Zwitterion-Immobilized Imprinted Polymers for Promoting the Crystallization of Proteins

Abstract

Zwitterion additives have been used in protein crystallization to prevent the appearance of crystal clusters. Herein, we have developed a novel approach for the immobilization of zwitterion onto molecularly imprinted polymers (MIPs) to yield high-quality single protein crystals. For lysozyme, trypsin, catalase, proteinase K, concanavalin A-type IV, and thaumatin, simply adding the selected zwitterion (3-(methacryloylamino)­propyl)-dimethyl­(3-sulfopropyl) ammonium hydroxide) into the free solution, the crystallization was improved. When further using the zwitterion-immobilized molecularly imprinted polymers (ziMIPs) developed in the current study, the formation of higher quality crystals was facilitated in a shorter time compared with regular MIPs and traditional crystallization trials. Most notably, concanavalin A-type IV, which has nonunique ordered assembly, gave only the form IV structure with higher resolution in the presence of ziMIPs, justifying the superior function of ziMIPs for the ordered assembly of protein molecules. Thus, the ziMIPs could be widely used in protein crystallization