Size-distribution analysis of macromolecules by sedimentation velocity ultracentrifugation and Lamm equation modeling
Size-distribution analysis of macromolecules by sedimentation velocity ultracentrifugation and Lamm equation modeling
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DOI：
10.1016/s0006-3495(00)76713-0
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发表时间：
2000-03-01
影响因子：
3.4
通讯作者：
Schuck, P
中科院分区：
文献类型：
--
作者：
Schuck, P
本文描述了一种通过沉降速度分析超速离心对聚合物进行粒度分布分析的新方法。它利用了拉莫方程建模的能力，以区分由样品异质性和扩散引起的沉降边界的扩展。针对大量离散的非相互作用物质的拉莫方程的有限元解与最大熵正则化相结合，以表示连续的粒度分布。如同在CONTIN程序中一样，通过方差分析将控制正则化约束的参数调整到预先定义的置信水平。利用大分子的偏比容和摩擦比的估计值来计算扩散系数，从而得到分辨率相对较高的沉降系数分布c(s)或摩尔质量分布c(M)。它可应用于存在系统噪声成分的干涉光学数据，且不需要建立溶液或溶剂平台。与范霍尔德 - 魏歇特分析相比，可以获得更多关于粒度分布的细节。借助离散和连续模型粒度分布的模拟沉降数据，并通过应用于连续和离散蛋白质混合物的实验数据，探讨了对正则化参数值和形状参数的敏感性。
A new method for the size-distribution analysis of polymers by sedimentation velocity analytical ultracentrifugation is described. It exploits the ability of Lamm equation modeling to discriminate between the spreading of the sedimentation boundary arising from sample heterogeneity and from diffusion. Finite element solutions of the Lamm equation for a large number of discrete noninteracting species are combined with maximum entropy regularization to represent a continuous size-distribution. As in the program CONTIN, the parameter governing the regularization constraint is adjusted by variance analysis to a predefined confidence level. Estimates of the partial specific volume and the frictional ratio of the macromolecules are used to calculate the diffusion coefficients, resulting in relatively high-resolution sedimentation coefficient distributions c(s) or molar mass distributions c(M). It can be applied to interference optical data that exhibit systematic noise components, and it does not require solution or solvent plateaus to be established. More details on the size-distribution can be obtained than from van Holde-Weischet analysis. The sensitivity to the values of the regularization parameter and to the shape parameters is explored with the help of simulated sedimentation data of discrete and continuous model size distributions, and by applications to experimental data of continuous and discrete protein mixtures.