Gallagher K, Sharp K
The Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6059 USA.
Biophys J. 1998 Aug;75(2):769-76. doi: 10.1016/S0006-3495(98)77566-6.
Significant heat capacity changes (DeltaCp) often accompany protein unfolding, protein binding, and specific DNA-ligand binding reactions. Such changes are widely used to analyze contributions arising from hydrophobic and polar hydration. Current models relate the magnitude of DeltaCp to the solvent accessible surface area (ASA) of the molecule. However, for many binding systems-particularly those involving non-peptide ligands-these models predict a DeltaCp that is significantly different from the experimentally measured value. Electrostatic interactions provide a potential source of heat capacity changes and do not scale with ASA. Using finite-difference Poisson-Boltzmann methods (FDPB), we have determined the contribution of electrostatics to the DeltaCp associated with binding for DNA binding reactions involving the ligands DAPI, netropsin, lexitropsin, and the lambda repressor binding domain.
显著的热容变化（ΔCp）常常伴随着蛋白质展开、蛋白质结合以及特定的DNA-配体结合反应。此类变化被广泛用于分析疏水性和极性水合作用产生的影响。当前模型将ΔCp的大小与分子的溶剂可及表面积（ASA）联系起来。然而，对于许多结合系统——尤其是那些涉及非肽配体的系统——这些模型预测的ΔCp与实验测量值显著不同。静电相互作用是热容变化的一个潜在来源，且不随ASA而变化。使用有限差分泊松-玻尔兹曼方法（FDPB），我们已经确定了静电作用对与涉及配体DAPI、纺锤菌素、偏端菌素以及λ阻遏物结合域的DNA结合反应相关的ΔCp的贡献。
