BL21 Competent Cells, Agilent Technologies
About this item
BL21 competent cells are an all-purpose strain for high-level protein expression and easy induction.
- High-level protein expression and easy induction
- Can be used with non-T7 RNA polymerase protein expression systems
- Allows the tightest control of protein expression for extremely toxic proteins
- Suitable for expressing proteins from all species, including mammals
- Ideal for difficult protein expression, especially when codon bias is a problem
- Increases transformation efficiency with Hte phenotype
- Derived from Agilent’s high performance BL21-Gold competent cell line
BL21 competent cells are an all-purpose strain for high-level protein expression and easy induction. The basic BL21 strain does not contain the T7 RNA polymerase gene and can be used with non-T7 RNA polymerase protein expression systems. BL21 has the tightest control of protein expression for extremely toxic proteins.
Agilent BL21-CodonPlus competent cells dramatically improve protein expression in E. coli by overcoming codon bias. Codon bias occurs when forced high-level expression of a gene containing codons rarely expressed in E. coli depletes internal tRNA pools. This often results in poor protein synthesis, early termination of the polypeptide chain, or misincorporation of amino acids into the expressed protein. BL21-CodonPlus competent cells are derived from Agilent’s high performance BL21-Gold competent cell line. These cells enable efficient high-level expression of heterologous proteins in Escherichia coli.;Overcoming codon bias saves time and labor by eliminating the need for site-directed mutagenesis or for expressing the protein in a eukaryotic expression system. L21-CodonPlus competent cells are derivatives of BL21-Gold cells that have been engineered to include extra copies of genes that encode tRNAs for these rare E. coli codons. The additional availability of these tRNAs facilitates high level expression of many heterologous recombinant genes in BL21-CodonPlus competent cells. Efficient production of heterologous proteins in E. coli is frequently limited by the rarity of certain tRNAs that are abundant in the organisms from which the heterologous proteins are derived. Forced high-level expression of heterologous proteins can deplete the pool of rare tRNAs and stall translation.
BL21-CodonPlus competent cells also feature the Hte phenotype present in Agilent’s highest efficiency competent cell strain, XL10-Gold. The presence of the Hte phenotype increases the transformation efficiency of the cells. In addition, the gene that encodes endonuclease I (endA), an enzyme that rapidly degrades plasmid DNA isolated by most miniprep procedures, has been inactivated in these cells. These two features enable direct cloning of many protein expression constructs.
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 two 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.
Caution: For research use only. Not for use in diagnostic procedures.
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Product Details & Documents
BL21 competent cells are an all-purpose strain for high-level protein expression and easy induction.
- High-level protein expression and easy induction
- Can be used with non-T7 RNA polymerase protein expression systems
- Allows the tightest control of protein expression for extremely toxic proteins
- Suitable for expressing proteins from all species, including mammals
- Ideal for difficult protein expression, especially when codon bias is a problem
- Increases transformation efficiency with Hte phenotype
- Derived from Agilent’s high performance BL21-Gold competent cell line
BL21 competent cells are an all-purpose strain for high-level protein expression and easy induction. The basic BL21 strain does not contain the T7 RNA polymerase gene and can be used with non-T7 RNA polymerase protein expression systems. BL21 has the tightest control of protein expression for extremely toxic proteins.
Agilent BL21-CodonPlus competent cells dramatically improve protein expression in E. coli by overcoming codon bias. Codon bias occurs when forced high-level expression of a gene containing codons rarely expressed in E. coli depletes internal tRNA pools. This often results in poor protein synthesis, early termination of the polypeptide chain, or misincorporation of amino acids into the expressed protein. BL21-CodonPlus competent cells are derived from Agilent’s high performance BL21-Gold competent cell line. These cells enable efficient high-level expression of heterologous proteins in Escherichia coli.;Overcoming codon bias saves time and labor by eliminating the need for site-directed mutagenesis or for expressing the protein in a eukaryotic expression system. L21-CodonPlus competent cells are derivatives of BL21-Gold cells that have been engineered to include extra copies of genes that encode tRNAs for these rare E. coli codons. The additional availability of these tRNAs facilitates high level expression of many heterologous recombinant genes in BL21-CodonPlus competent cells. Efficient production of heterologous proteins in E. coli is frequently limited by the rarity of certain tRNAs that are abundant in the organisms from which the heterologous proteins are derived. Forced high-level expression of heterologous proteins can deplete the pool of rare tRNAs and stall translation.
BL21-CodonPlus competent cells also feature the Hte phenotype present in Agilent’s highest efficiency competent cell strain, XL10-Gold. The presence of the Hte phenotype increases the transformation efficiency of the cells. In addition, the gene that encodes endonuclease I (endA), an enzyme that rapidly degrades plasmid DNA isolated by most miniprep procedures, has been inactivated in these cells. These two features enable direct cloning of many protein expression constructs.
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 two 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.
Caution: For research use only. Not for use in diagnostic procedures.
Documents
Certificates
Search by Lot NumberAgilent Molecular and Syn Bio solutions Agilent Molecular and Synthetic Biology Solutions
Product Literature
Manual BJ5183-AD-1 Electroporation Competent Cells Manual BL21-Gold Competent Cells, BL21-Gold(DE3) Competent Cells, and BL21-Gold(DE3)pLysS Competent Cells
Manual
TDS Competent cells for cloning
Datasheet
Specifications for Product Family
Specifications
- Catalog No:
- ST200133
- ST200131
- ST200132
- ST230130
- ST230132
- ST230134
- ST230240
- ST230245
- 99900-860
- ST230255
- 97066-330
- ST230275
- 76193-370
- Genotypes:
- E. coli B F– ompT hsdS(rB – mB–) dcm+ Tetr gal endA Hte [argU ileY leuW Camr]
- E. coli B F– ompT hsdS(rB– mB–) dcm+ Tetr gal endA Hte [argU proL Camr]
- E. coli B F– ompT hsdS(rB– mB–) dcm+ Tetr gal λ (DE3) endA Hte metA::Tn5(Kanr) [argU ileY leuW Camr]
Specifications
Product Family Options
Product Information
- SizeFeaturesAvailabilityPrice
- ST200133BL21 competent cellsBL21 competent cells5×0.2 mlFor extremely toxic proteins, use with lambda CE6 under the control of T7 RNA polymerase or use with non-T7 polymerase-based systemsLog in for availabilityEach$240.38Supplier Number: 200133Specifications:
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Specifications
Cat. No.ST200133Genotypes - ST200131BL21(DE3) competent cellsBL21(DE3) competent cells5×0.2 mlFor non-toxic proteins, encodes T7 RNA polymerase under the control of the lacUV5 promoter. Use with Variflex or Affinity pCAL vectors.Log in for availabilityEach$240.38Supplier Number: 200131Specifications:
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Specifications
Cat. No.ST200131Genotypes - ST200132BL21(DE3) pLysS competent cellsBL21(DE3) pLysS competent cells5×0.2 mlFor both toxic and non-toxic proteins, pLysS codes for T7 lysozyme, a T7 RNA polymerase inhibitor. Use with pET or pCAL vectors.Log in for availabilityEach$240.38Supplier Number: 200132Specifications:
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Specifications
Cat. No.ST200132Genotypes - BL21-Gold competent cells10×0.1 mlFor extremely toxic proteins, use with lambda CE6 under the control of T7 RNA polymerase or use with non-T7 polymerase-based system. Efficiency is ≥1×108 cfu/µg of supercoiled DNA.Log in for availabilityEach$295.69Supplier Number: 230130Specifications:
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Specifications
Cat. No.ST230130Genotypes - ST230132BL21-gold (DE3) competent cellsBL21-gold (DE3) competent cells10×0.1 mlFor non-toxic proteins, encodes T7 RNA polymerase under the control of the lacUV5 promoter. Use with Variflex or Affinity pCAL vectors. Efficiency is ≥1×108 cfu/µg of supercoiled DNA.Log in for availabilityEach$298.44Supplier Number: 230132Specifications:
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Specifications
Cat. No.ST230132Genotypes - BL21-gold (DE3)pLysS competent cells10×0.1 mlFor both toxic and non-toxic proteins, pLysS codes for T7 lysozome, a T7 RNA polymerase inhibitor. Use with Variflex or Affinity pCAL vectors. Efficiency is ≥1×108 cfu/ µg of supercoiled DNA.Log in for availabilityEach$298.44Supplier Number: 230134Specifications:
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Specifications
Cat. No.ST230134Genotypes - ST230240BL21-codonplus -RIL competent cellsBL21-codonplus -RIL competent cells10×0.1 mlFor extremely toxic proteins, use with lambda CE6 under the control of T7 RNA polymerase, 1×107 cfu/µg of supercoiled DNA.Log in for availabilityEach$365.46Supplier Number: 230240Specifications:
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Specifications
Cat. No.ST230240Genotypes - ST230245BL21-codonplus (DE3)-RIL competent cellsBL21-codonplus (DE3)-RIL competent cells10×0.1 mlEncodes T7 RNA polymerase under control of the lacUV5 promoter for easy protein expression, Use with pET or pCAL vectors, 1×107 cfu/µg of supercoiled DNALog in for availabilityEach$369.02Supplier Number: 230245Specifications:
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Specifications
Cat. No.ST230245GenotypesE. coli B F– ompT hsdS(rB – mB–) dcm+ Tetr gal endA Hte [argU ileY leuW Camr] - BL21-Codonplus -RP competent cells10×0.1 mlFor extremely toxic proteins, use with lambda CE6 under the control of T7 RNA polymerase, 1 x 107 cfu/µg of supercoiled DNA.Discontinued-Supplier Number: -Specifications:
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Specifications
Cat. No.99900-860GenotypesE. coli B F– ompT hsdS(rB– mB–) dcm+ Tetr gal endA Hte [argU proL Camr] - ST230255BL21-codonplus (DE3)-RP competent cellsBL21-codonplus (DE3)-RP competent cells10×0.1 mlEncodes T7 RNA polymerase under control of the lacUV5 promoter for easy protein expression, Use with pET or pCAL vectors, 1×107 cfu/µg of supercoiled DNA.Log in for availabilityEach$369.02Supplier Number: 230255Specifications:
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Specifications
Cat. No.ST230255Genotypes - 97066-330BL21-Codonplus (DE3)-RIL-X competent cellsBL21-Codonplus (DE3)-RIL-X competent cells10×0.1 mlEncodes T7 RNA polymerase under control of the lacUV5 promoter for easy protein expression plus methionine label, Use with pET or pCAL vectors, Used for labeling cells 1×107 cfu/µg of supercoiled DNA.Discontinued-Supplier Number: -Item requires temperature control for storage and delivery with additional fees. It's not eligible for return due to safety and quality concerns. Consider requirements before purchasing.Specifications:
More
Specifications
Cat. No.97066-330GenotypesE. coli B F– ompT hsdS(rB– mB–) dcm+ Tetr gal λ (DE3) endA Hte metA::Tn5(Kanr) [argU ileY leuW Camr] - BL21-codonplus (DE3)-RP-X competent cells10×0.1 mlEncodes T7 RNA polymerase under control of the lacUV5 promoter for easy protein expression plus methionine label, Use with pET or pCAL vectors, Used for labeling cells 1×107 cfu/µg of supercoiled DNA.Discontinued-Supplier Number: -Specifications:
More
Specifications
Cat. No.ST230275Genotypes - 76193-370BL21-Codonplus (DE3)-RIPL competent cellsBL21-Codonplus (DE3)-RIPL competent cells10×0.1 mlThese cells contain extra copies of rare E. coli argU, ileY, leuW, proL tRNA genes which corrects for codon bias and dramatically improves expression of sequences from other organisms.Log in for availabilityPack of 10$365.46Supplier Number: 230280Item requires temperature control for storage and delivery with additional fees. It's not eligible for return due to safety and quality concerns. Consider requirements before purchasing.Specifications:
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Specifications
Cat. No.76193-370Genotypes
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