X-ray diffraction evidence for the existence of 102.0- and 230.0-nm transverse periodicities in striated muscle.
X-ray diffraction evidence for the existence of 102.0- and 230.0-nm transverse periodicities in striated muscle.
复制标题
X射线衍射证据表明，在横纹肌肉中存在102.0- nm的横向周期性。
DOI：
10.1083/jcb.105.3.1311
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发表时间：
1987-09
影响因子：
7.8
通讯作者：
Nave, C
中科院分区：
文献类型：
--
作者：
Bordas, J;Mant, G R;Diakun, G P;Nave, C
同步辐射技术使我们能够以约 2,800 至 38 nm 的分辨率记录青蛙缝匠肌的经向 X 射线衍射图案（即与光学显微镜和低角度衍射相机通常可到达的区域重叠）。这些衍射图案代表了投影在肌节轴上并通过其重复进行采样的肌肉低分辨率结构的变换。改变肌节长度会导致对该变换的不同部分进行采样，从而引起衍射最大值的位置和积分强度的变化。该效应已用于以准连续方式确定肌肉轴上质量投影的变换。结果揭示了结构中长程周期性产生的最大值的存在。变换中零点的确定已用于获取相位信息，根据该相位信息计算电子密度图。 X射线衍射图和由此产生的电子密度图显示存在一系列质量带，这些质量带横向于肌节轴布置并以规则间隔分布。一组这些横向结构与细丝相关，它们的 102.0 nm 重复表明与其已知的分子成分有密切的结构关系。还存在第二组，间隔约 230.0 nm；根据衍射理论，我们必须得出这样的结论：这种重复同时存在于粗细丝区域中。
Synchrotron radiation techniques have enabled us to record meridional x- ray diffraction patterns from frog sartorius muscle at resolutions ranging from approximately 2,800 to 38 nm (i.e., overlapping with the optical microscope and the region normally accessible with low angle diffraction cameras). These diffraction patterns represent the transform of the low resolution structure of muscle projected on the sarcomere axis and sampled by its repeat. Altering the sarcomere length results in the sampling of different parts of this transform, which induces changes in the positions and the integrated intensities of the diffraction maxima. This effect has been used to determine the transform of the mass projection on the muscle axis in a quasicontinuous fashion. The results reveal the existence of maxima arising from long-range periodicities in the structure. Determination of the zeroes in the transforms has been used to obtain phase information from which electron density maps have been calculated. The x-ray diffraction diagrams and the resulting electron density maps show the existence of a series of mass bands, disposed transversely to the sarcomere axis and distributed at regular intervals. A set of these transverse structures is associated with thin filaments, and their 102.0-nm repeat suggests a close structural relationship with their known molecular components. A second set, spaced by approximately 230.0 nm, is also present; from diffraction theory one has to conclude that this repeat simultaneously exists in thick and thin filament regions.