Phase studies of model biomembranes: Complex behavior of DSPC/DOPC/cholesterol
Phase studies of model biomembranes: Complex behavior of DSPC/DOPC/cholesterol
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DOI：
10.1016/j.bbamem.2007.07.008
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发表时间：
2007-11-01
影响因子：
3.4
通讯作者：
Feigenson, Gerald W.
中科院分区：
文献类型：
--
作者：
Zhao, Jiang;Wu, Jing;Feigenson, Gerald W.
我们已经进行了一系列的实验，以检查细胞膜的各个组成部分的行为。在这里，我们报告这些实验的初始阶段，在化学上简单的脂质混合物的性质被仔细映射到相图。使用四种不同的实验方法来建立3组分混合物DSPC/DOPC/chol的相行为：（1）巨单层囊泡（GUV）的共聚焦荧光显微镜观察;（2）从二萘嵌苯到C20：0-Dil的FRET;（3）稀释染料C18：2-DiO和C20：0-Dil的荧光;以及（4）广角X射线衍射。这种特定的3组分混合物是针对组分的高水平的不可混溶性而分批选择的，以促进解决所有组合物的相行为。在23摄氏度下，该混合物的大部分可能组成产生固相。基于GUV的荧光显微术、FRET和稀释的C20：0-Dil荧光的组合，检测和定义{L α + L β +Lo}的三相共存区域。在非常低的胆固醇浓度下，固相是倾斜链相L β '。大多数相界已被确定为在组成的百分之几内。对这种精确相图边界扰动的测量可以作为理解一系列添加的脂质和蛋白质行为的手段。(c)2007 Elsevier B. V.保留所有权利。
We have undertaken a series of experiments to examine the behavior of individual components of cell membranes. Here we report an initial stage of these experiments, in which the properties of a chemically simple lipid mixture are carefully mapped onto a phase diagram. Four different experimental methods were used to establish the phase behavior of the 3-component mixture DSPC/DOPC/chol: (1) confocal fluorescence microscopy observation of giant unilamellar vesicles, GUVs; (2) FRET from perylene to C20:0-Dil; (3) fluorescence of dilute dyes C I 8:2-DiO and C20:0-Dil; and (4) wide angle X-ray diffraction. This particular 3-component mixture was chosen, in pail, for a high level of immiscibility of the components in order to facilitate solving the phase behavior at all compositions. At 23 degrees C, a large fraction of the possible compositions for this mixture give rise to a solid phase. A region of 3-phase coexistence of {L alpha + L beta +Lo} was detected and defined based on a combination of fluorescence microscopy of GUVs, FRET, and dilute C20:0-Dil fluorescence. At very low cholesterol concentrations, the solid phase is the tilted-chain phase L beta'. Most of the phase boundaries have been determined to be within a few percent of the composition. Measurements of the perturbations of the boundaries of this accurate phase diagram could serve as a means to understand the behaviors of a range of added lipids and proteins. (c) 2007 Elsevier B.V. All rights reserved.