expression - important (Oct/17/2006 )
I had tried to over express a protein in the E.coli strain BL21 and PlyS. I had induced it with 1mM IPTG . After running SDS-PAGE . The molecular weight of my protein of interest is 47 KDa. I see thick band in the uninduced culture than in the induced one. Please help me to know why this happens and how to overcome this.
what's your plasmid?
maybe it's leaking, so you see protein expression in non induced, and maybe your protein is toxic, so you don't see such an increase of protein expression because your bacteria are dying. Did you check the OD after induction?