Calcium-induced increase in the radius of gyration and maximum dimension of calmodulin measured by small-angle X-ray scattering.
Calcium-induced increase in the radius of gyration and maximum dimension of calmodulin measured by small-angle X-ray scattering.
复制标题
通过小角 X 射线散射测量钙诱导的回转半径和钙调蛋白最大尺寸的增加。
DOI：
10.1021/bi00345a002
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发表时间：
1985
期刊：
影响因子：
2.9
通讯作者：
Richards,FM
中科院分区：
文献类型：
--
作者：
Seaton,BA;Head,JF;Engelman,DM;Richards,FM
耶鲁大学分子生物物理和生化系，康涅狄格州纽黑文，06511，和生理系，波士顿，波士顿，马萨诸塞州02118，收到1985年8月9日摘要：我们已经使用溶液小角X射线散射来表征有无钙的牛脑钙调蛋白。在钙离子存在下，钙调蛋白在溶液中以细长的分子形式存在，其旋转半径为21.5？，最大载体长度约为62？这些值与最近测定的大鼠睾丸钙调蛋白晶型的尺寸一致。在无钙条件下，钙调素分子变短，回转半径减小到20.6°，最大载体长度减小到约58°。这种尺寸上的变化与蛋白质在钙调素中的两个叶相互靠近时的整体收缩是一致的。来自大分子的小角X射线散射(SAXS)1被用来测量单个分子在自由溶液中的形状相关参数。作为一种低分辨率技术，溶液散射对精细的结构特征不敏感，但可以准确地提供与尺寸和形状有关的细节。对于生物大分子，如蛋白质，与底物或调节剂的相互作用可以改变形状，X射线
Department of Molecular Biophysicsand Biochemistry, Yale University, New Haven, Connecticut 06511, and Department of Physiology, Boston University School of Medicine, Boston, Massachusetts 02118 Received August 9, 1985 abstract: We have used solution small-angle X-ray scattering to characterize bovine brain calmodulin in the presence and absence of calcium. In the presence of calcium, calmodulin exists in solution as an elongated molecule with a radius of gyration of 21.5 Á and a maximum vector length of approximately 62 Á. These values are consistent with the dimensions recently determined for the crystal form of rat testis calmodulin. In the absence of calcium, the calmodulin molecule is shorter, the radius of gyration decreases to 20.6 Á, and the maximum vector length decreases to approximately 58 Á. This change in dimensions is consistent with an overall contraction of the protein through movement of the two lobes closer to each other upon removal of calcium from calmodulin.Small-angle X-ray scattering (SAXS) 1 from macromolecules is used to measure shape-related parameters of individual molecules in free solution. As a low-resolution technique, solution scattering is insensitive to fine structural features but can accurately provide details related to size and shape. For biological macromolecules such as proteins, where interactions with substrates or regulators can change the shape, X-ray