The NEB(UK) website uses session and analytics cookies. By using this site you are agreeing to the use of cookies as described. Close Message
New England Biolabs UK Ltd NEB Technical Reference NEB Price List 2012 Free Delivery
Search:

Home > Products > Competent Cells

Competent E. coli from NEB

 

For many years staff scientists at New England Biolabs have been using their own line of optimized chemically competent E. coli cells for cloning and protein expression. Now when you are looking for a versatile cloning strain, rapid colony growth, or tight control of expression, you can benefit from the superior performance and high quality of these strains.
 

Advantages of NEB Competent Cells

  • Free of animal products
  • T1 phage resistance (fhuA2)
  • Media and control plasmid included with most strains
  • A variety of convenient formats, including single use transformation tubes and, on request, 96 well plates
  • Bulk sales capabilities with custom packaging

Strain Selection Chart

Characteristics Strain
Cloning and Sub Cloning Strains
Fastest Growth – Colonies Visible After 6.5 Hours

NEB Turbo High Efficiency

NEB Turbo Electrocompetent

Versatile Cloning Strain NEB 5-alpha High Efficiency
NEB 5-alpha Subcloning Efficiency
NEB 5-alpha Electrocompetent
Toxic Gene Cloning NEB 5-alpha F'Iq High Efficiency
Large Plasmid and BAC Cloning NEB 10-beta High Efficiency
NEB 10-beta Electrocompetent
dam/dcm Methyltransferase Free Plasmid Growth dam–/dcm–
Protein Expression Strains
Most Popular Protein Expression Strain NEB Express High Efficiency
Control of IPTG Induced Protein Expression NEB Express Iq High Efficiency
Most Popular T7 Protein Expression Strain T7 Express High Efficiency
Control of IPTG Induced Protein Expression T7 Express Iq High Efficiency
Tight Control of Protein Expressionby Inhibition of T7 RNA Polymerase T7 Express lysY High Efficiency
Highest Level of Protein Expression Control T7 Express lysY/Iq High Efficiency
For Crystallography Experiments / SeMet Labeling T7 Express Crystal High Efficiency
Enhanced capability to correctly fold proteins with multiple disulfide bonds in the cytoplasm SHuffle Express
Enhanced capability to correctly fold proteins with multiple disulfide bonds in the cytoplasm SHuffle T7 Express

Tight control/expression of toxic proteins / Enhanced capability to correctly fold proteins with multiple disulfide

bonds in the cytoplasm

SHuffle T7 Express lysY
Routine T7 expression BL21(DE3)

Tunable T7 expression for difficult targets such as membrane proteins, toxic proteins and proteins prone

to insoluble expression

Lemo21(DE3)
Enhanced capability to correctly fold protein with multiple disulfide bonds in the cytoplasm and T7 expression SHuffle T7
 
 
Competent Cells Product Comparison Chart - compare NEB cells with those from other suppliers
 

Strain Property Chart

Transform
Efficiency
(cfu/µg)
Strain T1
Phage
Resistant

Library Construct

-ion(1)

Cloning/

Sub

Cloning

Blue/
White
Screening
laclq lysY Colonies
Visible
after 6.5h
Endo-
nucleaseI
Deficient(2)
Protease(3)
Deficient
F' RecA-

T7 RNA

Polymer

-ase

Cytoplasmic

disulphide bond

formation(4)

NEB Turbo 1-3x109 K12 - - - - -
NEB Turbo Electrocompetent 1-4x1010 K12 - - - - -
NEB 5-alpha 1-3x109 K12 - - - - - - -
NEB 5-alpha Subcloning >1x106 K12 - - - - - - -
NEB 5-alpha Electrocompetent 1-4x1010 K12 - - - - - - -
NEB 5-alpha F'Iq >1-3x109 >K12 >√ >√ >√ >√ >√ >- >- >√ >- >√ >√ >- >-
NEB 10-beta 1-3x109 K12 - - - - - - -
NEB 10-beta Electrocompetent 1-4x1010 K12 - - - - - - -
dam–/dcm– 1-3x106 K12 - - - - - - - - -
NEB Express 0.6-1x109 B - - - - - - - -
NEB Express Iq 0.6-1x109 B - - - - - - -
T7 Express 0.6-1x109 B - - - - - - - -
T7 Express Iq 0.6-1x109 B - - - - - - -
T7 Express lysY 0.6-1x109 B - - - - - - -
T7 Express lysY/Iq 0.6-1x109 B - - - - - -
T7 Express Crystal 0.6-1x109 B - - - - - - - -
SHuffle T7 1x106 K12 - - - - - - - -
SHuffle Express 1x107 B - - - - - - - -
SHuffle T7 Express 1x107 B - - - - - - -
SHuffle T7 Express
lysY
1x107 B - - - - - -
BL21(DE3) 1-5x106 B - - - - - - - - - -
Lemo21(DE3) 1-3x107 B - - - - - - - - - -


(1) Restriction-deficient strain.
(2) Important for plasmid preparation.
(3) Lacks Lon and OmpT protease activity.
(4) Constitutively expresses a chromosomal copy of the disulfide bond isomerase DsbC.

 

Cloning
For cloning experiments choose from several high efficiency competent cell strains. These E. coli strains are T1 phage resistant and are endA deficient for high quality plasmid preparations. Additionally, all competent cells from NEB are free of animal products. NEB 5-alpha strains are enhanced DH5α™ derivatives, while NEB 10-beta is a DH10B™ derivative. NEB also offers a unique fast growing strain (NEB Turbo) and a dam–/dcm– strain.

Protein Expression
NEB offers several strains with varying levels of expression control, each with phage T1 resistance and extremely high transformation efficiencies. NEB Express is an enhanced BL21 derivative available with or without the added control of IPTG-induced expression of non-T7 plasmids from lacIq. T7 Express, an enhanced derivative of BL21 (DE3), is available with or without the added control of lacIq, and both versions can be purchased with or without the lysY feature for exceptional control of expression. LysY is a variant of T7 lysozyme lacking amidase activity, which make the cells less susceptible to lysis during induction, yet they retain the ability to inhibit T7 RNA polymerase. Basal expression of the target gene is minimized without inhibiting IPTG-induced expression. LysY is encoded on a single-copy miniF plasmid that does not require antibiotic selection for propagation. T7 Express lysY/Iq provides the highest level of expression control.

SHuffle strains enable disulfide bond formation in the cytoplasm. Normally, reductases in the E. coli cytoplasm keep cysteines in their reduced form, thereby preventing any disulfide bond formation in this compartment. The deletions of the genes for glutaredoxin reductase and thioredoxin reductase (Δgor ΔtrxB), allows disulfide bond formation in the cytoplasm with SHuffle. This combination of mutations is normally lethal, but the lethality is suppressed by a mutation in the peroxiredoxin enzyme (ahpC*). In addition, SHuffle expresses a version of the periplasmic disulfide bond isomerase DsbC which lacks its signal sequence, retaining it in the cytoplasm. This enzyme has been shown to act on proteins with multiple disulfide bonds, to correct mis-oxidized bonds and promote proper folding. The gene for the cytoplasmic DsbC is present on the chromosome.

BL21 (DE3) is available for routine T7 expression in addition to Lemo21(DE3) for tunable expression of difficult targets such as membrane proteins, toxic proteins and proteins prone to insoluble expression.

Formats
NEB provides these superior competent cell strains in several formats for your convenience. All are available as 50 µl single-use transformation tubes and many are available in larger, 200 µl tubes for multiple simultaneous reactions. Our most popular cloning strains are available as electrocompetent cells. NEB 5-alpha is also available in a lower efficiency, subcloning format for substantial value.

 

DH5α and DH10B are trademarks of Invitrogen Corporation.





Terms & Conditions | ISO Certification | Privacy | Returns | Delivery Conditions | Disclaimer | Contact Webmaster | NEB USA | NEB International | Cell Signaling Technology
Find NEB Online   hp youtube hp_twitter_icon Facebook     Find CST Online hp youtube hp_twitter_icon Facebook
©2002-2014, New England Biolabs (UK) Ltd