Molecular imprinted polymer with positively charged assistant recognition polymer chains for adsorption/enrichment of low content target protein

Here, we introduce a new type of molecular imprinted polymer （MIP） with immobilized assistant recognition polymer chains （ARPCs） to create effective recognition sites and with bacterial cloned protein as template for adsorbing the low content target protein from cell extract. In this work, cloned pig cyclophilin 18 （pCyP18）, a peptidyl-prolyl cis/trans-isomerase, was used as template. The template protein was selectively assembled with ARPCs from their library, which consists of numerous limited length polymer chains with randomly distributed recognition sites of positively charged amino groups and immobilizing sites. These assemblies were adsorbed by porous microsphers and immobilized on them. After removing the template, binding sites complementary to the target protein in size, shape and the position of recognition groups were exposed, and their confirmation was preserved by the cross-linked structure. The synthesized MIP was used to adsorb the cellular pCyP18, and its proportional content was enriched more than hundred times. The extended experiment on imprinting bovine serum albumin （BSA） with ARPCs shows that this method is also suitable for large protein.