Articles | Volume 4, issue 1
https://doi.org/10.5194/mr-4-1-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/mr-4-1-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
12 Jan 2023
Research article |
| 12 Jan 2023
| 12 Jan 2023
Intermolecular contributions, filtration effects and signal composition of SIFTER (single-frequency technique for refocusing)
Agathe Vanas
Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2,
8093 Zurich, Switzerland
Janne Soetbeer
Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2,
8093 Zurich, Switzerland
Frauke Diana Breitgoff
Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2,
8093 Zurich, Switzerland
Henrik Hintz
Department of Chemistry, Bielefeld University, Universitätsstrasse 25,
33615 Bielefeld, Germany
Muhammad Sajid
Department of Chemistry, Bielefeld University, Universitätsstrasse 25,
33615 Bielefeld, Germany
Yevhen Polyhach
Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2,
8093 Zurich, Switzerland
Adelheid Godt
Department of Chemistry, Bielefeld University, Universitätsstrasse 25,
33615 Bielefeld, Germany
Gunnar Jeschke
Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2,
8093 Zurich, Switzerland
Maxim Yulikov
CORRESPONDING AUTHOR
Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2,
8093 Zurich, Switzerland
Daniel Klose
CORRESPONDING AUTHOR
Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2,
8093 Zurich, Switzerland
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Magn. Reson., 1, 75–87, https://doi.org/10.5194/mr-1-75-2020, https://doi.org/10.5194/mr-1-75-2020, 2020
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Measuring distances between unpaired electron spins is an important application of electron paramagnetic resonance. The longest distance that is accessible is limited by the phase memory time of the electron spins. Here we show that strong continuous microwave irradiation can significantly slow down relaxation. Additionally, we introduce a phase-modulation scheme that allows measurement of the distance during the irradiation. Our approach could thus significantly extend the accessible distances.
Sergei Kuzin, Victoriya N. Syryamina, Mian Qi, Moritz Fischer, Miriam Hülsmann, Adelheid Godt, Gunnar Jeschke, and Maxim Yulikov
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Quantification of heterogeneous systems such as unstructured or semi-structured (bio)macromolecules is an important but challenging task. Pulse EPR methods can contribute by characterizing the local nuclear environment of a spin centre. Here, we provide a detailed assessment of a pulse EPR technique derived from a RIDME experiment. We review the theoretical principles, discuss the data analysis and demonstrate an application to a spin-labeled macromolecule supported by in silico modelling.
Gunnar Jeschke, Nino Wili, Yufei Wu, Sergei Kuzin, Hugo Karas, Henrik Hintz, and Adelheid Godt
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Electron spins sense their environment via magnetic interactions. An important contribution stems from nuclear spins in their vicinity. They cause loss of coherence and thus reduce resolution of spectra obtained by experiments on electron spins and the efficiency of transferring electron-spin magentization to other nuclear spins. Here we study how protons in trityl radicals contribute to coherence loss. Such coherence loss is slower in the presence of a strong microwave field.
Jörg Wolfgang Anselm Fischer, Julian Stropp, René Tschaggelar, Oliver Oberhänsli, Nicholas Alaniva, Mariko Inoue, Kazushi Mashima, Alexander Benjamin Barnes, Gunnar Jeschke, and Daniel Klose
Magn. Reson., 5, 143–152, https://doi.org/10.5194/mr-5-143-2024, https://doi.org/10.5194/mr-5-143-2024, 2024
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We show the design, simulations, and experimental performance of a 35 GHz electron paramagnetic resonance (EPR) resonator based on a cylindrical cavity with 3 mm sample access. The design is robust; simple to manufacture and maintain; and, with its elevated Q value, well-suited to sensitive EPR experiments using continuous-wave or low-power pulsed excitation. Thus, we make multi-frequency EPR spectroscopy, a powerful approach to deconvolute overlapping paramagnetic species, more accessible.
Julian Stropp, Nino Wili, Niels Christian Nielsen, and Daniel Klose
Magn. Reson. Discuss., https://doi.org/10.5194/mr-2024-14, https://doi.org/10.5194/mr-2024-14, 2024
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Sensitivity is often the limiting factor in ENDOR. Here, we demonstrate how using chirp radiofrequency pulses can improve ENDOR sensitivity up to 3-9-fold, with the strongest increase for broader lines often encountered in disordered solids for nuclei such as nitrogen and metals. The resulting drastic speed-up in acquisition times renders also 2D ENDOR more feasible, as we demonstrate in 2D TRIPLE showing correlations of Cu hyperfine couplings.
Nino Wili, Jan Henrik Ardenkjær-Larsen, and Gunnar Jeschke
Magn. Reson., 3, 161–168, https://doi.org/10.5194/mr-3-161-2022, https://doi.org/10.5194/mr-3-161-2022, 2022
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Dynamic nuclear polarisation (DNP) transfers polarisation from electron to nuclear spins. This is usually combined with direct detection of the latter. Here, we show that it is possible to reverse the transfer at 1.2 T. This allows us to investigate the spin dynamics of nuclear spins close to electrons – something that is notoriously difficult with established methods. We expect reverse DNP to be useful in the study of spin diffusion or as a building block for more elaborate pulse sequences.
Markus Teucher, Mian Qi, Ninive Cati, Henrik Hintz, Adelheid Godt, and Enrica Bordignon
Magn. Reson., 1, 285–299, https://doi.org/10.5194/mr-1-285-2020, https://doi.org/10.5194/mr-1-285-2020, 2020
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With a pulsed dipolar electron paramagnetic resonance technique named double electron–electron resonance (DEER), we measure nanometer distances between spin labels attached to biomolecules. If more than one spin type is present (A and B), we can separately address AA, AB, and BB distances via distinct spectroscopic channels, increasing the information content per sample. Here, we investigate the appearance of unwanted channel crosstalks in DEER and suggest ways to identify and suppress them.
Luis Fábregas Ibáñez, Gunnar Jeschke, and Stefan Stoll
Magn. Reson., 1, 209–224, https://doi.org/10.5194/mr-1-209-2020, https://doi.org/10.5194/mr-1-209-2020, 2020
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Dipolar electron paramagnetic resonance spectroscopy methods such as DEER provide data on how proteins change shape, thus giving detailed insight into how proteins work. We present DeerLab, a comprehensive open-source software for reliably analyzing the associated data. The software implements a series of theoretical and algorithmic innovations and thereby improves the quality and reproducibility of data analysis.
Nino Wili, Henrik Hintz, Agathe Vanas, Adelheid Godt, and Gunnar Jeschke
Magn. Reson., 1, 75–87, https://doi.org/10.5194/mr-1-75-2020, https://doi.org/10.5194/mr-1-75-2020, 2020
Short summary
Short summary
Measuring distances between unpaired electron spins is an important application of electron paramagnetic resonance. The longest distance that is accessible is limited by the phase memory time of the electron spins. Here we show that strong continuous microwave irradiation can significantly slow down relaxation. Additionally, we introduce a phase-modulation scheme that allows measurement of the distance during the irradiation. Our approach could thus significantly extend the accessible distances.
Related subject area
Field: EPR | Topic: Theory
Electron-spin decoherence in trityl radicals in the absence and presence of microwave irradiation
The effect of the zero-field splitting in light-induced pulsed dipolar electron paramagnetic resonance (EPR) spectroscopy
The effect of spin polarization on double electron–electron resonance (DEER) spectroscopy
Gunnar Jeschke, Nino Wili, Yufei Wu, Sergei Kuzin, Hugo Karas, Henrik Hintz, and Adelheid Godt
Magn. Reson. Discuss., https://doi.org/10.5194/mr-2024-17, https://doi.org/10.5194/mr-2024-17, 2024
Revised manuscript accepted for MR
Short summary
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Electron spins sense their environment via magnetic interactions. An important contribution stems from nuclear spins in their vicinity. They cause loss of coherence and thus reduce resolution of spectra obtained by experiments on electron spins and the efficiency of transferring electron-spin magentization to other nuclear spins. Here we study how protons in trityl radicals contribute to coherence loss. Such coherence loss is slower in the presence of a strong microwave field.
Andreas Scherer, Berk Yildirim, and Malte Drescher
Magn. Reson., 4, 27–46, https://doi.org/10.5194/mr-4-27-2023, https://doi.org/10.5194/mr-4-27-2023, 2023
Short summary
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Light-induced pulsed dipolar EPR spectroscopy (PDS) is an emerging field that uses photoexcited triplet states to determine distance restraints in the nanometer range. To date, light-induced PDS data have been analyzed with methods developed for techniques that do not invoke light-induced triplets. Here, we provide a new theoretical description that takes the full nature of the triplet state into account and demonstrate that it leads to more accurate fits of experimental data.
Sarah R. Sweger, Vasyl P. Denysenkov, Lutz Maibaum, Thomas F. Prisner, and Stefan Stoll
Magn. Reson., 3, 101–110, https://doi.org/10.5194/mr-3-101-2022, https://doi.org/10.5194/mr-3-101-2022, 2022
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This work examines the physics underlying double electron–electron resonance (DEER) spectroscopy, a magnetic-resonance method that provides nanoscale data about protein structure and conformations.
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Short summary
Nanometre distance measurements between spin labels by pulse EPR techniques yield structural information on the molecular level. Here, backed by experimental data, we derive a description for the total signal of the single-frequency technique for refocusing dipolar couplings (SIFTER), showing how the different spin–spin interactions give rise to dipolar signal and background – the latter has thus far been unknown.
Nanometre distance measurements between spin labels by pulse EPR techniques yield structural...
