Macromolecular size-and-shape distributions by sedimentation velocity analytical ultracentrifugation
Macromolecular size-and-shape distributions by sedimentation velocity analytical ultracentrifugation
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DOI：
10.1529/biophysj.106.081372
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发表时间：
2006-06-01
影响因子：
3.4
通讯作者：
Schuck, Peter
中科院分区：
文献类型：
--
作者：
Brown, Patrick H.;Schuck, Peter
沉降速度分析超速离心法是表征溶液中大分子和纳米颗粒的重要工具。拉姆方程解的沉降系数分布c(S)是基于由实验数据确定的所有颗粒的单个加权平均摩擦系数的近似，它将扩散系数标度为符合传统S类似于M-2/3幂定律的沉降系数。它提供了很高的流体力学分辨率，其中沉积边界的扩散加宽从沉积系数分布中反卷积。单一重量-平均摩擦比的近似得到了几个实验因素的支持，通常对化学上不太相似的大分子，如折叠蛋白质的混合物，会得到很好的结果。在本文中，我们研究了沉降系数和摩尔质量比的二维分布c(S，f(R))的推广，它代表了一组更一般的尺寸和形状分布，包括质量-斯托克斯半径分布c(M，R-S)和沉降系数-摩尔质量分布c(S，M)。我们表明，这可以用来确定大分子的平均摩尔质量和表征大分子的分布，而不需要近似计算流体力学和热力学参数之间的任何标度关系。
Sedimentation velocity analytical ultracentrifugation is an important tool in the characterization of macromolecules and nanoparticles in solution. The sedimentation coefficient distribution c(s) of Lamm equation solutions is based on the approximation of a single, weight-average frictional coefficient of all particles, determined from the experimental data, which scales the diffusion coefficient to the sedimentation coefficient consistent with the traditional s similar to M-2/3 power law. It provides a high hydrodynamic resolution, where diffusional broadening of the sedimentation boundaries is deconvoluted from the sedimentation coefficient distribution. The approximation of a single weight-average frictional ratio is favored by several experimental factors, and usually gives good results for chemically not too dissimilar macromolecules, such as mixtures of folded proteins. In this communication, we examine an extension to a two-dimensional distribution of sedimentation coefficient and frictional ratio, c( s, f(r)), which is representative of a more general set of size-and-shape distributions, including mass-Stokes radius distributions, c(M, R-S), and sedimentation coefficient-molar mass distributions c(s, M). We show that this can be used to determine average molar masses of macromolecules and characterize macromolecular distributions, without the approximation of any scaling relationship between hydrodynamic and thermodynamic parameters.