BINDING OF PEPTIDES WITH BASIC RESIDUES TO MEMBRANES CONTAINING ACIDIC PHOSPHOLIPIDS
BINDING OF PEPTIDES WITH BASIC RESIDUES TO MEMBRANES CONTAINING ACIDIC PHOSPHOLIPIDS
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DOI：
10.1016/s0006-3495(91)82037-9
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发表时间：
1991-07-01
影响因子：
3.4
通讯作者：
MCLAUGHLIN, S
中科院分区：
文献类型：
--
作者：
KIM, JY;MOSIOR, M;MCLAUGHLIN, S
在许多细胞质蛋白上存在碱性氨基酸簇，其瞬时结合到膜上（例如，蛋白激酶C）以及许多内在膜蛋白的胞质结构域（例如，血型糖蛋白）。为了探索这些碱性残基与单价酸性脂质静电结合的可能性，我们研究了肽Lys（n）和Arg（n）（n = 1 - 5）与含有磷脂酰丝氨酸（PS）或磷脂酰甘油（PG）的双层膜的结合。我们使用多层囊泡，荧光和平衡结合测量使用大单层囊泡，和表面电位测量使用单层的电泳迁移率测量。没有肽结合到从两性离子脂质磷脂酰胆碱（PC）形成的囊泡，但所有结合到从PC/PS或PC/PG混合物形成的囊泡。没有一个肽表现出PS和PG之间的特异性。每个赖氨酸残基，被添加到Lys2减少了一个数量级的逆转囊泡上的电荷所需的肽的浓度，相当于它增加了一个数量级的PS囊泡的肽的结合亲和力。最简单的解释是，每个添加的赖氨酸独立地结合到一个单独的PS，微观缔合常数为10 M-1或自由能约为1.4 kcal/mol。用Arg（n）肽获得类似但不相同的结果。一个简单的理论模型结合了Gouy-Chapman理论（其解释了肽在邻近膜的水性扩散双层中的非特异性静电积累）与质量作用方程（其解释了肽与> 1 PS的结合）。该模型可以定性地解释结合对肽中碱性残基数目和膜中PS摩尔分数的依赖性。
There are clusters of basic amino acids on many cytoplasmic proteins that bind transiently to membranes (e.g., protein kinase C) as well as on the cytoplasmic domain of many intrinsic membrane proteins (e.g., glycophorin). To explore the possibility that these basic residues bind electrostatically to monovalent acidic lipids, we studied the binding of the peptides Lys(n) and Arg(n) (n = 1-5) to bilayer membranes containing phosphatidylserine (PS) or phosphatidylglycerol (PG). We made electrophoretic mobility measurements using multilamellar vesicles, fluorescence and equilibrium binding measurements using large unilamellar vesicles, and surface potential measurements using monolayers. None of the peptides bound to vesicles formed from the zwitterionic lipid phosphatidylcholine (PC) but all bound to vesicles formed from PC/PS or PC/PG mixtures. None of the peptides exhibited specificity between PS and PG. Each lysine residue that was added to Lys2 decreased by one order of magnitude the concentration of peptide required to reverse the charge on the vesicle; equivalently it increased by one order of magnitude the binding affinity of the peptides for the PS vesicles. The simplest explanation is that each added lysine binds independently to a separate PS with a microscopic association constant of 10 M-1 or a free energy of approximately 1.4 kcal/mol. Similar, but not identical, results were obtained with the Arg(n) peptides. A simple theoretical model combines the Gouy-Chapman theory (which accounts for the nonspecific electrostatic accumulation of the peptides in the aqueous diffuse double layer adjacent to the membrane) with mass action equations (which account for the binding of the peptides to > 1 PS). This model can account qualitatively for the dependence of binding on both the number of basic residues in the peptides and the mole fraction of PS in the membrane.