FORMATION OF 2-DIMENSIONAL ARRAYS OF ANNEXIN-V ON PHOSPHATIDYLSERINE-CONTAINING LIPOSOMES
FORMATION OF 2-DIMENSIONAL ARRAYS OF ANNEXIN-V ON PHOSPHATIDYLSERINE-CONTAINING LIPOSOMES
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DOI：
10.1006/jmbi.1994.1129
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发表时间：
1994-02-11
影响因子：
5.6
通讯作者：
BRISSON, A
中科院分区：
文献类型：
--
作者：
PIGAULT, C;FOLLENIUSWUND, A;BRISSON, A
膜联蛋白是一种以钙离子依赖性方式与细胞膜结合的细胞内蛋白质，被认为在不同的膜过程中发挥调节作用。在本研究中，钙依赖性结合的膜联蛋白V的磷脂酰丝氨酸分子纳入脂质体的化学计量的荧光光谱法进行了研究。使用由二油酰磷脂酰丝氨酸（PS）和二油酰磷脂酰胆碱（PC）制成的脂质体测定结合的Ca 2+依赖性，PC/PS摩尔比范围为1至800。冷冻电子显微镜显示这些脂质体大多为单层。[Ca2+]膜联蛋白V半数最大结合所需的1/2浓度范围为57 μM（PC/PS=1）至96 mM（PC/PS=800）。可访问的PS分子的滴定表明，膜联蛋白V分子同样很好地结合到PC/PS比范围从1到400的脂质体。在低PS含量下测定的膜联蛋白V和PS之间的结合的化学计量为每一个PS分子八个膜联蛋白V分子。我们提出了一种新的模型的钙依赖性膜联蛋白V和脂质膜之间的相互作用，膜联蛋白V分子的二维阵列的形成的基础上，稳定的蛋白质-脂质和蛋白质-蛋白质的相互作用。
Annexins are intracellular proteins which bind to membranes in a Ca2+-dependent manner and which have been proposed to play regulatory roles in different membrane processes. In the present study, the stoichiometry of the Ca2+-dependent binding of annexin V to phosphatidylserine molecules incorporated into liposomes was studied by fluorescence spectroscopy. The Ca2+-dependence of the binding was determined using liposomes made of dioleoylphosphatidylserine (PS) and dioleoylphosphatidylcholine (PC), with a PC/PS molar ratio ranging from 1 to 800. These liposomes were shown to be mostly unilamellar by cryo-electron microscopy. [Ca2+]1/2concentrations required for half-maximal binding of annexin V range from 57 μM at PC/PS=1 up to 96 mM at PC/PS=800. Titration of accessible PS molecules showed that annexin V molecules bind equally well to liposomes of PC/PS ratio ranging from 1 to 400. The stoichiometry of the binding between annexin V and PS, determined at low PS content, is eight annexin V molecules per one PS molecule. We propose a novel model of the Ca2+-dependent interaction between annexin V and lipid membranes, based on the formation of two-dimensional arrays of annexin V molecules, stabilized by both protein-lipid and protein-protein interactions.