Coli strain for periplasmic expression

Michael Benedik bchs1b at Rosie.UH.EDU
Thu Mar 17 15:45:07 EST 1994

In article <2ma1ip$lr0 at>, dh124 at (Deborah Hodges (Rheumatol)) writes:
>	I am using the vector pASK-60 to express a heavily disulphide bonded
>protein in E.Coli. It uses the ompA signal sequence to target the protein to
>the periplasm. I've managed to get the thing to express but the yield
>is tiny. Admittedly I haven't tinkered with the medium but the cells, 
>(XL-Blues) seem to get very fragile as they express and I get cytoplasmic
>contamination of my periplasm preps.
>	My question is : Does anyone know of a Coli strain that would give
>me a better yield?
>	Thanks in advance
>		Debbie
>-------------------------------- ---------------------------------------     
>Debbie Hodges			|
>dh124 at	|	There's always something to eat 
>E6 Addenbrookes Cambridge UK	|	when you've got dwarf bread.

The first thing I would try is to get away from a recA mutant strain
and use a rec+ strain. With a RecA- about 50% of the cells are dead or
dying. Try JM101 or something similar if you need lacIq around, other
wise any rec+ strain.

 Michael Benedik				INTERNET: Benedik at
 Dept. of Biochemical & Biophysical Sciences	
 University of Houston				BITNET: Benedik at uhou

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