Ligand-induced myosin subfragment 1 global conformational change.
Ligand-induced myosin subfragment 1 global conformational change.
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配体诱导的肌球蛋白亚片段 1 整体构象变化。
DOI：
10.1021/bi00469a010
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发表时间：
1990
期刊：
影响因子：
2.9
通讯作者：
Eden,D
中科院分区：
文献类型：
--
作者：
Highsmith,S;Eden,D
(SI)通过使用瞬态电双折射技术进行比较。在3.5 ℃下，在具有匹配电阻抗的低离子强度（μ= 0.020 M）缓冲液中，将SI的成对稀释溶液与结合有Mg 2+、MgADP或MgADP-Vj的SI进行克尔定律范围内的6-7 μ s外部电场。测量了去除电场后的特定克尔常数和旋转布朗运动速率。Mg ~（2+）和MgADP对这两种可观察到的效应都没有可测量的影响，但当正钒酸盐（V）结合SI-MgADP时，它使旋转相关系数从267±6降低到244±10 ns。MgATP酶活性的平行测定表明，Sl-MgADP-V对MgATP酶活性的抑制率大于95%。这些结果证实了Aguirre等人的结论。[（1989）Biochemistry 28，799]证明，V与SI-MgADP结合增加了其旋转布朗运动的速率，并提供了与SI结构更定量相关的数据。V_r引起的转动相关系数的变化与当V_r结合时SI变得更灵活或更紧凑是一致的。假设SI-MgADP-V…是一个类似物的Sl-MgADP-Pj，在溶液中观察到的SI-配体复合物的结构变化进行了讨论有关可能的结构变化的中间体上的ATP酶水解的动力学途径。本文提出了一种新的肌肉SI力产生模型。
(SI) were compared by using transient electrical birefringence techniques. With pairs of dilute solutions of SI at 3.5 C in low ionic strength (µ= 0.020 M) buffers that had matched electrical impedances, SI with Mg2+, MgADP, or MgADP-Vj bound was subjected to 6-7-µ $ external electrical fields in the Kerr law range. Specific Kerr constants and the rates of rotationalBrownian motion after the electric field was removed were measured. Neither Mg2+ nor MgADP had a measurable effect on either observable, but when orthovanadate (V¡) bound SI-MgADP it decreased the rotational correlation coefficient from 267±6 to 244±10 ns. Parallel measurements of MgATPase activity indicated that Sl-MgADP-V¡ was greater than 95% inhibited. These results confirm the conclusion of Aguirre et al.[(1989) Biochemistry 28, 799] that V¡ binding to SI-MgADP increases its rate of rotational Brownian motion and provide data that are more quantitatively correlated with SI structure. The Vrinduced change in the rotational correlation coefficient is consistent with SI becoming more flexible or more compact when V¡ binds. Assuming that SI-MgADP-V¡ is an analogue for Sl-MgADP-Pj, the structural changes observed for SI-ligand complexes in solution are discussed in relation to possible structural changes of intermediates on the kinetic pathway of ATPase hydrolysis. A new model of force generation by SI inmuscle is hypothesized.