Cryo-atomic force microscopy of smooth muscle myosin.
Cryo-atomic force microscopy of smooth muscle myosin.
复制标题
平滑肌肌球蛋白的冷冻原子力显微镜。
DOI：
10.1016/s0006-3495(97)78777-0
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发表时间：
1997
影响因子：
3.4
通讯作者：
Somlyo,AV
中科院分区：
文献类型：
--
作者：
Zhang,Y;Shao,Z;Somlyo,AP;Somlyo,AV
在80-85 K下，用冷冻原子力显微镜对头部的马达和调节结构域以及延伸（6S）平滑肌肌球蛋白分子尾部的α-螺旋卷曲螺旋的14 nm间距进行成像，并检查调节轻链的硫代磷酸化的影响。在硫代磷酸化比非磷酸化肌球蛋白的尾巴短4 nm。第一个主要弯曲是不变的，在距离头尾连接处（H-T）约51 nm处，与配对线圈评分中的低概率一致。第二个主要的弯曲在非磷酸化的H-T连接处100 nm处，并且比硫代磷酸化分子中的弯曲（在95 nm处）更接近跳跃残基。由硫代磷酸化诱导的两个主要弯曲之间的较短的尾部和距离被解释为来自卷曲螺旋的熔化。发生了先前未报告的额外弯曲，频率较低，距离H-T约24 nm。在硫代磷酸化分子中，两个头部之间的分离范围更大。偶尔的高分辨率图像显示头部底部的螺旋线圈轻微解开。我们认为MLC 20的磷酸化可以影响扩展的6S肌球蛋白的结构。
The motor and regulatory domains of the head and the 14-nm pitch of the alpha-helical coiled-coil of the tail of extended (6S) smooth-muscle myosin molecules were imaged with cryo atomic force microscopy at 80–85 K, and the effects of thiophosphorylation of the regulatory light chain were examined. The tail was 4 nm shorter in thiophosphorylated than in nonphosphorylated myosin. The first major bend was invariant, at approximately 51 nm from the head-tail junction (H-T), coincident with low probability in the paircoil score. The second major bend was 100 nm from the H-T junction in nonphosphorylated and closer to a skip residue than the bend (at 95 nm) in thiophosphorylated molecules. The shorter tail and distance between the two major bends induced by thiophosphorylation are interpreted to result from melting of the coiled-coil. An additional bend not previously reported occurred, with a lower frequency, approximately 24 nm from the H-T. The range of separation between the two heads was greater in thiophosphorylated molecules. Occasional high-resolution images showed slight unwinding of the coiled-coil of the base of the heads. We suggest that phosphorylation of MLC20 can affect the structure of extended, 6S myosin.