Cell culture optimization for increased soluble expression of hepatitis B virus X protein.

• Main Author: Lim, Pei Yu.
• Other Authors: Susanna Leong Su Jan
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Chemical engineering::Biotechnology
• Online Access: http://hdl.handle.net/10356/39523
• Institution: Nanyang Technological University

Economical production of proteins is made possible by recombinant protein technology. However, recombinant proteins are frequently expressed as inclusion bodies in E. coli cells. This is unfavourable as inclusion bodies usually contain incorrectly folded and biologically inactive protein. Therefore, soluble expression of protein is usually preferred due to the ease of downstream processing and higher probability of getting the protein in bioactive form. This project aims to investigate the effects of different upstream expression parameters on soluble expression of Hepatitis B virus X protein (HBx). HBx protein has been suggested to be involved in Hepatitis B virus related hepatocellular carcinoma. Expression of HBx protein in the soluble form has been difficult based on earlier studies which report the expression of HBx in the insoluble form. In this study, several parameters were studied to optimize the soluble expression of HBx protein. Our results showed that the soluble expression of HBx protein did not improve with the following parameters tested: (i) lowering of induction temperature, (ii) reduced post-induction time, (iii) introduction of different carbon sources in medium composition, (iv) co-expression of chaperones, (v) expression with ArcticExpress strain, and (vi) expression of the protein with the GST fusion tag.