基于糖和苯硼酸动态共价键的高效蛋白质表面修饰方法

糖和蛋白质的相互作用参与了很多重要的生命过程.研究糖和蛋白质的相互作用有多种手段,石英晶体微天平(QCM)是其中重要的一种.研究中常需要将蛋白质通过共价键连接在天平芯片的表面.但是,用于检测糖分子的蛋白质多为植物凝集素,它们的分子量大,表面可修饰位点少,通过共价键修饰在芯片表面的效率偏低.本文提出一种基于糖和苯硼酸之间动态共价键的新修饰方法,能够大幅度提高蛋白质在芯片表面的修饰效率.

An Efficient Protein Modification Method Based on Dynamic Covalent Bonding between Sugar and Phenylboronic Acid

The interaction between sugar and protein occurs in many important biological processes.Several methods can be used to investigate this interaction.Compared to other methods,especially those in solution,quartz crystal microbalance (QCM) can detect interactions on liquid-solid interface,which might be more useful because the proteins are usually mobilized on the chip surface by covalent bond.However,most proteins used in this study belong to plant lectins with high molecular weight and less modification sites.The efficiency of covalent modification of lectins is quite low.In this paper,we propose a new method based on dynamic covalent bond between sugar and phenylboronic acid,which dramatically increases the modification efficiency on surface.On a gold chip of QCM,block copolymer PtBMA-co-PBOB was first coated by spin-coating,glycopolymers (PMan,PGal,PGlc) was then deposited on the surface via the dynamic covalent bond between benzoboroxole (BOB) and sugars.The three glycopolymers did not show much differences due to their relatively similar binding ability to BOB-containing polymers.Control experiments proved that the coating of glycopolymers was driven by the dynamic covalent bond.The glycopolymer coating was quite stable even at low pH and high concentration corresponding to monosaccharides.The lectin Concanavalin A (Con A) was immobilized via the interaction between Con A and mannopyranoside.It was found that the amount of Con A coated on gold chip,via the above-mentioned non-covalent method,was much higher than that by the traditional covalent method.By Sauerbrey equation,the amount of Con A deposited via non-covalent method was calculated to be 2832 ng/cm2,while that of Con A via covalent method was only 424.8 ng/cm2.Moreover,on the glycopolymer surface built by non-covalent method,Con A and glyco-micelles could be deposited layer-by-layer continuously,showing the robustness of this non-covalent method.We hope that this method could be further utilized to deposit sugar-coating nanomaterials and even cells with glycocalyx on certain surfaces.