One Shot™ TOP10 Chemically Competent E. coli
Need help? Find application-specific tips, troubleshooting help, and technical resources within our new Cloning Support Center.
One Shot&trade; TOP10 Chemically Competent <i>E. coli</i>
Invitrogen™

One Shot™ TOP10 Chemically Competent E. coli

One Shot TOP10 Chemically Competent E. coli are ideal for high-efficiency cloning and plasmid DNA propagation and are provided atRead more
Have Questions?
Change viewbuttonViewtableView
Catalog NumberQuantity
C40400321 x 50 μL
C40401011 x 50 μL
C40400642 x 50 μL
Catalog number C404003
Price (USD)
502.00
Each
Add to cart
Quantity:
21 x 50 μL
Price (USD)
502.00
Each
Add to cart

One Shot TOP10 Chemically Competent E. coli are ideal for high-efficiency cloning and plasmid DNA propagation and are provided at a transformation efficiency of 1 x 109 cfu/μg plasmid DNA. These cells allow stable replication of high-copy number plasmids and are the same competent cells that come with many of our cloning kits. TOP10 E. coli cells are genetically similar to the DH10B strain and have been reported to be more resilient to stress conditions like osmotic shock and acidic pH stress.

One Shot TOP10 cells:
• Maximize cloning efficiency in a single-tube format
• Provide enhanced genomic DNA cloning capabilities

TOP10 Chemically Competent E. coli cells carry mutations in the methylation-dependent restriction system (mcrA, mcrBC, and mrr) allowing the cloning of both prokaryotic and eukaryotic genomic DNA, as well as efficient plasmid rescue from eukaryotic genomes. Similar to other DH strains, TOP10 has the lacZΔM15 genotype, providing for the option of blue-white screening on plates containing either X-Gal or Bluo-Gal. The inclusion of recA1 and endA1 mutations increase insert stability and improve the quality of plasmid DNA prepared from minipreps.

One Shot TOP10 Chemically Competent E. coli cells offer:
• Transformation efficiencies of >1 x 109 cfu/μg
• 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 DNA preparations and better results in downstream applications due to elimination of nonspecific digestion by Endonuclease I
• recA1 for reduced occurrence of nonspecific recombination in cloned DNA
• Expression from the lac promoter without IPTG

Easy-to-use One Shot format
TOP10 Chemically Competent E. coli cells are supplied in the convenient, single-reaction One Shot format. The single-tube, single-use format accomodates allows all steps of the transformation protocol, up to plating, to take place in the same tube, helping save time and prevent contamination.

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

Find the strain and format that fit your needs 
We offer other DH strains in chemically competent and electrocompetent cell formats.
The TOP10 strain is available in several MultiShot formats for high throughput applications.
Explore bacterial growth media formats.

For Research Use Only. Not for use in diagnostic procedures.
Specifications
Product TypeChemically Competent Cells
Contains F' EpisomeNo
Improves Plasmid QualityYes (endA1)
Cloning Methylated DNAYes (mcrA)
Transformation Efficiency LevelHigh Efficiency (>1 x 109 cfu/μg)
Antibiotic Resistance BacterialYes (Streptomycin)
Cloning Unstable DNANot suitable for cloning unstable DNA
Blue/White ScreeningYes (lacZΔM15)
High-throughput CompatibilityLow
PlasmidHigh Copy Plasmid
Preparing Unmethylated DNANo
Reduces RecombinationYes (recA1)
Shipping ConditionDry Ice
T1 Phage - Resistant (tonA)No
SpeciesE. coli (K12)
FormatTube
Product LineOne Shot™
Quantity21 x 50 μL
Unit SizeEach
Contents & Storage
• One Shot TOP10 Chemically Competent E. coli (21 x 50 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 (6 mL)
Store S.O.C. Medium at 4°C or 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.

What generation is your ViraPower lentiviral expression system? Can I use it with a 2nd generation lentiviral packaging mix?

Our ViraPower lentiviral expression system is a 3rd generation system with regard to safety features. Our lentiviral expression vectors are derived from wild type HIV, but nearly all the wild type viral proteins (e.g., Vpr, Vpu, Vif, Nef, Tat) have been removed and the HIV envelope is not used. VSV-G (vesicular stomatitis virus G) envelope protein is used instead. Our ViraPower lentiviral expression system can be used with a 2nd generation lentiviral packaging mix. However, our lentiviral packaging mix would not be compatible with a 2nd generation lentiviral expression vector.

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.

View all One Shot™ TOP10 Chemically Competent E. coli FAQs