Expression of peptides in E.Coli

Laura Moen lmoen at odu.edu
Fri Jun 12 11:38:03 EST 1998


Yes,
  I have done this, only my peptide was a little longer - about 100 amino acids.
I can tell you the following based on my experience:  The expression is likely to
be poor.  This is because the peptide you are making does not have a defined
structure.  E. coli doesn't tolerate such formless proteins well, and may simply
degrade them completely as they are being made - depends on your luck at the
time.  I would suggest that in addition to the His tag, to express your protein
as a fusion construct with a larger well-expressed protein.  Design in an amino
acid sequence that will allow you to selectively cleave off your peptide of
interest after you have purified the fusion protein, and you may get a better
yield.  Good luck.  Laura


Svend Kjaer wrote:

> Hi all,
>
> I am in need of a peptide of the length of roughly 20 amino acids. Instead of
> having someone to synthesize it (who I will then have to pay), I thought of
> expressing it into the periplasme of E.coli and purifying it via a His-tag.
> However, small non-structured peptides of that length may be degraded by pro
> teases, so I would like to know if anyone has experience with such set-ups
>
> Thanks,
>
> Svend Kjaer,
>
> IMSB,
> University of Aarhus,
> Denmark






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