Competition of hydrophobic and Coulombic interactions between nanosized solutes
Competition of hydrophobic and Coulombic interactions between nanosized solutes
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DOI：
10.1063/1.1783274
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发表时间：
2004-09-15
影响因子：
4.4
通讯作者：
Hansen, JP
中科院分区：
文献类型：
--
作者：
Dzubiella, J;Hansen, JP
带电的，纳米尺寸的球形溶质在水中的溶剂化，和有效的，两个这样的溶质之间的溶剂诱导力进行了研究恒温和恒压分子动力学模拟模型溶质携带各种电荷模式。中性溶质的结果与早期的研究结果一致，并与简单的宏观考虑的预测：大量的疏水吸引力可以追溯到强烈的消耗（“干燥”）的溶质之间的溶剂。当溶质均匀带电时，这种疏水吸引力强烈降低，并且总力在足够高的电荷下变得排斥;阴离子和阳离子溶质对之间存在显着的不对称性，后者经历较小的疏水吸引力。当溶质携带离散的（而不是均匀的）电荷模式时，情况变得更加复杂。由于溶剂分子上产生的亲水性和疏水性“补丁”的拮抗作用，溶质周围的水再次显著耗尽，有效的相互作用恢复为主要是吸引力，尽管溶质之间存在直接的静电排斥。一个高度粗粒度的构型概率密度的检查表明，这两种溶质的相对取向是非常不同的显式溶剂，相比原油隐式溶剂表示的预测。本研究强烈表明，一个现实的球状蛋白质表面上的电荷分布的建模，以及水的分子处理，是任何可靠的蛋白质聚集研究的必要先决条件。(C)2004年，美国物理学会。
The solvation of charged, nanometer-sized spherical solutes in water, and the effective, solvent-induced force between two such solutes are investigated by constant temperature and pressure molecular dynamics simulations of model solutes carrying various charge patterns. The results for neutral solutes agree well with earlier findings, and with predictions of simple macroscopic considerations: substantial hydrophobic attraction may be traced back to strong depletion ("drying") of the solvent between the solutes. This hydrophobic attraction is strongly reduced when the solutes are uniformly charged, and the total force becomes repulsive at sufficiently high charge; there is a significant asymmetry between anionic and cationic solute pairs, the latter experiencing a lesser hydrophobic attraction. The situation becomes more complex when the solutes carry discrete (rather than uniform) charge patterns. Due to antagonistic effects of the resulting hydrophilic and hydrophobic "patches" on the solvent molecules, water is once more significantly depleted around the solutes, and the effective interaction reverts to being mainly attractive, despite the direct electrostatic repulsion between solutes. Examination of a highly coarse-grained configurational probability density shows that the relative orientation of the two solutes is very different in explicit solvent, compared to the prediction of the crude implicit solvent representation. The present study strongly suggests that a realistic modeling of the charge distribution on the surface of globular proteins, as well as the molecular treatment of water, are essential prerequisites for any reliable study of protein aggregation. (C) 2004 American Institute of Physics.