NEBuilder® HiFi DNA Assembly Chemical Transformation Protocol (E2621) also provides an interactive version of this protocol where you can discover and share optimizations with the research community. 

  1. Thaw chemically competent cells on ice.

  2. Transfer 50 μl of competent cells to a 1.5 ml microcentrifuge tube (if necessary).

  3. If the chemically competent cells are from New England Biolabs, add 2 μl of assembled product to NEB competent cells and go to step 4 directly. If competent cells are purchased from other manufacture, dilute assembled products 4-fold with H2O prior transformation. This can be achieved by mixing 5 μl of assembled products with 15 μl of H2O. Add 2 μl of the diluted assembled product to competent cells.

  4. Mix gently by pipetting up and down or flicking the tube 4–5 times. Do not vortex. Place the mixture on ice for 30 minutes. Do not mix.

  5. Heat shock at 42°C for 30 seconds.* Do not mix.

  6. Transfer tubes on ice for 2 minutes.

  7. Add 950 μl of room temperature SOC media* to tubes.

  8. Place the tube at 37°C for 60 minutes. Shake vigorously (250 rpm) or rotate.

  9. Warm selection plates to 37°C.

  10. Spread 100 μl of the cells onto the plates with appropriate antibiotics. Use Amp plates for positive control sample.

  11. Incubate plates overnight at 37°C.

    * Please note: Follow the manufacturer's protocols for the duration and temperature of the heat shock step, as well as the optimal medium for recovery. Typically, transformation of our positive control assembly product will yield more than 100 colonies on an Amp plate with greater than 80% colonies containing inserts.

    NEB recommends NEB 5-alpha Competent E. coli (NEB #C2987) for transformation of NEBuilder HiFi DNA Assembly products. It is also possible to use other NEB competent E. coli strains, with the exception of BL21, BL21(DE3), Lemo21(DE3) and Nico21(DE3). For example, Shuffle T7 Express Competent E. coli can be used for the expression of a difficult to express protein. When using competent E. coli from a vendor other than NEB, we have seen decreased robustness of transformation with the NEBuilder HiFi reaction.