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

Catalog number:  C601003

 Related applications:

Protein Expression

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One Shot® BL21 Star™ (DE3) Chemically Competent E. coli are designed for applications that require high-level expression of non-toxic recombinant proteins from low copy number, T7 promoter-based expression systems (e.g., Champion™ pET vectors). One Shot® BL21 Star™ (DE3) Chemically Competent cells are provided at a transformation efficiency of 1 x 108 cfu/µg plasmid DNA. Features of One Shot® BL21 Star™ cells:

• Contain a genotype that promotes high mRNA stability and protein yield
• Optimized for use with low copy number, T7 promoter-based plasmids
• Provided in a single-tube, single-use format—allows all transformation steps to take place in the same tube, thereby helping to save time and prevent contamination

Enhanced expression of nontoxic recombinant proteins
One Shot® BL21 Star™ (DE3) cells contain the DE3 lysogen that carries the gene for T7 RNA polymerase under control of the lacUV5 promoter. IPTG is required to induce expression. This strain also offers enhanced mRNA stability due to a mutation in the RNaseE gene (rne131) that reduces levels of endogenous RNases and mRNA degradation, thereby increasing the stability of mRNA transcripts and increasing protein yield. Protein expression is further enhanced by the absence of the lon and outer membrane (OmpT) proteases, which 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.

Genotype:F-ompT hsdSB (rB-, mB-) galdcmrne131 (DE3)

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, consider BL21-AI™ One Shot® Chemically Competent E. coli.
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)
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 reactions
Propagating ccdB Vectors: Not for ccdB vector propagation
Reduces Recombination: No
T1 Phage - Resistant (tonA): No
Transformation Efficiency: > 1x10^8

Contents & storage

• One Shot® BL21 Star™ (DE3) E.coli: 20 vials, 50 µl each (total of 1 ml)
• pUC19 DNA (10 pg/ul): 1 vial, 50 µl
• SOC Medium: 1 bottle, 6 ml

Store Competent Cells at -80°C. Store pUC19 DNA at -20°C. Store SOC Medium at 4°C or at room temperature.


Manuals & protocols