Abstract：
We apply a coarse-grained self-consistent field Poisson-Boltzmann framework to study interaction between Bovine Serum Albumin (BSA) and a planar polyelectropyte brush. Both cases of negatively (polyanionic) and positively (polycationic) charged brushes are considered. Our theoretical model accounts for (1) re-ionization free energy of the amino acid residues upon protein insertion into the brush; (2) osmotic force repelling the protein globule from the brush; (3) hydrophobic interactions between non-polar areas on the globule surface and the brush-forming chains. We demonstrate that calculated position-dependent insertion free energy exhibits different patterns, corresponding to either thermodynamically favourable BSA absorption in the brush or thermodynamically or kinetically hindered absorption (expulsion) depending on the pH and ionic strength of the solution. The theory predicts that due to the re-ionization of BSA within the brush, a polyanionic brush can efficiently absorb BSA over a wider pH range on the \"wrong side\" of the isoelectric point (IEP) compared to a polycationic brush. The results of our theoretical analysis correlate with available experimental data and thus validate the developed model for prediction of the interaction patterns for various globular proteins with polyelectrolyte brushes.
摘要：
我们应用粗粒度的自洽场Poisson-Boltzmann框架来研究牛血清白蛋白（BSA）与平面多电极刷之间的相互作用。考虑了带负电荷（聚阴离子）和带正电荷（聚阳离子）的刷子两种情况。我们的理论模型考虑了（1）蛋白质插入刷子后氨基酸残基的再电离自由能；（2）渗透力从刷子排斥蛋白质球；（3）小球表面的非极性区域与刷形成链之间的疏水相互作用。我们证明了计算的位置相关插入自由能表现出不同的模式，根据溶液的pH和离子强度，对应于刷子中热力学有利的BSA吸收或热力学或动力学受阻的吸收（排出）。该理论预测，由于刷体内BSA的重新电离，与聚阳离子刷相比，聚阴离子刷可以在等电点（IEP）的“错误侧”的更宽pH范围内有效吸收BSA。我们的理论分析结果与可用的实验数据相关，从而验证了所开发的模型，用于预测各种球状蛋白质与聚电解质刷的相互作用模式。
