Description_x000D_ General description_x000D_ OverExpress™ Electrocompetent and Chemically Competent Cells are E. coli strains that are effective in expressing toxic proteins from all classes of organisms, including eubacteria, yeasts, plants, viruses, and mammals. The effectiveness of these new strains in expressing toxic proteins has been validated in more than 350 publications. The OverExpress™ strains contain genetic mutations phenotypically selected for conferring tolerance to toxic proteins. The strain C41(DE3) was derived from BL21(DE3). This strain has at least one mutation, which prevents cell death associated with expression of many recombinant toxic proteins. The strain C43(DE3) was derived from C41(DE3) by selecting for resistance to a different toxic protein and can express a different set of toxic proteins to C41(DE3). OverExpress C41(DE3)pLysS and C43(DE3)pLysS also carry a chloramphenicol-resistant plasmid that encodes T7 lysozyme, which is a natural inhibitor of T7 RNA polymerase. Cells containing pLysS produce a small amount of T7 lysozyme. These strains are used to suppress basal expression of T7 RNA polymerase prior to induction, thus stabilizing recombinants encoding particularly toxic proteins._x000D_ Genotype_x000D_ F – ompT hsdSB (rB- mB-) gal dcm (DE3) pLysS (CmR)_x000D_ Features and Benefits_x000D_ • Express genes cloned into any T7 vector with these BL21(DE3) derivatives_x000D_ • Effective in expressing toxic & membrane proteins_x000D_ • Cited in over 350 research articles_x000D_ Components_x000D_ • OverExpress C41(DE3) pLysS chemically competent cells_x000D_ • pUC 19 transformation control DNA_x000D_ • recovery medium for expression_x000D_ Legal Information_x000D_ OverExpress is a trademark of Imaxio, S.A.