ELUSIVE AFFINITIES
ELUSIVE AFFINITIES
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DOI：
10.1002/prot.340210105
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发表时间：
1995-01-01
期刊：
影响因子：
--
通讯作者：
JANIN, J
中科院分区：
文献类型：
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作者：
JANIN, J
两个分子彼此的亲和力及其温度依赖性由解离时的焓、自由焓、熵和热容的变化决定。由于我们知道稳定蛋白质-蛋白质或蛋白质-DNA缔合的力以及复合物的三维结构，原则上我们可以推导出这些参数中每一个的值。首先在气相中通过分子力学进行计算，然后在溶液中借助小分子校准的水合参数进行计算。然而，即使在复合物的组分作为刚体缔合的近似下，气相中的焓和熵变化的估计也具有过大的误差条。最后不能指望有可靠的结果。拟合来自结合和量热测量的实验值是穷人，除了解离热容量。该参数主要归因于水化步骤，并且与界面的尺寸相关。许多蛋白质-蛋白质复合物的界面面积在1200-2000埃（2）范围内，只有很小的构象变化，因此刚体近似适用。它在蛋白质-DNA复合物中不太有效，这些复合物的界面覆盖2200-3100埃（2），解离热容量大，并且影响其组分的构象和动力学。(C)1995 Wiley-Liss，Inc.
The affinity of two molecules for each other and its temperature dependence are determined by the change in enthalpy, free enthalpy, entropy, and heat capacity upon dissociation. As we know the forces that stabilize protein-protein or protein-DNA association and the three-dimensional structures of the complex, we can in principle derive values for each one of these parameters. The calculation is done first in gas phase by molecular mechanics, then in solution with the help of hydration parameters calibrated on small molecules. However, estimates of enthalpy and entropy changes in gas phase have excessively large error bars even under the approximation that the components of the complex associate as rigid bodies. No reliable result can be expected at the end. The fit to experimental values derived from binding and calorimetric measurements is poor, except for the dissociation heat capacity. This parameter can be attributed mostly to the hydration step and it correlates with the size of the interface. Many protein-protein complexes have interface areas in the range 1200-2000 Angstrom(2) and only small conformation changes, so the rigid body approximation applies. It is less generally valid in protein-DNA complexes, which have interfaces covering 2200-3100 Angstrom(2), large dissociation heat capacities, and affect both the conformation and the dynamics of their components. (C) 1995 Wiley-Liss, Inc.