F Prisner
- Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max von Laue Straße 7, 60438 Frankfurt am Main, Germany
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6
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Casto J, Bogetti X, Hunter HR, Hasanbasri Z, Saxena S. "Store-bought is fine": Sensitivity considerations using shaped pulses for DEER measurements on Cu(II) labels. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 349:107413. [PMID: 36867974 DOI: 10.1016/j.jmr.2023.107413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/27/2023] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
The narrow excitation bandwidth of monochromic pulses is a sensitivity limitation for pulsed dipolar spectroscopy on Cu(II)-based measurements. In response, frequency-swept pulses with large excitation bandwidths have been adopted to probe a greater range of the EPR spectrum. However, much of the work utilizing frequency-swept pulses in Cu(II) distance measurements has been carried out on home-built spectrometers and equipment. Herein, we carry out systematic Cu(II) based distance measurements to demonstrate the capability of chirp pulses on commercial instrumentation. More importantly we delineate sensitivity considerations under acquisition schemes that are necessary for robust distance measurements using Cu(II) labels for proteins. We show that a 200 MHz sweeping bandwidth chirp pulse can improve the sensitivity of long-range distance measurements by factors of three to four. The sensitivity of short-range distances only increases slightly due to special considerations for the chirp pulse duration relative to the period length of the modulated dipolar signal. Enhancements in sensitivity also dramatically reduce measurement collection times enabling rapid collection of orientationally averaged Cu(II) distance measurements in under two hours.
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Affiliation(s)
- Joshua Casto
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Xiaowei Bogetti
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Hannah R Hunter
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Zikri Hasanbasri
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States.
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7
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Campanella AJ, Üngör Ö, Zadrozny JM. Quantum Mimicry With Inorganic Chemistry. COMMENT INORG CHEM 2023; 44:11-53. [PMID: 38515928 PMCID: PMC10954259 DOI: 10.1080/02603594.2023.2173588] [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] [Indexed: 02/15/2023]
Abstract
Quantum objects, such as atoms, spins, and subatomic particles, have important properties due to their unique physical properties that could be useful for many different applications, ranging from quantum information processing to magnetic resonance imaging. Molecular species also exhibit quantum properties, and these properties are fundamentally tunable by synthetic design, unlike ions isolated in a quadrupolar trap, for example. In this comment, we collect multiple, distinct, scientific efforts into an emergent field that is devoted to designing molecules that mimic the quantum properties of objects like trapped atoms or defects in solids. Mimicry is endemic in inorganic chemistry and featured heavily in the research interests of groups across the world. We describe a new field of using inorganic chemistry to design molecules that mimic the quantum properties (e.g. the lifetime of spin superpositions, or the resonant frequencies thereof) of other quantum objects, "quantum mimicry." In this comment, we describe the philosophical design strategies and recent exciting results from application of these strategies.
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Affiliation(s)
- Anthony J. Campanella
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA, Address: 200 W. Lake St, Campus Delivery 1872, Fort Collins, CO 80523, USA
| | - Ökten Üngör
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA, Address: 200 W. Lake St, Campus Delivery 1872, Fort Collins, CO 80523, USA
| | - Joseph M. Zadrozny
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA, Address: 200 W. Lake St, Campus Delivery 1872, Fort Collins, CO 80523, USA
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8
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Hasanbasri Z, Poncelet M, Hunter H, Driesschaert B, Saxena S. A new 13C trityl-based spin label enables the use of DEER for distance measurements. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 347:107363. [PMID: 36620971 PMCID: PMC9928843 DOI: 10.1016/j.jmr.2022.107363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/15/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Triarylmethyl (TAM)-based labels, while still underutilized, are a powerful class of labels for pulsed-Electron Spin Resonance (ESR) distance measurements. They feature slow relaxation rates for long-lasting signals, high stability for cellular experiments, and narrow spectral features for efficient excitation of the spins. However, the typical narrow line shape limits the available distance measurements to only single-frequency experiments, such as Double Quantum Coherence (DQC) and Relaxation Induced Dipolar Modulation Enhancement (RIDME), which can be complicated to perform or hard to process. Therefore, widespread usage of TAM labels can be enhanced by the use of Double Electron-Electron Resonance (DEER) distance measurements. In this work, we developed a new spin label, 13C1-mOX063-d24, with a 13C isotope as the radical center. Due to the resolved hyperfine splitting, the spectrum is sufficiently broadened to permit DEER-based experiments at Q-band spectrometers. Additionally, this new label can be incorporated orthogonally with Cu(II)-based protein label. The orthogonal labeling scheme enables DEER distance measurement at X-band frequencies. Overall, the new trityl label allows for DEER-based distance measurements that complement existing TAM-label DQC and RIDME experiments.
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Affiliation(s)
- Zikri Hasanbasri
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Martin Poncelet
- Department of Pharmaceutical Sciences, School of Pharmacy & In Vivo Multifunctional Magnetic Resonance (IMMR) Center, Health Sciences Center, West Virginia University, Morgantown, WV 26506, United States
| | - Hannah Hunter
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Benoit Driesschaert
- Department of Pharmaceutical Sciences, School of Pharmacy & In Vivo Multifunctional Magnetic Resonance (IMMR) Center, Health Sciences Center, West Virginia University, Morgantown, WV 26506, United States; C. Eugene Bennett Department of Chemistry West Virginia University, Morgantown, WV 26506, United States.
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States.
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9
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Li X, Wang YL, Chen C, Han YF. Luminescent Crystalline Carbon- and Nitrogen-Centered Organic Radicals Based on N-Heterocyclic Carbene-Triphenylamine Hybrids. Chemistry 2023; 29:e202203242. [PMID: 36331436 DOI: 10.1002/chem.202203242] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/02/2022] [Accepted: 11/04/2022] [Indexed: 11/06/2022]
Abstract
Developing luminescent radicals with tunable emission is a challenging task due to the limitation of alternative skeletons. Herein, a series of carbene-triphenylamine hybrids were prepared by the direct C2-arylation of N-heterocyclic carbenes with 4-bromo-N,N-bis(4-methoxyphenyl)aniline. These hybrids showed multiple redox-active properties and could be converted to carbon-centered luminescent radicals with blue-to-cyan emissions (λmax : 436-486 nm) or nitrogen-centered luminescent radicals with orange emissions (λmax : 590-623 nm) through chemical reduction or oxidation, respectively. The radical species were characterized by electron paramagnetic resonance spectroscopy, ultraviolet-visible spectroscopy, and single-crystal X-ray diffractometry analysis. Notably, the corresponding nitrogen-centered radicals exhibited good stability in atmospheric air, and their thermal decomposition temperatures were determined to be above 200 °C. In addition, spectral and theoretical calculations indicate that all radicals exhibit anti-Kasha emissions.
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Affiliation(s)
- Xin Li
- Key Laboratory of Synthetic and, Natural Functional Molecule of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China
| | - Yi-Lin Wang
- Key Laboratory of Synthetic and, Natural Functional Molecule of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China
| | - Can Chen
- Key Laboratory of Synthetic and, Natural Functional Molecule of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China
| | - Ying-Feng Han
- Key Laboratory of Synthetic and, Natural Functional Molecule of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China
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10
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Gluth TD, Poncelet M, Gencheva M, Hoblitzell EH, Khramtsov VV, Eubank TD, Driesschaert B. Biocompatible Monophosphonated Trityl Spin Probe, HOPE71, for In Vivo Measurement of pO 2, pH, and [P i] by Electron Paramagnetic Resonance Spectroscopy. Anal Chem 2023; 95:946-954. [PMID: 36537829 PMCID: PMC9852220 DOI: 10.1021/acs.analchem.2c03476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Hypoxia, acidosis, and elevated inorganic phosphate concentration are characteristics of the tumor microenvironment in solid tumors. There are a number of methods for measuring each parameter individually in vivo, but the only method to date for noninvasive measurement of all three variables simultaneously in vivo is electron paramagnetic spectroscopy paired with a monophosphonated trityl radical, pTAM/HOPE. While HOPE has been successfully used for in vivo studies upon intratissue injection, it cannot be delivered intravenously due to systemic toxicity and albumin binding, which causes significant signal loss. Therefore, we present HOPE71, a monophosphonated trityl radical derived from the very biocompatible trityl probe, Ox071. Here, we describe a straightforward synthesis of HOPE71 starting with Ox071 and report its EPR sensitivities to pO2, pH, and [Pi] with X-band and L-band EPR spectroscopy. We also confirm that HOPE71 lacks albumin binding, shows low cytotoxicity, and has systemic tolerance. Finally, we demonstrate its ability to profile the tumor microenvironment in vivo in a mouse model of breast cancer.
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Affiliation(s)
- Teresa D. Gluth
- Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, WV, 26506, USA
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
| | - Martin Poncelet
- Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, WV, 26506, USA
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
| | - Marieta Gencheva
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- Department of Biochemistry and Molecular Medicine, West Virginia University, School of Medicine, Morgantown, WV, 26506, USA
| | - Emily H. Hoblitzell
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, School of Medicine, Morgantown, WV, 26506, USA
| | - Valery V. Khramtsov
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- Department of Biochemistry and Molecular Medicine, West Virginia University, School of Medicine, Morgantown, WV, 26506, USA
| | - Timothy D. Eubank
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, School of Medicine, Morgantown, WV, 26506, USA
| | - Benoit Driesschaert
- Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, WV, 26506, USA
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
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11
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Poncelet M, Ngendahimana T, Gluth TD, Hoblitzell EH, Eubank TD, Eaton GR, Eaton SS, Driesschaert B. Synthesis and characterization of a biocompatible 13C 1 isotopologue of trityl radical OX071 for in vivo EPR viscometry. Analyst 2022; 147:5643-5648. [PMID: 36373434 PMCID: PMC9729415 DOI: 10.1039/d2an01527g] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2023]
Abstract
We describe the synthesis, characterization, and application of an isotopologue of the trityl radical OX071, labeled with 13C at the central carbon (13C1). This spin probe features large anisotropy of the hyperfine coupling with the 13C1 (I = 1/2), leading to an EPR spectrum highly sensitive to molecular tumbling. The high biocompatibility and lack of interaction with blood albumin allow for systemic delivery and in vivo measurement of tissue microviscosity by EPR.
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Affiliation(s)
- Martin Poncelet
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV, 26506, USA
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA.
| | - Thacien Ngendahimana
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80210, USA
| | - Teresa D Gluth
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV, 26506, USA
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA.
| | - Emily H Hoblitzell
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA.
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, School of Medicine, Morgantown, WV, 26506, USA
| | - Timothy D Eubank
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA.
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, School of Medicine, Morgantown, WV, 26506, USA
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80210, USA
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80210, USA
| | - Benoit Driesschaert
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV, 26506, USA
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA.
- Eugene Bennett Department of Chemistry, West Virginia University, WV, 26506, USA
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12
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Moore W, Huffman JL, Driesschaert B, Eaton SS, Eaton GR. Impact of Chlorine Substitution on Electron Spin Relaxation of a Trityl Radical. APPLIED MAGNETIC RESONANCE 2022; 53:797-808. [PMID: 35601029 PMCID: PMC9122340 DOI: 10.1007/s00723-021-01405-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A perchlorotriarylmethyl tricarboxylic acid radical 99% enriched in 13C at the central carbon (13C1-PTMTC) was characterized in phosphate buffered saline solution (pH = 7.2) (PBS) at ambient temperature. Samples immobilized in 1:1 PBS:glycerol or in 9:1 trehalose:sucrose were studied as a function of temperature. Isotope enrichment at C1 creates a trityl that can be used to accurately measure microscopic viscosity. Understanding of the impact of the 13C hyperfine interaction on electron spin relaxation is important for application of this trityl in oximetry and distance measurements. The anisotropic 13C1 hyperfine couplings (Ax = Ay = 24 ± 2 MHz, Az = 200 ± 1 MHz) are larger than for the related 13C1-perdeuterated Finland trityl (13C1-dFT) and the g anisotropy (gx = 2.0013, gy = 2.0016, gz = 2.0042) is slightly larger than for 13C1-dFT. The tumbling correlation times (τR) for 13C1-PTMTC are 0.20 ± 0.02 ns in PBS and 0.40 ± 0.05 ns in 3:1 PBS:glycerol, which are shorter than for 13C1-dFT in the same solutions. T1 for 13C1-PTMTC is 3.5 ± 0.5 μs in PBS and 5.3 ± 0.4 μs in 3:1 PBS:glycerol, which are shorter than for 13C1-dFT due to faster tumbling, larger anisotropy of the 13C1 hyperfine, and about 30% larger contribution from the local mode. In immobilized samples T1 for 13C1-PTMTC is similar to that for 13C1-dFT and other trityls without chlorine or 13C1 substituents, indicating that the 13C1 and Cl substituents on the phenyl rings have little impact on T1. The temperature dependence of T1 was modeled with contributions from the direct, Raman, and local mode processes. Broadening of CW linewidths of about 0.6 G in fluid solution and about 2 G in rigid lattice is attributed to unresolved 35,37Cl hyperfine couplings.
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Affiliation(s)
- Whylder Moore
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80210, USA
| | - Justin L. Huffman
- Department of Pharmaceutical Sciences, School of Pharmacy & In Vivo Multifunctional Magnetic Resonance Center, West Virginia University, Morgantown, WV 26506, USA
| | - Benoit Driesschaert
- Department of Pharmaceutical Sciences, School of Pharmacy & In Vivo Multifunctional Magnetic Resonance Center, West Virginia University, Morgantown, WV 26506, USA
| | - Sandra S. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80210, USA
| | - Gareth R. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80210, USA
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13
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Cui X, Zhang Z, Yang Y, Li S, Lee C. Organic radical materials in biomedical applications: State of the art and perspectives. EXPLORATION (BEIJING, CHINA) 2022; 2:20210264. [PMID: 37323877 PMCID: PMC10190988 DOI: 10.1002/exp.20210264] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/24/2022] [Indexed: 06/17/2023]
Abstract
Owing to their unique chemical reactivities and paramagnetism, organic radicals with unpaired electrons have found widespread exploration in physical, chemical, and biological fields. However, most radicals are too short-lived to be separated and only a few of them can maintain stable radical forms via stereochemical strategies. How to utilize these raw radicals for developing stable radical-containing materials have long been a research hotspot for many years. This perspective introduces fundamental characteristics of organic radical materials and highlights their applications in biomedical fields, particularly for bioimaging, biosensing, and photo-triggered therapies. Molecular design of these radical materials is considered with reference to their outstanding imaging and therapeutic performances. Various challenges currently limiting the wide applications of these organic radical materials and their future development are also discussed.
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Affiliation(s)
- Xiao Cui
- Department of ChemistryInstitution Center of Super‐Diamond and Advanced Films (COSDAF)City University of Hong KongKowloonHong Kong SARChina
| | - Zhen Zhang
- Department of ChemistryInstitution Center of Super‐Diamond and Advanced Films (COSDAF)City University of Hong KongKowloonHong Kong SARChina
| | - Yuliang Yang
- College of Pharmaceutical SciencesSoochow UniversitySuzhouChina
| | - Shengliang Li
- College of Pharmaceutical SciencesSoochow UniversitySuzhouChina
| | - Chun‐Sing Lee
- Department of ChemistryInstitution Center of Super‐Diamond and Advanced Films (COSDAF)City University of Hong KongKowloonHong Kong SARChina
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14
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15
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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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16
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Zhao Y, Zhu H, Sung S, Wink DJ, Zadrozny JM, Driver TG. Counterion Control of
t
‐BuO‐Mediated Single Electron Transfer to Nitrostilbenes to Construct
N
‐Hydroxyindoles or Oxindoles. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202104319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yingwei Zhao
- Department of Chemistry University of Illinois at Chicago 845 W Taylor St. MC 111 Chicago IL 60607 USA
- College of Chemical Engineering Huaqiao University, Xiamen 668 Jimei Boulevard Xiamen Fujian 361021 P. R. China
| | - Haoran Zhu
- Department of Chemistry University of Illinois at Chicago 845 W Taylor St. MC 111 Chicago IL 60607 USA
| | - Siyoung Sung
- Department of Chemistry Colorado State University Fort Collins CO 80523 USA
| | - Donald J. Wink
- Department of Chemistry University of Illinois at Chicago 845 W Taylor St. MC 111 Chicago IL 60607 USA
| | - Joseph M. Zadrozny
- Department of Chemistry Colorado State University Fort Collins CO 80523 USA
| | - Tom G. Driver
- Department of Chemistry University of Illinois at Chicago 845 W Taylor St. MC 111 Chicago IL 60607 USA
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17
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Zhao Y, Zhu H, Sung S, Wink DJ, Zadrozny JM, Driver TG. Counterion Control of t-BuO-Mediated Single Electron Transfer to Nitrostilbenes to Construct N-Hydroxyindoles or Oxindoles. Angew Chem Int Ed Engl 2021; 60:19207-19213. [PMID: 34129257 PMCID: PMC8380450 DOI: 10.1002/anie.202104319] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Indexed: 12/15/2022]
Abstract
tert-Butoxide unlocks new reactivity patterns embedded in nitroarenes. Exposure of nitrostilbenes to sodium tert-butoxide was found to produce N-hydroxyindoles at room temperature without an additive. Changing the counterion to potassium changed the reaction outcome to yield solely oxindoles through an unprecedented dioxygen-transfer reaction followed by a 1,2-phenyl migration. Mechanistic experiments established that these reactions proceed via radical intermediates and suggest that counterion coordination controls whether an oxindole or N-hydroxyindole product is formed.
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Affiliation(s)
- Yingwei Zhao
- Department of Chemistry, University of Illinois at Chicago, 845 W Taylor St. MC 111, Chicago, IL, 60607, USA
- College of Chemical Engineering, Huaqiao University, Xiamen, 668 Jimei Boulevard, Xiamen, Fujian, 361021, P. R. China
| | - Haoran Zhu
- Department of Chemistry, University of Illinois at Chicago, 845 W Taylor St. MC 111, Chicago, IL, 60607, USA
| | - Siyoung Sung
- Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA
| | - Donald J Wink
- Department of Chemistry, University of Illinois at Chicago, 845 W Taylor St. MC 111, Chicago, IL, 60607, USA
| | - Joseph M Zadrozny
- Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA
| | - Tom G Driver
- Department of Chemistry, University of Illinois at Chicago, 845 W Taylor St. MC 111, Chicago, IL, 60607, USA
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18
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Gluth TD, Poncelet M, DeVience S, Gencheva M, Hoblitzell EH, Khramtsov VV, Eubank TD, Driesschaert B. Large-scale synthesis of a monophosphonated tetrathiatriarylmethyl spin probe for concurrent in vivo measurement of pO 2, pH and inorganic phosphate by EPR. RSC Adv 2021; 11:25951-25954. [PMID: 34354828 PMCID: PMC8314523 DOI: 10.1039/d1ra04551b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 07/21/2021] [Indexed: 11/21/2022] Open
Abstract
Low-field electron paramagnetic resonance spectroscopy paired with pTAM, a mono-phosphonated triarylmethyl radical, is an unmatched technique for concurrent and non-invasive measurement of oxygen concentration, pH, and inorganic phosphate concentration for in vivo investigations. However, the prior reported synthesis is limited by its low yield and poor scalability, making wide-spread application of pTAM unfeasible. Here, we report a new strategy for the synthesis of pTAM with significantly greater yields demonstrated on a large scale. We also present a standalone application with user-friendly interface for automatic spectrum fitting and extraction of pO2, pH, and [Pi] values. Finally, we confirm that pTAM remains in the extracellular space and has low cytotoxicity appropriate for local injection.
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Affiliation(s)
- Teresa D Gluth
- Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy Morgantown WV 26506 USA .,In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University Morgantown WV 26506 USA
| | - Martin Poncelet
- Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy Morgantown WV 26506 USA .,In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University Morgantown WV 26506 USA
| | - Stephen DeVience
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University Morgantown WV 26506 USA.,Department of Biochemistry, West Virginia University, School of Medicine Morgantown WV 26506 USA
| | - Marieta Gencheva
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University Morgantown WV 26506 USA.,Department of Biochemistry, West Virginia University, School of Medicine Morgantown WV 26506 USA
| | - Emily H Hoblitzell
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University Morgantown WV 26506 USA.,Department of Microbiology, Immunology, and Cell Biology, West Virginia University, School of Medicine Morgantown WV 26506 USA
| | - Valery V Khramtsov
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University Morgantown WV 26506 USA.,Department of Biochemistry, West Virginia University, School of Medicine Morgantown WV 26506 USA
| | - Timothy D Eubank
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University Morgantown WV 26506 USA.,Department of Microbiology, Immunology, and Cell Biology, West Virginia University, School of Medicine Morgantown WV 26506 USA
| | - Benoit Driesschaert
- Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy Morgantown WV 26506 USA .,In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University Morgantown WV 26506 USA
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19
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Huffman JL, Poncelet M, Moore W, Eaton SS, Eaton GR, Driesschaert B. Perchlorinated Triarylmethyl Radical 99% Enriched 13C at the Central Carbon as EPR Spin Probe Highly Sensitive to Molecular Tumbling. J Phys Chem B 2021; 125:7380-7387. [PMID: 34213354 PMCID: PMC8378891 DOI: 10.1021/acs.jpcb.1c03778] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Soluble stable radicals are used as spin probes and spin labels for in vitro and in vivo electron paramagnetic resonance (EPR) spectroscopy and imaging applications. We report the synthesis and characterization of a perchlorinated triarylmethyl radical enriched 99% at the central carbon, 13C1-PTMTC. The anisotropy of the hyperfine splitting with the 13C1 (Ax = 26, Ay = 25, Az = 199.5 MHz) and the g (gx = 2.0015, gy = 2.0015, gz = 2.0040) are responsible for a strong effect of the radical tumbling rate on the EPR spectrum. The rotational correlation time can be determined by spectral simulation or via the line width or the apparent Az after calibration, so the spin probe 13C1-PTMTC can be used to measure media microviscosity with high sensitivity.
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Affiliation(s)
- Justin L Huffman
- Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, West Virginia 26506, United States.,In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Martin Poncelet
- Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, West Virginia 26506, United States.,In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Whylder Moore
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80210, United States
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80210, United States
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80210, United States
| | - Benoit Driesschaert
- Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, West Virginia 26506, United States.,In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States
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20
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Chen L, Wu L, Tan X, Rockenbauer A, Song Y, Liu Y. Synthesis and Redox Properties of Water-Soluble Asymmetric Trityl Radicals. J Org Chem 2021; 86:8351-8364. [PMID: 34043350 DOI: 10.1021/acs.joc.1c00766] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tetrathiatriarylmethyl (trityl) radicals have been recently shown to react with biological oxidoreductants including glutathione (GSH), ascorbic acid (Asc), and superoxide anion radical (O2•-). However, how the substituents affect the reactivity of trityl radicals is still unknown. In this work, five asymmetric trityl radicals were synthesized and their reactivities with GSH, Asc, and O2•- investigated. Under aerobic conditions, GSH induces fast decays for the thioether- (TSA) and N-methyleneglycine-substituted (TGA) derivatives and slow decay for the 4-carboxyphenyl-containing one (TPA). Under anaerobic conditions, the direct reduction of these radicals by GSH also occurs with rate constants (kGSH) from 1.8 × 10-4 M-1 s-1 for TPA to 1.0 × 10-2 M-1 s-1 for TGA. Moreover, these radicals can also react with O2•- with rate constants (kSO) from 1.2 × 103 M-1 s-1 for ET-01 to 1.6 × 104 M-1 s-1 for TGA. Surprisingly, these radicals are completely inert to Asc in both aerobic and anaerobic conditions. Additionally, the substituents exert an important effect on redox potentials of these trityl radicals. This work demonstrates that the redox properties of the trityl radicals strongly depend on their substituents, and TPA with high stability toward GSH shows great potential for intracellular applications.
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Affiliation(s)
- Li Chen
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, Department of Medicinal Chemistry, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Lanlan Wu
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, Department of Medicinal Chemistry, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Xiaoli Tan
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, Department of Medicinal Chemistry, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Antal Rockenbauer
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Hungary.,Department of Physics, Budapest University of Technology and Economics, Budafoki ut 8, 1111 Budapest, Hungary
| | - Yuguang Song
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, Department of Medicinal Chemistry, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Yangping Liu
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, Department of Medicinal Chemistry, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
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21
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Velayutham M, Poncelet M, Eubank TD, Driesschaert B, Khramtsov VV. Biological Applications of Electron Paramagnetic Resonance Viscometry Using a 13C-Labeled Trityl Spin Probe. Molecules 2021; 26:molecules26092781. [PMID: 34066858 PMCID: PMC8125944 DOI: 10.3390/molecules26092781] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 12/27/2022] Open
Abstract
Alterations in viscosity of biological fluids and tissues play an important role in health and diseases. It has been demonstrated that the electron paramagnetic resonance (EPR) spectrum of a 13C-labeled trityl spin probe (13C-dFT) is highly sensitive to the local viscosity of its microenvironment. In the present study, we demonstrate that X-band (9.5 GHz) EPR viscometry using 13C-dFT provides a simple tool to accurately measure the microviscosity of human blood in microliter volumes obtained from healthy volunteers. An application of low-field L-band (1.2 GHz) EPR with a penetration depth of 1–2 cm allowed for microviscosity measurements using 13C-dFT in the living tissues from isolated organs and in vivo in anesthetized mice. In summary, this study demonstrates that EPR viscometry using a 13C-dFT probe can be used to noninvasively and rapidly measure the microviscosity of blood and interstitial fluids in living tissues and potentially to evaluate this biophysical marker of microenvironment under various physiological and pathological conditions in preclinical and clinical settings.
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Affiliation(s)
- Murugesan Velayutham
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506, USA; (M.V.); (M.P.); (T.D.E.)
- Department of Biochemistry, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
| | - Martin Poncelet
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506, USA; (M.V.); (M.P.); (T.D.E.)
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV 26506, USA
| | - Timothy D. Eubank
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506, USA; (M.V.); (M.P.); (T.D.E.)
- Department of Microbiology, Immunology & Cell Biology, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
| | - Benoit Driesschaert
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506, USA; (M.V.); (M.P.); (T.D.E.)
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV 26506, USA
- Correspondence: (B.D.); (V.V.K.); Tel.: +1-304-293-7401 (B.D.); +1-304-293-4470 (V.V.K.)
| | - Valery V. Khramtsov
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506, USA; (M.V.); (M.P.); (T.D.E.)
- Department of Biochemistry, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
- Correspondence: (B.D.); (V.V.K.); Tel.: +1-304-293-7401 (B.D.); +1-304-293-4470 (V.V.K.)
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22
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Fleck N, Heubach C, Hett T, Spicher S, Grimme S, Schiemann O. Ox-SLIM: Synthesis of and Site-Specific Labelling with a Highly Hydrophilic Trityl Spin Label. Chemistry 2021; 27:5292-5297. [PMID: 33404074 PMCID: PMC8048664 DOI: 10.1002/chem.202100013] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Indexed: 01/04/2023]
Abstract
The combination of pulsed dipolar electron paramagnetic resonance spectroscopy (PDS) with site-directed spin labelling is a powerful tool in structural biology. Rational design of trityl-based spin labels has enabled studying biomolecular structures at room temperature and within cells. However, most current trityl spin labels suffer either from aggregation with proteins due to their hydrophobicity, or from bioconjugation groups not suitable for in-cell measurements. Therefore, we introduce here the highly hydrophilic trityl spin label Ox-SLIM. Engineered as a short-linked maleimide, it combines the most recent developments in one single molecule, as it does not aggregate with proteins, exhibits high resistance under in-cell conditions, provides a short linker, and allows for selective and efficient spin labelling via cysteines. Beyond establishing synthetic access to Ox-SLIM, its suitability as a spin label is illustrated and ultimately, highly sensitive PDS measurements are presented down to protein concentrations as low as 45 nm resolving interspin distances of up to 5.5 nm.
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Affiliation(s)
- Nico Fleck
- University of BonnInstitute of Physical and Theoretical ChemistryWegelerstr. 1253115BonnGermany
| | - Caspar Heubach
- University of BonnInstitute of Physical and Theoretical ChemistryWegelerstr. 1253115BonnGermany
| | - Tobias Hett
- University of BonnInstitute of Physical and Theoretical ChemistryWegelerstr. 1253115BonnGermany
| | - Sebastian Spicher
- University of BonnInstitute of Physical and Theoretical ChemistryBeringstr. 453115BonnGermany
| | - Stefan Grimme
- University of BonnInstitute of Physical and Theoretical ChemistryBeringstr. 453115BonnGermany
| | - Olav Schiemann
- University of BonnInstitute of Physical and Theoretical ChemistryWegelerstr. 1253115BonnGermany
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23
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Ketter S, Gopinath A, Rogozhnikova O, Trukhin D, Tormyshev VM, Bagryanskaya EG, Joseph B. In Situ Labeling and Distance Measurements of Membrane Proteins in E. coli Using Finland and OX063 Trityl Labels. Chemistry 2021; 27:2299-2304. [PMID: 33197077 PMCID: PMC7898545 DOI: 10.1002/chem.202004606] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 11/13/2020] [Indexed: 01/03/2023]
Abstract
In situ investigation of membrane proteins is a challenging task. Previously we demonstrated that nitroxide labels combined with pulsed ESR spectroscopy is a promising tool for this purpose. However, the nitroxide labels suffer from poor stability, high background labeling, and low sensitivity. Here we show that Finland (FTAM) and OX063 based labels enable labeling of the cobalamin transporter BtuB and BamA, the central component of the β-barrel assembly machinery (BAM) complex, in E coli. Compared to the methanethiosulfonate spin label (MTSL), trityl labels eliminated the background signals and enabled specific in situ labeling of the proteins with high efficiency. The OX063 labels show a long phase memory time (TM ) of ≈5 μs. All the trityls enabled distance measurements between BtuB and an orthogonally labeled substrate with high selectivity and sensitivity down to a few μm concentration. Our data corroborate the BtuB and BamA conformations in the cellular environment of E. coli.
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Affiliation(s)
- Sophie Ketter
- Institute of BiophysicsDepartment of PhysicsGoethe University FrankfurtMax-von-Laue-Str. 160438Frankfurt/MainGermany
| | - Aathira Gopinath
- Institute of BiophysicsDepartment of PhysicsGoethe University FrankfurtMax-von-Laue-Str. 160438Frankfurt/MainGermany
| | - Olga Rogozhnikova
- N. N. Vorozhtsov Novosibirsk Institute of Organic ChemistrySB RASPr. Lavrentieva 9Novosibirsk630090Russia
| | - Dmitrii Trukhin
- N. N. Vorozhtsov Novosibirsk Institute of Organic ChemistrySB RASPr. Lavrentieva 9Novosibirsk630090Russia
| | - Victor M. Tormyshev
- N. N. Vorozhtsov Novosibirsk Institute of Organic ChemistrySB RASPr. Lavrentieva 9Novosibirsk630090Russia
| | - Elena G. Bagryanskaya
- N. N. Vorozhtsov Novosibirsk Institute of Organic ChemistrySB RASPr. Lavrentieva 9Novosibirsk630090Russia
| | - Benesh Joseph
- Institute of BiophysicsDepartment of PhysicsGoethe University FrankfurtMax-von-Laue-Str. 160438Frankfurt/MainGermany
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24
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Moore W, McPeak JE, Poncelet M, Driesschaert B, Eaton SS, Eaton GR. 13C isotope enrichment of the central trityl carbon decreases fluid solution electron spin relaxation times. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 318:106797. [PMID: 32769018 PMCID: PMC7492462 DOI: 10.1016/j.jmr.2020.106797] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/21/2020] [Accepted: 07/22/2020] [Indexed: 05/19/2023]
Abstract
Electron spin relaxation times for perdeuterated Finland trityl 99% enriched in 13C at the central carbon (13C1-dFT) were measured in phosphate buffered saline (pH = 7.2) (PBS) solution at X-band. The anisotropic 13C1 hyperfine (Ax = Ay = 18 ± 2, Az = 162 ± 1 MHz) and g values (2.0033, 2.0032, 2.00275) in a 9:1 trehalose:sucrose glass at 293 K and in 1:1 PBS:glycerol at 160 K were determined by simulation of spectra at X-band and Q-band. In PBS at room temperature the tumbling correlation time, τR, is 0.29 ± 0.02 ns. The linewidths are broadened by incomplete motional averaging of the hyperfine anisotropy and T2 is 0.13 ± 0.02 µs, which is shorter than the T2 ~ 3.8 µs for natural abundance dFT at low concentration in PBS. T1 for 13C1-dFT in deoxygenated PBS is 5.9 ± 0.5 µs, which is shorter than for natural abundance dFT in PBS (16 µs) but much longer than in air-saturated solution (0.48 ± 0.04 µs). The tumbling dependence of T1 in PBS, 3:1 PBS:glycerol (τR = 0.80 ± 0.05 ns, T1 = 9.7 ± 0.7 µs) and 1:1 PBS:glycerol (τR = 3.4 ± 0.3 ns, T1 = 12.0 ± 1.0 µs) was modeled with contributions to the relaxation predominantly from modulation of hyperfine anisotropy and a local mode. The 1/T1 rate for the 1% 12C1-dFT in the predominantly 13C labeled sample is about a factor of 6 more strongly concentration dependent than for natural abundance 12C1-trityl, which reflects the importance of Heisenberg exchange with molecules with different resonance frequencies and faster relaxation rates. In glassy matrices at 160 K, T1 and Tm for 13C1-dFT are in good agreement with previously reported values for 12C1-dFT consistent with the expectation that modulation of nuclear hyperfine does not contribute to electron spin relaxation in a rigid lattice.
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Affiliation(s)
- Whylder Moore
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80210, USA
| | - Joseph E McPeak
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80210, USA
| | - Martin Poncelet
- Department of Pharmaceutical Sciences, School of Pharmacy & In Vivo Multifunctional Magnetic Resonance Center, West Virginia University, Morgantown, WV 26506, USA
| | - Benoit Driesschaert
- Department of Pharmaceutical Sciences, School of Pharmacy & In Vivo Multifunctional Magnetic Resonance Center, West Virginia University, Morgantown, WV 26506, USA
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80210, USA
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80210, USA.
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25
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Kopp K, Schiemann O, Fleck N. Improved, Odorless Access to Benzo[1,2-d;4,5-d']- bis[1,3]dithioles and Tert-butyl Arylsulfides via C-S Cross Coupling. Molecules 2020; 25:molecules25163666. [PMID: 32806560 PMCID: PMC7464442 DOI: 10.3390/molecules25163666] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/07/2020] [Accepted: 08/11/2020] [Indexed: 11/26/2022] Open
Abstract
Benzo[1,2-d;4,5-d′]bis[1,3]dithioles are important building blocks within a range of functional materials such as fluorescent dyes, conjugated polymers, and stable trityl radicals. Access to these is usually gained via tert-butyl aryl sulfides, the synthesis of which requires the use of highly malodorous tert-butyl thiol and relies on SNAr-chemistry requiring harsh reaction conditions, while giving low yields. In the present work, S-tert-butyl isothiouronium bromide is successfully applied as an odorless surrogate for tert-butyl thiol. The C-S bond formation is carried out under palladium catalysis with the thiolate formed in situ resulting in high yields of tert-butyl aryl sulfides. The subsequent formation of benzo[1,2-d;4,5-d′]bis[1,3]dithioles is here achieved with scandium(III)triflate, a less harmful reagent than the usually used Lewis acids, e.g., boron trifluoride or tetrafluoroboric acid. This enables a convenient and environmentally more compliant access to high yields of benzo[1,2-d;4,5-d′]bis[1,3]dithioles.
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26
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Sanzhaeva U, Poncelet M, Tseytlin O, Tseytlin M, Gencheva M, Eubank TD, Khramtsov VV, Driesschaert B. Synthesis, Characterization, and Application of a Highly Hydrophilic Triarylmethyl Radical for Biomedical EPR. J Org Chem 2020; 85:10388-10398. [PMID: 32698583 DOI: 10.1021/acs.joc.0c00557] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Stable tetrathiatriarylmethyl radicals have significantly contributed to the recent progress in biomedical electron paramagnetic resonance (EPR) due to their unmatched stability in biological media and long relaxation times. However, the lipophilic core of the most commonly used structure (Finland trityl) is responsible for its interaction with plasma biomacromolecules, such as albumin, and self-aggregation at high concentrations and/or low pH. While Finland trityl is generally considered inert toward many reactive radical species, we report that sulfite anion radical efficiently substitutes the three carboxyl moieties of Finland trityl with a high rate constant of 3.53 × 108 M-1 s-1, leading to a trisulfonated Finland trityl radical. This newly synthesized highly hydrophilic trityl radical shows an ultranarrow linewidth (ΔBpp = 24 mG), a lower affinity for albumin than Finland trityl, and a high aqueous solubility even at acidic pH. Therefore, this new tetrathiatriarylmethyl radical can be considered as a superior spin probe in comparison to the widely used Finland trityl. One of its potential applications was demonstrated by in vivo mapping oxygen in a mouse model of breast cancer. Moreover, we showed that one of the three sulfo groups can be easily substituted with S-, N-, and P-nucleophiles, opening access to various monofunctionalized sulfonated trityl radicals.
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Affiliation(s)
- Urikhan Sanzhaeva
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States.,Department of Biochemistry, West Virginia University, School of Medicine, Morgantown, West Virginia 26506, United States
| | - Martin Poncelet
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States.,Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, West Virginia 26506, United States
| | - Oxana Tseytlin
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States.,Department of Biochemistry, West Virginia University, School of Medicine, Morgantown, West Virginia 26506, United States
| | - Mark Tseytlin
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States.,Department of Biochemistry, West Virginia University, School of Medicine, Morgantown, West Virginia 26506, United States
| | - Marieta Gencheva
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States.,Department of Microbiology, Immunology, and Cell Biology, West Virginia University, School of Medicine, Morgantown, West Virginia 26506, United States
| | - Timothy D Eubank
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States.,Department of Microbiology, Immunology, and Cell Biology, West Virginia University, School of Medicine, Morgantown, West Virginia 26506, United States
| | - Valery V Khramtsov
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States.,Department of Biochemistry, West Virginia University, School of Medicine, Morgantown, West Virginia 26506, United States
| | - Benoit Driesschaert
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States.,Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, West Virginia 26506, United States
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