Solubilization and purification studies of GST-HBx-6His

The Hepatitis B Virus X (HBx) protein is a protein expressed within an organism’s body infected with the Hepatitis B Virus (HBV). Its characterization in depth could develop an improved treatment for both acute and chronic Hepatitis B patients. However expression of HBx in Escherichia coli (E. coli) resulted in inclusion body formation, creating a hurdle in its purification and production as a bioactive protein. As such, the overall aim of this Final Year Project is to improve bioprocessing of ‘inclusion body’-derived HBx protein for higher process yield via a simpler bioprocess flow sheet. The HBx model protein used in this work is expressed as a Glutathione S-Transferase (GST) fusion protein. The use of detergents (i.e. N-Lauroylsarcosine sodium salt) was found to improve solubility of the fusion protein during the cell lysis step. Two methods to simultaneously purify and cleave the GST tag from the GST-HBx-6His protein were also developed and studied. Both methods showed potential in producing the HBx-6His protein. Fusion protein recovery and cleavage produced HBx-6His protein in purer forms from the bioprocess utilizing Glutathione Agarose beads as compared to the bioprocess utilizing Nickel NitriloTriacetic Acid beads.Bachelor of Engineering (Chemical and Biomolecular Engineering