EFFECTS OF MEMBRANE-COMPOSITION AND LIPID STRUCTURE ON THE PHOTO-POLYMERIZATION OF LIPID DIACETYLENES IN BILAYER-MEMBRANES
EFFECTS OF MEMBRANE-COMPOSITION AND LIPID STRUCTURE ON THE PHOTO-POLYMERIZATION OF LIPID DIACETYLENES IN BILAYER-MEMBRANES
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DOI：
10.1016/0005-2736(82)90451-5
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发表时间：
1982-01-01
期刊：
影响因子：
--
通讯作者：
WHITESIDES, TH
中科院分区：
文献类型：
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作者：
LOPEZ, E;OBRIEN, DF;WHITESIDES, TH
制备了类似于生物和合成脂质的分子，其长烷基链中具有共轭二乙炔部分。这些脂质二乙炔在悬浮于水性缓冲液中时形成双层结构。UV光（254 nm）曝光引发脂双层中的二乙炔的聚合，得到完全共轭的高度着色的产物。该反应是拓扑立构的，其效率取决于单体单元的正确排列。因此，如果烃链处于在低于脂质转变温度的温度下发现的规则晶格中，则脂质二乙炔是可光聚合的;聚合在高于该转变的温度下被抑制。在脂质双层膜中的二乙炔甘油磷脂酰胆碱的光聚合在2组分混合物中观察到与不可聚合的脂质，二油酰磷脂酰胆碱或二硬脂酰磷脂酰胆碱。光化学和热化学特征表明，二炔甘油磷酸胆碱主要存在于混合双层中的独立区域。类似于二烷基二甲基铵盐和磷酸二烷基酯的脂质二乙炔具有对称平面，这表明两条链均渗透到双层中。这些对称合成物质的光聚合比二乙炔甘油磷酸胆碱的光聚合效率高> 103倍。这些差异在脂质分子的预期构象偏好方面是不可解释的。
Molecules analogous to biological and synthetic lipids were prepared with conjugated diacetylene moieties in the long alkyl chain. These lipid diacetylenes from bilayer structures when suspended in aqueous buffers. UV light (254 nm) exposure initiates the polymerization of the diacetylenes in the lipid bilayer to give a fully conjugated, highly colored product. The reaction is topotactic, and its efficiency depends on the correct alignment of the monomeric units. Thus, the lipid diacetylenes are photopolymerizable if the hydrocarbon chains are in a regular lattice found at temperatures below the lipid transition temperature; polymerization is inhibited above this transition. The photopolymerization of a diacetylenic glycerophosphocholine in lipid bilayer membranes was observed in 2 component mixtures with a nonpolymerizable lipid, either dioleoylphosphatidylcholine or distearoylphosphatidylcholine. The photochemical and thermochemical characteristics suggest that the diacetylenic glycerophosphocholine exists largely in separate domains in the mixed bilayers. Lipid diacetylenes analogous to a dialkyldimethylammonium salt and to a dialkyl phosphate have a plane of symmetry, which suggests that both chains penetrate equally into the bilayer. The photopolymerization of these symmetrical synthetic species is > 103-times more efficient than that of the diacetylenic glycerophosphocholine. These differences are intrepretable in terms of the expected conformational preference of the lipid molecules.