Using Protein-imprinted Polymers as Artificial Antibodies to Isolate Immunoglobulin Binding Protein (BiP) and Study Protein–Protein Interactions

In this work, protein-imprinted polymers (PIPs) synthesized by introducing assistant recognition polymer chains (ARPCs) could be used as artificial antibodies in a similar manner to study protein protein interactions by immunoprecipitation by using biological antibodies. Bacterially expressed BiP was used as template. The ARPCs could enhance the recognition specificity of the PIPs for template protein significantly. It was confirmed that FK506-binding protein (FKBP23) could bind to immunoglobulin-binding protein (BiP) in the ER regulated by concentration of Ca2+ using artificial antibodies of PIP. The concentration of Ca2+ at which the interactions between BiP and FKBP23 were disrupted was in accordance with results obtained by using biological antibodies. Therefore, this new type of PIP provides a feasible alternative to biological antibodies in biochemical research.