Epr Spectroscopy
Epr Spectroscopy - Related Videos
11:07
Electron Paramagnetic Resonance (EPR) Spectroscopy
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2023
Source: David C. Powers, Tamara M. Powers, Texas A&M In this video, we will learn the basic principles behind Electron Paramagnetic Resonance (EPR). We will use EPR spectroscopy to study how dibutylhydroxy toluene (BHT) behaves as an antioxidant in the autoxidation of aliphatic aldehydes.
01:17
Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals
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2023
Ideally, an unpaired electron shows a single peak in the EPR spectrum due to the transition between the two spin energy states. However, coupling interactions can occur between the spins of the unpaired electron and any neighboring spin-active nuclei. This hyperfine coupling results in hyperfine splitting, where the EPR signal is split into multiplets. The signals split into 2nI + 1 peaks, where n is the number of equivalent nuclei and I is the nuclear spin. These splitting patterns provide...
06:01
EPR Monitored Redox Titration of the Cofactors of Saccharomyces cerevisiae Nar1
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Cited by 6 •
2014
The goal of this protocol is to use electron paramagnetic resonance (EPR) monitored redox titrations to identify different cofactors of Saccharomyces cerevisiae Nar1. Redox titrations offer a very robust way to obtain midpoint potentials of different redox active cofactors in enzymes and proteins.
11:19
Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels
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Cited by 7 •
2016
This article describes methods for site-directed spin labeling and reconstitution of pentameric ligand-gated channels for Electron Paramagnetic Resonance studies. This protocol can be adapted for any membrane protein. The reconstitution method described here can also be used for patch-clamp measurements of macroscopic and single-channel currents in a defined lipid system.
09:21
Mössbauer Spectroscopy
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2023
Source: Joshua Wofford, Tamara M. Powers, Department of Chemistry, Texas A&M University Mössbauer spectroscopy is a bulk characterization technique that examines the nuclear excitation of an atom by gamma rays in the solid state. The resulting Mössbauer spectrum provides information about the oxidation state, spin state, and electronic environment around the target atom, which, in combination, gives evidence about the electronic structure and ligand arrangement (geometry) of the molecule.
FAQs
The applied magnetic field controls the energy separation between electron-spin levels. As the field reaches the value at which that separation matches the supplied microwave radiation, the sample absorbs microwave energy and produces a resonance signal. Recording the absorption while changing the field creates the spectrum, allowing researchers to examine spin behavior rather than simply detect the presence of a species.
The g-factor helps characterize the electron’s magnetic behavior and provides information about its surroundings. Because the spectrum also reflects the local environment, examining g-factor-related features can help researchers investigate whether a signal is associated with a biological radical or a paramagnetic metal center. This supports connections between spectral observations, molecular structure, and biological function.
Hyperfine interactions provide detail beyond the main resonance feature. Their appearance in a spectrum contributes to characterization of the unpaired-electron species and its local environment. In biological studies, this information helps researchers analyze signals from radicals and paramagnetic metal centers more closely, strengthening interpretations of enzyme mechanisms, electron-transfer reactions, and metalloprotein behavior.
Interpretation begins by identifying whether the biological sample is being examined for a radical, a paramagnetic metal center, or both. The sample is measured in a magnetic field while microwave absorption is observed at resonance. Researchers then use spectral features, including the g-factor, hyperfine interactions, and local-environment information, to characterize the species and relate it to biological function.
In biology, the technique can be applied to enzyme mechanisms, oxidative stress, electron-transfer reactions, and metalloprotein structure. These applications use paramagnetic signals to examine how reactive species or metal-containing proteins behave. Consequently, EPR measurements can connect spectroscopic evidence with processes that control radical chemistry, electron movement, and the function of metalloproteins.
Its ability to identify short-lived radical intermediates allows researchers to examine transient species during studies of biological reactions. Detecting these intermediates can clarify enzyme mechanisms and oxidative processes, while also helping explain how reactive species participate in cellular chemistry. The resulting information connects brief molecular events with broader biological processes involving radicals, electron transfer, or metal-containing proteins.