BL21 Star™ (DE3)pLysS One Shot™ Chemically Competent E. coli

Catalog number:  C602003

 Related applications:

Protein Expression

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One Shot® BL21 Star™ (DE3) pLysS E. coli are chemically competent cells designed for applications that require high-level expression of non-toxic recombinant proteins from high copy number, T7 promoter-based expression systems (e.g., pRSET T7 vectors). One Shot® BL21 Star™ (DE3) pLysS Chemically Competent cells have a transformation efficiency of >1 x 108 cfu/ µg plasmid DNA.
• High mRNA stability results in increased protein yield
• Ideal for use with high copy number, T7 promoter-based plasmids
• Low background expression in uninduced cells

Increased mRNA Stability Improves Protein Yield
One Shot® BL21 Star™ (DE3) pLysS E. coli offers enhanced mRNA stability so that abundant mRNA is available for protein expression. This enhanced stability is due to a mutation in the RNaseE gene (rne131), which is involved in mRNA degradation.

High Expression of Non-Toxic Recombinant Proteins
One Shot® BL21 Star™ (DE3) pLysS cells are ideal for high-level expression of non-toxic but potentially growth-inhibiting recombinant proteins from high copy number, T7 promoter-based expression systems. The pLysS CamR plasmid carried by the BL21 Star™ (DE3) pLysS strain expresses T7 lysozyme, a T7 RNA polymerase inhibitor that prevents leaky expression in uninduced cells. The p15a origin of pLysS makes this plasmid compatible with pUC or pBR322-derived plasmids. This strain also contains the DE3 lysogen that carries the T7 RNA polymerase gene under control of the lacUV5 promoter, and IPTG is required to induce expression of the T7 RNA polymerase. One Shot® BL21 Star™ (DE3) pLysS cells do not contain the lon protease and are also deficient in the outer membrane protease, OmpT. The absence of these proteases reduces degradation of heterologous proteins.

Note: The BL21 Star™ strains have higher basal expression of heterologous genes than BL21 strains, due to the increased stability of mRNA. Therefore, these strains may not be useful for expression of toxic genes. However, the BL21 Star™ (DE3) pLysS strains offer lower expression levels than the BL21 Star™ strains.

F-ompT hsdSB (rB-, mB-) galdcmrne131 (DE3) pLysS (CamR)

Easy-to-use, Single Tube Format
The single tube, single use, format allows for all steps of transformation up to plating to take place in the same tube, thereby helping to save time and prevent contamination.

Find the Strain and Format That You Need
We also offer many other different strains and formats of chemically competent cells and electrocompetent cells to help meet your specific transformation needs. For expression of toxic proteins, choose BL21-AI™ One Shot® Chemically Competent E. coli. For expression of non-toxic recombinant proteins from low copy number (e.g. Champion™ pET vectors), T7 promoter-based expression system, choose our One Shot® BL21 Star™ (DE3) chemically competent cells.

For Research Use Only. Not intended for animal or human diagnostic or therapeutic use.
For Research Use Only. Not for use in diagnostic procedures.


Competent Cell Type: Chemically Competent
Species: E. coli
Format: One Shot
Blue-White Screening: No
Bacterial or Yeast Strain: BL21 Star™(DE3)pLysS
Cloning Methylated DNA: No
F' Episome (to make ssDNA): Lacks F' Episome
High Throughput Compatibility: Not High Throughput-Compatible (Manual)
Improves Plasmid Quality: No
Product Line: One Shot™
Product Size: 20 x 50 µL
Propagating ccdB Vectors: Not for ccdB vector propagation
Reduces Recombination: No
T1 Phage - Resistant (tonA): No
Transformation Efficiency: > 1x10^8

Contents & storage

Both BL21 Star™(DE3) and BL21 Star™(DE3)pLysS Chemically Competent E. coli are provided in single-use 50 µl aliquots, with S.O.C. medium, and supercoiled control plasmid. Store competent cells at -80°C.


Manuals & protocols