Culture of Escherichia coli in SOC medium improves the cloning efficiency of toxic protein genes.

In this paper, we report a useful protocol for cloning toxic protein genes. Use of the SOC medium, which is a glucose-containing rich medium, significantly improved the transformation efficiency of a recombinant plasmid containing a toxic plant subtilase SaSBT1 cDNA. Both glucose and rich nutrients present in the SOC medium prevented the unintended activation of the lac promoter carried on the cloning vector, and led to significantly improved transformation efficiency of recombinant plasmids containing toxic protein genes and an increased rate of transformant growth.