protein activity with extra N-terminal peptide

Hi,
I have a expression vector based on the pTriX1.0 vector.
the vector was constructed with three cut sites (Nco, Spe, BamH) in
front of the protein to be expressed, which results in expression with
the few extra residues before the real start codon of the protein:
M G L T S G S - [M ... actualy protein sequence]
would this be a problem to affect the activities of the protein i am
expressing?
do general expressing vectors have extra residues before the actual protein?
Thanks very much
Isaac

Isaac Li wrote:


It really depends on the protein and it's overall function/structure.
Some proteins have no problem coping with a few extra residues, others
would not function properly.


Generally one aims to clone the gene of interest into the first ATG
downstream of the translation initiation region.

That said, many commercial vectors contain different N-terminal fusion
partners to achieve effecient translocation, expression, isolation, etc.

Trond Erik