XJ Autolysis™ E. coli Strains
 
• Fast-Track transformation procedure with transformation efficiencies of 108 -109 transformants/µg of plasmid DNA.
• Simple and controlled autolysis of E. coli.
• XJ Autolysis™ E. coli can by lysed in minutes following isolation.
• Lysis procedure is compatible with most buffer systems.
• Simplifies protein expression and purification procedures, also applicable for extraction of nucleic acids.
• Easy scale-up for the lysis of multiple samples and larger sample volumes.
• Derived from popular strains:
XJa - JM109 Origin
XJb - BL21 Origin
 
STRAIN GENOTYPES
XJa Autolysis™ E. coli K recA1 supE44 endA1 hsdR17 (rk-,mk+) gyrA96 relA1 thi mcrA Δ(lac-proAB) ΔaraB::λR, cat F’[traD36 proAB+ lacIq lacZΔM15]
XJb Autolysis™ E. coli B F- ompT hsdSB(rB- mB-) gal dcm ΔaraB::λR, cat
 

The use of XJ Autolysis™ E. coli strains offers a new alternative to current methods for bacterial transformation and bacterial cell lysis. XJ Autolysis™ E. coli strains are efficiently lysed following arabinose induced expression of the bacteriophage lambda lysozyme (i.e., endolysin) protein coupled to a single freeze-thaw cycle. Lysis is quick, reproducible, and simpler compared to current lysis methods. XJ Autolysis™ E. coli strains are suitable to accomodate processing of multiple samples as well as scaling up to larger sampling volumes.
Zymo Research offers a range of chemically competent strains of E. coli having transformation efficiencies >108 transformants/µg pUC19 DNA. With the needs of the researcher in mind, the scientists at Zymo Research developed a unique method to make E. coli stains chemically competent and avoid the requirement of heat-shocking and related procedures. This dramatically reduces processing time, and, in most instances the entire procedure is complete in 10-20 minutes bypassing the need for a lengthy outgrowth period. For transformation, simply mix DNA with competent cells, incubate on ice 10-20 minutes, and spread onto a selection plate.

 
 
    XJa Autolysis™
(E. coli K, strain JM109)		   XJb Autolysis™
(E. coli B, strain BL21)
Cell Growth   Grows quite well, especially when media is supplemented with 1 mM magnesium.   A very robust strain, reaching higher OD’s than E. coli K.
Autolysis   This strain lyses very easily. Actually, the parent strain JM109 itself will release about 20% of cellular protein after one freeze-thaw cycle. This strain will lyse in a wide range of buffer conditions.   XJb lysis efficiency is 10-20 % lower compared to XJa. To achieve optimal lysis, more care needs to be taken when selecting lysis buffer. However, even very low concentrations of a detergent improve lysis significantly.
Protein Expression   Suitable for general screening, but proteases may degrade the recombinant proteins, especially small or otherwise unstable proteins.   Higher protein yields are usually obtained using this strain. XJb is also deficient in both Lon and OmpT proteases, making it especially suitable for recombinant protein expression.
DNA Extraction   This strain is EndA negative and thus yielding high quality DNA preparations.   XJb is not the best strain for DNA extraction. If necessary to do so, techniques should be chosen that yield highly purified DNA in the least amount of time.
DNA Stability   The RecA negative mutation in XJa stabilizes repetitive DNA sequences.   This strain is RecA positive.
 
Product Catalog No. Format Price Store
XJa Autolysis™ T5021 1 glycerol stock
1 ml 500X L-Arabinose		 $
  T3021 10x 100 µl Z-competent cells
1 ml 500X L-Arabinose		 $
XJb Autolysis™ T5041 1 glycerol stock
1 ml 500X L-Arabinose		 $
  T3041 10x 100 µl Z-competent cells
1 ml 500X L-Arabinose		 $
 
Components Available