pUC18 question

Cornelius Krasel zxmkr08 at studserv.zdv.uni-tuebingen.de
Wed Jun 23 10:45:17 EST 1993

In <2061h1$s70 at pollux.usc.edu> adleman at pollux.usc.edu (Len Adleman) writes:

>I would like to induce the expression of a short peptide (8 amino
>acids) in E. coli. I intended to use pUC18. How can I avoid making a
>fusion protein where my peptide is proceeded by Thr Met Ile Thr Asn
>Ser (which are encoded by the base pairs preceding the polylinker)?

I am not sure at all if it is possible to express such short
peptides via the translational apparatus. It is striking that
short peptides in vivo are usually produced by cleavage of
longer pre-peptides (e.g. in the case of peptide hormones).

The next point is that translation in E.coli starts at an
AUG codon which codes for N-formyl methionine. The formyl
group is split off afterwards, but the methionine usually remains.

Finally, I assume that short peptides are extremely susceptible
to intracellular proteases.

To sum it up: if you can afford it, try to get your peptide
from your peptide synthesizing dept. or from a peptide-
making company.

/* Cornelius Krasel, Department of Physiological Chemistry, U Tuebingen    */ 
/* email: krasel at studserv.zdv.uni-tuebingen.de                             */
/* "People are DNA's way of making more DNA." (R. Dawkins / anonymous)     */

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