Protease deficient strains for expression

Bret Sellman bsellman at
Fri Sep 22 15:12:39 EST 1995

We frequently express a toxin in E. coli which is sensitive to
proteolytic activation and the "normal" strains of E. coli only
produced processed toxin.  To overcome this problem we have cloned the
toxin into the protease deficient strains of E. coli from Novagen.  We
use two different strains BL21(DE3) and BLR(DE3).  BLR is the recA
deficient strain of BL21.  Both of these strains are deficient in lon
and ompT proteases. Good luck!!

Bret Sellman
bsellman at
Department of Microbiology and Immunology
University of Oklahoma Health Sciences Center  

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