Ternary phase diagram of dipalmitoyl-PC/dilauroyl-PC/cholesterol: Nanoscopic domain formation driven by cholesterol
Ternary phase diagram of dipalmitoyl-PC/dilauroyl-PC/cholesterol: Nanoscopic domain formation driven by cholesterol
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DOI：
10.1016/s0006-3495(01)76245-5
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发表时间：
2001-06-01
影响因子：
3.4
通讯作者：
Buboltz, JT
中科院分区：
文献类型：
--
作者：
Feigenson, GW;Buboltz, JT
本文提出了二棕榈酰磷脂酰胆碱/二月桂酰磷脂酰胆碱/胆固醇（DPPC/DLPC/胆固醇）水化层状脂质混合物在室温下的三元相图。整个组成空间已被彻底映射的互补实验技术，揭示了有趣的相行为，以前没有描述。共聚焦荧光显微镜显示富含DPPC的有序和富含DLPC的流体层状相共存，其上边界明显恒定，胆固醇摩尔分数X-chol类似于0.16。荧光共振能量转移实验证实了这种两相制度的识别和程度，而且，揭示了1-相制度之间的X-胆固醇类似于0.16和0.25，有序和流体纳米级域组成。Dipyrene-PC激基缔合物/单体测量证实了类似于0.16和0.25的X-chol之间的新机制，并且还显示了类似于0.25的X-chol周围刚性有序相似乎消失。这项研究应该被认为是一个更全面的了解生物膜内的横向异质性的一步。胆固醇可能在纳米尺度上的畴分离中起作用。
A ternary phase diagram is proposed for the hydrated lamellar lipid mixture dipalmitoylphosphatidylcholine/ dilauroylphosphatidylcholine/cholesterol (DPPC/DLPC/cholesterol) at room temperature. The entire composition space has been thoroughly mapped by complementary experimental techniques, revealing interesting phase behavior that has not been previously described. Confocal fluorescence microscopy shows a regime of coexisting DPPC-rich ordered and DLPC-rich fluid lamellar phases, having an upper boundary at apparently constant cholesterol mole fraction X-chol similar to 0.16. Fluorescence resonance energy transfer experiments confirm the identification and extent of this two-phase regime and, furthermore, reveal a 1-phase regime between X-chol similar to 0.16 and 0.25, consisting of ordered and fluid nanoscopic domains. Dipyrene-PC excimer/monomer measurements confirm the new regime between X-chol similar to 0.16 and 0.25 and also show that rigidly ordered phases seem to disappear around X-chol similar to 0.25. This study should be considered as a step toward a more complete understanding of lateral heterogeneity within biomembranes. Cholesterol may play a role in domain separation on the nanometer scale.