Sen A, Brain A P, Quinn P J, Williams W P
Biochim Biophys Acta. 1982 Apr 7;686(2):215-24. doi: 10.1016/0005-2736(82)90115-8.
The formation of 'lipidic' particles corresponding to inverted lipid micelles in freeze-fracture replicas of aqueous dispersions of mono- and digalactosyldiacylglycerols can be greatly enhanced either by increasing the temperature from which the samples are thermally quenched or by the addition of cryoprotectants such as ethylene glycol. In the case of the heated samples, the lipids tend to form quasi-crystalline structures consisting of sheets of 8-9 nm diameter particles organised on an orthorhombic lattice. The orientation of alternate sheets varies giving rise to a characteristic herring-bone pattern. Ethylene glycol-treated samples, in contrast, form more regular structures consisting of 13-16 nm diameter particles. Lowering the temperature from which the samples are quenched and/or decreasing the concentration of ethylene glycol reduces the frequency of formation of such structures. A number of intermediate states associated with the reincorporation of the lipid molecules of the inverted micelles into the lamella phase are also identified. The factors influencing particle formation are briefly discussed. It is concluded that the destabilisation of lipid-water interactions play a major role in this process.
在单半乳糖基二酰基甘油和双半乳糖基二酰基甘油水分散体的冷冻断裂复制品中，对应于反相脂质微团的“脂质”颗粒的形成可以通过提高样品热猝灭的温度或添加诸如乙二醇之类的冷冻保护剂而大大增强。对于加热的样品，脂质倾向于形成准晶体结构，该结构由排列在正交晶格上的直径为8 - 9纳米的颗粒片组成。交替片层的取向不同，产生特征性的人字形图案。相比之下，经乙二醇处理的样品形成更规则的结构，由直径为13 - 16纳米的颗粒组成。降低样品猝灭的温度和/或降低乙二醇的浓度会降低此类结构形成的频率。还确定了与反相微团的脂质分子重新掺入片层相相关的一些中间状态。简要讨论了影响颗粒形成的因素。得出的结论是，脂质 - 水相互作用的不稳定在这个过程中起主要作用。
