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β-谷固醇對POPE膜物理特性的影響

Thesis published in 2014 by Yan-Jiun 陳彥均;Chen
This paper was not found in any repository; the policy of its publisher is unknown or unclear.
This paper was not found in any repository; the policy of its publisher is unknown or unclear.

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Abstract

膽固醇及其他種類的固醇對於形成脂質筏扮演重要的角色,現在普遍認為脂質筏區塊處於lo態。從過去對人造細胞膜的研究可知,固醇可以誘發脂雙層膜形成lo態,但大部分的研究都以PC類脂膜為主,較少對PE類脂膜進行研究。為進一步瞭解脂質筏的形成,探究固醇與PE類脂膜的交互作用是必要的。我們使用氘核磁共振(2H NMR)研究植物固醇對POPE人造細胞膜的物理特性之影響。其方法是先將POPE上sn-1的氫代換成氘,再將其混合不同濃度的植物固醇而成多個樣本,並將各樣本隨溫度改變量測得一系列光譜。 M1(T)值顯示,植物固醇對於gel態及lc態POPE膜的有序程度之影響是不一樣的:植物固醇對gel態膜的有序程度沒有明顯的改變;然而,它會增加lc態POPE膜的有序度,但此影響在植物固醇為20 mol%時達到飽和。此外,分析NMR光譜可得到溫度-濃度相圖,可觀察到兩個兩項共存區。;Cholesterol and other sterols are important for the formation of lipid raft. It is now generally agreed that raft domains are in the liquid-ordered (lo) phase. Previous research on model membranes has found that sterol induces the formation of the lo-phase in lipid bilayers. While most studies were conducted in phosphatidylcholine lipid bilayers, fewer were conducted in phosphoethanolamine (PE) lipid biayers. To further understand the raft formation, exploring the interaction of sterol and PE lipid is necessary.We investigate the effect of phytosterol on the physical properties of 1-[2H31]palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) multibilayers using deuterium nuclear magnetic resonance(2H NMR). The sn-1 chain of POPE was deuterium labeled. 2H NMR spectra were taken as a function of temperature andphytosterol concentration. The spectral first moments show that the ordering effects of phytosterol on the gel-phase and liquid crystalline (lc)-phase POPE membranes are different: It has no significant effect on the membrane order in the gel phase.In contrast, it increases the chain order of lc-phase POPE,but this effect saturates at 20 mol% phytosterol.Moreover, the temperature-composition phase diagram, established from the NMR spectra, is presented. Two two-phase coexistence regions were observed.