Product Class: Other

T7 Express lysY/Iq Competent E. coli (High Efficiency)

Product Introduction

High efficiency chemically competent E. coli cells suitable for T7 expression with highest level of expression control.

  • Enhanced BL21 derivative
  • T7 RNA Polymerase in the lac operon - no λ prophage
  • Tight control of expression by laclq allows potentially toxic genes to be cloned
  • Control of T7 RNA Polymerase by lysozyme allows potentially toxic genes to be expressed
  • 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
C3013I 6 x 0.2 ml

Product Information

Description

Highlights

  • Enhanced BL21 derivative for T7 expression
  • T7 RNA Polymerase in the lac operon - no λ prophage
  • Tight control of expression by laclq allows potentially toxic genes to be cloned
  • Control of T7 RNA Polymerase by lysozyme allows toxic genes to be expressed
  • Lys Y is a variant of T7 lysozyme lacking any amidase activity, thus cells are less susceptible to lysis during induction
  • Maintenance of lysozyme/lacIq plasmid does not require antibiotic selection
  • Deficient in proteases Lon and OmpT
  • Resistant to phage T1 (fhuA2)
  • Does not restrict methylated DNA (McrA-, McrBC-, EcoBr-m-, Mrr-)
  • B Strain
  • Free of animal products

Transformation Efficiency

0.6-1 x 109 cfu/μg pUC19 DNA T7 Express lysY/Iq Competent E. coli (High Efficiency) is an enhanced BL21-derived strain engineered to provide exceptional control of target protein expression with extremely low basal expression levels. These chemically competent, IPTG-inducible E. coli cells enable high-efficiency transformation and robust T7 promoter-driven expression of proteins, including those that are potentially toxic.

Figure 1: Transformation of a toxic mammalian clone into E. coli hosts 

Bar graph comparing percent transformants for various strains
A T7 expression plasmid and the same plasmid containing a gene encoding a toxic mammalian protein were transformed into each host. Comparison of the relative transformation efficiencies demonstrates that the T7 Express hosts provide the levels of control necessary for transformation of potentially toxic clones. BL21(DE3) could not be transformed with the toxic clone.


Figure 2: T7-controlled expression of a non-toxic protein in E. coli hosts


A T7 expression plasmid containing a gene encoding an E. coli protein was transformed into each host, grown to 0.6 OD and induced for 3 hours. Comparison of soluble extracts from uninduced (-) and induced (+) cells shows superior control of basal expression in the T7 Express hosts while maintaining high levels of induced expression.


Figure 3: Effect of heat shock time on T7 Express lysY/Iq competent E.coli transformation efficiency

Line graph depicting effect of heat shock time
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 4: Effect of DNA incubation time on T7 Express lysY/Iq competent E.coli transformation efficiency

Line graph depicting effect 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

MiniF lysY lacIq(CamR) / fhuA2 lacZ::T7 gene1 [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:
T7 Expression,
E. coli Protein Expression Strains,
E. coli Expression Strains,
Protein Expression,
This product can be used in the following applications:
T7 Expression,
Toxic Protein Expression,
Membrane Protein Expression,
Expression of Difficult Proteins,
Peptide Ligation,
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
  • NEB # Stored at (°C)
    C3013I -80
    Component Name Component # Stored at (°C) Amount Concentration
    T7 Express lysY/Iq Competent E. coli (High Efficiency) C3013IVIAL -80 6 x 0.2 ml Not Applicable

Properties & Usage

Antibiotic for Plasmid Selection

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

Shipping Notes

  • Ships on dry ice

Antibiotic Resistance

  • nit
  • cam

Features

  • T7 expression
  • Protease deficient
  • Highest level of expression control

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.
  3. Maintenance of the miniF plasmid does not require antibiotic selection. If chloramphenicol is added, use 10 µg/ml final concentration.

Tools & Resources

Selection Charts

FAQs & Troubleshooting

FAQs

  1. Why are there no colonies or no growth in liquid culture (C3013)?
  2. Why is there no protein visible on gel or no activity (C3013)?
  3. Why is induced protein insoluble (C3013)?
  4. What are the solutions/recipes (C3013)?
  5. Can I store competent cells at -20°C instead of -80°C?
  6. What is the difference between NEB #C3013H and NEB #C3013I?
  7. What are the strain properties (C3013)?
  8. What is the optimal heat shock time for this strain (NEB #C3013H and NEB #C3013I)?
  9. How long should I incubate cells on ice after DNA has been added (NEB #C3013H and NEB #C3013I)?
  10. Is T7 Express lysY/Iq (NEB #C3013H and NEB #C3013I) compatible with auto-induction procedures?
  11. Which kind of transformation tubes should be used?
  12. What volume of DNA can be added into competent cells?
  13. What is the shelf life for this strain (NEB #C3013H and NEB #C3013I)?
  14. Are NEB's competent cells compatible with the “Mix & Go" protocol?
  15. Is antibiotic selection necessary to maintain the MiniF-lysY-lacIq plasmid?
  16. Is T7 expression subject to catabolite repression in NEB T7 Express or SHuffle strains?

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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