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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
- No animal products used
- T1 phage resistance
- Media and control plasmid included
- 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 |
| Fastest Growth – Colonies Visible After 6.5 Hours | |
| Versatile Cloning Strain | NEB 5-alpha High Efficiency NEB 5-alpha Subcloning Efficiency NEB 5-alpha Eletrocompetent |
| 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– |
| 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 |
Strain Property Chart
| Transform Efficiency (cfu/µg) |
Strain | T1 Phage Resistant |
Blue/ White Screening |
laclq | lysY | Colonies Visible after 8h |
Endo- nucleaseI Deficient |
Protease Deficient |
Eukaryotic DNA Cloning |
M13 Phage Capable (F+) |
RecA Deficient |
|
| NEB Turbo | 1-3x109 | K12 | √ | √ | √ | - | √ | √ | - | - | √ | - |
| NEB Turbo Electrocompetent | 1x1010 | K12 | √ | √ | √ | - | √ | √ | - | - | √ | - |
| NEB 5-alpha | 1-3x109 | K12 | √ | √ | - | - | - | √ | - | - | - | √ |
| NEB 5-alpha Subcloning | 1x106 | K12 | √ | √ | - | - | - | √ | - | - | - | √ |
| NEB 5-alpha Electrocompetent | 2-4x1010 | K12 | √ | √ | - | - | - | √ | - | - | - | √ |
| NEB 5-alpha F'Iq | 1-3x109 | K12 | √ | √ | √ | - | - | √ | - | - | √ | √ |
| NEB 10-beta | 1-3x109 | K12 | √ | √ | - | - | - | √ | - | √ | - | √ |
| NEB 10-beta Electrocompetent | 2-4x1010 | 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 | √ | - | - | - | - | √ | √ | √ | - | - |
Cloning Strains
NEB 5-alpha is a high efficiency derivative of DH5α™, the industry standard cloning strain. It is also offered in a lacIq version for the cloning of toxic genes. NEB Turbo brings unmatchable speed to your transformations with visible colonies after just 8 hours. Other cloning strains include NEB 10-beta, a DH10B™ derivative, that can be used for transforming large plasmids and BACs, as well as dam-/dcm-, a strain for dam and dcm methylation-free plasmid growth.
Protein Expression
Our protein expression strains offer an extra level of confidence. NEB Express is an enhanced BL21 derivative available with or without the added control of IPTG-induced expression of non-T7 plasmids from lacIq. Several NEB strains feature the lysY gene for exceptional control of expression. LysY is a variant of T7 lysozyme lacking amidase activity making the cells less susceptible to lysis during induction, while retaining 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 (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. T7 Express lysY/Iq provides the highest level of uninduced control. The last strain of this series, T7 Express Crystal, is a metB strain optimized for crystallographic experiments.
Formats
For your convenience, we offer all of these strains in two formats; 20 single-use transformation tubes (50 µl each) or 6 tubes containing 200 µl each. Both formats are supplied with SOC Outgrowth Media and a pUC19 plasmid control. The most popular cloning strain, NEB 5-alpha is offered at a subcloning efficiency for substantial value.
NEB 5-alpha and NEB 10-beta are also available in electrocompetent formats. See www.neb.com for tips on Enhancing Transformation Efficiencies and for the availability of these exciting new strains.
Note: DH5α and DH10B are trademarks of Invitrogen Corporation.