Measurement of biomolecular association via static and dynamic light scattering

1.我们同时收集了非相互作用蛋白质和相互作用蛋白质混合物的与组成相关的静态和动态光散射数据，并对这两个量的组成依赖关系进行了全局分析。与预期相反，动态光散射数据的添加并没有提高仅使用静态光散射数据所能获得的表征的分辨率。去年的报告对这项工作作了初步说明，但此后对数据的分析进行了改进和扩展，使之能够更详细地分析这两类数据的相对信息内容。(B.蒙特罗索，CIB) 2.我们测量了在不同浓度的镁离子存在下，含有GTP和GPCPP的FtsZ溶液中的光散射强度与蛋白质浓度的关系。对观察到的依赖性的最简单解释是，FtsZ-GTP或FtsZ-GPCPP的自缔合最初是根据不确定的等键方案通过线性增长进行的，随后合作形成稳定的低聚物或被认为是环状的30-40亚基的窄尺寸分布的低聚物。去年的报告对这项工作作了初步说明。在过去一年中，静态光散射结果已扩展到包括角度依赖关系，动态光散射和沉积测量获得的结果使先前得出的结论得以显著改进和扩展(G.Rivas，CIB)。

1. We have simultaneously collected composition-dependent static and dynamic light scattering data on mixtures of non-interacting and interacting proteins, and developed a global analysis of the composition-dependence of both quantities. Contrary to expectation, addition of dynamic light scattering data did not enhance the resolution of characterization obtainable using static light scattering data only. A preliminary description of this work was presented in last year's report, but analysis of the data has since been refined and extended, enabling a more detailed analysis of the relative information content of the two types of data. (B. Monterroso, CIB) 2. We have measured the dependence of the intensity of light scattering upon protein concentration in solutions of FtsZ containing either GTP an a GTP-regenerating system or GPCPP, a slowly hydrolyzable GTP analog, in the presence of varying concentrations of Mg++ ion. The simplest interpretation of the observed dependence is that self-association of either FtsZ-GTP or FtsZ-GPCPP proceeds initially by linear growtn according to an indefinite isodesmic scheme, followed by cooperative formation of a stable oligomer or narrow size distribution of oligomers of size 30-40 subunits that are thought to be cyclic. A preliminary description of this work was presented in last year's report. During the last year, the static light scattering results have been extended to include angular dependence, and results obtained from measurements of dynamic light scattering and sedimentation have enabled a significant refinement and extension of conclusions previously derived (G. Rivas, CIB).