The effect of dolichol C(95) on the structure and thermotropic phase behaviour of dipalmitoylphosphatidylcholine, dipalmitoylphosphatidylethanolamine and stearoyloleoylphosphatidylethanolamine has been examined by synchrotron X-ray diffraction and differential scanning calorimetry. The presence of dolichol C(95) had no detectable effects on the temperature of either the gel to ripple or the ripple to liquid-crystal phase transition of dipalmitoylphosphatidylcholine. A proportionate increase of a few degrees in the temperature of the gel to lamellar liquid-crystal phase transition is observed in dispersions of dipalmitoylphosphatidylethanolamine and significantly there is a decrease in the temperature of the lamellar to non-lamellar phase transition of stearoyloleoylphosphatidylethanolamine. There was no significant change in the bilayer repeat spacing of all three mixed dispersions in gel phase in the presence of up to 20 mol% dolichol C(95). Electron density calculations showed that there was no change of bilayer thickness of dipalmitoylphosphatidylcholine with incorporation of up to 7.5 mol% dolichol C(95). These data suggest that effect of dolichol on the phospholipid model membranes depend on both the head group and the hydrocarbon chains of the phospholipid molecules. The presence of dolichol in phosphatidylcholine bilayers conforms to a model in which the polyisoprene compound is phase separated into a central domain sandwiched between the two monolayers in gel phase. In bilayers of phosphatidylethanolamines dolichol tends to stabilize the bilayers in gel phase at low temperatures and destabilize the bilayers in lamellar disordered structure at high temperatures. Non-lamellar structures coexist with lamellar disordered phase over a wide temperature range suggesting that dolichol is enriched in domains of non-lamellar structure and depleted from lamellar phase. These findings are useful to understand the function of dolichol in cell membranes.

中文翻译：

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多元醇对磷脂模型膜的结构和相行为的影响。

通过同步加速器X射线衍射和差示扫描量热法研究了二元醇C（95）对二棕榈酰磷脂酰胆碱，二棕榈酰磷脂酰乙醇胺和硬脂酰油酰磷脂酰乙醇胺的结构和热致相行为的影响。多元醇C（95）的存在对凝胶温度至波纹或二棕榈酰磷脂酰胆碱向液晶相转变的温度均无可检测的影响。在二棕榈酰磷脂酰乙醇胺的分散体中观察到凝胶温度向层状液晶相转变的比例升高几度，并且硬脂酰油酰基磷脂酰乙醇胺的层状转变为非层状相的温度显着降低。在存在高达20摩尔％的多元醇C（95）的情况下，凝胶相中所有三种混合分散体的双层重复间隔没有明显变化。电子密度计算表明，在掺入高达7.5 mol％的多元醇C时，二棕榈酰磷脂酰胆碱的双层厚度没有变化（95）。这些数据表明，二氢乙醇对磷脂模型膜的影响取决于磷脂分子的头基和烃链。磷脂酰胆碱双层中存在二元醇符合其中聚异戊二烯化合物被相分离成夹在凝胶相中的两个单层之间的中心区域的模型。在磷脂酰乙醇胺的双层中，二元醇倾向于在低温下使凝胶相中的双层稳定并且在高温下使层状无序结构中的双层不稳定。非薄片结构在很宽的温度范围内与层状无序相共存，表明二元醇在非层状结构域中富集并且从层状相中耗尽。这些发现对于理解二元醇在细胞膜中的功能是有用的。