Toxic protein for E. coli (M15)

Bertrand Collet b.collet at
Thu Sep 5 03:26:56 EST 2002

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

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 ?

I tried to reduce the level of expression (lower temperature 28 deg,
lower IPTG concentrations ... but no clear results so far).

Thanks in advance for any advises,

Bertrand Collet

More information about the Proteins mailing list