XL10 gold xells for protein expression?

Dr. Duncan Clark news at hgmp.mrc.ac.uk
Wed Jul 25 06:51:14 EST 2001

In article <3B5EF75E.25468.1029EF8 at localhost>, the eminent Wolfgang
Schechinger at messy. wrote
>Has anyone experience in XL10 (ultracompetent) e.coli for 
>protein expression? Wich expression systems (inducers) will 
>work? Strategene recommends BL21, but I don't want to buy 
>another strain.

What is your induction system, presumably not T7? I'd guess they are
suggesting BL21 because it is OmpT minus (outer membrane protease). If
you have BL21(DE3) then I can't see why that would not do. Granted you
will induce T7 RNA pol with IPTG from the DE3 lysogen bit but that may
not be a problem. Another reason for BL21 is that it is closer to a wild
type E.coli than a highly mutated XL10 and therefore will grow to
probably a much higher OD. Why not just try XL10 and see what happens. 

Ideally I would try every strain (within reason!) you have, providing
they meet your biological safety needs, and see which work best.  

The problem with the gene pool is that there is no lifeguard.

Duncan Clark
GeneSys Ltd.
Tel: +44(0)1252376288
FAX: +44(0)8701640382

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