FAQ: Why are there no colonies or no growth in liquid culture (C2523)?

There may be basal expression in the NEBExpress host. If toxicity of the expressed protein is likely, transformation of the expression plasmid should be carried out in:

» NEB Express Iq (NEB# C3037): over-expression of the LacI repressor reduces basal expression.

Incubation at 30°C or room temperature may also alleviate toxicity issues. In addition, check antibiotic concentration (test with control plasmid).