The fidelity of response by nitroxide spin probes to changes in membrane organization: the condensing effect of cholesterol.

摘要: Abstract The response of doxyl fatty acid spin probes in egg lecithin bilayers to added cholesterol is compared with results from 2 H-NMR. Large differences are found between the profiles order parameter vs. label position and concentration. At constant content, ESR probe decreases continuously as moved toward terminal methyl region bilayer whereas an ‘plateau’ observed for upper by In addition, parameters smaller than those Differences also content each position. detect a maximal central portion chains much weaker responses near both ends chains. contrast, H-NMR indicate large, approximately first ten positions decreasing group. For all examined, show that A direct measure perturbing effect made comparing deuterium quadrupole splittings lecithin-cholesterol stearic without attached moiety. spin-labelled has reduced splitting opposite addition.