کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1945610 | 1053269 | 2008 | 12 صفحه PDF | دانلود رایگان |
Several studies have indicated the involvement of steryl glycosides in the cellular stress response. In this work, we have compared the effect of 1-O-cholesteryl-β-d-glucoside, 1-O-cholesteryl-β-d-galactoside and cholesterol on the properties of glycerophospholipid and sphingolipid bilayers. The studies were performed in order to gain insight into the change in membrane properties that would follow upon the glycosylation of cholesterol in cells subjected to stress. DPH anisotropy measurements indicated that the cholesteryl glycosides (10–40 mol%) increased the order of the hydrophobic region of a POPC bilayer almost as efficiently as cholesterol. In a PSM bilayer, the cholesteryl glycosides were however shown to be much less effective compared to cholesterol in ordering the hydrocarbon chain region at temperatures above the gel to liquid-crystalline phase transition. Fluorescence quenching analysis of multicomponent lipid bilayers demonstrated that the cholesteryl glycosides, in contrast to cholesterol, were unable to stabilize ordered domains rich in PSM against temperature-induced dissociation. When the sterols were incorporated into bilayers composed of both POPC and PSM, the cholesteryl glycosides showed a higher propensity, compared to cholesterol, to influence the endothermal component representing the melting of POPC-rich domains, as determined by differential scanning calorimetry. Taken together, the results indicate that the glycosylation of cholesterol diminishes the ability of the sterol to reside in lateral domains constituted by membrane lipids having highly ordered hydrocarbon chains.
Journal: Biochimica et Biophysica Acta (BBA) - Biomembranes - Volume 1778, Issue 4, April 2008, Pages 1100–1111