Why does my protein expression in E.coli BL21DE3 pLysS not work in every culture I grow?

We are expressing T7 DNA polymerase. Because the protein is lethal to the cells in which it is produced, we transformed the plasmid to a pLysS system and induce expression with 0.4 mM IPTG at an...

19 January 2015 1,070 19 View