Toxic protein for E. coli (M15)

Frank Fürst ffrank at rz.uni-potsdam.de
Thu Sep 5 07:28:53 EST 2002

Bertrand Collet <b.collet at abdn.ac.uk> schrieb:

> Dear all,
> I am new to recombinant protein production and I am attempting to
> produce a fish DNA-binding protein in E. coli.
> I use the pQE30 expression vector in M15 bacterial strain.
> I noticed that the growth rate of the bacterial cultures is the same
> without inducer for pQE30 only and for pQE30 expressing my protein.
> However, when I induce with IPTG (1mM) pQE30 continue to grow normally
> but my expression plasmid culture grow very very slowly: It appears that
> my protein is toxic for E. coli but that I do not have any leaking
> expression.
> Under these conditions, is there a good method to make E. coli produce a
> toxic protein, or do I have to switch to
> another expression system ?

Try to grow the culture to high OD, just at the end of the growth phase,
and then add IPTG and let them express the protein for a short time (1
hour, perhaps 2). They'll probably do some of your work before they

HTH, Frank
[Gesucht war ein MTA für Massenmailing]
Aus Stabilitätsgründen würde ich es allerdings vorziehen, wenn als
Server-OS nicht Debian-Linux sondern Windows-95 verwendet wird.
[Elmar Haneke in debian-user-de@]

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