Maltose Binding Protein (MBP) Fusion Proteins with Low or No Affinity to Amylose Resins Can Be Single-Step Purified Using a Novel Anti-MBP Monoclonal Antibody

Abstract

The maltose binding protein (MBP) fusion protein expression system is a powerful tool to produce and isolate recombinant proteins in E. coli. Whereas the conventional isolation technique for MBP-fusion proteins takes advantage of the binding affinity of MBP to maltose, this method is limited insofar as the biological activity of MBP has to be fully conserved for a successful purification. In this study, a novel monoclonal antibody (mAb) specific for MBP, termed HAM-19, was generated and its application in the purification and detection of MBP-fusion proteins determined. Using anti-MBP immunoaffinity columns, even recombinant MBP fusion products with lowered or impaired binding affinity to maltose were purified in a single step procedure. In comparison to amylose resins, HAM-19 immunoaffinity columns showed a higher binding capacity and affinity to MBP-fusion proteins. Furthermore, the mAb HAM-19 also provides a technical improvement over polyclonal antisera for the detection and analysis of MBP-fusion proteins which are under use in various forms in the fields of molecular and cellular biology.