Rapid-Scan EPR of Immobilized Nitroxides

Authors

Zhelin Yu, University of Denver
Richard W. Quine, University of Denver
George A. Rinard, University of Denver
Mark Tseitlin, University of Denver
Hanan Elajaili, University of Denver
Velavan Kathirvelu, University of Denver
Laura J. Clouston, University of Nebraska-Lincoln
Przemysław J. Boratyński, University of Nebraska-Lincoln
Andrzej Rajca, University of Nebraska - LincolnFollow
Richard A. Stein, Vanderbilt UniversityFollow
Hassane Mchaourab, Vanderbilt University
Sandra S. Eaton, University of Denver
Gareth R. Eaton, University of Denver

Date of this Version

2014

Citation

J Magn Reson. 2014 October ; 247: 67–71.

Comments

Copyright © 2014 Elsevier Inc.

Abstract

X-band electron paramagnetic resonance spectra of immobilized nitroxides were obtained by rapid scan at 293 K. Scan widths were 155 G with 13.4 kHz scan frequency for ¹⁴N-perdeuterated tempone and for T4 lysozyme doubly spin labeled with an iodoacetamide spirocyclohexyl nitroxide and 100 G with 20.9 kHz scan frequency for ¹⁵N-perdeuterated tempone. These wide scans were made possible by modifications to our rapid-scan driver, scan coils made of Litz wire, and the placement of highly conducting aluminum plates on the poles of a Bruker 10" magnet to reduce resistive losses in the magnet pole faces. For the same data acquisition time, the signal-to-noise for the rapid-scan absorption spectra was about an order of magnitude higher than for continuous wave first-derivative spectra recorded with modulation amplitudes that do not broaden the lineshapes.