Wetterau J R, Jonas A
J Biol Chem. 1982 Sep 25;257(18):10961-6.
Large unilamellar vesicles of dipalmitoylphosphatidylcholine (DPPC) were prepared by sonication and were fractionated by gel filtration on Sepharose Cl-2B in the size range from 180- to 380-A Stokes radii. Negatively stained electron micrographs of these preparations indicated the presence of unilamellar, spheroidal structures of the expected size. Fluorescence polarization of diphenylhexatriene, dissolved in the vesicles, revealed progressively broader phase transitions, shifted to lower temperatures for vesicles of decreasing sizes. The fractionated unilamellar vesicles and multilamellar vesicles of DPPC were reacted with human apolipoprotein A-I at 41 degrees C for periods from 1 to 120 h. The reaction mixtures were then passed through a Bio-Gel A-5m column to separate unreacted lipid vesicles and protein from micellar complexes of DPPC with apolipoprotein A-I. Smaller vesicles were much more reactive than larger vesicles or multilamellar vesicles with the apolipoprotein. This difference in reactivity was explained by the increasing bilayer curvature of smaller vesicles which changes the packing of DPPC molecules in the bilayer and facilitates its penetration by the apolipoprotein.
通过超声处理制备了二棕榈酰磷脂酰胆碱（DPPC）的大单层囊泡，并在Sepharose Cl - 2B上进行凝胶过滤分级，其斯托克斯半径范围为180至380埃。这些制剂的负染色电子显微镜照片显示存在预期大小的单层球形结构。溶解在囊泡中的二苯基己三烯的荧光偏振显示相变逐渐变宽，对于尺寸减小的囊泡，相变温度向低温移动。将分级的DPPC单层囊泡和多层囊泡与人载脂蛋白A - I在41℃下反应1至120小时。然后将反应混合物通过Bio - Gel A - 5m柱，以从未反应的脂质囊泡和蛋白质中分离出DPPC与载脂蛋白A - I的胶束复合物。较小的囊泡比大囊泡或多层囊泡与载脂蛋白的反应性高得多。这种反应性差异的解释是，较小囊泡的双层曲率增加，这改变了双层中DPPC分子的堆积，并促进了载脂蛋白对其的渗透。
