Specific ion binding to macromolecules:: Effects of hydrophobicity and ion pairing
Specific ion binding to macromolecules:: Effects of hydrophobicity and ion pairing
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DOI：
10.1021/la7034104
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发表时间：
2008-04-01
期刊：
影响因子：
3.9
通讯作者：
Jungwirth, Pavel
中科院分区：
文献类型：
--
作者：
Lund, Mikael;Vacha, Robert;Jungwirth, Pavel
利用分子动力学模拟在一个明确的水溶液中，我们研究了结合的氟化物与碘化物的球形大分子与bothhydrophobic和带正电的补丁。为了证实我们的观察结果，我们将离子缔合相互作用分为两种机制：（1）溶剂化程度低的碘离子被吸引到疏水表面补丁，而（2）溶剂化程度高的氟离子和碘离子通过阳离子-阴离子相互作用结合。定量而言，结合亲和力随带电基团的可及性以及表面电位而显著变化;因此，我们预期离子-大分子缔合将由（生物）大分子的局部表面特征来调制。所观察到的阳离子-阴离子配对偏好与实验数据非常吻合。
Using molecular dynamics simulations in an explicit aqueous solvent, we examine the binding of fluoride versus iodide to a spherical macromolecule with bothhydrophobic and positively charged patches. Rationalizing our observations, we divide the ion association interaction into two mechanisms: (1) poorly solvated iodide ions are attracted to hydrophobic surface patches, while (2) the strongly solvated fluoride and to a minor extent also iodide bind via cation-anion interactions. Quantitatively, the binding affinities vary significantly with the accessibility of the charged groups as well as the surface potential; therefore, we expect the ion-macromolecule association to be modulated by the local Surface characteristics of the (bio-)macromolecule. The observed cation-anion pairing preference is in excellent agreement with experimental data.