Enhanced Solubilization and Purification of 3ABC Non-structural Protein of Foot-and-Mouth Disease Virus from Bacterial Inclusion Bodies

Nonstructural 3ABC protein of foot-and-mouth disease virus (FMDV) is used to differentiate vaccinated from naturally infected animals. The 3ABC protein is a polyprotein which is cleaved into membrane associated 3A protein, three copies of 3B and 3Cpro mediated by virally encoded 3C protease. The expression of this protein in E. coli results into the formation of inclusion bodies which require solubilization in high concentration of chaotropes and extensive refolding process prior to purification of the native protein. Protein aggregation during refolding leads to the poor recovery of protein in functional form. Alternatively, mild solubilization methods have been proposed to recover the native and soluble protein from inclusion bodies present in E. coli. In this study, 3ABC protein was expressed predominantly as inclusion bodies using E. coli host and solubilized in mild nonionic detergent followed by purification through Ni-NTA chromatography. The protein recovery using this solubilization method, showed higher yield than previous solubilization methods for 3ABC protein. This method also favored higher stability of the 3ABC recombinant protein stored at different temperatures. The reactivity of the proteins was analyzed by western blotting and ELISA which showed their ability to use them as antigen for the development of immunoassays. In conclusion, this study demonstrates an efficient and high yielding purification method of this protein without refolding process than previously described methods involving renaturation steps.