An efficient strategy for the expression of Jingzhaotoxin-III in Escherichia coli

摘要

ABSTRACT Jingzhaotoxin-III (JZTX-III), a 36-residue peptide cardiotoxin containing three pairs of disulphide bonds, has been characterized from the venom of the Chinese tarantula Chilobrachys jingzhao . JZTX-III is a promising target for drug development and clinical application, due to its specific inhibitory effects on the human voltage-gated potassium channel subtype hKv2.1 and sodium channel subtype hNav1.5, which are mainly expressed in the cardiac myocytes. The most direct way to obtain JZTX-III is by extraction from the native venom of the tarantula jingzhao , but the amount is often insufficient to meet research and clinical demands. Therefore, there is need for an efficient expression system that can provide a larger quantity of JZTX-III. In this paper, we utilized a galactose auto-induction system to assist the Escherichia coli strain SHuffle T7 Express to express recombinant JZTX-III, followed by in situ purification on a Ni-nitrilotriacetic acid (Ni-NTA) column. Subsequent experiments were performed to demonstrate the advantages of the galactose auto-induction method and to optimize the incubation conditions. Under the optimal expression conditions, the product of the purified bioactive recombinant JZTX-III reached 12.1 mg/L. Furthermore, it is expected that this expression method can be widely applied to the heterologous expression of other disulphide-bond-rich peptides.