Miller C, Racker E
J Membr Biol. 1976 May;26(4):319-33. doi: 10.1007/BF01868880.
Reconstituted cytochrome oxidase liposomes were fused with liposomes reconstituted with mitochondrial hydrophobic protein, which acts as a membrane-bound uncoupler of cytochrome oxidase. Fusion was assayed by the loss of respiratory control of cytochrome oxidase as measured by the increased rate of ascorbate oxidation induced by hydrophobic protein when both proteins shared the same vesicles. Fusion was dependent on the presence of phosphatidylserine in the liposomes Ca++ in the aqueous medium. Phosphatidylcholine-phosphatidylserine liposomes required higher concentrations of phosphatidylserine and Ca++ than did phosphatidylethanolamine-phosphatidylserine liposomes. Cytochrome oxidase vesicles containing high concentrations of phosphatidylserine showed little or no respiratory control, while those with lower concentrations showed high respiratory control; respiratory control could be induced by fusing cytochrome oxidase vesicles containing high phosphatidylserine with protein-free liposomes containing low phosphatidylserine concentration. If cytochrome oxidase vesicles and hydrophobic protein vesicles were prefused separately for 15 min, they lost the ability to fuse upon being subsequently mixed together. The reconstituted vesicles had diameters of about 200 A; fusion yielded vesicles with diameters in excess of 1000 A.
重组细胞色素氧化酶脂质体与用线粒体疏水蛋白重组的脂质体融合，该线粒体疏水蛋白作为细胞色素氧化酶的膜结合解偶联剂。当两种蛋白质共处于同一囊泡中时，通过疏水蛋白诱导的抗坏血酸氧化速率增加来测量细胞色素氧化酶呼吸控制的丧失，以此检测融合情况。融合依赖于脂质体中磷脂酰丝氨酸的存在以及水相介质中的Ca++。与磷脂酰乙醇胺 - 磷脂酰丝氨酸脂质体相比，磷脂酰胆碱 - 磷脂酰丝氨酸脂质体需要更高浓度的磷脂酰丝氨酸和Ca++。含有高浓度磷脂酰丝氨酸的细胞色素氧化酶囊泡几乎没有或没有呼吸控制，而含有较低浓度磷脂酰丝氨酸的囊泡则表现出高呼吸控制；通过将含有高磷脂酰丝氨酸的细胞色素氧化酶囊泡与含有低磷脂酰丝氨酸浓度的无蛋白脂质体融合，可以诱导呼吸控制。如果细胞色素氧化酶囊泡和疏水蛋白囊泡分别预先融合15分钟，那么它们随后混合在一起时就会失去融合能力。重组囊泡的直径约为200埃；融合产生直径超过1000埃的囊泡。
