Lipid Interactions and Organization in Complex Bilayer Membranes
Lipid Interactions and Organization in Complex Bilayer Membranes
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DOI：
10.1016/j.bpj.2015.12.043
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发表时间：
2016-04-12
影响因子：
3.4
通讯作者：
Slotte, J. Peter
中科院分区：
文献类型：
--
作者：
Engberg, Oskar;Yasuda, Tomokazu;Slotte, J. Peter
双层脂质影响膜的横向结构，但脂质性质和形成的横向结构之间的关系并不总是清楚的。对含有胆固醇和各种磷脂（PL）的双层的模型膜研究表明，高温和低温熔融PL可能分离，特别是在胆固醇的存在下。不同的PL头基对双层膜横向结构的影响也不清楚。在这里，我们已经研究了日益复杂的（多达五个组件）多层双层的横向异质性的形成。我们已经使用了时间分辨荧光光谱与域选择性荧光探针（PL共轭反式parinaric酸），和H-2 NMR光谱与网站或全氘代PL。我们已经测量了双层秩序的变化，使用这种结构域选择性探针作为温度和组合物的函数。我们的时间分辨荧光和H-2 NMR的结果表明，在三元双层，酰基链的顺序和热稳定性在鞘磷脂丰富的域没有受到任何更大程度的影响，由头基结构的单不饱和磷脂（磷脂酰胆碱，磷脂酰乙醇胺，或磷脂酰丝氨酸）的双层。在复杂的五组分双层，我们不能检测到胆固醇诱导的顺序不同的单不饱和磷脂之间的重大差异。然而，胆固醇显然影响氘代N-棕榈酰鞘磷脂不同于其他氘代PL，这表明胆固醇有利于N-棕榈酰鞘磷脂超过其他PL。两者合计，荧光光谱和H-2 NMR数据表明，复杂的五组分膜显示横向异质性，至少在较低的温度方案检查。
Bilayer lipids influence the lateral structure of the membranes, but the relationship between lipid properties and the lateral structure formed is not always understood. Model membrane studies on bilayers containing cholesterol and various phospholipids (PLs) suggest that high and low temperature melting PLs may segregate, especially in the presence of cholesterol. The effect of different PL headgroups on lateral structure of bilayers is also not clear. Here, we have examined the formation of lateral heterogeneity in increasingly complex (up to five-component) multilamellar bilayers. We have used time-resolved fluorescence spectroscopy with domain-selective fluorescent probes (PL-conjugated trans-parinaric acid), and H-2 NMR spectroscopy with site or perdeuterated PLs. We have measured changes in bilayer order using such domain-selective probes both as a function of temperature and composition. Our results from time-resolved fluorescence and H-2 NMR showed that in ternary bilayers, acyl chain order and thermostability in sphingomyelin-rich domains were not affected to any greater extent by the headgroup structure of the monounsaturated PLs (phosphatidylcholine, phosphatidylethanolamine, or phosphatidylserine) in the bilayer. In the complex five-component bilayers, we could not detect major differences between the different monounsaturated PLs regarding cholesterol-induced ordering. However, cholesterol clearly influenced deuterated N-palmitoyl sphingomyelin differently than the other deuterated PLs, suggesting that cholesterol favored N-palmitoyl sphingomyelin over the other PLs. Taken together, both the fluorescence spectroscopy and H-2 NMR data suggest that the complex five-component membranes displayed lateral heterogeneity, at least in the lower temperature regimen examined.