Field Theoretical Analysis of Driving Forces for the Uptake of Proteins by Like-Charged Polyelectrolyte Brushes: Effects of Charge Regulation and Patchiness
Field Theoretical Analysis of Driving Forces for the Uptake of Proteins by Like-Charged Polyelectrolyte Brushes: Effects of Charge Regulation and Patchiness
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DOI：
10.1021/la902079u
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发表时间：
2010-01-05
期刊：
影响因子：
3.9
通讯作者：
Kleijn, J. Mieke
中科院分区：
文献类型：
--
作者：
de Vos, Wiebe M.;Leermakers, Frans A. M.;Kleijn, J. Mieke
目前，对于实验发现存在两种相互竞争的解释，即带净负电荷的蛋白质吸附油或吸收带负电荷的聚电解质刷。一种解释是基于充电调节的可能性。这个想法是，当蛋白质存在刷子的高静电势时，它可以反转其电荷，然后称为插入。其他解释 蛋白质的电荷各向异性，即它带有带正电和带负电的斑块。带正电的区域通过与负电刷的相互作用获得的能量比带负电的贴片损失的能量更多，特别是当电荷密度和静电势较高时，从而提供净吸引力。我们提出了一个结合了两种机制的模型。我们确认，油本身的电荷各向异性和电荷调节效应可能导致等电点（IEP）“错误”一侧的蛋白质吸收，此外，我们发现各自的效应是相加的。事实上，考虑到这两种效应会导致在 IEP 下 PE 刷和蛋白质之间产生更强的吸引力，并且发现这种吸引力比单独效应可能实现的 IEP 更高。尽管如此，为了使斑块发挥重要作用，斑块需要非常高的电荷密度。因此，我们认为，对于大多数类型的蛋白质，电荷反转将是 IEP 错误一侧吸附的主要驱动力，而斑块性的贡献较小。
At the moment two competing explanations exist for the experimental finding that net negatively charged proteins adsorb oil or absorb in negatively charged polyelectrolyte brushes. One explanation is based on the possibility of charge regulation. The idea is that a protein can reverse its charge when it is in the presence of the high electrostatic potential of the brush and then call be inserted. file other explanation relics oil the charge anisotropy of proteins, that is, that it carries positively charged and negatively charged patches. The positively charged region gains more energy from interacting with the negative brush than the negative charged patch loses, especially when the charge densities and electrostatic potentials are high, thus providing a net attraction. We present a model in which both mechanisms are combined. We confirm that both charge anisotropy and charge regulation effects oil their own can be responsible for protein uptake at the "wrong" side of the isoelectric point (IEP), In addition, we find that the respective effects are additive. Indeed, taking both effects into account results in a stronger attraction between a PE brush and protein at the IEP, and the attraction is found further above the IEP than the individual effects Would have made possible. Still, for patchiness to have a strong contribution, the patches need very high charge densities. Therefore, we argue that for most types of protein charge reversal will be the main driving force for adsorption on the wrong side of the IEP, While patchiness will contribute less.