[Codon optimization of recombinant staphylococcal enterotoxin O enhances the expression level in Escherichia coli].

OBJECTIVE: To enhance the expression level of staphylococcal enterotoxin O (SEO) by optimization of rare codons. METHODS: The gene of mature SEO (His-tag included) was cloned to pET28a, and 15 rare codons on the gene were optimized by PCR technology. These recombinant plasmids then were transformed into E.coli BL21(DE3), respectively. After IPTG induced, the expression levels of those mutants were analyzed by SDS-PAGE. The proteins were purified and their bioactivities were determined. RESULT: After the optimization of rare codons, the expression levels were increased from 7.49% to 19.8% in total cell proteins. The optimized SEO had bioactivity to stimulate the proliferation of murine lymphocytes, which was equivalent to that of non-optimized SEO in vitro. CONCLUSION: Optimization of rare codons can enhance the expression of SEO effectively.