The effect of glucocerebroside (GlcCer) on the structure and thermotropic phase behavior of aqueous dispersions of palmitoyloleoylphosphatidylethanolamine (POPE) has been examined using simultaneous small-angle and wide-angle X-ray diffraction methods. Binary mixtures of GlcCer:POPE in molar ratios of 2:100, 5:100, 10:100, 20:100, 30:100, and 40:100 were examined in the temperature range 20-90 degrees C. Cubic phase has been observed in binary mixtures comprised of molar ratios greater than 5:100 in the temperature range of 60-90 degrees C upon heating at a rate of 2 degrees C/min. The cubic phase is relatively stable and coexists with inverted hexagonal or lamellar phases. It persists in the codispersions throughout subsequent cooling scans to 30 degrees C. The space group of the cubic phase is determined to be Pn3m or Pn3. The lattice constant of the Pn3m cubic phase was found to be almost constant when it coexists with lamellar liquid-crystal phase. Marked temperature-dependent changes were observed when cubic phase coexists with hexagonal phase or lamellar-gel phases. This is the first report of cubic phases formed by codispersions of glycosphingolipids and phospholipids. The mechanism of cubic phase formation and the interaction between GlcCer and POPE is discussed in terms of the putative biological functions of glycolipids.

中文翻译：

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葡糖脑苷和棕榈酰油酰磷脂酰乙醇胺共分散体中的稳定立方相。

使用同时的小角度和广角X射线衍射方法研究了葡糖脑苷（GlcCer）对棕榈酰油酰磷脂酰乙醇胺（POPE）水分散体的结构和热致相行为的影响。在20-90摄氏度的温度范围内检查了摩尔比为2：100、5：100、10：100、20：100、30：100和40：100的GlcCer：POPE的二元混合物。在以2℃/ min的速率加热时，在60-90℃的温度范围内，在摩尔比大于5：100的二元混合物中观察到了上述结果。立方相相对稳定，并与倒置的六方或层状相共存。在随后的冷却至30摄氏度的整个扫描过程中，它始终保持在共分散状态。立方相的空间群确定为Pn3m或Pn3。当Pn 3m立方相与层状液晶相共存时，其晶格常数几乎恒定。当立方相与六方相或层状凝胶相共存时，观察到明显的温度依赖性变化。这是糖鞘脂和磷脂共分散形成的立方相的首次报道。根据糖脂的假定生物学功能讨论了立方相形成的机理以及GlcCer与POPE之间的相互作用。