JM109 is a K strain that is recA- and endA- to minimize recombination and improve the quality of plasmid DNA. In addition, the cells carry the F´ episome, which allows blue/white screening. JM109 Competent Cells are available for convenient transformation in two efficiencies: High Efficiency at greater than 108cfu/µg and Subcloning Efficiency at greater than 107cfu/µg. HB101 cells are recA-, which minimizes recombination events, and contain a restriction-minus background (hsdS20) that allows better representation when cloning methylated DNA. HB101 Competent Cells are suitable for vectors that do not require alpha-complementation for blue/white screening. For researchers doing more than one transformation, competent cells are available in standard format (200µl aliquots). For added convenience, single-use competent cells (50µl aliquots) also are offered. JM109 and HB101 Competent Cells are prepared according to a modified procedure of Hanahan. JM109 Genotype: endA1, recA1, gyrA96, thi, hsdR17 (r(k)-, m(k)+), relA1, supE44, Delta(lac-proAB), [F' traD36, proAB, laqI(q)ZDeltaM15]. HB101 Genotype: F-, thi-1, hsdS20 (r(B)-, m(B)-), supE44, recA13, ara-14, leuB6, proA2, lacY1, galK2, rpsL20 (str(r)), xyl-5, mtl-1.|
Convenient: Ready to use; no preparation time necessary.Reliable: Transformation efficiencies guaranteed.Safe: The recA- mutation prevents undesirable recombination events, and the endA- mutation in JM109 cells prevents carryover nuclease in miniprep DNA.