Optimization of condition for recombinant l-isoleucine dioxygenase expression in escherich coli bl21(de3)

Abstract

L-isoleucine dioxygenase (IDO) is a kind of Fe(II)/α-ketoglutarate (α-KG)-dependent hydroxylase, with the ability of converting l-isoleucine to (2S,3R,4S)-4-hydroxyisoleucine (4-HIL). IDO encoding gene ido from Bucillus thuringiensis TCCC 11826 was cloned into Escherich coli BL21(DE3) to express IDO. To optimized the condition for recombinant IDO expression in E. coli BL21(DE3), the effect of isopropyl-β-d-thiogalactoside (IPTG) concentration, induction temperature, induction time and expression time on expression were studied. E. coli BL21/pEThis-ido was successfully constructed and the amount of expressed protein was detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDA-PAGE). Results showed that induction for 6 h with 0.15 mmol/L IPTG after recombinant E. coli BL21(DE3) cultured for 4 h at 37 °C lead to the highest recombinant IDO level. This work will lay basis on the microbial expression technology of IDO and Fe(II)/(α-KG)-dependent hydroxylase.