Hui S W, Nir S, Stewart T P, Boni L T, Huang S K
Biophysics Department, Roswell Park Memorial Institute, Buffalo, NY 14263.
Biochim Biophys Acta. 1988 Jun 22;941(2):130-40. doi: 10.1016/0005-2736(88)90173-3.
Large unilamellar vesicles (REV) containing phosphatidylserine and phosphatidylethanolamine at a ratio of 1:3 were induced to fuse by adding calcium (4 mM). The kinetics of fusion was monitored by fluorometry using terbium or dipicolinic acid-containing vesicles. The morphology and the states of vesicle aggregation and fusion were examined at approx. 2, 30, 60, 150 and 900 s after calcium addition, by rapid quenching and freeze-fracture electron microscopy. The size and the state of aggregation of vesicles are quantitated from 4000 randomly selected vesicles. The aggregation and fusion kinetics as assayed by fluorescence volume mixing is very well simulated and predicted by the mass action model. The model essentially predicts the time course of the distribution of the aggregates and the increase in size of fused particles as measured by electron microscopy, although in some cases the predicted fusion rate exceeds that by morphometric measurement. No morphological features can be defined as fusion intermediates, although bead-like and rim-like materials may be attributed to the remnants of broken diaphragms between fusion partners.
通过添加钙（4 mM）诱导含有磷脂酰丝氨酸和磷脂酰乙醇胺且比例为1:3的大单层囊泡（REV）融合。使用含铽或含二吡啶甲酸的囊泡通过荧光测定法监测融合动力学。在添加钙后约2、30、60、150和900秒，通过快速淬灭和冷冻断裂电子显微镜检查囊泡聚集和融合的形态及状态。从4000个随机选择的囊泡中定量囊泡的大小和聚集状态。通过荧光体积混合测定的聚集和融合动力学由质量作用模型很好地模拟和预测。该模型基本上预测了聚集体分布的时间进程以及通过电子显微镜测量的融合颗粒大小的增加，尽管在某些情况下预测的融合速率超过了形态测量的速率。虽然珠状和边缘状物质可能归因于融合伙伴之间破裂隔膜的残余物，但没有形态特征可被定义为融合中间体。
