pET and ampicillin

Dr. R.A. Brooksbank rbrooksb at
Mon Nov 14 13:45:43 EST 1994

I found that clavulanic acid did seem to help when expressing proteins in
E.coli. I too found that with ampicillin the pET vector construct was lost 
from the culture. I used Timentin, this is a mixture of clavulanic acid and an
ampicillin analogue (sorry I don't have the info on what!). Timentin is a
propriatry name made by Smith Kline Beecham (if my memory serves me well). A
point to be aware of is the fact that it is very hard to start a culture in
the presence of Timentin, I grew starter culture to a very low density (barely
visible turbidity) using ampicillin and then used these to innoculate a larger
culture containing the timentin. Can't promise it will work for you but good 
Rob Brooksbank        rab at
The Sanger Centre, Hinxton Hall, Cambridge
P.S. You could also try later (eg pET11 onwards) versions of the vectors?

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