T7 Express Iq Competent E. coli (High Efficiency)
T7 Express lysY/Iq competent E.coli (C3013I) is available as a superior alternative to T7 Express Iq competent E.coli (C3016 ). The additional lysY gene expresses a phage T7 lysozyme variant that inhibits basal T7 RNA polymerase activity. The net result of employing lysY/Iq cells as a host strain is greater clone stability and equivalent or improved expression of recombinant protein.
- This product was discontinued on March 31, 2015
Ordering Information
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Product Information
Enhanced BL21 E. Coli derivative, chemically competent E. coli cells suitable for high efficiency transformation and protein expression. Highlights
- Transformation efficiency: 0.6-1 x 109 cfu/μg pUC19 DNA
- Enhanced BL21 derivative for T7 expression
- T7 RNA Polymerase in the lac operon - no lambda prophage
- Tight control of expression by laclq allows potentially toxic genes to be cloned
- Deficient in proteases Lon and OmpT
- Resistant to phage T1 (fhuA2), Cam, Nit
- Does not restrict methylated DNA (McrA-, McrBC-, EcoBr-, Mrr-)
- B Strain
- Free of animal products
- lacq on miniF for stability
- no Cam requirement
Genotype
MiniF lacIq(CamR) / fhuA2 lacZ::T7 gene1 [lon] ompT gal sulA11 R(mcr-73::miniTn10--TetS)2 [dcm] R(zgb-210::Tn10--TetS) endA1 Δ(mcrC-mrr)114::IS10Reagents Supplied
The following reagents are supplied with this product:
Store at (°C) Concentration SOC Outgrowth Medium 4 1 X pUC19 Vector -20 0.05 ng/μl - Product Categories:
- Discontinued
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Advantages and Features
Features
- T7 expression
- Protease deficient
- Reduced basal expression
Application Features
Transformation of a toxic mammalian clone into E. coli hosts. A T7 expression plasmid and the same plasmid containing a gene encoding a toxic mammalian protein were transformed into each host. Comparison of the relative transformation efficiencies demonstrates that the T7 Express hosts provide the levels of control necessary for transformation of potentially toxic clones. BL21(DE3) could not be transformed with the toxic clone. 
T7-controlled expression of a non-toxic protein in E. coli hosts. A T7 expression plasmid containing a gene encoding an E. coli protein was transformed into each host, grown to 0.6 OD and induced for 3 hours. Comparison of soluble extracts from uninduced (-) and induced (+) cells shows superior control of basal expression in the T7 Express hosts while maintaining high levels of induced expression. 
* Ideally, DNA for transformation should be purified and resuspended in water or TE. However, up to 10 µl of DNA directly from a ligation mix can be used with only a two-fold loss of transformation efficiency. Where it is necessary to maximize the number of transformants (e.g. a library), a purification step, either a spin column or phenol/chloroform extraction and ethanol precipitation should be added. 
Effect of heat shock time on T7 Express Iq competent E.coli transformation efficiency: 50 μl of competent cells were transformed with 100 pg of pUC19 control DNA following the provided High Efficiency Transformation Protocol except heat shock time varied from 0 to 80 seconds. 
Effect of DNA incubation time on T7 Express Iq competent E.coli transformation efficiency: 50 μl of competent cells were transformed with 100 pg of pUC19 control DNA following the provided High Efficiency Transformation Protocol except DNA incubation time varied from 0 to 40 minutes. - Properties and Usage
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