Morris E P, Lehrer S S
Biochemistry. 1984 May 8;23(10):2214-20. doi: 10.1021/bi00305a018.
We have studied the interaction between troponin and tropomyosin by means of a fluorescent probe, N-(1- anilinonaphth -4-yl)maleimide (ANM), attached to the cysteine-190 residues of tropomyosin. The binding of troponin and troponin T to ANM-tropomyosin produces substantial increases in the label fluorescence. Analysis of the binding profiles indicates that both troponin and troponin T bind with a 1:1 stoichiometry. We have obtained and characterized several chymotryptic fragments of troponin T by digestion of isolated troponin T or whole troponin. An N-terminal fragment from troponin T which is slightly less than two-thirds of the whole molecule binds to tropomyosin without affecting the label fluorescence; a C-terminal fragment composed of the rest of the troponin T molecule causes a substantial enhancement of the label fluorescence. We have also isolated a complex containing the C-terminal troponin T fragment together with troponin I and troponin C from whole troponin, which also enhanced the label fluorescence. These observations indicate an elongated region of attachment between troponin T and tropomyosin.
我们通过连接到原肌球蛋白半胱氨酸 - 190残基上的荧光探针N -（1 - 苯胺基萘 - 4 - 基）马来酰亚胺（ANM），研究了肌钙蛋白与原肌球蛋白之间的相互作用。肌钙蛋白和肌钙蛋白T与ANM - 原肌球蛋白的结合会使标记荧光显著增强。结合曲线分析表明，肌钙蛋白和肌钙蛋白T均以1:1的化学计量比结合。我们通过消化分离的肌钙蛋白T或完整肌钙蛋白，获得并表征了肌钙蛋白T的几个胰凝乳蛋白酶片段。肌钙蛋白T的一个N端片段略小于整个分子的三分之二，它与原肌球蛋白结合而不影响标记荧光；由肌钙蛋白T分子其余部分组成的C端片段会使标记荧光显著增强。我们还从完整肌钙蛋白中分离出了一个包含肌钙蛋白T C端片段以及肌钙蛋白I和肌钙蛋白C的复合物，它也增强了标记荧光。这些观察结果表明肌钙蛋白T与原肌球蛋白之间存在一个伸长的附着区域。
