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Updated: May 16, 2025

Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels
Published on: July 4, 2016
Sigmatropic rearrangement enables access to a highly stable spirocyclic nitroxide for protein spin labelling
Mateusz P Sowiński1, Elena M Mocanu2, Hannah Ruskin-Dodd2
1Department of Chemistry, UiT The Arctic University of Norway, 9037 Tromsø, Norway. marius.haugland-grange@uit.no.
Abstract:
Spin labelling enables the study of biomolecules using electron paramagnetic resonance (EPR) spectroscopy. Here, we describe the synthesis of a cysteine-reactive spin label based on a spirocyclic pyrrolidinyl nitroxide containing an iodoacetamide moiety. The spin label was shown to be highly persistent under reducing conditions while maintaining excellent EPR relaxation parameters up to a temperature of 180 K. After successful double spin labelling of a calmodulin variant, interspin distances were measured by the EPR experiment double electron-electron resonance (DEER) at 120 K.
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