| Anisotropic motion effects in CW non-linear EPR spectra: relaxation enhancement of lipid spin labels. | |
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MedLine Citation:
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PMID: 12810029 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Continuous-wave (CW) EPR measurements of enhancements in spin-lattice (T(1)-) relaxation rate find wide application for determining spin-label locations in biological systems. Often, especially in membranes, the spin-label rotational motion is anisotropic and subject to an orientational potential. We investigate here the effects of anisotropic diffusion and ordering on non-linear CW-EPR methods for determining T(1) of nitroxyl spin labels. Spectral simulations are performed for progressive saturation of the conventional in-phase, first-harmonic EPR signal, and for the first-harmonic absorption EPR signals detected 90 degrees -out-of-phase with respect to the Zeeman field modulation. Motional models used are either rapid rotational diffusion, or strong-jump diffusion of unrestricted frequency, within a cone of fixed maximum amplitude. Calculations of the T(1)-sensitive parameters are made for both classes of CW-experiment by using motional parameters (i.e., order parameters and correlation times), intrinsic homogeneous and inhomogeneous linewidth parameters, and spin-Hamiltonian hyperfine- and g-tensors, that are established from simulation of the linear CW-EPR spectra. Experimental examples are given for spin-labelled lipids in membranes. |
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Authors:
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V A Livshits; B G Dzikovski; D Marsh |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of magnetic resonance (San Diego, Calif. : 1997) Volume: 162 ISSN: 1090-7807 ISO Abbreviation: J. Magn. Reson. Publication Date: 2003 Jun |
Date Detail:
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Created Date: 2003-06-17 Completed Date: 2004-01-20 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 9707935 Medline TA: J Magn Reson Country: United States |
Other Details:
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Languages: eng Pagination: 429-42 Citation Subset: IM |
Affiliation:
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Centre of Photochemistry, Russian Academy of Sciences, 117427, Moscow, Russian Federation. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Anisotropy Electron Spin Resonance Spectroscopy* Linear Models Models, Theoretical Phosphatidylcholines / chemistry* |
| Chemical | |
Reg. No./Substance:
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0/Phosphatidylcholines |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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