TFB Electro 10BF'™

TFB Electro 10BF’™ Competent Cells are electrocompetent E. coli cells and are intended to be transformed by electroporation. The high transformation efficiency of these cells makes them ideally suited for demanding applications such as cDNA or genomic library construction. TFB Electro 10BF’™ cells are suitable for the generation of ssDNA and other applications where infection with M13 or other fd-type bacteriophage is desired. TFB Electro 10BF’™ cells are resistant to bacteriophage T1, an especially virulent virus which attacks E. coli, and can be rapidly spread via aerosols. The increased amount of Lac repressor in these cells, due to the presence of the lacIq marker, gives tighter control over Lac-based promoter systems making them ideal for cloning and expression of toxic genes.

 Handling and Storage

• Upon receipt, store cells immediately at -70°C or below.
• Competent cells should be thawed on wet ice (~ 10 minutes) and should be used promptly after thawing.
• Thawed cells can be refrozen by placing them in dry ice although a drop in transformation efficiency of ≥50% may be observed.
• Cells stored properly will remain stable for up to 2 years.

Kit Contents

• TFB Electro 10BF’™ Competent Cells
• pUC19 Control DNA (10 pg / µl)
• SOC

Genotype

F′ [lacI^qZΔM15 Tn10 (Tet^R)] mcrA Δ(mrr-hsdRMS-mcrBC) Φ80dlacZΔM15 ΔlacX74 recA1 endA1 hsdR araD139 Δ(ara leu)7697 galU galK rpsL nupG λ- fhuA (T1^R).
Note: The Δ(mrr-hsdRMS-mcrBC) deletion, together with the mcrA mutation, allow cloning of methylated DNA such as genomic DNA from eukaryotic sources. For optimal repression of the lacZ promoter, grow cells at 30°C.

Quality Control
Each lot of TFB Electro 10B™ cells is tested to verify transformation efficiencies of ≥1 x 10¹⁰ transformants/µg with limiting amounts of supercoiled pUC19 DNA (10 pg). Saturating amounts of DNA (250ng) give ≥1 x 10⁸ colonies/ 20µl reaction. Untransformed cells are also tested for resistance to bacteriophage T5, a standard test for resistance to phage T1, as well as other relevant genetic markers and sensitivities to antibiotics.

Considerations in Choosing Competent Cells

Key Genetic Markers:

• recA - eliminates homologous recombination; stabilizes inserts.
• endA - endonuclease deficiency improves yield and quality of plasmid DNA.
• hsd - classical restriction/modification system, deficiency allows cloning from non-E. coli sources, e.g. PCR products.
• F’ - episome required for infection by M13 and other phagemids. Important in generation of ssDNA.
• mcrA, mcrBC, mrr - mutations in these genes allows efficient cloning of genomic from mammalian or other higher eucaryotes, and methylated cDNA.
• lacZΔM15 - omega donor; allows a-complementation for blue/white screening.

Product Selection Guide:

• Competent Cells Selection Guide