FLUORESCENCE STUDIES OF MUSCLE REGULATORY PROTEINS

在横纹肌中，细丝由聚合的 肌动蛋白，它装饰着调节蛋白肌钙蛋白C (TNC)和原肌球蛋白。TnC是一种单链多肽蛋白，具有 分子量接近18,000。我们研究了跨国公司的调节域 使用基因产生的突变体从鸡的骨骼肌中 在第22、52和90位含有单一色氨酸。《量子》 在镁(2-mg)存在下，色氨酸-22的产率分别为0.33和0.25 状态)和钙(4-Ca状态)。的各向异性衰减 所有三种色氨酸都显示出两个旋转关联时间。这个 观察到Trp-22和Trp-90的长相关时间表明 不对称的水动力形状。在中心获得的数据显示， 当结合激活剂钙离子时，TNC变得更不对称。

In striated muscle, the thin filament consists of polymerized actin, which is decorated with the regulatory proteins troponin C (TnC) and tropomyosin. TnC is a single-polypeptide protein with a molecular weight near 18,000. We study the regulatory domain of TnC from chiken skeletal muscle using genetically generated mutants which contain a single tryptophan at positions 22, 52, and 90. The quantum yields of Trp-22 are 0.33 and 0.25 in the presence of Mg2+ (2-Mg state) and Ca2+ (4-Ca state), respectively. The anisotropy decay of of all three tryptophans show two rotational correlation times. The long correlation time observed for Trp-22 and Trp-90 suggest an asymmetric hydrodynamic shape. Data obtained at the CFS showed that TnC becomes more asymmetric upon binding the activator Ca2+.