静电力驱动蛋白质在疏水蛋白表面的吸附

疏水蛋白是丝状真菌产生的一种外泌蛋白质, 它们可以在不同表面形成双亲性蛋白膜. 疏水蛋白也是一种优良的蛋白质固定化基质, 然而蛋白质在疏水蛋白表面吸附的驱动机制却是未知的. 本文系统研究了不同pH和离子浓度下蛋白质在疏水蛋白表面的吸附. 首先, 用石英晶体微天平技术研究了不同pH和离子浓度下, Ⅰ型疏水蛋白HGFI和Ⅱ型疏水蛋白HFBI在聚苯乙烯表面的吸附. 结果发现, pH和离子强度对HGFI在聚苯乙烯表面的吸附影响较大, 对HFBI的吸附影响与HGFI相比则较小; HGFI在聚苯乙烯表面主要形成的是弹性膜, 而HFBI在聚苯乙烯表面主要形成的是刚性膜. 随后又研究了不同pH和离子浓度下牛血清白蛋白(BSA)和亲和素(Avidin)在HGFI和HFB上吸附, 结果表明, pH和离子强度对BSA和Avidin在HGFI和HFB上吸附有显著影响, 说明BSA和Avidin在两种疏水蛋白上吸附的主要驱动力为静电力. 本文研究结果为实现疏水蛋白表面可控地固定蛋白质提供了理论指导.

Adsorption of Protein on Hydrophobin Surface Driven by Electrostatic Force

Hydrophobins are small secreted proteins produced by filamentous fungi, which can form an amphipathic membrane at various surfaces. Hydrophobins have been considered as excellent substrates for protein immobilization. However, the driven force for protein adsorption on hydrophobin surface is not clear. In this work, we systematically investigated the protein adsorption on hydrophobins at different pH and ionic strength. Firstly, the adsorption of class Ⅰ hydrophobin HGFI and class Ⅱ hydrophobin HFBI on the surfaces of polystyrene were investigated via quartz crystal microbalance with dissipation monitoring(QCM-D) at different pH and ionic strength. The results show that both pH and ionic strength have greater impacts on the adsorption of HGFI on polystyrene than that of HFBI. Moreover, HGFI can form soft films on the polystyrene, whereas HFBI formed very rigid films under the same conditions. The adsorption of BSA and avidin on the HGFI and HFBI were further investigated by using QCM-D at the same pH and ionic strength. The results indicate that adsorptions of BSA and avidin on the HGFI and HFBI are dramatically affected by both pH and ionic strength, suggesting that the major driving force dominating the protein adsorption on hydrophobin is the electrostatic force. This study provides a theoretical guide for a controllable immobilization of a protein on a hydrophobin surface.