BL21(DE3) and trc promoter

[Michael R. Thompson]

Couple of pertinent papers are:
'Construction and characterization of a set of E. coli strains deficient in
all known loci affecting the proteolytic stability of secreted recombinant
proteins.' Meerman & Georgiou (1994). Bio/Technology 12: 1107. (May be the
one Duncan referred to), and
'Minimizing proteolysis in Escherichia coli: genetic solutions. Gottesman
(1990). Meth. Enzymol. 185: 119.
I have succcessfully used some of Dr. Gottesman's strains (which she makes
available on request), especially SG12036 and SG21173.


Dr. Duncan Clark wrote in message ...
>In article <Pine.GSO.4.21.0002090952300.8351-100000 at sun3.oulu.fi>, Petri
>Kursula <pkursula at cc.oulu.fi> writes
>>Is this a cell line suitable for expression in general, or does it
>>have a bunch of nasty proteases?
>
>I would work on the assumption that all E.coli's have a bunch of
>proteases. Whether they are nasty will depend upon your protein. I'm
>sure that maybe in the last 3-5 years there was a paper in Nature
>Biotechnology where the E.coli proteases were gradually all knocked out.
....