Analysis of nitroxide spin label motion in a protein-protein complex using multiple frequency EPR spectroscopy

White, G. F., Ottignon, L., Georgiou, T., Kleanthous, C., Moore, G. R., Thomson, A. J. and Oganesyan, V. S. ORCID: (2007) Analysis of nitroxide spin label motion in a protein-protein complex using multiple frequency EPR spectroscopy. Journal of Magnetic Resonance, 185 (2). pp. 191-203. ISSN 1090-7807

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X- and W-band EPR spectra, at room and low temperatures, are reported for nitroxide spin labels attached to cysteine residues selectively introduced into two proteins, the DNase domain of colicin-E9 and its immunity protein, Im9. The dynamics of each site of attachment on the individual proteins and in the tight DNase-Im9 complex have been analysed by computer simulations of the spectra using a model of Brownian dynamics trajectories for the spin label and protein. Ordering potentials have been introduced to describe mobility of labels restricted by the protein domain. Label mobility varies with position from completely immobilised, to motionally restricted and to freely rotating. Bi-modal dynamics of the spin label have been observed for several sites. We show that W-band spectra are particularly useful for detection of anisotropy of spin label motion. On complex formation significant changes are observed in the dynamics of labels at the binding interface region. This work reveals multi-frequency EPR as a sensitive and valuable tool for detecting conformational changes in protein structure and dynamics especially in protein-protein complexes.

Item Type: Article
Uncontrolled Keywords: colicin-e9,computer simulation of epr spectra,electron paramagnetic resonance (epr),protein structure and dynamics,biophysics,biochemistry,nuclear and high energy physics,condensed matter physics ,/dk/atira/pure/subjectarea/asjc/1300/1304
Faculty \ School: Faculty of Science > School of Chemical Sciences and Pharmacy (former - to 2009)
Faculty of Science > School of Chemistry
UEA Research Groups: Faculty of Science > Research Groups > Centre for Photonics and Quantum Science
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Depositing User: LivePure Connector
Date Deposited: 08 Jul 2021 00:06
Last Modified: 05 Aug 2023 00:38
DOI: 10.1016/j.jmr.2006.12.009

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