Charkviani G G, Kulikov A V, Eristavi T M, Dzhaparidze Z O
Biofizika. 1981 Sep-Oct;26(5):920-3.
Interlocation of sulfhydryl groups S1 and corresponding divalent ions binding sites in myosin has been studied. S1-SH groups were labelled with iodacetamide spin labels and their saturation curves were measured in the presence of Ca2+ and Mn2+. The spin-lattice relaxation rates 1/T1 of labels were calculated from saturation curves and according to their changes caused by replacing Ca2+ by Mn2+ the distance between sulfhydryl groups S1 and divalent ions binding sites were estimated to be 45 +/- 2.5 A. The addition of ATP to this system has not changed the character of interaction. An analysis of saturation curves measured within temperature range 20-100 K suggests that two myosin subfragments J differ in conformation at least in the range where S1-SH groups are located.
已对肌球蛋白中巯基 S1 与相应二价离子结合位点的相互位置进行了研究。用碘乙酰胺自旋标记物标记 S1-SH 基团，并在 Ca2+ 和 Mn2+ 存在的情况下测量其饱和曲线。根据饱和曲线计算标记物的自旋晶格弛豫率 1/T1，并根据用 Mn2+ 替代 Ca2+ 引起的变化，估计巯基 S1 与二价离子结合位点之间的距离为 45±2.5 Å。向该系统中添加 ATP 并未改变相互作用的性质。对在 20-100 K 温度范围内测量的饱和曲线的分析表明，两个肌球蛋白亚片段 J 至少在 S1-SH 基团所在的范围内构象不同。
