Protein Expression Competent Cell Pack
The pack includes BL21(DE3) competent cells for nontoxic proteins and BL21(DE3) pLysS competent cells for both toxic and nontoxic proteins. DE3 derivatives of BL21 allow protein expression and easy induction. The pack also includes BL21-Gold(DE3) competent cells and BL21 Gold (DE3) pLysS competent cells. The BL21-Gold cells incorporate major improvements and offer higher transformation efficiencies.
BL21-Gold competent cells feature the high transformation efficiency phenotype (Hte) and have the gene encoding endonuclease I (endA) inactivated. Together, these two features allow direct cloning for most protein expression constructs. By cloning directly in the strain, you can save 2 days of work normally spent on subcloning procedures. The DE3-derivatives of BL21 contain the T7 RNA polymerase gene controlled by the lacUV5 promoter. This all-purpose derivative yields high-level expression and provides easy induction. Use this derivative with nontoxic proteins.