Terminal membrane C5b-9 complex of human complement: transition from an amphiphilic to a hydrophilic state through binding of the S protein from serum.
Terminal membrane C5b-9 complex of human complement: transition from an amphiphilic to a hydrophilic state through binding of the S protein from serum.
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人类补体的末端膜C5B-9复合物：通过血清中S蛋白的结合从两亲性到亲水状态的过渡。
DOI：
10.1083/jcb.94.3.755
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发表时间：
1982-09
期刊：
影响因子：
--
通讯作者：
Tranum-Jensen J
中科院分区：
文献类型：
--
作者：
Bhakdi S;Tranum-Jensen J
补体的膜损伤C5b-9(m)复合物是一种圆柱形结构的两亲分子，在补体攻击时在靶膜上产生。分离的C5b-9(m)复合物具有结合存在于人血浆中的一种称为“S”蛋白的能力。这种蛋白质的结合显然屏蔽了C5b-9(m)的极性表面，因为由此产生的“SC5b-9(m)”复合物是亲水的，不再聚集在无洗涤剂的溶液中。分散的SC5b-9(m)配合物在蔗糖密度梯度上的表观沉降系数为29S，相当于分子量约为140万。SDS - PAGE分析表明，每个C5b-9(m)复合物结合3-4个s蛋白分子。这些数据与C5b-9(m)配合物的单体性质和分子量为1- 110万相一致。SC5b- 9(m)的超微结构分析显示，C5b-9(m)保留了空心圆柱形结构。额外的物质，可能代表s蛋白本身，可以可视化地附着在大分子最初的膜嵌入部分。因此，通过血清蛋白的结合，可以直接探测和可视化分子上极性表面的地形。
The membrane-damaging C5b-9(m) complex of complement is a cylindrically structured, amphiphilic molecule that is generated on a target membrane during complement attack. Isolated C5b-9(m) complexes are shown here to possess the capacity of binding a protein, termed "S"-protein, that is present in human plasma. Binding of this protein apparently shields the apolar surfaces of C5b-9(m), since the resulting "SC5b-9(m)" complex is hydrophilic and no longer aggregates in detergentfree solution. Dispersed SC5b-9(m) complexes exhibit an apparent sedimentation coefficient of 29S in sucrose density gradients, corresponding to a molecular weight of approximately 1.4 million. SDS PAGE analyses indicate binding of 3-4 molecules of S-protein per C5b-9(m) complex. These data are consistent with a monomer nature and molecular weight of 1-1.1 million of the C5b-9(m) complex. Ultrastructural analysis of SC5b- 9(m) shows preservation of the hollow cylindrical C5b-9(m) structure. Additional material, probably representing the S-protein itself, can be visualized attached to the originally membrane-embedded portion of the macromolecule. The topography of apolar surfaces on a molecule thus appears directly probed and visualized through the binding of a serum protein.