Iam engaged in expressing a gene of gram positive orgin in E.coli M15 cells through pQE-30 vector. Initially i got good expression; but following trials went waste as i could not express the protein. I tried different expression conditions & checked all the reagents used, all went vein. The insert is there in the cloned cell as confirmed by PCR. What could b the possible cause?
Note: Ive expressed the protein once so it could not b toxic to the E.coli.
reproducing protein expression