Electron microscopy of cardiac myosin: its shape and properties as determined by the regulatory light chain.
Electron microscopy of cardiac myosin: its shape and properties as determined by the regulatory light chain.
复制标题
心肌肌球蛋白的电子显微镜：其形状和特性由调节轻链决定。
DOI：
10.1007/bf01578433
复制
发表时间：
1987
影响因子：
2.7
通讯作者：
Slayter,HS
中科院分区：
文献类型：
--
作者：
Margossian,SS;Slayter,HS
通过电子显微镜研究了狗心肌肌球蛋白的结构特性以及调节轻链（LC2）对肌球蛋白头形状的影响。使用来自肌病仓鼠的中性蛋白酶可逆地去除 LC2 (Margossian, J. Biol. Chem.260(1985) 13747–54)。肌球蛋白头部长度分布集中在17 nm左右，平均长度为18.9 nm。统计分析表明，去除 LC2 后，肌球蛋白头变得更加球形。 LC2 解离后，无论是通过沉降速度还是通过在非变性条件下运行的凝胶，均未检测到肌球蛋白的广泛聚集。无论 LC2 是否存在，头之间的中心距保持恒定在约 21 nm。球状区域的长度分布显示在 7.5 和 9.5 nm 处有两个峰，表明该区域具有延长和较短的配置。 LC2 去除后头/尾连接处质量的减少表明它是调节轻链的结合位点。有时会注意到距头/尾关节 57 nm 处的弯曲，对应于肌球蛋白铰链区域。在高分辨率显微照片中，单个颗粒显示出沿着头部轮廓的内陷，可能描绘出头部内结构域的边界。在存在和不存在 LC2 的情况下，研究了用亚片段 1 (S1) 或重片段肌球蛋白 (HMM) 修饰的肌动蛋白中箭头的构象。
Structural properties of dog cardiac myosin and the influence of the regulatory light chain (LC2) on the shape of myosin heads were investigated by electron microscopy. LC2 was reversibly removed using a neutral protease from myopathic hamsters (Margossian,J. Biol. Chem.260(1985) 13747–54). The distribution of myosin head length centred around 17 nm with the mean length being 18.9 nm. Statistical analysis suggested that myosin heads became more globular upon removal of LC2. No extensive aggregation of myosin could be detected after LC2 was dissociated, either by sedimentation velocity or by gels run under non-denaturing conditions. The centre-to-centre distance between heads remained constant at about 21 nm, regardless of the presence or absence of LC2. The distribution of length of the globular region reveals two peaks at 7.5 and 9.5 nm, suggesting an extended and a shorter configuration of this region. The decrease in mass at the head/tail junction upon LC2 removal suggests that it is the binding site for the regulatory light chains. A bend at 57 nm from the head/tail joint was sometimes noticed, corresponding to the myosin hinge region. In high resolution micrographs individual particles revealed invaginations along the contours of the head, possibly delineating the boundaries of structural domains within the head. The conformation of arrowheads in actin decorated with either subfragment 1 (S1) or heavy meromyosin (HMM) was investigated in the presence and absence of LC2.