Binding of heavy meromyosin and subfragment-1 to thin filaments in myofibrils and single muscle fibers.
Binding of heavy meromyosin and subfragment-1 to thin filaments in myofibrils and single muscle fibers.
复制标题
重 meromyosin 和 subfragment-1 与肌原纤维和单肌纤维中的细丝结合。
DOI：
10.1021/bi00562a033
复制
发表时间：
1980
期刊：
影响因子：
2.9
通讯作者：
O. Assulin
中科院分区：
文献类型：
--
作者：
J. Borejdo;O. Assulin
荧光标记的重酶解肌球蛋白（HMM）和重酶解肌球蛋白亚片段-1（S-1）的肌原纤维和兔腰肌肌纤维的细丝的结合进行了测量的条件下的僵硬和收缩。碎片迅速扩散到肌原纤维空间，并特异性地结合到细丝上。片段结合最强，并在一个统一的方式，从本地肌球蛋白的竞争被废除，通过删除它与Hasselbach-Schneider解决方案的肌原纤维。在这些条件下，HMM和S-1的严谨性Ka值分别为1.5 x 10（6）M-1和4.8 x 10（4）M-1。通过独立估计肌动蛋白位点的浓度来测量结合的化学计量。发现S-1能够饱和肌原纤维或纤维中所有可用的肌动蛋白位点，但HMM只能占据50%的位点。
The binding of fluorescently labeled heavy meromyosin (HMM) and heavy meromyosin subfragment-1 (S-1) to thin filaments of myofibrils and of rabbit psoas muscle fibers was measured under conditions of rigor and contraction. The fragments diffused rapidly into the myofibrillar space and bound specifically to the thin filaments. The fragments bound strongest and in a uniform fashion to myofibrils in which the competition from indigenous myosin was abolished by removing it with Hasselbach-Schneider solution. Under these conditions, the rigor Ka values for HMM and S-1 were 1.5 x 10(6) M-1 and 4.8 x 10(4) M-1, respectively. The stoichiometry of binding was measured by independently estimating the concentration of actin sites. S-1 was found to be capable of saturating all available actin sites in a myofibril or a fiber, but HMM could only occupy 50% of the sites.