Rapid-Scan EPR of Nitroxide Spin Labels and Semiquinones

Eaton, Sandra S.; Eaton, Gareth R.

doi:10.1016/bs.mie.2015.06.027

Cited by 8 publications

(4 citation statements)

References 30 publications

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“…Rapid-scan EPR is based on continuous direct detection of the spin response as the magnetic field is scanned upfield and downfield through the resonance thousands of times per second. The method provides an improved signal-to-noise ratio for a wide range of samples, including immobilized radicals [ 23 ]. In contrast, conventional continuous wave (CW) EPR uses phase-sensitive detection at the modulation frequency.…”

Section: Electron Paramagnetic Resonance (Epr) Spectroscopy Technimentioning

confidence: 99%

Detection of Reactive Oxygen and Nitrogen Species by Electron Paramagnetic Resonance (EPR) Technique

2017

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During the last decade there has been growing interest in physical-chemical oxidation processes and the behavior of free radicals in living systems. Radicals are known as intermediate species in a variety of biochemical reactions. Numerous techniques, assays and biomarkers have been used to measure reactive oxygen and nitrogen species (ROS and RNS), and to examine oxidative stress. However, many of these assays are not entirely satisfactory or are used inappropriately. The purpose of this chapter is to review current EPR (Electron Paramagnetic Resonance) spectroscopy methods for measuring ROS, RNS, and their secondary products, and to discuss the strengths and limitations of specific methodological approaches.

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Section: Electron Paramagnetic Resonance (Epr) Spectroscopy Technimentioning

confidence: 99%

Detection of Reactive Oxygen and Nitrogen Species by Electron Paramagnetic Resonance (EPR) Technique

2017

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“…At 250 MHz rapid scan improves S/N relative to CW by about a factor of 10 for EPR imaging [38, 39]. Examples for a wide range of samples are discussed in prior reviews [2, 40]. …”

Section: Improved Signal-to-noise For Rapid Scan Relative To Cwmentioning

confidence: 99%

Rapid-scan EPR imaging

Eaton

Shi

Woodcock

et al. 2017

Journal of Magnetic Resonance

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In rapid-scan EPR the magnetic field or frequency is repeatedly scanned through the spectrum at rates that are much faster than in conventional continuous wave EPR. The signal is directly-detected with a mixer at the source frequency. Rapid-scan EPR is particularly advantageous when the scan rate through resonance is fast relative to electron spin relaxation rates. In such scans, there may be oscillations on the trailing edge of the spectrum. These oscillations can be removed by mathematical deconvolution to recover the slow-scan absorption spectrum. In cases of inhomogeneous broadening, the oscillations may interfere destructively to the extent that they are not visible. The deconvolution can be used even when it is not required, so spectra can be obtained in which some portions of the spectrum are in the rapid-scan regime and some are not. The technology developed for rapid-scan EPR can be applied generally so long as spectra are obtained in the linear response region. The detection of the full spectrum in each scan, the ability to use higher microwave power without saturation, and the noise filtering inherent in coherent averaging results in substantial improvement in signal-to-noise relative to conventional continuous wave spectroscopy, which is particularly advantageous for low-frequency EPR imaging. This overview describes the principles of rapid-scan EPR and the hardware used to generate the spectra. Examples are provided of its application to imaging of nitroxide radicals, diradicals, and spin-trapped radicals at a Larmor frequency of ca. 250 MHz.

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“…To overcome these limitations, we used rapid scan (RS) EPR spectroscopy [35,36]. We have already successfully used this technology to study aS-lipid interaction, where changes in the spectral shape accounted for the binding of aS to lipid membranes revealing their interaction even inside living cells [37].…”

Section: Introductionmentioning

confidence: 99%

Rapid Scan Electron Paramagnetic Resonance Spectroscopy Is a Suitable Tool to Study Intermolecular Interactions of Intrinsically Disordered Protein

Dröden

Drescher

2023

Biology

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Intrinsically disordered proteins (IDPs) are involved in most crucial cellular processes. However, they lack a well-defined fold hampering the investigation of their structural ensemble and interactions. Suitable biophysical methods able to manage their inherent flexibility and broad conformational ensemble are scarce. Here, we used rapid scan (RS) electron paramagnetic resonance (EPR) spectroscopy to study the intermolecular interactions of the IDP α-synuclein (aS). aS aggregation and fibril deposition is the hallmark of Parkinson’s disease, and specific point mutations, among them A30P and A53T, were linked to the early onset of the disease. To understand the pathological processes, research intensively investigates aS aggregation kinetics, which was reported to be accelerated in the presence of ethanol. Conventional techniques fail to capture these fast processes due to their limited time resolution and, thus, lose kinetic information. We have demonstrated that RS EPR spectroscopy is suitable for studying aS aggregation by resolving underlying kinetics and highlighting differences in fibrillization behavior. RS EPR spectroscopy outperforms traditional EPR methods in terms of sensitivity by a factor of 5 in our case while significantly reducing data acquisition time. Thus, we were able to sample short time intervals capturing single events taking place during the aggregation process. Further studies will therefore be able to shed light on biological processes proceeding on fast time scales.

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Rapid-Scan EPR of Nitroxide Spin Labels and Semiquinones

Cited by 8 publications

References 30 publications

Detection of Reactive Oxygen and Nitrogen Species by Electron Paramagnetic Resonance (EPR) Technique

Detection of Reactive Oxygen and Nitrogen Species by Electron Paramagnetic Resonance (EPR) Technique

Rapid-scan EPR imaging

Rapid Scan Electron Paramagnetic Resonance Spectroscopy Is a Suitable Tool to Study Intermolecular Interactions of Intrinsically Disordered Protein

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