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Invitrogen™ ElectroMAX™ DH5α-E Competent Cells
Description
Includes
ElectroMAX DH5α-E Competent Cells: 5 vials, 100μL each, pUC19 DNA (10pg/μL): 1 vial, 50μL, S.O.C. medium: 2 bottles, 6mL each
ElectroMAX DH5α-E Competent Cells are derived from the DH5α strain and are suitable for transformation by electroporation. It is challenging to achieve high transformation efficiency by electroporation using the standard DH5α strain (chemical transformation is more efficient) thus additional mutations were introduced to create the DH5α-E strain that is able to reach >1 x 1010 efficiency by electroporation with non-saturating amounts of DNA. Using this strain, 10 to 50 times greater colony number may be obtained in a single transformation than using the chemically competent DH5α cells. Therefore DH5α-E competent cells are ideal for challenging applications, such as generation of cDNA libraries or in transformations with limited DNA input.
ElectroMAX DH5α-E Competent Cells share several key genetic properties. They carry the hsdR mutation to prevent restriction of foreign DNA and the endA1 mutation that increases the yield of plasmid DNA prepared using miniprep protocols. The lacZΔM15 marker provides α-complementation of the ß-galactosidase gene, allowing blue-white screening on agar plates containing X-gal or Bluo-gal. DH5α-E allows efficient transformation of large plasmids and can also serve as a host for M13mp cloning vectors if a lawn of DH5αF′IQ is provided to allow plaque formation. We do not recommended using this strain for direct cloning of methylated genomic DNA.
ElectroMAX DH5α-E Competent Cell features
• Greatly increased plasmid yield and quality due to endA1 mutation
• High-efficiency transformation with plasmids 30 kb in size
• Blue/white screening of recombinant clones due to lacZΔM15
• Ensured insert stability due to recA1 mutation
• hsdR for efficient transformation of unmethylated DNA from PCR applications
Note: A high-voltage electroporation apparatus is required.
Genotype
F– φ80lacZΔM15 Δ(lacZYA-argF)U169 recA1 endA1 hsdR17(rK–, mK+) gal phoA supE44 λ-thi-1 gyrA96 relA1
Genetic marker descriptions
Find the strain and format that fits your needs
• DH strains are available in chemically competent and electrocompetent cell formats.
• Explore Multishot format for high throughput applications.
• MAX Efficiency DH5αF´IQ Competent Cells (Cat. No. 18288019) are available in chemically competent format.
Order Info
Shipping Condition: Dry Ice
Specifications
Specifications
| Product Type | Electrocompetent Cells |
| Contains F' Episome | No |
| Improves Plasmid Quality | Yes (endA1) |
| Cloning Methylated DNA | No |
| Transformation Efficiency Level | High Efficiency (>1 x 109 cfu/μg) |
| Content And Storage | • ElectroMAX DH5α-E Competent Cells (5 x 100 μL) Store Competent Cells at –80°C. • pUC19 DNA (50 μL at 10 pg/μL) Store pUC19 DNA at –20°C. • S.O.C. Medium (2 x 6 mL) Store S.O.C. Medium at 4°C or room temperature. |
| Antibiotic Resistance Bacterial | No |
| Cloning Unstable DNA | Not suitable for cloning unstable DNA |
| Blue/White Screening | Yes (lacZΔM15) |
| High-throughput Compatibility | Low |
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Frequently Asked Questions (FAQs)
For best results, DNA used in electroporation must have a very low ionic strength and a high resistance. A high-salt DNA sample may be purified by either ethanol precipitation or dialysis.
The following suggested protocols are for ligation reactions of 20ul. The volumes may be adjusted to suit the amount being prepared.
Purifying DNA by Precipitation: Add 5 to 10 ug of tRNA to a 20ul ligation reaction. Adjust the solution to 2.5 M in ammonium acetate using a 7.5 M ammonium acetate stock solution. Mix well. Add two volumes of 100 % ethanol. Centrifuge at 12,000 x g for 15 min at 4C. Remove the supernatant with a micropipet. Wash the pellet with 60ul of 70% ethanol. Centrifuge at 12,000 x g for 15 min at room temperature. Remove the supernatant with a micropipet. Air dry the pellet. Resuspend the DNA in 0.5X TE buffer [5 mM Tris-HCl, 0.5 mM EDTA (pH 7.5)] to a concentration of 10 ng/ul of DNA. Use 1 ul per transformation of 20 ul of cell suspension.
Purifying DNA by Microdialysis: Float a Millipore filter, type VS 0.025 um, on a pool of 0.5X TE buffer (or 10% glycerol) in a small plastic container. Place 20ul of the DNA solution as a drop on top of the filter. Incubate at room temperature for several hours. Withdraw the DNA drop from the filter and place it in a polypropylene microcentrifuge tube. Use 1ul of this DNA for each electrotransformation reaction.
Cosolvents may be used when there is a failure of amplification, either because the template contains stable hairpin-loops or the region of amplification is GC-rich. Keep in mind that all of these cosolvents have the effect of lowering enzyme activity, which will decrease amplification yield. For more information see P Landre et al (1995). The use of co-solvents to enhance amplification by the polymerase chain reaction. In: PCR Strategies, edited by MA Innis, DH Gelfand, JJ Sninsky. Academic Press, San Diego, CA, pp. 3-16.
Additionally, when amplifying very long PCR fragments (greater than 5 kb) the use of cosolvents is often recommended to help compensate for the increased melting temperature of these fragments.
For Research Use Only. Not for use in diagnostic procedures.