Yun C H, Kim H
Department of Biological Science and Engineering, Korea Advanced Institute of Science and Technology, Seoul.
J Biochem. 1989 Mar;105(3):406-11. doi: 10.1093/oxfordjournals.jbchem.a122677.
The interactions of ovalbumin (OA) with large unilamellar vesicles (LUV) of phosphatidylserine (PS) and PS/phosphatidylethanolamine (PE) were studied. It was observed that OA induces aggregation, destabilization, and fusion of these LUV composed of acidic phospholipids at low pH levels. The fusion of LUV by OA was monitored by measuring the intermixing of internal aqueous contents of vesicles, by resonance energy transfer assay which follows the mixing of the membrane components, and by thin-sectioning electron microscopy. The pH profile of fusion was found to be similar to the pH-dependent binding of OA to the same phospholipid vesicles. Proteolytic digestion and hydrophobic labeling with dansyl chloride and photoreactive phosphatidylcholine (PC) of the OA-vesicle complex showed that a segment of OA with a molecular weight of approximately 2,500 penetrates the bilayer. The amino acid composition of this segment indicated that it is the 291-322 fragment and not the putative signal sequence.
研究了卵清蛋白（OA）与磷脂酰丝氨酸（PS）和PS/磷脂酰乙醇胺（PE）的大单层囊泡（LUV）之间的相互作用。观察到在低pH值下，OA会诱导由酸性磷脂组成的这些LUV发生聚集、不稳定和融合。通过测量囊泡内部水相内容物的混合情况、通过跟踪膜成分混合的共振能量转移测定法以及通过超薄切片电子显微镜来监测OA诱导的LUV融合。发现融合的pH曲线与OA与相同磷脂囊泡的pH依赖性结合相似。对OA-囊泡复合物进行蛋白水解消化以及用丹磺酰氯和光反应性磷脂酰胆碱（PC）进行疏水标记表明，分子量约为2500的OA片段可穿透双层膜。该片段的氨基酸组成表明它是291-322片段，而不是假定的信号序列。
