BL21(DE3)

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Sources

BCCM/GeneCorner Plasmid Collection

Chromosomal Genotype

E. coli B dcm ompT hsdS(r_B^-m_B^-) gal

Phage

λDE3

Notes

The strain contains DE3, a λ prophage carrying the T7 RNA polymerase gene under control of the lac UV5 promoter and lacIq. IPTG is required to induce expression of the T7 RNA polymerase. Protein expression from transforming plasmids containing a T7 promoter-driven expression system is repressed until IPTG induction of T7 RNA polymerase expression occurs. The strain does not contain the lon protease and is also deficient in the outer membrane protease, OmpT. The lack of two key proteases reduces the degradation of heterologous proteinsexpressed in the strain

References

Studier and Moffatt, J. Mol. Biol. 189 (1986), 113-130 PMID: 3537305