Wills P R, Jacobsen M P, Winzor D J
Department of Physics, University of Auckland, Auckland, New Zealand.
Biophys J. 2000 Oct;79(4):2178-87. doi: 10.1016/S0006-3495(00)76466-6.
A rigorous statistical-mechanical approach is adopted to derive general quantitative expressions that allow for the effects of thermodynamic nonideality in equilibrium measurements reflecting interaction between dissimilar macromolecular reactants. An analytical procedure based on these expressions is then formulated for obtaining global estimates of equilibrium constants and the corresponding reference thermodynamic activities of the free reactants in each of several sedimentation equilibrium experiments. The method is demonstrated by application to results from an ultracentrifugal study of an electrostatic interaction between ovalbumin and cytochrome c (Winzor, D. J., M. P. Jacobsen, and P. R. Wills. 1998. Biochemistry. 37:2226-2233). It is demonstrated that reliable estimates of relevant thermodynamic parameters are extracted from the data through statistical analysis by means of a simple nonlinear fitting procedure.
采用一种严格的统计力学方法来推导通用的定量表达式,这些表达式考虑了热力学非理想性在反映不同大分子反应物之间相互作用的平衡测量中的影响。然后基于这些表达式制定一种分析程序,以在几个沉降平衡实验中的每一个中获得平衡常数的全局估计值以及游离反应物相应的参考热力学活度。通过将该方法应用于对卵清蛋白和细胞色素c之间静电相互作用的超速离心研究结果(Winzor, D. J., M. P. Jacobsen, and P. R. Wills. 1998. Biochemistry. 37:2226 - 2233)来证明该方法。结果表明,通过简单的非线性拟合程序进行统计分析,可以从数据中提取相关热力学参数的可靠估计值。