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Tkach I, Bejenke I, Hecker F, Kehl A, Kasanmascheff M, Gromov I, Prisecaru I, Höfer P, Hiller M, Bennati M. 1H high field electron-nuclear double resonance spectroscopy at 263 GHz/9.4 T. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 303:17-27. [PMID: 30991287 DOI: 10.1016/j.jmr.2019.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 03/18/2019] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
We present and discuss the performance of 1H electron-nuclear double resonance (ENDOR) at 263 GHz/9.4 T by employing a prototype, commercial quasi optical spectrometer. Basic instrumental features of the setup are described alongside a comprehensive characterization of the new ENDOR probe head design. The performance of three different ENDOR pulse sequences (Davies, Mims and CP-ENDOR) is evaluated using the 1H BDPA radical. A key feature of 263 GHz spectroscopy - the increase in orientation selectivity in comparison with 94 GHz experiments - is discussed in detail. For this purpose, the resolution of 1H ENDOR spectra at 263 GHz is verified using a representative protein sample containing approximately 15 picomoles of a tyrosyl radical. Davies ENDOR spectra recorded at 5 K reveal previously obscured spectral features, which are interpreted by spectral simulations aided by DFT calculations. Our analysis shows that seven internal proton couplings are detectable for this specific radical if sufficient orientation selectivity is achieved. The results prove the fidelity of 263 GHz experiments in reporting orientation-selected 1H ENDOR spectra and demonstrate that new significant information can be uncovered in complex molecular systems, owing to the enhanced resolution combined with high absolute sensitivity and no compromise in acquisition time.
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Affiliation(s)
- Igor Tkach
- Research Group EPR Spectroscopy, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
| | - Isabel Bejenke
- Research Group EPR Spectroscopy, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Fabian Hecker
- Research Group EPR Spectroscopy, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Annemarie Kehl
- Research Group EPR Spectroscopy, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany; Department of Chemistry, Georg-August University of Göttingen, Tammannstr. 2, Göttingen, Germany
| | - Müge Kasanmascheff
- Research Group EPR Spectroscopy, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Igor Gromov
- Bruker Biospin GmbH, Silberstreifen 4, 76287 Rheinstetten, Germany
| | - Ion Prisecaru
- Bruker Biospin GmbH, Silberstreifen 4, 76287 Rheinstetten, Germany
| | - Peter Höfer
- Bruker Biospin GmbH, Silberstreifen 4, 76287 Rheinstetten, Germany
| | - Markus Hiller
- Research Group EPR Spectroscopy, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Marina Bennati
- Research Group EPR Spectroscopy, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany; Department of Chemistry, Georg-August University of Göttingen, Tammannstr. 2, Göttingen, Germany.
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Joshi G, Teferi MY, Miller R, Jamali S, Baird D, van Tol J, Malissa H, Lupton JM, Boehme C. Isotropic Effective Spin-Orbit Coupling in a Conjugated Polymer. J Am Chem Soc 2018; 140:6758-6762. [DOI: 10.1021/jacs.8b03069] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Gajadhar Joshi
- Department of Physics and Astronomy, University of Utah, 115 S, 1400 E, Salt Lake City, Utah 84112, United States
| | - Mandefro Y. Teferi
- Department of Physics and Astronomy, University of Utah, 115 S, 1400 E, Salt Lake City, Utah 84112, United States
| | - Richards Miller
- Department of Physics and Astronomy, University of Utah, 115 S, 1400 E, Salt Lake City, Utah 84112, United States
| | - Shirin Jamali
- Department of Physics and Astronomy, University of Utah, 115 S, 1400 E, Salt Lake City, Utah 84112, United States
| | - Douglas Baird
- Department of Physics and Astronomy, University of Utah, 115 S, 1400 E, Salt Lake City, Utah 84112, United States
| | - Johan van Tol
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Hans Malissa
- Department of Physics and Astronomy, University of Utah, 115 S, 1400 E, Salt Lake City, Utah 84112, United States
| | - John M. Lupton
- Department of Physics and Astronomy, University of Utah, 115 S, 1400 E, Salt Lake City, Utah 84112, United States
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93040 Regensburg, Germany
| | - Christoph Boehme
- Department of Physics and Astronomy, University of Utah, 115 S, 1400 E, Salt Lake City, Utah 84112, United States
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