Home Protocols Protocol for Protein Expression Using BL21 (C2530)

Protocol for Protein Expression Using BL21 (C2530)

Protocol

  1. Transform expression plasmid into BL21. Plate on antibiotic selection plates and incubate overnight at 37°C.
  2. Resuspend a single colony in liquid culture with antibiotic to produce a starter culture. Inoculate starter culture at a 1:100 dilution into expression media containing antibiotic.
  3. Incubate at 37°C with shaking until OD600 reaches 0.4–0.8.
  4. For most vector systems, induce with 40 or 400 μM IPTG and express protein for 3 hours at 37°C, 5 hours at 30°C or overnight at 16°C or 23°C.
  5. For large scale, inoculate 1 Liter of liquid medium (with antibiotic) with a freshly grown colony or 10 ml of freshly grown culture. Incubate at 37°C until OD600 reaches 0.4–0.8. Add 40 or 400 μM IPTG and express protein using optimal time/temperature determined in a small scale trial.