Binding behaviour and conformational properties of globular proteins in the presence of immobilised non-polar ligands used in reversed-phase liquid chromatography.
Binding behaviour and conformational properties of globular proteins in the presence of immobilised non-polar ligands used in reversed-phase liquid chromatography.
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DOI：
10.1016/j.chroma.2005.03.097
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发表时间：
2005-06
期刊：
影响因子：
--
通讯作者：
R. Boysen;A. Jong;M. Hearn
中科院分区：
文献类型：
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作者：
R. Boysen;A. Jong;M. Hearn
本文研究了在278 ~ 338 K温度范围内，五种类型的细胞色素c在不同组成的水-乙腈混合物中，在固定化正辛基配体存在下的热力学和超热力学依赖性。从观察到的非线性Van 't霍夫图中计算了这些球状蛋白质在这些非均相体系中的相应的热容量、熵和热容参数Δ Hasvic °、Δ Sasvic °和ΔCp°。这些蛋白质-非极性配体相互作用的自由能依赖性，各种分子参数和额外的热力学依赖性（经验相关性）之间的关系也进行了研究。因此，参与的熵-熵补偿效应已被记录为这些细胞色素C的溶剂化的正辛基配体的结合。此外，结果证实，这种实验方法允许分子表面积的变化，由于这些蛋白质的解折叠与非极性配体作为温度的函数与其他生物物理性质相关的关联。因此，这项研究提供了一个一般的程序，从而相应的自由能依赖于球状蛋白质与溶剂化的非极性配体在非均相两相系统的关联，可以定量评估的基本分子参数。
The thermodynamic and extra-thermodynamic dependencies of five types of cytochrome c in water–acetonitrile mixtures of different composition in the presence of immobilised n-octyl ligands as a function of temperature from 278K to 338K have been investigated. The corresponding enthalpic, entropic and heat capacity parameters, ΔHassoc°, ΔSassoc° and ΔCp°, have been evaluated from the observed non-linear Van’t Hoff plots of these globular proteins in these heterogeneous systems. The relationships between the free energy dependencies, various molecular parameters and extra-thermodynamic dependencies (empirical correlations) of these protein–non-polar ligand interactions have also been examined. Thus, the involvement of enthalpy-entropy compensation effects has been documented for the binding of these cytochrome cs to solvated n-octyl ligands. Moreover, the results confirm that this experimental approach permits changes in molecular surface area due to the unfolding of these proteins on association with non-polar ligands as a function of temperature to be correlated with other biophysical properties. This study thus provides a general procedure whereby the corresponding free energy dependencies of globular proteins on association with solvated non-polar ligands in heterogeneous two-phase systems can be quantitatively evaluated in terms of fundamental molecular parameters.