Investigation of the shape and size of myosin subfragment 1 using small-angle X-ray scattering.
Investigation of the shape and size of myosin subfragment 1 using small-angle X-ray scattering.
复制标题
使用小角 X 射线散射研究肌球蛋白亚片段 1 的形状和大小。
DOI：
10.1021/bi00605a009
复制
发表时间：
1978
期刊：
影响因子：
2.9
通讯作者：
M. Morales
中科院分区：
文献类型：
--
作者：
K. Kretzschmar;R. Mendelson;M. Morales
用肌球蛋白亚片段1(S1)的溶液测量非常小角度的X射线散射，得到的旋转半径为3.24 nm(平均值)+/-0.03 nm(N=9的标准误差)。假设S1为旋转椭球，电子密度均匀，分子量为1.15×10(5)，部分比体积为0.73cm3g-1，则椭球的轴比为2.89+/-0.06(长方形)或0.26+/-0.01(扁平)，长轴为13.0+/-0.2 nm(长方形)或10.1+/-0.1 nm(扁平)。在较大角度下的测量允许测试S1形态的模型；计算了不同旋转椭球的理论散射曲线。观测到的散射体可以用轴比为2.0~3.0(长形)或0.25~0.4(扁平)的椭球体的散射近似。在0-30mrad的散射角范围内，符合数据的模型有：长椭球，轴比2.3，长轴12 nm；扁平椭球，轴比0.4，长轴10 nm。因此，用不同的方法对散射曲线的两部分进行了分析，结果表明，S_1是球形的，其形态可以用上述维度的椭球体来近似。
Measurement of x-ray scattering at very small angles by solutions of myosin subfragment 1 (S1) yields a radius of gyration of 3.24 nm (mean) +/- 0.03 nm (standard error for N = 9). If S1 is assumed to be ellipsoid of revolution, of uniform electron density, with a molecular weight of 1.15 X 10(5) and a partial specific volume of 0.73 cm3 g-1, then the axial ratio of the ellipsoid is 2.89 +/- 0.06 (prolate) or 0.26 +/- 0.01 (oblate), and the major axis is 13.0 +/- 0.2 nm (prolate) or 10.1 +/- 0.1 nm (oblate). Measurements at larger angles allow models of S1 morphology to be tested; theoretical scattering curves for various ellipsoids of revolution were calculated. The observed scatterina can be approximated by the scattering from ellipsoids with axial ratio 2.0 to 3.0 (prolate), or 0.25 to 0.4 (oblate). Models that fit the data over the range of scattering angles from 0 to 30 mrad are: prolate ellipsoid with axial ratio 2.3, major axis 12 nm; and oblate ellipsoid with axial ratio 0.4 and major axis 10 nm. Thus analyses of two parts of the scattering curve, by different methods, indicate that S1 is fae from spherical, and that its morphology may be approximated by ellipsoids of the aforesaid dimensions.