Expression, purification and characterization of recombinant exfoliative toxin A from Staphylococcus aureus

For the expression of Staphylococcus aureus exfoliative toxin A in Escherichia coli regulated by a T5 promoter, the gene was amplified by polymerase chain reaction and cloned into expression vector pQE-30 to generate pQE-ETA. The maximum production of His6-tagged protein by E. coli M15 ( PQE-ETA) was obtained with 0.1 mM IPTG induction for 4 h at 25 degrees C. The expressed protein was purified by Ni2+-nitrilotriacetate resin to a specific activity of 0.25 mg/ml recombinant protein. The molecular mass of the purified protein was estimated to be 27 kDa by SDS-PAGE. Western blot showed that, the recombinant protein was recognized by sheep anti-ETA antibody and the recombinant protein could split the stratum granulosum of the mouse skin. In conclusion, it was found that the recombinant ETA exhibited no important differences from those properties described for the native protein.