The mature core protein of the Hepatitis C virus (HCVC173) carrying pelB as a signal peptide (PelB: core) was overexpressed in Escherichia coli as 18% and 23.3% of the host’s total protein, in flask and fermentor cultivation, respectively. A final specific yield of 25±1 mg HCVC173/g dry cell weight and an overall productivity of 51±1 mg HCVC173/l/h were obtained in the stirred-tank fermentor. The recombinant PelB:: core protein was overexpressed as the inclusion body (IB) form, higher than the expected level when compared to the HCVC173, which was also showed by the analysis of secondary structure of mRNAs and calculation of the Codon Adaptation Index of the gene.
The results showed that the combined effects of protein fusion and the signal sequence significantly enhanced the production of recombinant mature HCVC173 in E. coli. Therefore, the fusion form of the mature HCV core protein and the conditions defined in this study provide an alternative strategy for HCVC173 production in high cell density culture of E. coli.