Protein expression problems (very hard to find an aswer)

Michael R. Thompson Mike.Thompson at
Fri Sep 1 10:42:48 EST 2000

There is an interesting paper (Miroux and Walker, 1996, J. Mol. Biol. 260:
289-298) that describes selection of a mutant host cell line from a
population of cells transformed with pET-type plasmids. This host cell line
stably expresses moderately toxic recombinant proteins, in contrast to the
original cell line which can quickly be overgrown with poorly producing
cells. I don't know if this is what you are experiencing, but it might be
worth a look. Good luck!

Mizar wrote in message
<01c01414$b71e6da0$5aaccec1 at>...
>Dear colleague, I have a very intriguing question for you.
>Well the story is very simple.
>We built 4 years ago a good expression system in E. coli (BL21 DE3 pLys)
>on the pT7.7 vector and it worked well for a long time.
>Now it seems not to work as well as it did (I have about 1/10 of initial
>I'm going mad to try the answer. Someone have an idea?


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