Efficient expression of anthrax edema factor in Escherichia coli and its single-step purification

Abstract:

[Objective] To develop a new method for efficient expression and rapid preparation of biologically active anthrax edema factor (EF). [Methods] EF was fused with GST and expressed in the host E. coli BL21-CodonPlus (DE3)-RIL by IPTG induction. The crud protein was extracted by permeabilization, and then EF was purified by onestep affinity chromatography. cAMP assay, Native-PAGE and competitive inhibition analysis were carried out to evaluate EF's biological activity. [Results] EF was expressed in soluble form and then purified to 96% purity by single-step. The recombinant EF was able to bind furin-nicked protective antigen (PA) to form edema toxin, which could elevate the intracellular cAMP level of CHO-K1 cells dramatically. [Conclusion] This work provides a timesaving method for purification of EF with high purity and good biological activity, which might be valuable for anthrax-related study.

Key words:anthrax;edema toxin;recombinant expression;affinity chromatography