BL21(DE3)pLysS Competent Cells allow high-efficiency protein expression of any gene that is under the control of a T7 promoter and has a ribosome binding site. BL21(DE3)pLysS is lysogenic for lambda-DE3, which contains the T7 bacteriophage gene I, encoding T7 RNA polymerase under the control of the lac UV5 promoter. BL21(DE3)pLysS also contains a plasmid, pLysS, which carries the gene encoding T7 lysozyme. T7 lysozyme lowers the background expression level of target genes under the control of the T7 promoter but does not interfere with the level of expression achieved following induction by IPTG. For researchers doing more than one transformation, competent cells are available in standard format (200ul aliquots). For added convenience, single-use competent cells (50ul aliquots) also are offered. Genotype: F-, ompT, hsdS(B) (r(B)-, m(B)-), dcm, gal, lambda(DE3), pLysS, Cm(r).|
T7 RNA Polymerase Under the Control of the lac UV5 Promoter: Inducible protein expression. Deficient in Proteases lon and OmpT: Increased stability of expressed protein.pLysS Plasmid: Lower background expression of target genes.