truncation of protein expression - (Apr/23/2009 )

I was using pet20b vector and instert my cloning between xbaI and bamhI restriction sites, but after over-expression with IPTG induction, the protein is truncated from one amino acid after the 1st methionine to another 14 amino acids following. The DNA sequence is checked. Does anyone here have any idea or similar experience like this? Is that because of rbs site missing in the vector? if it is I am wondering why the same 14 amino acids sequence is truncated , the experiment is repeated 3 times. Thanks in advance.

-deepbluedna-

Hey,

I am not sure what you mean by this but if it is a Nter truncation, it could be because of some protease. U can try some protease inhibitors during purification and see if that helps. However, in one of the proteins that we have cloned in the lab, truncation is seen and proteases don't help.

Best,
TC

deepbluedna on Apr 23 2009, 08:24 PM said:

the protein is truncated from one amino acid after the 1st methionine to another 14 amino acids following.

-T C-