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The Single Step (KRX) Competent Cells are designed for efficient transformation and tightly controlled protein expression. These cells consolidate the best attributes of these two steps into one strain to evaluate protein expression in E. coli.
Transformation efficiencies are greater than 108 cfu/μg, similar to other highly competent cells. The single step cells are available in single transformation size (50μl). KRX also can be used for blue/white screening.
Single Step (KRX) is an E. coli K strain that contains a chromosomal copy of the T7 RNA polymerase driven by a rhamnose promoter (rhaBAD) to provide dr...
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Single Step (KRX) is an E. coli K strain that contains a chromosomal copy of the T7 RNA polymerase driven by a rhamnose promoter (rhaBAD) to provide dramatic control of the proteins expressed via a T7 promoter. Pre-induced expression protein levels are significantly lower than those of BL21(DE3)-derived strains. This feature facilitates cloning and expression of proteins toxic to E. coli.
Genotype: [F´, traD36, ΔompP, proA+B+, lacIq, Δ(lacZ)M15] ΔompT, endA1, recA1, gyrA96 (Nalr), thi-1, hsdR17 (rk–, mk+), e14– (McrA–), relA1, supE44, Δ(lac-proAB), Δ(rhaBAD)::T7 RNA polymerase.
For more information, see the Protocols & Applications Guide.
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Single Step (KRX) Competent Cells
Always store competent cells at –70°C. Thaw on ice when ready for use. Do not refreeze thawed, unused aliquots.
For product intended use please see Patents & Disclaimers tab.
This one strain consolidates the best attributes of both good cloning and good expression strains avoiding the need to transfer to another strain specifically for expression.
Lane 1, BL21(DE3); lane 2, BL21(DE3)pLysS; lane 3, Rosetta 2(DE3) pLysS; lane 4, Single Step (KRX) Competent Cells.
L3002, L5701, L5702 For Research Use Only. Not for Use in Diagnostic Procedures.
L3002 Patent Pending.
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