Structure and function of Heads A and B of Myosin

肌球蛋白 A 头和 B 头的结构和功能

基本信息

批准号：
05454629
负责人：
INOUE Akio
金额：
$ 4.48万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1995
项目状态：
已结题

项目摘要

We prepared antibodies specific to heads A and B of myosin using the difference in the amino-acid sequences of two heads of myosin. We studied whether one myosin molecula has A-B heterodimer structure. It has shown that there exists two defferent heads, A and B.We fixed antibodies thus obtained to protein-A which binds to insoluble materials, and examined whether myosin or S-1 (myosin head) can bind with these antibodies. We found that almost all the myosin added was absorbed by either anti-A or anti-B antibody. Therefore, we concluded that most of the myosin molecule has A-B heterodimer structure. The difference in the chemical structure between heads A and B of the myosin molecule has not yet been elucidated, except the amino-acid sequence around 86th reactive lysine residue. Then, we studied the tryptic digestion of s-1 using antibodies specific to two heads. When S-1 was digested by trypsin myosin heavy chain (100 kDa) was digested into three fragments with molecular masses of 25,50, and 21 kDa. Only 25 kDa peptide which contain the reactive lysine residue. was stained by the antibodies. The 25 kDa peptide was formed via 27 kDa peptide, which is the complex of 25 KDa peptidew and 2 kDa junction peptide. The 27 kDa peptide was stained only by anti-B antibodies. This result suggested that the structure around 25 k-50 k junction differs between heads A and B.Since the ATPase active site was located between the domains of 25 kDa and 50 kDa, the structure of ATPase active site may differs between heads A and B.

我们利用肌球蛋白两个头的氨基酸序列的差异制备了肌球蛋白头A和B的特异性抗体。我们研究了一种肌球蛋白分子是否具有A-B异二聚体结构。表明存在两个不同的头，A和B。我们将由此获得的抗体固定到与不溶性物质结合的蛋白-A上，并检查肌球蛋白或S-1(肌球蛋白头)是否可以与这些抗体结合。我们发现几乎所有添加的肌球蛋白都被抗 A 或抗 B 抗体吸收。因此，我们得出结论，大部分肌球蛋白分子具有A-B异二聚体结构。除了第 86 个活性赖氨酸残基周围的氨基酸序列外，肌球蛋白分子 A 头和 B 头之间化学结构的差异尚未阐明。然后，我们使用两个头特异性的抗体研究了 s-1 的胰蛋白酶消化。当S-1被胰蛋白酶消化时，肌球蛋白重链(100 kDa)被消化成三个片段，分子量分别为25,50和21 kDa。仅 25 kDa 的肽含有反应性赖氨酸残基。被抗体染色。 25 kDa 肽是通过 27 kDa 肽形成的，它是 25 KDa 肽w 和 2 kDa 连接肽的复合物。 27 kDa 肽仅被抗 B 抗体染色。该结果表明头 A 和 B 之间 25 k-50 k 连接处周围的结构不同。由于 ATPase 活性位点位于 25 kDa 和 50 kDa 的结构域之间，头 A 和 B 之间 ATPase 活性位点的结构可能不同。