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Mitin D, Bullinger F, Dobrynin S, Engelmann J, Scheffler K, Kolokolov M, Krumkacheva O, Buckenmaier K, Kirilyuk I, Chubarov A. Contrast Agents Based on Human Serum Albumin and Nitroxides for 1H-MRI and Overhauser-Enhanced MRI. Int J Mol Sci 2024; 25:4041. [PMID: 38612851 PMCID: PMC11012161 DOI: 10.3390/ijms25074041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 03/18/2024] [Accepted: 03/20/2024] [Indexed: 04/14/2024] Open
Abstract
In cancer diagnostics, magnetic resonance imaging (MRI) uses contrast agents to enhance the distinction between the target tissue and background. Several promising approaches have been developed to increase MRI sensitivity, one of which is Overhauser dynamic nuclear polarization (ODNP)-enhanced MRI (OMRI). In this study, a macromolecular construct based on human serum albumin and nitroxyl radicals (HSA-NIT) was developed using a new synthesis method that significantly increased the modification to 21 nitroxide residues per protein. This was confirmed by electron paramagnetic resonance (EPR) spectroscopy and matrix-assisted laser desorption/ionization time-of-flight (MALDI ToF) mass spectrometry. Gel electrophoresis and circular dichroism showed no significant changes in the structure of HSA-NITs, and no oligomers were formed during modification. The cytotoxicity of HSA-NITs was comparable to that of native albumin. HSA-NITs were evaluated as potential "metal-free" organic radical relaxation-based contrast agents for 1H-MRI and as hyperpolarizing contrast agents for OMRI. Relaxivities (longitudinal and transversal relaxation rates r1 and r2) for HSA-NITs were measured at different magnetic field strengths (1.88, 3, 7, and 14 T). Phantoms were used to demonstrate the potential use of HSA-NIT as a T1- and T2-weighted relaxation-based contrast agent at 3 T and 14 T. The efficacy of 1H Overhauser dynamic nuclear polarization (ODNP) in liquids at an ultralow magnetic field (ULF, B0 = 92 ± 0.8 μT) was investigated for HSA-NIT conjugates. The HSA-NITs themselves did not show ODNP enhancement; however, under the proteolysis conditions simulating cancer tissue, HSA-NIT conjugates were cleaved into lower-molecular-weight (MW) protein fragments that activate ODNP capabilities, resulting in a maximum achievable enhancement |Emax| of 40-50 and a radiofrequency power required to achieve half of Emax, P1/2, of 21-27 W. The HSA-NIT with a higher degree of modification released increased the number of spin probes upon biodegradation, which significantly enhanced the Overhauser effect. Thus, HSA-NITs may represent a new class of MRI relaxation-based contrast agents as well as novel cleavable conjugates for use as hyperpolarizing contrast agents (HCAs) in OMRI.
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Affiliation(s)
- Dmitry Mitin
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 630090 Novosibirsk, Russia;
| | - Friedemann Bullinger
- High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, 72076 Tuebingen, Germany; (F.B.); (J.E.); (K.S.); (K.B.)
| | - Sergey Dobrynin
- N.N. Vorozhtsov Institute of Organic Chemistry SB RAS, 630090 Novosibirsk, Russia;
| | - Jörn Engelmann
- High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, 72076 Tuebingen, Germany; (F.B.); (J.E.); (K.S.); (K.B.)
| | - Klaus Scheffler
- High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, 72076 Tuebingen, Germany; (F.B.); (J.E.); (K.S.); (K.B.)
- Department of Biomedical Magnetic Resonance, Eberhard-Karls University, 72076 Tuebingen, Germany
| | - Mikhail Kolokolov
- International Tomography Center SB RAS, 630090 Novosibirsk, Russia; (M.K.); (O.K.)
| | - Olesya Krumkacheva
- International Tomography Center SB RAS, 630090 Novosibirsk, Russia; (M.K.); (O.K.)
| | - Kai Buckenmaier
- High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, 72076 Tuebingen, Germany; (F.B.); (J.E.); (K.S.); (K.B.)
| | - Igor Kirilyuk
- N.N. Vorozhtsov Institute of Organic Chemistry SB RAS, 630090 Novosibirsk, Russia;
| | - Alexey Chubarov
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 630090 Novosibirsk, Russia;
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Vesković A, Nakarada Đ, Pavićević A, Prokić B, Perović M, Kanazir S, Popović-Bijelić A, Mojović M. In Vivo/Ex Vivo EPR Investigation of the Brain Redox Status and Blood-Brain Barrier Integrity in the 5xFAD Mouse Model of Alzheimer's Disease. Curr Alzheimer Res 2021; 18:25-34. [PMID: 33761860 DOI: 10.2174/1567205018666210324121156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 12/27/2020] [Accepted: 03/15/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) is the most common neurodegenerative disorder characterized by cognitive decline and total brain atrophy. Despite the substantial scientific effort, the pathological mechanisms underlying neurodegeneration in AD are currently unknown. In most studies, amyloid β peptide has been considered the key pathological change in AD. However, numerous Aβ-targeting treatments have failed in clinical trials. This implies the need to shift the research focus from Aβ to other pathological features of the disease. OBJECTIVE The aim of this study was to examine the interplay between mitochondrial dysfunction, oxidative stress and blood-brain barrier (BBB) disruption in AD pathology, using a novel approach that involves the application of electron paramagnetic resonance (EPR) spectroscopy. METHODS In vivo and ex vivo EPR spectroscopy using two spin probes (aminoxyl radicals) exhibiting different cell-membrane and BBB permeability were employed to assess BBB integrity and brain tissue redox status in the 5xFAD mouse model of AD. In vivo spin probe reduction decay was analyzed using a two-compartment pharmacokinetic model. Furthermore, 15 K EPR spectroscopy was employed to investigate the brain metal content. RESULTS This study has revealed an altered brain redox state, BBB breakdown, as well as ROS-mediated damage to mitochondrial iron-sulfur clusters, and up-regulation of MnSOD in the 5xFAD model. CONCLUSION The EPR spin probes were shown to be excellent in vivo reporters of the 5xFAD neuronal tissue redox state, as well as the BBB integrity, indicating the importance of in vivo EPR spectroscopy application in preclinical studies of neurodegenerative diseases.
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Affiliation(s)
- Ana Vesković
- Faculty of Physical Chemistry, University of Belgrade, Belgrade,Serbia
| | - Đura Nakarada
- Faculty of Physical Chemistry, University of Belgrade, Belgrade,Serbia
| | | | - Bogomir Prokić
- Faculty of Veterinary Medicine, University of Belgrade, Belgrade,Serbia
| | - Milka Perović
- Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade,Serbia
| | - Selma Kanazir
- Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade,Serbia
| | | | - Miloš Mojović
- Faculty of Physical Chemistry, University of Belgrade, Belgrade,Serbia
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Poncelet M, Driesschaert B. A 13 C-Labeled Triarylmethyl Radical as an EPR Spin Probe Highly Sensitive to Molecular Tumbling. Angew Chem Int Ed Engl 2020; 59:16451-16454. [PMID: 32542924 PMCID: PMC7901239 DOI: 10.1002/anie.202006591] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Indexed: 12/21/2022]
Abstract
A stable triarylmethyl spin probe whose electron paramagnetic resonance (EPR) spectrum is highly sensitive to molecular tumbling is reported. The strong anisotropy of the hyperfine coupling tensor with the central carbon of a 13 C1 -labeled triarylmethyl radical enables the measurement of the probe rotational correlation time with applications to measure microviscosity and molecular dynamics.
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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
| | - 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
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Dobrynin S, Kutseikin S, Morozov D, Krumkacheva O, Spitsyna A, Gatilov Y, Silnikov V, Angelovski G, Bowman MK, Kirilyuk I, Chubarov A. Human Serum Albumin Labelled with Sterically-Hindered Nitroxides as Potential MRI Contrast Agents. Molecules 2020; 25:E1709. [PMID: 32276437 DOI: 10.3390/molecules25071709] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/03/2020] [Accepted: 04/07/2020] [Indexed: 11/29/2022] Open
Abstract
Four albumin-nitroxide conjugates were prepared and tested as metal-free organic radical contrast agents (ORCAs) for magnetic resonance imaging (MRI). Each human serum albumin (HSA) carrier bears multiple nitroxides conjugated via homocysteine thiolactones. These molecular conjugates retain important physical and biological properties of their HSA component, and the resistance of their nitroxide groups to bioreduction was retained or enhanced. The relaxivities are similar for these four conjugates and are much greater than those of their individual components: the HSA or the small nitroxide molecules. This new family of conjugates has excellent prospects for optimization as ORCAs.
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Zhurko IF, Dobrynin S, Gorodetskii AA, Glazachev YI, Rybalova TV, Chernyak EI, Asanbaeva N, Bagryanskaya EG, Kirilyuk IA. 2-Butyl-2-tert-butyl-5,5-diethylpyrrolidine-1-oxyls: Synthesis and Properties. Molecules 2020; 25:E845. [PMID: 32075085 DOI: 10.3390/molecules25040845] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 02/13/2020] [Indexed: 12/04/2022] Open
Abstract
Nitroxides are broadly used as molecular probes and labels in biophysics, structural biology, and biomedical research. Resistance of a nitroxide group bearing an unpaired electron to chemical reduction with low-molecular-weight antioxidants and enzymatic systems is of critical importance for these applications. The redox properties of nitroxides are known to depend on the ring size (for cyclic nitroxides) and electronic and steric effects of the substituents. Here, two highly strained nitroxides, 5-(tert-butyl)-5-butyl-2,2-diethyl-3-hydroxypyrrolidin-1-oxyl (4) and 2-(tert-butyl)-2-butyl-5,5-diethyl-3,4-bis(hydroxymethyl)pyrrolidin-1-oxyl (5), were prepared via a reaction of the corresponding 2-tert-butyl-1-pyrroline 1-oxides with butyllithium. Thermal stability and kinetics of reduction of the new nitroxides by ascorbic acid were studied. Nitroxide 5 showed the highest resistance to reduction.
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Catte A, White GF, Wilson MR, Oganesyan VS. Direct Prediction of EPR Spectra from Lipid Bilayers: Understanding Structure and Dynamics in Biological Membranes. Chemphyschem 2018; 19:2183-2193. [PMID: 29858887 PMCID: PMC6175124 DOI: 10.1002/cphc.201800386] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Indexed: 11/16/2022]
Abstract
Of the many biophysical techniques now being brought to bear on studies of membranes, electron paramagnetic resonance (EPR) of nitroxide spin probes was the first to provide information about both mobility and ordering in lipid membranes. Here, we report the first prediction of variable temperature EPR spectra of model lipid bilayers in the presence and absence of cholesterol from the results of large scale fully atomistic molecular dynamics (MD) simulations. Three types of structurally different spin probes were employed in order to study different parts of the bilayer. Our results demonstrate very good agreement with experiment and thus confirm the accuracy of the latest lipid force fields. The atomic resolution of the simulations allows the interpretation of the molecular motions and interactions in terms of their impact on the sensitive EPR line shapes. Direct versus indirect effects of cholesterol on the dynamics of spin probes are analysed. Given the complexity of structural organisation in lipid bilayers, the advantage of using a combined MD-EPR simulation approach is two-fold. Firstly, prediction of EPR line shapes directly from MD trajectories of actual phospholipid structures allows unambiguous interpretation of EPR spectra of biological membranes in terms of complex motions. Secondly, such an approach provides an ultimate test bed for the up-to-date MD simulation models employed in the studies of biological membranes, an area that currently attracts great attention.
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Affiliation(s)
- Andrea Catte
- School of ChemistryUniversity of East AngliaNorwichNR4 7TJUK
| | - Gaye F. White
- School of ChemistryUniversity of East AngliaNorwichNR4 7TJUK
| | - Mark R. Wilson
- Department of ChemistryDurham University, Lower MountjoySouth RoadDurhamDH1 3 LEUK
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Prior C, Oganesyan VS. Prediction of EPR Spectra of Lyotropic Liquid Crystals using a Combination of Molecular Dynamics Simulations and the Model-Free Approach. Chemistry 2017; 23:13192-13204. [PMID: 28741312 DOI: 10.1002/chem.201702682] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Indexed: 12/17/2022]
Abstract
We report the first application of fully atomistic molecular dynamics (MD) simulations to the prediction of the motional electron paramagnetic resonance (EPR) spectra of lyotropic liquid crystals in different aggregation states doped with a paramagnetic spin probe. The purpose of this study is twofold. First, given that EPR spectra are highly sensitive to the motions and order of the spin probes doped within lyotropic aggregates, simulation of EPR line shapes from the results of MD modelling provides an ultimate test bed for the force fields currently employed to model such systems. Second, the EPR line shapes are simulated using the motional parameters extracted from MD trajectories using the Model-Free (MF) approach. Thus a combined MD-EPR methodology allowed us to test directly the validity of the application of the MF approach to systems with multi-component molecular motions. All-atom MD simulations using the General AMBER Force Field (GAFF) have been performed on sodium dodecyl sulfate (SDS) and dodecyltrimethylammonium chloride (DTAC) liquid crystals. The resulting MD trajectories were used to predict and interpret the EPR spectra of pre-micellar, micellar, rod and lamellar aggregates. The predicted EPR spectra demonstrate good agreement with most of experimental line shapes thus confirming the validity of both the force fields employed and the MF approach for the studied systems. At the same time simulation results confirm that GAFF tends to overestimate the packing and the order of the carbonyl chains of the surfactant molecules.
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Affiliation(s)
- Christopher Prior
- School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK
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8
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Gorodetsky AA, Kirilyuk IA, Khramtsov VV, Komarov DA. Functional electron paramagnetic resonance imaging of ischemic rat heart: Monitoring of tissue oxygenation and pH. Magn Reson Med 2015; 76:350-8. [PMID: 26301868 DOI: 10.1002/mrm.25867] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/29/2015] [Accepted: 07/13/2015] [Indexed: 12/14/2022]
Abstract
PURPOSE Electron paramagnetic resonance (EPR) imaging in the spectral-spatial domain with application of soluble paramagnetic probes provides an opportunity for spatially resolved functional measurements of living objects. The purpose of this study was to develop EPR methods for visualization of oxygenation and acidosis of ischemic myocardium. METHODS EPR oxygen measurements were performed using isotopically substituted (2) H,(15) N-dicarboxyproxyl. The radical has an EPR line width of 320 mG and oxygen-induced line broadening of 0.53 mG/mm Hg, providing oxygen sensitivity down to 5 μM. pH measurements were performed using previously developed pH-sensitive imidazoline nitroxide. The radical has an EPR spectrum with pH-dependable hyperfine splitting, pK = 6.6, providing pH sensitivity of approximately 0.05 U in the physiological range. RESULTS EPR imaging of isolated and perfused rat hearts was performed in the two-dimensional + spectral domain. The spatial resolution of the measurements was about 1.4 mm. Marked tissue hypoxia was observed in the ischemic area of the heart after occlusion of the left anterior descending coronary artery. Tissue oxygenation was partly restored upon reperfusion. EPR mapping of myocardial pH indicated acidosis of the ischemic area down to pH 6.7-6.8. CONCLUSION This study demonstrates the capability of low-field EPR and the nitroxide spin probes for mapping of myocardial oxygenation and pH. The developed approaches might be used for noninvasive investigation of microenvironment on living objects. Magn Reson Med 76:350-358, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Artem A Gorodetsky
- Vorozhtsov Institute of Organic Chemistry, Novosibirsk, Russia.,Novosibirsk State University, Novosibirsk, Russia
| | - Igor A Kirilyuk
- Vorozhtsov Institute of Organic Chemistry, Novosibirsk, Russia.,Novosibirsk State University, Novosibirsk, Russia
| | - Valery V Khramtsov
- Heart & Lung Research Institute, Ohio State University, Columbus, Ohio, USA.,Department of Biochemistry, School of Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Denis A Komarov
- Vorozhtsov Institute of Organic Chemistry, Novosibirsk, Russia.,Meshalkin State Research Institute of Circulation Pathology, Novosibirsk, Russia
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Abstract
Conformational entropy (SΩ) has long been used to theoretically characterize the dynamics of proteins, DNA, and other polymers. Though recent advances enabled its calculation also from simulations and nuclear magnetic resonance (NMR) relaxation experiments, correlated molecular motion has hitherto greatly hindered both numerical and experimental determination, requiring demanding empirical and computational calibrations. Herein, we show that these motional correlations can be estimated directly from the temperature-dependent SΩ series that reveal effective persistence lengths of the polymers, which we demonstrate by measuring SΩ of amphiphilic molecules in model lipid systems by spin-labeling electron paramagnetic resonance (EPR) spectroscopy. We validate our correlation-corrected SΩ meter against the basic biophysical interactions underlying biomembrane formation and stability, against the changes in enthalpy and diffusion coefficients upon phase transitions, and against the energetics of fatty acid dissociation. As the method can be directly applied to conformational analysis of proteins and other polymers, as well as adapted to NMR or polarized fluorescence techniques, we believe that the approach can greatly enrich the scope of experimentally available statistical thermodynamics, offering new physical insights into the behavior of biomolecules.
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Affiliation(s)
- Iztok Urbančič
- Laboratory of Biophysics, Condensed Matter Physics Department, "Jožef Stefan" Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia
| | - Ajasja Ljubetič
- Laboratory of Biophysics, Condensed Matter Physics Department, "Jožef Stefan" Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia
| | - Janez Štrancar
- Laboratory of Biophysics, Condensed Matter Physics Department, "Jožef Stefan" Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia
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Sheveleva AM, Kolokolov DI, Gabrienko AA, Stepanov AG, Gromilov SA, Shundrina IK, Sagdeev RZ, Fedin MV, Bagryanskaya EG. Structural Dynamics in a "Breathing" Metal-Organic Framework Studied by Electron Paramagnetic Resonance of Nitroxide Spin Probes. J Phys Chem Lett 2014; 5:20-24. [PMID: 26276175 DOI: 10.1021/jz402357v] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Reversible structural rearrangements ("breathing") of metal-organic frameworks (MOFs) are interesting and complex phenomena with many potential applications. They are often triggered by small amounts of adsorbed guest molecules; therefore, the guest-host interactions in breathing MOFs are intensively investigated. Due to the sensitivity limitations, most analytical methods require relatively high concentrations of guests in these studies. However, because guest molecules are not "innocent", breathing behavior may become suppressed and unperturbed structural states inaccessible. We propose here the use of guest nitroxide molecules in tiny concentrations (such as 1 molecule per 1000 unit cells), which serve as spin probes for electron paramagnetic resonance (EPR), for effective study of breathing phenomena in MOFs. Using a perspective MIL-53(Al) framework as an example, we demonstrate the great advantage of this general approach, which avoids perturbation of the framework structure and allows in-depth investigation of guest-host interactions in the breathing mode.
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Affiliation(s)
- Alena M Sheveleva
- †International Tomography Center SB RAS, Institutskaya 3a, 630090 Novosibirsk, Russia
- ‡Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia
| | - Daniil I Kolokolov
- ‡Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia
- ∥Boreskov Institute of Catalysis SB RAS, Lavrentiev av. 5, 630090 Novosibirsk, Russia
| | - Anton A Gabrienko
- ∥Boreskov Institute of Catalysis SB RAS, Lavrentiev av. 5, 630090 Novosibirsk, Russia
| | - Alexander G Stepanov
- ‡Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia
- ∥Boreskov Institute of Catalysis SB RAS, Lavrentiev av. 5, 630090 Novosibirsk, Russia
| | - Sergey A Gromilov
- ⊥Nikolaev Institute of Inorganic Chemistry SB RAS, Lavrentiev av. 3, 630090 Novosibirsk, Russia
| | - Inna K Shundrina
- #N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev av. 9, 630090 Novosibirsk, Russia
| | - Renad Z Sagdeev
- †International Tomography Center SB RAS, Institutskaya 3a, 630090 Novosibirsk, Russia
| | - Matvey V Fedin
- †International Tomography Center SB RAS, Institutskaya 3a, 630090 Novosibirsk, Russia
| | - Elena G Bagryanskaya
- †International Tomography Center SB RAS, Institutskaya 3a, 630090 Novosibirsk, Russia
- #N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev av. 9, 630090 Novosibirsk, Russia
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Baldauf C, Schulze K, Lueders P, Bordignon E, Tampé R. In-situ spin labeling of his-tagged proteins: distance measurements under in-cell conditions. Chemistry 2013; 19:13714-9. [PMID: 24038571 DOI: 10.1002/chem.201301921] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Indexed: 12/29/2022]
Abstract
New spin labeling strategies have immense potential in studying protein structure and dynamics under physiological conditions with electron paramagnetic resonance (EPR) spectroscopy. Here, a new spin-labeled chemical recognition unit for switchable and concomitantly high affinity binding to His-tagged proteins was synthesized. In combination with an orthogonal site-directed spin label, this novel spin probe, Proxyl-trisNTA (P-trisNTA) allows the extraction of structural constraints within proteins and macromolecular complexes by EPR. By using the multisubunit maltose import system of E. coli: 1) the topology of the substrate-binding protein, 2) its substrate-dependent conformational change, and 3) the formation of the membrane multiprotein complex can be extracted. Notably, the same distance information was retrieved both in vitro and in situ allowing for site-specific spin labeling in cell lysates under in-cell conditions. This approach will open new avenues towards in-cell EPR.
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Affiliation(s)
- Christoph Baldauf
- Institute of Biochemistry, Biocenter, Cluster of Excellence-Macromolecular Complexes (CEF-MC), Goethe-University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt a.M. (Germany)
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Gopee H, Cammidge AN, Oganesyan VS. Probing columnar discotic liquid crystals by EPR spectroscopy with a rigid-core nitroxide spin probe. Angew Chem Int Ed Engl 2013; 52:8917-20. [PMID: 23873587 PMCID: PMC4499263 DOI: 10.1002/anie.201303194] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 06/25/2013] [Indexed: 12/04/2022]
Affiliation(s)
- Hemant Gopee
- School of Chemistry, University of East Anglia, Norwich Research ParkNorwich, NR4 7TJ (UK)
| | - Andrew N Cammidge
- School of Chemistry, University of East Anglia, Norwich Research ParkNorwich, NR4 7TJ (UK)
| | - Vasily S Oganesyan
- School of Chemistry, University of East Anglia, Norwich Research ParkNorwich, NR4 7TJ (UK)
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Ganini D, Canistro D, Jang J, Stadler K, Mason RP, Kadiiska MB. Ceruloplasmin (ferroxidase) oxidizes hydroxylamine probes: deceptive implications for free radical detection. Free Radic Biol Med 2012; 53:1514-21. [PMID: 22824865 PMCID: PMC3448871 DOI: 10.1016/j.freeradbiomed.2012.07.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 06/22/2012] [Accepted: 07/16/2012] [Indexed: 11/25/2022]
Abstract
Ceruloplasmin (ferroxidase) is a copper-binding protein known to promote Fe(2+) oxidation in plasma of mammals. In addition to its classical ferroxidase activity, ceruloplasmin is known to catalyze the oxidation of various substrates, such as amines and catechols. Assays based on cyclic hydroxylamine oxidation are used to quantify and detect free radicals in biological samples ex vivo and in vitro. We show here that human ceruloplasmin promotes the oxidation of the cyclic hydroxylamine 1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine hydrochloride (CPH) and related probes in Chelex-treated phosphate buffer and rat serum. The reaction is suppressed by the metal chelators DTPA, EDTA, and desferal, whereas heparin and bathocuproine have no effect. Catalase or superoxide dismutase additions do not interfere with the CPH-oxidation yield, demonstrating that oxygen-derived free radicals are not involved in the CPH oxidation mediated by ceruloplasmin. Plasma samples immunodepleted of ceruloplasmin have lower levels of CPH oxidation, which confirms the role of ceruloplasmin (ferroxidase) as a biological oxidizing agent of cyclic hydroxylamines. In conclusion, we show that the ferroxidase activity of ceruloplasmin is a possible biological source of artifacts in the cyclic hydroxylamine-oxidation assay used for reactive oxygen species detection and quantification.
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Affiliation(s)
- Douglas Ganini
- Free Radical Metabolism Section, Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Donatella Canistro
- Department of Pharmacology, Molecular Toxicology Unit, Alma Mater Studiorum-University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - JinJie Jang
- Free Radical Metabolism Section, Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Krisztian Stadler
- Oxidative Stress and Disease Laboratory, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA 70808, USA
| | - Ronald P. Mason
- Free Radical Metabolism Section, Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Maria B. Kadiiska
- Free Radical Metabolism Section, Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
- Corresponding author: Maria B. Kadiiska, Free Radical Metabolism Section, Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA. Telephone number: (919) 541-0201. Fax number: (919) 541-1043.
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