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Updated: Apr 1, 2026

Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels
Published on: July 4, 2016
The use of the Rx spin label in orientation measurement on proteins, by EPR
M A Stevens1, J E McKay2, J L S Robinson1
1Nucleic Acid Structure Research Group, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK. d.g.norman@dundee.ac.uk.
Abstract:
The bipedal spin label Rx is more restricted in its conformation and dynamics than its monopodal counterpart R1. To systematically investigate the utility of the Rx label, we have attempted to comprehensively survey the attachment of Rx to protein secondary structures. We have examined the formation, structure and dynamics of the spin label in relation to the underlying protein in order to determine feasibility and optimum conditions for distance and orientation measurement by pulsed EPR. The labeled proteins have been studied using molecular dynamics, CW EPR, pulsed EPR distance measurement at X-band and orientation measurement at W-band. The utility of different modes and positions of attachment have been compared and contrasted.
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