The role of amino-terminal disulfide bonds in the structure and assembly of human fibrinogen.
The role of amino-terminal disulfide bonds in the structure and assembly of human fibrinogen.
复制标题
DOI：
10.1006/bbrc.1993.1074
复制
发表时间：
1993-01
影响因子：
3.1
通讯作者：
S. Huang;Z. Cao;E. Davie
中科院分区：
文献类型：
--
作者：
S. Huang;Z. Cao;E. Davie
人纤维蛋白原含有两个半分子，每个半分子由通过二硫键连接的α、β和γ链组成。两个半分子（α、β、γ）通过位于每条链氨基末端的额外二硫键在天然蛋白中保持在一起。进行定点诱变，其中氨基末端Cys残基（α-Cys 28和36、β-Cys 65和γ-Cys 8和9）转化为Ser，以研究氨基末端二硫键在纤维蛋白原的结构和组装中的作用。采用这些突变的各种组合对转染的幼仓鼠肾（BHK）细胞中合成的纤维蛋白原进行分析，揭示了α-Cys 36和β-Cys 65在两个α β γ半分子之间而不是在同一半分子内形成二硫键;此外，这两个二硫键足以将两个α β γ半分子保持在一起作为完整的纤维蛋白原。由γ-Cys 8和9形成的二硫键也足以将两个纤维蛋白原α β γ半分子保持在一起，而在不存在连接α和β链以及两个γ链的二硫键的情况下，两个α-Cys 28残基之间的二硫键未能形成。
Human fibrinogen contains two half-molecules, each composed of an alpha, beta, and gamma chain linked by disulfide bonds. The two half-molecules (alpha beta gamma) are held together in the native protein by additional disulfide bonds located in the amino terminus of each chain. Site-directed mutagenesis, in which the amino-terminal Cys residues (alpha-Cys28 and 36, beta-Cys65, and gamma-Cys8 and 9) were converted to Ser, was carried out in order to study the role of the amino-terminal disulfide bonds in the structure and assembly of fibrinogen. An analysis of the fibrinogen synthesized in transfected baby hamster kidney (BHK) cells employing various combinations of these mutations revealed that alpha-Cys36 and beta-Cys65 form disulfide bonds between two alpha beta gamma half-molecules, rather than within the same half-molecule; furthermore, these two disulfide bonds are sufficient to hold the two alpha beta gamma half-molecules together as intact fibrinogen. Disulfide bonds formed by gamma-Cys8 and 9 were also sufficient to hold the two fibrinogen alpha beta gamma half-molecules together, while the disulfide bond between the two alpha-Cys28 residues failed to form in the absence of the disulfide bonds linking the alpha and beta chains and the two gamma chains.