FLUORESCENCE STUDIES OF MUSCLE REGULATORY PROTEINS

在横纹肌中，细丝由聚合的 肌动蛋白，其被调节蛋白肌钙蛋白C修饰 (TnC)和原肌球蛋白。 TnC是一种单多肽蛋白， 分子量接近18000。 我们研究了TnC的调节结构域， 从鸡的骨骼肌中提取蛋白质， 在位置22、52和90处含有单个色氨酸。 量子 在Mg ~（2+）存在下，色氨酸-22的产率分别为0.33和0.25 状态）和Ca 2+（4-Ca状态）。 的各向异性衰减 的所有三个Dahan显示两个旋转相关时间。 的 观察到Trp-22和Trp-90的长相关时间表明， 不对称的流体动力学形状。 中心的数据显示， TnC在结合激活剂Ca 2+后变得更加不对称。

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+.