Goodfellow J M
Proc Natl Acad Sci U S A. 1982 Aug;79(16):4977-9. doi: 10.1073/pnas.79.16.4977.
Monte Carlo computer simulation techniques have been used to model non-pair-additive (cooperative) effects in the water organization around several biomolecules. Although most models for water assume pair-additive potentials, both quantum mechanical calculations and experimental data indicate that cooperative effects are not negligible in hydrogen-bounded systems such as water. The many-body polarizable electropole (PE) model for water is used to examine the extent and the consequences of this cooperative behavior in several biomolecule hydrate crystals. Increases in the dipole moments of water molecules are predicted in all systems studied so far and can be as much as 50% more than the monomer value of 1.855 debyes. The average value of the individual dipole moments for any one system differs from that of another system and, therefore, should be considered a property of the system and not of the water molecule itself. When this previously calculated average value of the dipole moment for water molecules in a given system is used as a fixed parameter in the simulation, we find differences between this fixed calculation and the original unfixed simulation. An alternative procedure, which allows for a spread in dipole moments and is not dependent on a predetermined average value, has been developed to make simulations of large water-protein systems, including cooperative effects, computationally feasible.
蒙特卡罗计算机模拟技术已被用于对几种生物分子周围水的组织中的非成对加和（协同）效应进行建模。尽管大多数水模型假定成对加和势，但量子力学计算和实验数据均表明，在诸如水这样的氢键系统中，协同效应不可忽略。水的多体极化电极（PE）模型用于研究几种生物分子水合物晶体中这种协同行为的程度和后果。在目前研究的所有系统中，水分子的偶极矩预计会增加，并且可能比单体值1.855德拜高出50%。任何一个系统中单个偶极矩的平均值与另一个系统的不同，因此，应将其视为系统的属性而非水分子本身的属性。当将给定系统中水分子偶极矩的先前计算平均值用作模拟中的固定参数时，我们发现这种固定计算与原始非固定模拟之间存在差异。已开发出一种替代程序，该程序允许偶极矩有一定范围且不依赖于预先确定的平均值，以使包括协同效应在内的大型水 - 蛋白质系统的模拟在计算上可行。
