Structure of the myosin projections on native thick filaments from vertebrate skeletal muscle.
Structure of the myosin projections on native thick filaments from vertebrate skeletal muscle.
复制标题
脊椎动物骨骼肌天然粗丝上肌球蛋白投射的结构。
DOI：
10.1016/0022-2836(84)90295-x
复制
发表时间：
1984
影响因子：
5.6
通讯作者：
J. Trinick
中科院分区：
文献类型：
--
作者：
P. Knight;J. Trinick
兔腰肌肌丝，从非甘油化的肌肉松弛缓冲液中分离，已被施加到亲水性碳膜和醋酸双氧铀染色。电子显微照片是在低剂量条件下获得的，以尽量减少标本的损伤。除了裸露区域外，肌丝骨架周围是清晰可辨的肌球蛋白头的边缘。通常，可以看到单个肌球蛋白分子的两个头部，有时可以看到尾部的一部分将头部连接到主链。大约可以计数到预期头数的一半，它们沿丝沿着均匀分布。大部分的头部都是弯曲的。从另一个角度看，其余部分可能是弯曲的头部。顺时针方向弯曲的头部是反时针方向弯曲的头部的三倍，这表明头部的一侧优先与碳膜结合。肌球蛋白分子的两个头部呈现出顺时针、逆时针和直头的所有可能组合，对它们的相对频率的分析表明，头部自由且独立地旋转。头部也采用了广泛的角度连接到尾巴。头部的长度覆盖14至26 nm的范围，峰值在19 nm处。平均最大宽度为6.5 nm。这两个测量值与阴影分子的值非常一致。由于我们的数据是从头部吸附到膜在放松条件下和阴影的分子是免费的核苷酸，总的形状变化是不可能产生的核苷酸binding.Length之间的头部和骨干的连接被发现在10 nm和52 nm之间变化，在约25 nm处的宽峰。因此，在孤立分子的尾部检测到的铰链点通常不是横桥从细丝表面摆动出来的点。连接件与灯丝轴线所成的角度在20 °和80 °之间。最大值约为45 °。这些长度和角度与我们观察到的30 nm的灯丝表面的横桥的平均极限一致。这足以使肌原纤维晶格中的头伸出最近的细丝之外，并应允许相当大的灵活性立体特异性结合到活动肌肉中的肌动蛋白。
Rabbit psoas muscle filaments, isolated in relaxing buffer from non-glycerinated muscle, have been applied to hydrophilic carbon films and stained with uranyl acetate. Electron micrographs were obtained under low-dose conditions to minimize specimen damage.Surrounding the filament backbone, except in the bare zone, is a fringe of clearly identifiable myosin heads. Frequently, both heads of individual myosin molecules are seen, and sometimes a section of the tail can be seen connecting the heads to the backbone. About half the expected number of heads can be counted, and they are uniformly distributed along the filament. The majority of heads appear curved. The remainder could be curved heads viewed from another aspect. Three times as many heads curve in a clockwise sense than in an anticlockwise sense, suggesting a preferential binding of one side of the head to the carbon film. The two heads of myosin molecules exhibit all the possible combinations of clockwise, anticlockwise and straight heads, and analysis of their relative frequencies suggests that the heads rotate freely and independently. The heads also adopt a wide range of angles of attachment to the tail. The lengths of heads cover a range of 14 to 26 nm, with a peak at 19 nm. The average maximum width is 6.5 nm. Both measurements are in excellent agreement with values for shadowed molecules. Since our data are from heads adsorbed to the film in relaxing conditions and the shadowed molecules were free of nucleotide, gross shape changes are not likely to be produced by nucleotide binding.The length of the link between the heads and the backbone was found to vary between 10 nm and 52 nm, with a broad peak at about 25 nm. Thus, the hinge point detected in the tail of isolated molecules was not usually the point from which the crossbridges swung out from the filament surface. The angle made by the link to the filament axis was between 20 ° and 80 °. with a broad maximum around 45 °. These lengths and angles concur with our observation of an average limit of the crossbridges from the filament surface of 30 nm. This is sufficient to enable heads in the myofibril lattice to reach out beyond the nearest thin filament and should allow considerable flexibility for stereospecific binding to actin in active muscle.
来自低角 X 射线散射的肌球蛋白亚片段 1 的结构。
影响因子：
2.9
作者：
Mendelson,R;Kretzschmar,KM
通讯作者：
Kretzschmar,KM
通过平衡离心获得肌球蛋白亚片段的均质性。
影响因子：
2.9
作者：
Margossian,SS;Stafford3rd,WF;Lowey,S
通讯作者：
Lowey,S
用 Ca2 调节肌球蛋白装饰的细丝的三维重建。
影响因子：
5.6
作者：
Vibert,P;Craig,R
通讯作者：
Craig,R