(a) Hstrail Protein Expression And Refolding (b) Reorganization Of Bacillus Subtilis Glutamine Synthetase Induction Of Expression And Medium Optimization

In order to get the active hsTRAIL protein, the renaturation of hsTRAIL inclusion bodies was analyzed in detail. The purity of the inclusion bodies was enhanced to over 90%; the purity of renatured hsTRAIL is over 98%. The renaturation rate of dilution is about 65%, the renaturation rate of dialysis is about 33%. The purified protein shows obvious biological activity, which can induce the Hela cell to apoptosis while make no effection on HEK293. The gene of Bacillus Subtilis Glutamine Synthetase (GS EC 6.3.1.2) was amplified and cloned into pET3C; the recombinant plasmid was then transformed into BL-21(DE3). Lactose and IPTG(isopropyl-β-D-thiogalacto-pyranoside) were used to induce gene expression at 37℃separately. Both of them can induce the Glutamine Synthetase gene efficiently. Many types of M9 medium and LB medium were used respectively to culture the bacteria. The factors such as lactose concentration, the point of induction, the duration of the induction phase, the re-addition of lactose, medium selection, carbon source composition, dose of carbon source, best combination of carbon source and inducer were analyzed in detail. The inducing efficiency of lactose was basically the same as IPTG.The expression efficiency of optimized M9 medium and LB medium are almost the same, which provides evidence that optimized M9 medium is a promising replacement of LB medium in the industrial production of recombinant Glutamine Synthetase in the future.