非均匀介质中沉降的模型。I. 沉降共溶质产生的动态密度梯度

A model for sedimentation in inhomogeneous media. I. Dynamic density gradients from sedimenting co-solutes.

作者信息

Schuck Peter

机构信息

Division of Bioengineering and Physical Science, ORS, OD, National Institutes of Health, Building 13, Room 3N17, 13 South Drive, Bethesda, MD 20892-5766, USA.

出版信息

Biophys Chem. 2004 Mar 1;108(1-3):187-200. doi: 10.1016/j.bpc.2003.10.016.

DOI:10.1016/j.bpc.2003.10.016

PMID:15043929

Abstract

Macromolecular sedimentation in inhomogeneous media is of great practical importance. Dynamic density gradients have a long tradition in analytical ultracentrifugation, and are frequently used in preparative ultracentrifugation. In this paper, a new theoretical model for sedimentation in inhomogeneous media is presented, based on finite element solutions of the Lamm equation with spatial and temporal variation of the local solvent density and viscosity. It is applied to macromolecular sedimentation in the presence of a dynamic density gradient formed by the sedimentation of a co-solute at high concentration. It is implemented in the software SEDFIT for the analysis of experimental macromolecular concentration distributions. The model agrees well with the measured sedimentation profiles of a protein in a dynamic cesium chloride gradient, and may provide a measure for the effects of hydration or preferential solvation parameters. General features of protein sedimentation in dynamic density gradients are described.

摘要

非均匀介质中的大分子沉降具有重大的实际意义。动态密度梯度在分析超速离心中由来已久，且常用于制备超速离心。本文基于局部溶剂密度和粘度随空间和时间变化的Lamm方程的有限元解，提出了一种非均匀介质中沉降的新理论模型。该模型应用于在高浓度共溶质沉降形成的动态密度梯度存在下的大分子沉降。它在软件SEDFIT中实现，用于分析实验大分子浓度分布。该模型与蛋白质在动态氯化铯梯度中的测量沉降曲线吻合良好，并可为水合作用或优先溶剂化参数的影响提供一种度量。描述了动态密度梯度中蛋白质沉降的一般特征。