TFB 5 Alpha™
The high transformation efficiency of TFB 5 Alpha™ cells make them ideally suited for demanding applications such as cDNA library construction, cloning of PCR products, and gene banks.
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| Recommended Use | cDNA library construction, cloning of PCR products, and gene banks |
| Efficiency | ≥ 10^9 cfu / µg |
| Shipping | Dry ice |
| Genotype | F-Φ80dlacZΔM15 Δ(lacZYA-argF)U169 recA1 endA1 hsdR17(r-k, m+k) phoA supE44 λ- thi-1 gyrA96 relA1 fhuA (T1R). |
TFB 5 Alpha™ (TFB 5α™) Competent Cells are chemically competent E. coli cells and are intended to be transformed by heat-shock. The high transformation efficiency of these cells make them ideally suited for demanding applications such as cDNA library construction, cloning of PCR products, and gene banks. TFB 5α™ cells are resistant to bacteriophage T1, an especially virulent virus which attacks E. coli, and can be rapidly spread via aerosols.
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 5α™ Chemically Competent Cells
- pUC19 Control DNA (10 pg / µl)
- SOC
Genotype
F-Φ80dlacZΔM15 Δ(lacZYA-argF)U169 recA1 endA1 hsdR17(r-k, m+k) phoA supE44 λ- thi-1 gyrA96 relA1 fhuA (T1R).
Quality Control
Each lot of TFB 5α™ cells is tested to verify transformation efficiencies of ≥ 1 x 109 transformants/µg with limiting amounts of supercoiled pUC19 DNA (50 pg) and ≥ 1 x 106 cfu's per 100 µl transformation when using 25 ng of pUC19 (i.e., “saturating amounts”). 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:
