The binding of heavy meromyosin to F-actin.
The binding of heavy meromyosin to F-actin.
复制标题
重片段肌球蛋白与 F-肌动蛋白的结合。
DOI：
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发表时间：
1980
影响因子：
4.8
通讯作者：
E. Eisenberg
中科院分区：
文献类型：
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作者：
L. Greene;E. Eisenberg
在Mu=0.22M，22℃条件下，研究了肌球蛋白的可溶性双头片段重肌球蛋白(HMM)与F-肌动蛋白的结合。通过使HMM与亚段1(S-1)竞争F-肌动蛋白上的位点，确定了肌动蛋白-HMM结合常数。在这些实验中，将不同浓度的S-1添加到固定浓度的HMM和F-肌动蛋白中。F-肌动蛋白和结合片段(HMM和S-1)沉淀后，测定游离片段的浓度。使用Hill((1978)Natural 274,825-826)提出的一组理论方程对数据进行分析，这些方程提供了一种简单的方法来分析单头和双头配体的相对结合。利用这些方程，确定了肌动蛋白-HMM结合常数为3×10(9)M-1，而在相同条件下，肌动蛋白-S-1结合常数为5×10(6)M-1(在前文(Greene，L.E.和Eisenberg，E.(1980)J.Biol，Chem)中测定)。255、543-548))。因此，在这种条件下，HMM与肌动蛋白的结合强度是S-1的600倍，表明两个HMM头部都能与肌动蛋白强烈结合。
The binding of heavy meromyosin (HMM), a soluble two-headed fragment of myosin, to F-actin was examined at mu = 0.22 M, 22 degrees C. The actin-HMM association constant was determined by having HMM and subfragment 1 (S-1) compete for sites on F-actin. In these experiments, varying concentrations of S-1 were added to a fixed concentration of HMM and F-actin. F-actin and bound fragments (HMM and S-1) then were sedimented and the concentration of unbound fragments was determined. The data were analyzed using a set of theoretical equations proposed by Hill ((1978) Nature 274, 825-826) that provide a simple way of analyzing the relative binding of one- and two-headed ligands. Using these equations, the actin-HMM association constant was determined to be 3 x 10(9) M-1, while under the same conditions the actin-S-1 association constant is 5 x 10(6) M-1 (determined in preceding paper (Greene, L. E., and Eisenberg, E. (1980) J. Biol, Chem. 255, 543-548)). Therefore, under these conditions, HMM binds 600-fold stronger to actin than does S-1, indicating that both of the HMM heads can bind strongly to actin.