Mix & Go! XJb (DE3) Autolysis Competent Cells


Mix & Go! XJb (DE3) Autolysis Competent Cells


Cat # Name Size Price Quantity
T3051 Mix & Go! XJb (DE3) Autolysis Competent Cells, 1 ml 500x L-Arabinose 10 x 100 µl $219.00
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Mix & Go! XJb (DE3) Autolysis Competent Cells


  • Fast: 80 - 90% of E.coli are lysed in only 10 minutes after harvesting.
  • High Transformation Efficiencies: Achieve 108 - 109 transformants per µg of plasmid DNA.
  • DE3 Lysogen: Encodes the T7 polymerase for expressing recombinant proteins under the control of the T7 promoter.


While there are many cell lysis methods available to scientists, unfortunately none of these methods combine all the ideal features for simple, efficient, economical, and gentle lysis of E. coli cells. The E. coli XJ autolysing strains from Zymo Research were engineered to address this problem. Mild expression of a chromosomally encoded bacteriophage λ R gene, encoding the λ lysozyme, also known as λ endolysin, is induced during growth. Cells are harvested intact while the peptidoglycan layer of the cell walls has been protected from digestion by the cytoplasmic membrane. The membrane is, however, amenable to disruption by a brief physico-chemical stress such as a freeze-thaw cycle after harvesting the cells. The XJ Autolysis™ method is highly efficient and takes only minutes (unlike traditional multiple freeze-thaw cycles). It can be applied to any number of samples without increasing processing time and labor (unlike sonication or French-press), is reliable and repeatable (unlike lysozyme treatment), and finally, is fully compatible with a wide range of buffers. Additionally, it does not require use of any potentially interfering components such as detergents, commonly found in various lytic buffers. They are also applicable for nucleic acid purification, and available with a DE3 lysogen encoding the T7 polymerase for expressing recombinant proteins driven by the T7 promoter.

Technical Specifications

Autolysis XJb lysis efficiency is 10-20 % lower than XJa. For optimal lysis, more care needs to be taken when selecting the lysis buffer. However, even very low concentrations of detergent may improve lysis significantly.
Cell Growth A very robust strain, reaching higher OD’s than E. coli K-strains.
DNA Extraction XJb is not optimal for DNA extraction.
DNA Stability This strain is RecA positive.
Genotype F- ompT hsdSB(rB - mB -) gal dcm ΔaraB::λR, cat (CmR), λ(DE3)
Processing Time 10 minutes
Product Storage -70°C to -80°C
Protein Expression XJb is ideal for recombinant protein expression. It lacks Lon and OmpT proteases, leading to higher protein yields.
Transformation Efficiency 108 - 109 transformants per µg of plasmid DNA

Product FAQ

Q1: Can glucose be added to the growth media?

Q2: Can glycerol be present during the freeze-thaw cycle?

Q3: What if the lysate is extremely viscous?

Q4: How do you improve lysis efficiency?

Q5: Do heat shock and outgrowth steps have to be performed when transforming XJb Autolysis E. coli?

Q6: Is a starter culture necessary?

Q7: Will chitin be degraded?

Q8: What buffer should the cell pellet be resuspended in?

Q9: Are competent cells GMOs?

Q10: Are the Mix & Go strains dam+ and dcm+?

Q11: Do the Mix & Go strains methylate DNA?

Q12: Which strains are equivalent to the Zymo strains?

Q13: How to reduce satellite colonies on agar plates?

Q14: Is it possible to dilute the competent cells?

Q15: Which antibiotics can be used with the Mix & Go! procedure?

Q16: Which Plasmid Size can be used for transformation?

Q17: Which is the recommended DNA concentration and volume for transformation?

Q18: What are some tips to improve transformation efficiency?

Q19: How will a heat-shock affect my Transformation Efficiency?


To clone new GFP-like fluorescent proteins from Obelia medusa, the authors identified the potential genes using expression libraries and cloned the genes into a vector. Expression of the proteins was facilitated by using XJb Autolysis E. coli cells from Zymo Research. The authors were able to purify three proteins from Obelia medusa that fluoresce in three different colors: cyan, green, and yellow.

Aglyamova, G.V. et al. (2011) Multi-colored homologs of the green fluorescent protein from hydromedusa Obelia sp. Photochem Photobiol Sci (8):1303-9.