TOP10 Electrocomp™ Kit
TOP10 Electrocomp™ Kit
Invitrogen™

TOP10 Electrocomp™ Kit

TOP10 Electrocomp E. coli cells are provided at a transformation efficiency of 1 x 1010 cfu/μg supercoiled DNA and areRead more
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Catalog NumberQuantity
C664555 x 100 μL
C6641110 x 100 μL
Catalog number C66455
Price (USD)
314.00
5 x 100 µL
Add to cart
Quantity:
5 x 100 μL
Price (USD)
314.00
5 x 100 µL
Add to cart

TOP10 Electrocomp E. coli cells are provided at a transformation efficiency of 1 x 1010 cfu/μg supercoiled DNA and are ideal for high-efficiency cloning and plasmid propagation. This strain is used in wide range of applications and allows stable replication of high-copy number plasmids and maintenance of large plasmids. 

The TOP10 genotype is similar to the DH10B strain and features:
• hsdR for efficient transformation of unmethylated DNA from PCR amplifications
• mcrA for efficient transformation of methylated DNA from genomic preparations
• lacZΔM15 for blue/white color screening of recombinant clones
• endA1 for cleaner preparations of DNA and better results in downstream applications due to the elimination of non-specific digestion by Endonuclease I
• recA1 for reduced occurrence of non-specific recombination in cloned DNA

Notes
Please see the product manual for reaction scale recommendations. A high-voltage electroporation apparatus is required.

Genotype
F- mcrA Δ(mrr-hsdRMS-mcrBC) φ80lacZΔM15 ΔlacX74 recA1 araD139 Δ(ara-leu)7697 galU galK rpsL endA1 nupG

Find the strain and format that fits your needs
TOP10 is available in chemically competent and electrocompetent cell formats.
Choose MultiShot competent cells for high-throughput cloning applications.
Email us for more information about custom formats.

For Research Use Only. Not for use in diagnostic procedures.
Specifications
Product TypeElectrocompetent Cells
Contains F' EpisomeNo
Improves Plasmid QualityYes (endA1)
Cloning Methylated DNAYes (mcrA)
Transformation Efficiency LevelHigh Efficiency (>1 x 1010 cfu/μg)
Antibiotic Resistance BacterialYes (Streptomycin)
Cloning Unstable DNANot suitable for cloning unstable DNA
Blue/White ScreeningYes (lacΔM15)
High-throughput CompatibilityLow
PlasmidMay be used for plasmids >20 kb
Preparing Unmethylated DNANo
Reduces RecombinationYes (recA1)
Shipping ConditionDry Ice
T1 Phage - Resistant (tonA)No
SpeciesE. coli (K12)
FormatTube
Product LineElectrocomp™
Quantity5 x 100 μL
Unit Size5 x 100 µL
Contents & Storage
• 5 x 100μL TOP10 Electrocomp E. coli
• 50 μL pUC19 vector (10 pg/μL)
Store at –80°C.

• S.O.C. Medium (15 mL)
Store at room temperature.

Frequently asked questions (FAQs)

What is the difference between TOP10 and TOP10F' cells?

The only difference between TOP10 and TOP10F' cells is that the latter contain the F' episome that carries the tetracycline resistance gene and allows isolation of single-stranded DNA from vectors that have an f1 origin of replication. The F' episome also carries the lacIq repressor for inducible expression from trc, tac, and lac promoters using IPTG. TOP10F' cells require IPTG induction for blue/white screening.

I am trying to clone an insert that is supposedly pretty toxic. I used DH5? and TOP10 cells for the transformation and got no colonies on the plate. Do you have any suggestions for me?

If the insert is potentially toxic to the host cells, here are some suggestions that you can try:

- After transforming TOP10 or DH5? cells, incubate at 25-30°C instead of 37°C. This will slow down the growth and will increase the chances of cloning a potentially toxic insert.
- Try using TOP10F' cells for the transformation, but do not add IPTG to the plates. These cells carry the lacIq repressor that represses expression from the lac promoter and so allows cloning of toxic genes. Keep in mind that in the absence of IPTG, blue-white screening cannot be performed.
- Try using Stbl2 cells for the transformation.

Can I directly clone, propagate and express in BL21 without using TOP10?

It is imperative that a cloning strain such as TOP10 be used for characterization of the plasmid, propagation, and maintenance. BL21 cells are wild-type for endA and recA, which could result in poor miniprep quality and a greater chance of plasmid rearrangements due to recombination. In addition, BL21 cells contain the T7 RNA polymerase gene which is expressed at low levels even in the absence of inducer. If the gene is toxic to E. coli, plasmid instability and/or cell death can result.

I need to clone unmethylated DNA from a PCR reaction using a strain that has the hsdRMS mutation to avoid restriction after transformation. Is TOP10 suitable for my purposes?

Yes, TOP10 has the hsdRMS mutation, so this strain can be used to clone DNA from PCR reactions and other non-methylated sources. hsdRMS is a mutation in the system that E. coli uses to recognize foreign DNA. There are two parts to this system, methylation and restriction. E. coli methylate DNA at certain sequences, and if the DNA is not methylated at these sequences it will be recognized as foreign and restricted. Thus, if unmethylated DNA is transformed into E.coli that does not carry the hsdRMS genotype, it is recognized as foreign and enzymatically degraded.

Are TOP10 cells lacIq+ (plus) or lacIq- (minus)? That is, do they produce the lambda lacIq repressor protein?

TOP10 cells are lacIq- (minus). They do not have the lacIq gene and therefore do not produce the lacIq repressor protein. lacIq is most commonly found on an F' episome, and therefore is present in TOP10F', JM101, JM109, and NM522 strains.