Competent Cells Selection Guide

All Epicentre Competent Cells have the following features:

Endonuclease minus (endA 1) Endonuclease A is a DNase that can survive boiling lysis and can degrade plasmid DNA, reducing the DNA yield from plasmid purifications.
lacZΔM15 A deletion in the lacZ gene which codes for part of the amino-terminal of the β-galactosidase enzyme. A plasmid containing sequences of the amino terminus can complement this deletion to give functional β-galactosidase. When X-gal is used as the substrate, β-galactosidase produces a blue product; the colonies of these cells appear blue. When the complimentary sequence on the vector is disrupted by inserting a cloned fragment of DNA, the enzyme is no longer functional and cannot produce a blue product; the colonies of these cells are white. On a plate of mixed blue and white colonies, the white colonies should contain the cloned DNA.
Recombination minus (recA 1) The recA gene codes for a DNA-dependent ATPase that is essential for genetic recombination in E. coli. Bacterial strains deficient in recA are defective in recombination. Plasmids in these strains are maintained as monomers (do not form multimeric circles) and are less likely to incur deletions.
Restriction minus
(mcrA, Δ[mrr-hsdRMS-mcrBC])
Restriction systems are designed to protect bacterial cells from foreign DNA. Deleting the host cells' restriction system allows efficient cloning of DNA with different methylation patterns, such as DNA found in mammals, higher plants, and many prokaryotes.

 

Electrocompetent E. coli

Strain Name T1 & T5 Phage Resistant Catalog Number Transformation Efficiency (cfu/µg pUC19) Used with Specific Vector Ori Accepts Large DNA Applications
TransforMax™ EC100™ No

EC10010
10 x 100 µl

>1 X 1010 No 145 kb General Purpose
TransforMax™ EC100D™ pir+ No ECP09500
5 x 100 µl
>5 X 109 R6Kγori
15 copies/cell
Up to 100 kb Rescue cloning using EZ-Tn5™ or HyperMu™ Transposome™ Complexes
TransforMax™ EC100D™ pir-116 No EC6P095H
5 x 100 µl
>5 X 109 R6Kγori
250 copies/cell
Up to 50 kb Rescue cloning using EZ-Tn5™ or HyperMu™ Transposome™ Complexes
TransforMax™ EPI300™ No

EC300105
5 x 100 µl

EC300110
10 x 100 µl

EC300150
50 x 100 µl

>1 X 1010 Vectors containing both F-factor and oriV replicons

At least 145 kb

Good for Libraries

Use with CopyControl™ Vectors for inducible single to multiple copies/cell

Clone toxic genes and unstable DNA

TransforMax™ EPI300™-T1R Yes

EC02T110
10 x 100 µl

>1 X 1010 Vectors containing both F-factor and oriV replicons

At least 145 kb

Good for Libraries

Use with CopyControl™ Vectors for inducible single to multiple copies/cell

Clone toxic genes and unstable DNA

CopyCutter™ EPI400™ Yes C400EL10
10 x 50 µl
>1 X 1010 ColE1-type
replicons
145 kb

Controls copy number of common vectors

Clone toxic genes and unstable DNA

 

Chemically Competent E. coli

Strain Name T1 & T5 Phage Resistant Catalog Number Transformation Efficiency (cfu/µg pUC19) Used with Specific Vector Ori Accepts Large DNA Applications
TransforMax™ EC100™ No CC02810
10 x 50 µl
>1 X 108 No At least 23 kb General Purpose
TransforMax™ EPI300™ No C300C105
10 x 50 µl
>5 X 108 Vectors containing both F-factor and oriV replicons At least 23 kb

Use with CopyControl™ Vectors for inducible single to multiple copies/cell

Clone toxic genes and unstable DNA

CopyCutter™ EPI400™ Yes C400CH10 10 x 50 µl >1 X 107 ColE1-type replicons At least 23 kb

Controls copy number of common vectors

Clone toxic genes and unstable DNA