Closed-loop miscibility gap and quantitative tie-lines in ternary membranes containing diphytanoyl PC.
Closed-loop miscibility gap and quantitative tie-lines in ternary membranes containing diphytanoyl PC.
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DOI：
10.1529/biophysj.105.080283
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发表时间：
2006-06
影响因子：
3.4
通讯作者：
S. Veatch;K. Gawrisch;S. Keller
中科院分区：
文献类型：
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作者：
S. Veatch;K. Gawrisch;S. Keller
含有二植烷酰磷脂酰胆碱、二棕榈酰磷脂酰胆碱（DPPC）和胆固醇的三元混合物的囊泡在异常大的温度和组成范围内产生共存的液相。液体域保持远高于DPPC链熔融温度（41 ° C），导致在固定温度下由两个临界点界定的闭环可溶解性间隙。使用新型分析直接从2 H NMR光谱中确定定量联系线，并发现将富含二植烷酰基PC的液体无序相与富含DPPC的液体有序相连接。连接线的方向意味着二元DPPC/胆固醇混合物在41 ℃以上处于一个均匀相。通过独立的荧光显微镜检查结果验证了连接线的所有2 H NMR结果。
Vesicles containing ternary mixtures of diphytanoylphosphatidylcholine, dipalmitoylphosphatidylcholine (DPPC), and cholesterol produce coexisting liquid phases over an unusually large range of temperature and composition. Liquid domains persist well above the DPPC chain melting temperature (41 degrees C), resulting in a closed-loop miscibility gap bounded by two critical points at fixed temperature. Quantitative tie-lines are determined directly from 2H NMR spectra using a novel analysis, and are found to connect a liquid-disordered phase rich in diphytanoyl PC with a liquid-ordered phase rich in DPPC. The direction of the tie-lines implies that binary DPPC/cholesterol mixtures are in one uniform phase above 41 degrees C. All 2H NMR results for tie-lines are verified by independent fluorescence microscopy results.