The effects of cholesterol on lateral diffusion and vertical fluctuations in lipid bilayers. An electron-electron double resonance (ELDOR) study. Biophys J 1987 Dec;52(6):1031-8
Date
12/01/1987Pubmed ID
2827800Pubmed Central ID
PMC1330102DOI
10.1016/S0006-3495(87)83296-4Scopus ID
2-s2.0-0023503514 (requires institutional sign-in at Scopus site) 18 CitationsAbstract
Electron-electron double resonance (ELDOR) and saturation-recovery spectroscopy employing 14N:15N stearic acid spin-label pairs have been used to study the effects of cholesterol on lateral diffusion and vertical fluctuations in lipid bilayers. The 14N:15N continuous wave electron-electron double resonance (CW ELDOR) theory has been developed using rate equations based on the relaxation model. The collision frequency between 14N-16 doxyl stearate and 15N-16 doxyl stearate, WHex (16:16), is indicative of lateral diffusion of the spin probes, while the collision frequency between 14N-16 doxyl stearate and 15N-5 doxyl stearate, WHex (16:5), provides information on vertical fluctuations of the 14N-16 doxyl stearate spin probe toward the membrane surface. Our results show that: (a) cholesterol decreases the electron spin-lattice relaxation time Tle of 14N-16 doxyl stearate spin label in dimyristoylphosphatidylcholine (DMPC) and egg yolk phosphatidylcholine (egg PC). (b) Cholesterol increases the biomolecular collision frequency WHex (16:16) and decreases WHex (16:5), suggesting that incorporation of cholesterol significantly orders the part of the bilayer that it occupies and disorders the interior region of the bilayer. (c) Alkyl chain unsaturation of the host lipid moderates the effect of cholesterol on both vertical fluctuations and lateral diffusion of 14N-16 doxyl stearate. And (d), there are marked differences in the effects of cholesterol on lateral diffusion and vertical fluctuations between 0-30 mol% and 30-50 mol% of cholesterol that suggest an inhomogeneous distribution of cholesterol in the membrane.
Author List
Yin JJ, Feix JB, Hyde JSAuthor
Jimmy B. Feix PhD Professor in the Biophysics department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
CholesterolCyclic N-Oxides
Diffusion
Dimyristoylphosphatidylcholine
Electron Spin Resonance Spectroscopy
Lipid Bilayers
Mathematics
Models, Biological
Nitrogen Isotopes
Nitrogen Radioisotopes
Spin Labels