Please, I need help. I bought a synthetic gene from Genscript which came already cloned in a expression vector, pET28a. I'm experienced in protein overexpression, I'm following all standard methods for protein overexpression. Other proteins are been overxpressed normally at my lab, however this particular one isn't. I double checked the sequence, the codons are optimized and everything looks fine. However, the protein does not express at all in BL21(DE3) background. Any clue or suggestion?