Single Step (KRX) Competent Cells

Single Step (KRX) Competent Cells offer efficient transformation and tightly controlled protein expression, consolidating the best attributes of these 2 steps into 1 strain to evaluate protein expression in E. coli. Transformation efficiencies are greater than 10(8) cfu/ug, similar to other highly competent cells. Available in both single (50ul) and multiple transformation (200ul) sizes, KRX can be used for blue/white screening; it is an E. coli K strain containing a chromosomal copy of T7 RNA polymerase driven by a rhamnose promoter (rhaBAD) to provide dramatic control of proteins expressed via a T7 promoter. Pre-induced expression protein levels are significantly lower than those of BL21(DE3)-derived strains, facilitating cloning/expression of proteins toxic to E. coli. Genotype: [F', traD36, DeltaompP, proA+B+, lacIq, Delta(lacZ)M15] DeltaompT, endA1, recA1, gyrA96 (Nal(r)), thi-1, hsdR17 (r(k)-, m(k)+), e14- (McrA-), relA1, supE44, Delta(lac-proAB), Delta(rhaBAD)::T7 RNA polymerase