hosts for pMal-p vectors

Andrew S Heath ash at umich.edu
Tue Mar 19 00:16:03 EST 1996

MertensR at JRF.be (MertensR at JRF.be) wrote:
: Does anyone know if there are better expression hosts for the bacterial 
: (Escherichia coli) expression vector pMal-p (from New England Biolabs) 
: than the TB1 strain?
: Did anyone try a protease-deficient strain?
: I'm expressing G protein coupled receptors and the yield is pretty low 
: (40 fmol/1000000000bacteria). If someone knows how to boost the 
: production please let me know. (I have tried to change the OD600 for 
: induction and the growth time after induction and the temperature...)

I used pMalc2 in TB1, BW401?, SA2817, and two SG### strains (whose numbers
I have forgotten).  Susan Gottesman suggested these strains to us; she 
has a chapter in Methods of Enzymology on the protease deficients.  We 
saw far better expression/yield in each than TB1; lowering temperatures 
from 37C to 30C also helped expression/yeild.  SA2817 (ompT-, and one 
other genotype that slips my mind) worked best; we hypothesized that 
outer membrane proteins were shredding our protein (MBP-MGA from 
Strep. Pyogenes) when the cells burst. Also, protease inhibitors are an 
option; but, they run the risk of inhibiting your protein's activity.

Andrew S Heath			ash at umich.edu

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