1
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Saito K, Sail D, Yamamoto K, Matsumoto S, Blackman B, Kishimoto S, Brender JR, Swenson RE, Mitchell JB, Krishna MC. Synthesis and evaluation of 13C-labeled 5-5-dimethyl-1-pyrroline-N-oxide aimed at in vivo detection of reactive oxygen species using hyperpolarized 13C-MRI. Free Radic Biol Med 2019; 131:18-26. [PMID: 30471347 PMCID: PMC6983923 DOI: 10.1016/j.freeradbiomed.2018.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/30/2018] [Accepted: 11/13/2018] [Indexed: 02/08/2023]
Abstract
Effective means to identify the role of reactive oxygen species (ROS) mediating several diseases including cancer, ischemic heart disease, stroke, Alzheimer's and other inflammatory conditions in in vivo models would be useful. The cyclic nitrone 5,5-Dimethyl-1-pyrroline-N-oxide (DMPO) is a spin trap frequently used to detect free radicals in vitro using Electron Paramagnetic Resonance (EPR) spectroscopy. In this study, we synthesized 13C-labeled DMPO for hyperpolarization by dynamic nuclear polarization, in which 13C NMR signal increases more than 10,000-fold. This allows in vivo 13C MRI to investigate the feasibility of in vivo ROS detection by the 13C-MRI. DMPO was 13C-labeled at C5 position, and deuterated to prolong the T1 relaxation time. The overall yield achieved for 5-13C-DMPO-d9 was 15%. Hyperpolarized 5-13C-DMPO-d9 provided a single peak at 76 ppm in the 13C-spectrum, and the T1 was 60 s in phosphate buffer making it optimal for in vivo 13C MRI. The buffered solution of hyperpolarized 5-13C-DMPO-d9 was injected into a mouse placed in a 3 T scanner, and 13C-spectra were acquired every 1 s. In vivo studies showed the signal of 5-13C-DMPO-d9 was detected in the mouse, and the T1 decay of 13C signal of hyperpolarized 5-13C-DMPO-d9 was 29 s. 13C-chemical shift imaging revealed that 5-13C-DMPO-d9 was distributed throughout the body in a minute after the intravenous injection. A strong signal of 5-13C-DMPO-d9 was detected in heart/lung and kidney, whereas the signal in liver was small compared to other organs. The results indicate hyperpolarized 5-13C-DMPO-d9 provided sufficient 13C signal to be detected in the mouse in several organs, and can be used to detect ROS in vivo.
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Affiliation(s)
- Keita Saito
- Radiation Biology Branch, National Cancer Institute, Bethesda, MD, USA
| | - Deepak Sail
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute, Rockville, MD, USA
| | | | - Shingo Matsumoto
- Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Burchelle Blackman
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute, Rockville, MD, USA
| | - Shun Kishimoto
- Radiation Biology Branch, National Cancer Institute, Bethesda, MD, USA
| | - Jeffrey R Brender
- Radiation Biology Branch, National Cancer Institute, Bethesda, MD, USA
| | - Rolf E Swenson
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute, Rockville, MD, USA
| | - James B Mitchell
- Radiation Biology Branch, National Cancer Institute, Bethesda, MD, USA
| | - Murali C Krishna
- Radiation Biology Branch, National Cancer Institute, Bethesda, MD, USA.
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2
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David Jebaraj D, Utsumi H, Milton Franklin Benial A. Electron spin resonance studies on deuterated nitroxyl spin probes used in Overhauser-enhanced magnetic resonance imaging. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2017; 55:700-705. [PMID: 28052402 DOI: 10.1002/mrc.4576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 12/30/2016] [Indexed: 06/06/2023]
Abstract
The electron spin resonance studies were carried out for 2 mm concentration of 14 N-labeled and 15 N-labeled 3-carbamoyl-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl, 3-carboxy-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl, 3-methoxycarbonyl-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl and their deuterated nitroxyl radicals using X-band electron spin resonance spectrometer. The electron spin resonance line shape analysis was carried out. The electron spin resonance parameters such as linewidth, Lorentzian component, signal intensity ratio, rotational correlation time, hyperfine coupling constant and g-factor were estimated. The deuterated nitroxyl radicals have narrow linewidth and an increase in Lorentzian component, compared with undeuterated nitroxyl radicals. The dynamic nuclear polarization factor was observed for all nitroxyl radicals. Upon 2 H labeling, about 70% and 40% increase in dynamic nuclear polarization factor were observed for 14 N-labeled and 15 N-labeled nitroxyl radicals, respectively. The signal intensity ratio and g-value indicate the isotropic nature of the nitroxyl radicals in pure water. Therefore, the deuterated nitroxyl radicals are suitable spin probes for in vivo/in vitro electron spin resonance and Overhauser-enhanced magnetic resonance imaging modalities. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- D David Jebaraj
- Department of Physics, The American College, Madurai, 625 002, Tamilnadu, India
| | - Hideo Utsumi
- Innovation Center for Medical Redox Navigation, Kyushu University, Fukuoka, 812 8582, Japan
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3
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Weaver J, Burks SR, Liu KJ, Kao JPY, Rosen GM. In vivo EPR oximetry using an isotopically-substituted nitroxide: Potential for quantitative measurement of tissue oxygen. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 271:68-74. [PMID: 27567323 PMCID: PMC5266518 DOI: 10.1016/j.jmr.2016.08.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 08/12/2016] [Accepted: 08/15/2016] [Indexed: 06/06/2023]
Abstract
Variations in brain oxygen (O2) concentration can have profound effects on brain physiology. Thus, the ability to quantitate local O2 concentrations noninvasively in vivo could significantly enhance understanding of several brain pathologies. However, quantitative O2 mapping in the brain has proven difficult. The electron paramagnetic resonance (EPR) spectra of nitroxides are sensitive to molecular O2 and can be used to estimate O2 concentrations in aqueous media. We recently synthesized labile-ester-containing nitroxides, such as 3-acetoxymethoxycarbonyl-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (nitroxide 4), which accumulate in cerebral tissue after in situ hydrolysis, and thus enable spatial mapping of O2 concentrations in the mouse brain by EPR imaging. In an effort to improve O2 quantitation, we prepared 3-acetoxymethoxycarbonyl-2,2,5,5-tetra((2)H3)methyl-1-(3,4,4-(2)H3,1-(15)N)pyrrolidinyloxyl (nitroxide 2), which proved to be a more sensitive probe than its normo-isotopic version for quantifying O2 in aqueous solutions of various O2 concentrations. We now demonstrate that this isotopically substituted nitroxide is ∼2-fold more sensitive in vivo than the normo-isotopic nitroxide 4. Moreover, in vitro and in vivo EPR spectral-spatial imaging results with nitroxide 2 demonstrate significant improvement in resolution, reconstruction and spectral response to local O2 concentrations in cerebral tissue. Thus, isotopic-substituted nitroxides, such as 2, are excellent sensors for in vivo O2 quantitation in tissues, such as the brain.
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Affiliation(s)
- John Weaver
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States; Center of Biomedical Research Excellence, College of Pharmacy, University of New Mexico, Albuquerque, NM 87131, United States.
| | - Scott R Burks
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, United States; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States; Center for EPR Imaging In Vivo Physiology, University of Maryland, Baltimore, MD 21201, United States
| | - Ke Jian Liu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States; Center of Biomedical Research Excellence, College of Pharmacy, University of New Mexico, Albuquerque, NM 87131, United States
| | - Joseph P Y Kao
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, United States; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States; Center for EPR Imaging In Vivo Physiology, University of Maryland, Baltimore, MD 21201, United States
| | - Gerald M Rosen
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, United States; Center for EPR Imaging In Vivo Physiology, University of Maryland, Baltimore, MD 21201, United States; Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
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Lin YJ, Teicher BA, Halpern HJ. Synthesis of 4-protio-3-carbamoyl-2,2,5,5-tetraperdeuteromethyl-3-pyrrolin-1-yloxy (mHCTPO): A selectively isotopically labeled compound for use in T2 spin label oxymetry. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580280602] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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5
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Yost Y, Polnaszek CF, Holtzman JL. Application of spin labeling to drug assays. III. [15N, 2H13]2,2,5,5-tetramethylpyrroline-1-oxyl-3-carboxylic acid coupled to phenytoin. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580200605] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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6
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Wu G. Synthesis of two series of cysteine-specific spin labels containing a 15N substituted nitroxide. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580361207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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7
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Venkataramu SD, Pearson DE, Beth AH, Balasubramanian K, Park CR, Park JH. Synthesis of 15N-5-doxylstearic acid for improved EPR characterization of lipid motion in biomembranes. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580200402] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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8
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Bates BA, Johnson ME, Currie BL. Stable isotope substituted spin labels. 2. An improved synthesis of perdeuterio-15N-(1-oxyl-2,2,6,6-tetramethyl- 4-piperidinyl)maleimide. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580200106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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9
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Hustedt EJ, Beth AH. The sensitivity of saturation transfer electron paramagnetic resonance spectra to restricted amplitude uniaxial rotational diffusion. Biophys J 2001; 81:3156-65. [PMID: 11720982 PMCID: PMC1301776 DOI: 10.1016/s0006-3495(01)75952-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Computational methods have been developed to model the effects of constrained or restricted amplitude uniaxial rotational diffusion (URD) on saturation transfer electron paramagnetic resonance (ST-EPR) signals observed from nitroxide spin labels. These methods, which have been developed to model the global rotational motion of intrinsic membrane proteins that can interact with the cytoskeleton or other peripheral proteins, are an extension of previous work that described computationally efficient algorithms for calculating ST-EPR spectra for unconstrained URD (Hustedt and Beth, 1995, Biophys. J. 69:1409-1423). Calculations are presented that demonstrate the dependence of the ST-EPR signal (V'(2)) on the width (Delta) of a square-well potential as a function of the microwave frequency, the correlation time for URD, and the orientation of the spin-label with respect to the URD axis. At a correlation time of 10 micros, the V'(2) signal is very sensitive to Delta in the range from 0 to 60 degrees, marginally sensitive from 60 degrees to 90 degrees, and insensitive beyond 90 degrees. Sensitivity to Delta depends on the correlation time for URD with higher sensitivity to large values of Delta at the shorter correlation times, on the microwave frequency, and on the orientation of the spin-label relative to the URD axis. The computational algorithm has been incorporated into a global nonlinear least-squares analysis approach, based upon the Marquardt-Levenberg method (Blackman et al., 2001, Biophys. J. 81:3363-3376). This has permitted determination of the correlation time for URD and the width of the square-well potential by automated fitting of experimental ST-EPR data sets obtained from a spin-labeled membrane protein and provided a new automated method for analysis of data obtained from any system that exhibits restricted amplitude URD.
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Affiliation(s)
- E J Hustedt
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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10
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Hustedt EJ, Smirnov AI, Laub CF, Cobb CE, Beth AH. Molecular distances from dipolar coupled spin-labels: the global analysis of multifrequency continuous wave electron paramagnetic resonance data. Biophys J 1997; 72:1861-77. [PMID: 9083690 PMCID: PMC1184380 DOI: 10.1016/s0006-3495(97)78832-5] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
For immobilized nitroxide spin-labels with a well-defined interprobe geometry, resolved dipolar splittings can be observed in continuous wave electron paramagnetic resonance (CW-EPR) spectra for interelectron distances as large as 30 A using perdeuterated probes. In this work, algorithms are developed for calculating CW-EPR spectra of immobilized, dipolar coupled nitroxides, and then used to define the limits of sensitivity to the interelectron distance as a function of geometry and microwave frequency. Secondly, the CW-EPR spectra of N epsilon-spin-labeled coenzyme NAD+ bound to microcrystalline, tetrameric glyceraldehyde-3-phosphate dehydrogenase (GAPDH) have been collected at 9.8, 34, and 94 GHz. These data have been analyzed, using a combination of simulated annealing and global analysis, to obtain a unique fit to the data. The values of the intermitroxide distance and the five angles defining the relative orientation of the two nitroxides are in reasonable agreement with a molecular model built from the known crystal structure. Finally, the effect of rigid body isotropic rotational diffusion on the CW-EPR spectra of dipolar coupled nitroxides has been investigated using an algorithm based on Brownian dynamics trajectories. These calculations demonstrate the sensitivity of CW-EPR spectra to dipolar coupling in the presence of rigid body rotational diffusion.
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Affiliation(s)
- E J Hustedt
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232, USA
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11
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Makino K, Nagahara S, Konishi Y, Mukae M, Ide H, Murakami A. Detection of specific base sequences in solution using DNA probes labeled with d- and/or 15N-substituted spin-labels. FREE RADICAL RESEARCH COMMUNICATIONS 1993; 19 Suppl 1:S109-16. [PMID: 8282213 DOI: 10.3109/10715769309056s109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In order to enhance the sensitivity and the accuracy of the detection by the DNA probe method in which spin-labeled oligonucleotides are used as probes, 4-amino-2,2,6,6-tetramethylpiperidine-15N-oxyl-d16 (4-amino-TEMPO-15N-d16) and 4-amino-2,2,6,6-tetramethylpiperidine-14N-oxyl-d16 (4-amino-TEMPO-14N-d16) were incorporated into the phosphate linkage of oligonucleotides by the hydrogen phosphonate method and these DNA probes were used for the detection of target DNAs in solution. The intensities of the electron paramagnetic resonance (EPR) signals of the oligonucleotides labeled with 4-amino-TEMPO-14N-d16 and 4-amino-TEMPO-15N-d16 were 3-fold and 4-fold larger than that of the oligonucleotide labeled with 4-amino-TEMPO-14N, respectively. Also, the EPR lines of these labeled oligonucleotides do not overlap each other, allowing the detection of two different regions in the same target DNA by the single EPR measurement.
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Affiliation(s)
- K Makino
- Department of Polymer Science and Engineering, Kyoto Institute of Technology, Japan
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12
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Wojcicki WE, Beth AH. Structural and binding properties of the stilbenedisulfonate sites on erythrocyte band 3: an electron paramagnetic resonance study using spin-labeled stilbenedisulfonates. Biochemistry 1993; 32:9454-64. [PMID: 8396432 DOI: 10.1021/bi00087a025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Two new spin-label derivatives of 4,4'-diaminodihydrostilbene-2,2'-disulfonate (H2-DADS) have been chemically synthesized and employed in electron paramagnetic resonance (EPR) studies of binding to the anion exchange protein (band 3) in intact human erythrocytes. Equilibrium binding studies with the 4-monoacyl-spin-label derivative (mono-SL-H2-DADS) indicated an effective dissociation constant of 11 microM and substantial negative cooperativity in isotonic citrate buffer, pH 7.4, at 20 degrees C. The 4,4'-diacyl-spin-label derivative (di-SL-H2-DADS) bound with an effective dissociation constant of 54 microM and no detectable cooperativity under the same binding conditions. The findings of substantial negative cooperativity in binding of the less bulky mono-SL-H2-DADS and no cooperativity for di-SL-H2-DADS suggest the presence of an allosteric coupling between the stilbenedisulfonate sites on adjacent band 3 monomers rather than steric interactions. There were approximately 1 x 10(6) binding sites per erythrocyte for both the mono- and di-SL-H2-DADS derivatives, and the binding of each was blocked by pretreatment of intact cells with 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS), a highly specific covalent inhibitor of anion exchange. EPR spectra collected over a wide range of concentrations of mono-SL-H2-DADS indicated that binding resulted in immobilization of the probe and that, even upon near saturation of available binding sites, there were no detectable dipole-dipole interactions between bound probes. EPR spectra collected using di-SL-H2-DADS revealed the presence of intramolecular dipole-dipole interactions between spin-label moieties on opposite ends of this biradical probe, but no intermolecular dipole-dipole interactions between separate bound probes. These data indicate that di-SL-H2-DADS binds to the stilbenedisulfonate binding site on band 3 in a bent conformation and further suggest that the termini of these binding sites on adjacent monomers are greater than 20 A apart.
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Affiliation(s)
- W E Wojcicki
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232-0615
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13
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Ajtai K, Ringler A, Burghardt TP. Probing cross-bridge angular transitions using multiple extrinsic reporter groups. Biochemistry 1992; 31:207-17. [PMID: 1310031 DOI: 10.1021/bi00116a030] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
15N- and 2H-substituted maleimido-TEMPO spin label ([15N,2H]MTSL) and the fluorescent label 1,5-IAEDANS were used to specifically modify sulfhydryl 1 of myosin to study the orientation of myosin cross-bridges in skeletal muscle fibers. The electron paramagnetic resonance (EPR) spectrum from muscle fibers decorated with labeled myosin subfragment 1 ([15N,2H]MTSL-S1) or the fluorescence polarization spectrum from fibers directly labeled with 1,5-IAEDANS was measured from fibers in various physiological conditions. The EPR spectra from fibers with the fiber axis oriented at 90 degrees to the Zeeman field show a clear spectral shift from the rigor spectrum when the myosin cross-bridge binds MgADP. This shift is attributable to a change in the torsion angle of the spin probe from cross-bridge rotation and is observable due mainly to the improved angular resolution of the substituted probe. The EPR data from [15N,2H]MTSL-S1 decorating fibers are combined with the fluorescence polarization data from the 1,5-IAEDANS-labeled fibers to map the global angular transition of the labeled cross-bridges due to nucleotide binding by an analytical method described in the accompanying paper [Burghardt, T. P., & Ajtai, K. (1992) Biochemistry (preceding paper in this issue)]. We find that the spin and fluorescent probes are quantitatively consistent in the finding that the actin-bound cross-bridge rotates through a large angle upon binding MgADP. We also find that, if the shape of the cross-bridge is described as an ellipsoid with two equivalent minor axes, then cross-bridge rotation takes place mainly about an axis parallel to the major axis of the ellipsoid. This type of rotation may imitate the rotation motion of cross-bridges during force generation.
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Affiliation(s)
- K Ajtai
- Department of Biochemistry and Molecular Biology, Mayo Foundation, Rochester, Minnesota 55905
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14
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Pou S, Peric M, Halpern HJ, Rosen GM. Use of a low-frequency ESR spectrometer: implications for spin-trapping free radicals, in situ. FREE RADICAL RESEARCH COMMUNICATIONS 1991; 12-13 Pt 1:39-46. [PMID: 1649099 DOI: 10.3109/10715769109145765] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have adapted the low-frequency ESR spectrometer, designed and built by H.J. Halpern, to the physiologic needs of organ preparations operating at 250 MHz. Initial studies have allowed us to detect nitroxides in an isolated perfused heart. These in situ measurements were made with nitroxides specifically designed to mimic the lipophilic nature of 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) and 2,2-dimethyl-5-hydroxy-1-pyrrolidinyloxyl (DMPO-OH). These spin labels provided information about the influence of dynamic factors of the heart, such as flow rate, different cell populations and unequal distribution between compartments on our ability to conduct and interpret spin trapping experiments. They also clarified the sacrifice in sensitivity involved in operating at the lower frequencies. To deal with this later problem, we have increased the sensitivity of the spin trapping method by synthesizing a family of 15N- and deuterium-containing DMPO analogs and by determining their ability to spin trap free radicals generated by the model superoxide system of xanthine/xanthine oxidase. Finally, since activated neutrophils are one of the few cells known to generate free radicals as part of their physiologic function, we used these phagocytic cells, as a source of superoxide.
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Affiliation(s)
- S Pou
- Department of Pharmacology and Toxicology, University of Maryland School of Pharmacy, Baltimore 21201
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Beth AH, Robinson BH. Nitrogen-15 and Deuterium Substituted Spin Labels for Studies of Very Slow Rotational Motion. SPIN LABELING 1989. [DOI: 10.1007/978-1-4613-0743-3_4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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19
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Park JH, Trommer WE. Advantages of 15N and Deuterium Spin Probes for Biomedical Electron Paramagnetic Resonance Investigations. ACTA ACUST UNITED AC 1989. [DOI: 10.1007/978-1-4613-0743-3_11] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
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20
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Alonso A, Nascimento OR, Tabak M. Single-crystal ESR studies of a nitroxide radical. ACTA ACUST UNITED AC 1987. [DOI: 10.1007/bf02458055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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21
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Chapman D, Hayward JA. New biophysical techniques and their application to the study of membranes. Biochem J 1985; 228:281-95. [PMID: 3893419 PMCID: PMC1144986 DOI: 10.1042/bj2280281] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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22
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Venkataramu SD, Pearson DE, Beth AH, Park CR, Park JH. High resolution spin labeled fatty acid: synthesis and EPR spectral characteristics. Tetrahedron Lett 1985. [DOI: 10.1016/s0040-4039(00)99056-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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23
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Beth AH, Robinson BH, Cobb CE, Dalton LR, Trommer WE, Birktoft JJ, Park JH. Interactions and spatial arrangement of spin-labeled NAD+ bound to glyceraldehyde-3-phosphate dehydrogenase. Comparison of EPR and X-ray modeling data. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)42759-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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24
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Recent Developments in Spin Label EPR Methodology for Biomembrane Studies. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/b978-0-12-152513-2.50010-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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25
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Johnson ME, Lee L, Fung LW. Models for slow anisotropic rotational diffusion in saturation transfer electron paramagnetic resonance at 9 and 35 GHz. Biochemistry 1982; 21:4459-67. [PMID: 6289883 DOI: 10.1021/bi00261a041] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Model systems of cholestane and 5-doxylstearic acid analogue spin probes in lipid bilayer dispersions of dipalmitoylphosphatidylcholine and cholesterol (9:1 w/w) are used to analyze saturation transfer electron paramagnetic resonance spectral behavior for slow rotational diffusion in an anisotropic medium. Measurements are made at both 9 and 35 GHz to provide enhanced spectral resolution for different types of motion. Parameter correlation plots of spectral parameters from different regions of the saturation transfer spectra appear to be potentially useful in characterizing different types of motion. Anisotropic rotational diffusion about a symmetry axis coincident with the nitroxide y principal axis is clearly distinguishable from isotropic rotational diffusion and may be distinguishable from rotational diffusion about the nitroxide z principal axis. Approximate anisotropic rotational diffusion about a symmetry axis coincident with the nitroxide z principal axis is distinguishable from isotropic rotational diffusion under some, but not all, conditions.
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26
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Johnson ME, Thiyagarajan P, Bates B, Currie BL. A comparison of resolution-enhancement methods in saturation-transfer EPR. 15N isotopically substituted spin labels and 35 GHz high-frequency operation. Biophys J 1982; 37:563-7. [PMID: 6277404 PMCID: PMC1328836 DOI: 10.1016/s0006-3495(82)84700-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The use of (15)N isotopic substitution and 35 GHz (Q-band) operation as resolution enhancement methods in saturation-transfer electron paramagnetic resonance (ST-EPR) are compared. We find that both methods offer roughly comparable enhancements in ST-EPR resolution. The most powerful approach to resolving complex ST-EPR spectral behavior, however, will probably be the combined use of multiple-frequency X- and Q-band operation with (15)N isotopically substituted spin labels.
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Beth AH, Balasubramanian K, Wilder RT, Venkataramu SD, Robinson BH, Dalton LR, Pearson DE, Park JH. Structural and motional changes in glyceraldehyde-3-phosphate dehydrogenase upon binding to the band-3 protein of the erythrocyte membrane examined with [15N,2H]maleimide spin label and electron paramagnetic resonance. Proc Natl Acad Sci U S A 1981; 78:4955-9. [PMID: 6272285 PMCID: PMC320307 DOI: 10.1073/pnas.78.8.4955] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Binding of the glycolytic enzyme, glyceraldehyde-3-phosphate dehydrogenase [GAPDHase; D-glyceraldehyde-3-phosphate:NAD+ oxidoreductase (phosphorylating EC 1.2.1.12], to the cytoplasmic segment of band-3 protein in the erythrocyte (RBC) membrane has been examined by electron paramagnetic resonance (EPR) and saturation transfer EPR (ST-EPR) spectroscopies. GAPDHase, which was isolated from rabbit muscle and labeled with the resolution-enhancing deuterated N-(15N-1-oxyl-2,2,6,6-tetramethyl-4-piperidinyl)maleimide spin label ([15N,2H]MSL), showed the same binding specificity for the transmembrane band-3 protein of human erythrocyte membranes as reported for unlabeled GAPDHase from human RBC. Experimental EPR lineshapes from soluble and membrane-bound enzymes were analyzed by direct stimulation of spectra and indicated a structural alteration of the bound GAPDHase in the vicinity of the spin label, which was attached covalently to the active-site cysteine-149 residue. A rigorous theoretical analysis of the ST-EPR spectra of soluble and membrane-bound enzyme is presented and utilized in conjunction with model system analysis to demonstrate that the motion of membrane-bound GAPDHase could be characterized by an effective isotropic rotational correlation time of 20 microseconds. This indicated that the GAPDHase--band-4 complex exhibits motional freedom relative to the membrane-spanning segment of the band-3 protein or the RBC. The double substituted spin label [15N,2H]MSL affords gains in sensitivity and resolution that permit studies of membrane-bound enzymes at physiological levels and quantitative simulations of the EPR and ST-EPR lineshapes with reasonable computation times.
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