Product Class: Other

NEBExpress® Competent E. coli (High Efficiency)

Having trouble opening your tubes? NEB Tube Opener can help!

Product Introduction

High efficiency chemically competent E. coli cells suitable for non-T7 protein expression.

  • Deficient in proteases Lon and OmpT
  • Resistant to phage T1 (fhuA2)
  • Free of animal products
  • No dry ice surcharge on competent cell shipments
Bioz Badge Exists : True
Catalog # Size Concentration
C2523H 20 x 0.05 ml
C2523I 6 x 0.2 ml

Product Information

Description

Highlights

  • Enhanced BL21 derivative ideal for Plac, Ptac, Ptrc expression vectors
  • Deficient in proteases Lon and OmpT
  • Resistant to phage T1 (fhuA2)
  • Does not restrict methylated DNA (McrA-, McrBC-, EcoBr-m-, Mrr-)
  • Free of animal products

Transformation Efficiency

0.6-1 x 109 cfu/μg pUC19 DNA

Chemically competent E. coli cells suitable for high efficiency transformation and protein expression. Recommended host strain for pMAL Protein Fusion and Purification System.


Figure 1: DNA effects on transformation efficiency and colony output

Line graph depicting DNA effects on transformation efficiency and colony output 
The optimal amount of DNA to use in a transformation reaction is lower than commonly recognized. Using clean, supercoiled pUC19, the efficiency of transformation is highest in the 100 pg-1 ng range. However, the total colonies which can be obtained from a single transformation reaction increase up to about 100 ng.


Figure 2: Effect of heat shock time on NEBExpress Competent E. coli transformation efficiency

Line graph depicting effect of heat shock time on transformation efficiency  
50 μl of competent cells were transformed with 100 pg of pUC19 control DNA following the provided High Efficiency Transformation Protocol except heat shock time varied from 0 to 80 seconds.


Figure 3: Effect of DNA incubation time on NEBExpress Competent E. coli transformation efficiency

Line graph depicting effects of DNA incubation time on transformation efficiency 
50 μl of competent cells were transformed with 100 pg of pUC19 control DNA following the provided High Efficiency Transformation Protocol except DNA incubation time varied from 0 to 40 minutes.

Genotype

fhuA2 [lon] ompT gal sulA11 R(mcr-73::miniTn10--TetS)2 [dcm] R(zgb-210::Tn10--TetS) endA1 Δ(mcrC-mrr)114::IS10
This product is related to the following categories:
Non-T7 Expression,
E. coli Protein Expression Strains,
E. coli Expression Strains,
Protein Expression,
This product can be used in the following applications:
Non-T7 Expression,
Protein Expression in E. coli,
Protein Expression

Reagents Supplied

Reagents Supplied

The following reagents are supplied with this product:

NEB # Component Name Component # Stored at (°C) Amount Concentration

Properties & Usage

Antibiotic for Plasmid Selection

Antibiotics for Plasmid Selection Working Concentration
Ampicillin 100 µg/ml
Carbenicillin 100 µg/ml
Chloramphenicol 33 µg/ml
Kanamycin 30 µg/ml
Tetracycline 15 µg/ml
Streptomycin 25 µg/ml

Shipping Notes

  • Ships on dry ice

Antibiotic Resistance

  • nit

Features

  • Versatile non-T7 expression strain
  • Protease deficient

Product Notes

  1. CAUTION: This product contains DMSO, a hazardous material. Review the MSDS before handling.
  2. STORAGE AND HANDLING: Competent cells should be stored at -80°C. Storage at -20°C will result in a significant decrease in transformation efficiency. Cells lose efficiency whenever they are warmed above -80°C, even if they do not thaw.

Tools & Resources

Selection Charts

FAQs & Troubleshooting

FAQs

  1. Does New England Biolabs offer strains of Competent E.coli suited for protein expression?
  2. How long should I incubate cells on ice after DNA has been added (NEB #C2523H and NEB #C2523I)?
  3. What are the solutions/recipes (C2523)?
  4. What are the strain properties (C2523)?
  5. What is the difference between NEB #C2523H and NEB #C2523I?
  6. Why are there no colonies or no growth in liquid culture (C2523)?
  7. Why is induced protein insoluble (C2523)?
  8. Why is there no protein visible on gel or no activity (C2523)?
  9. Can I store competent cells at -20°C instead of -80°C?
  10. Can the NEBExpress Competent E.coli (High Efficiency) be used for the expression of constructs containing a T7 promoter?
  11. What is the optimal heat shock time for this strain (NEB #C2523H and NEB #C2523I)?
  12. Which kind of transformation tubes should be used?
  13. What volume of DNA can be added into competent cells?
  14. What is the shelf life for this strain (NEB #C2523H and NEB #C2323I)?
  15. Are NEB's competent cells compatible with the “Mix & Go" protocol?
  16. How should I store SOC Outgrowth Medium? The SOC I received with my competent cells recommends storage at either room temperature or 4°C, however, when I purchase it as a stand alone product, it recommends storing it at 4°C. Which is better?

Quality, Safety & Legal

Quality Assurance Statement

Quality Control tests are performed on each new lot of NEB product to meet the specifications designated for it. Specifications and individual lot data from the tests that are performed for this particular product can be found and downloaded on the Product Specification Sheet, Certificate of Analysis, data card or product manual. Further information regarding NEB product quality can be found here.

Specifications

The Specification sheet is a document that includes the storage temperature, shelf life and the specifications designated for the product. The following file naming structure is used to name these document files: [Product Number]_[Size]_[Version]

Certificate Of Analysis

The Certificate of Analysis (COA) is a signed document that includes the storage temperature, expiration date and quality controls for an individual lot. The following file naming structure is used to name these document files: [Product Number]_[Size]_[Version]_[Lot Number]

Safety DataSheets

The following is a list of Safety Data Sheet (SDS) that apply to this product to help you use it safely.

Legal and Disclaimers

Products and content are covered by one or more patents, trademarks and/or copyrights owned or controlled by New England Biolabs, Inc (NEB). The use of trademark symbols does not necessarily indicate that the name is trademarked in the country where it is being read; it indicates where the content was originally developed. The use of this product may require the buyer to obtain additional third-party intellectual property rights for certain applications. For more information, please email busdev@neb.com.

This product is intended for research purposes only. This product is not intended to be used for therapeutic or diagnostic purposes in humans or animals.

New England Biolabs (NEB) is committed to practicing ethical science – we believe it is our job as researchers to ask the important questions that when answered will help preserve our quality of life and the world that we live in. However, this research should always be done in safe and ethical manner. Learn more.

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