Hello everyone. I am struggling with the solubility or expression of my proteins in BL21DE3 E.coli expression cells. In one of my construct I have a Sumo-His fusion at the n-terminal of my protein. After induction what I see is the expression of the Sumo tag only. My sequencing results are fine and there is no mistake in cloning. I wonder why I am seeing only the expression of the Sumo tag although my fusion protein is in frame with this tag. My second question is related with the very low expression of one of my gene. A brief literature search suggests so many things to improve the expression like changing the host, vector, media etc. It is a nuclease and cloned in vector with a Sumo-His tag on it. I am able to purify the little amount from E coli BL21DE3 host. The problem is related with low expression which is clearly observed in difference in the pre and post induction lysate on SDS PAGE. Out of so many option available in the literature I am confused what to try first. Any general idea?
Your suggestions can help a lot. Kahkashan Ph.D student Delhi University India
