Guidelines for GST fusion

T. S. Pillay tpillay at
Sat Mar 5 02:04:48 EST 1994

Subject: Guidelines for GST fusion
From: Jason Lei, leij at
Date: Thu, 3 Mar 1994 13:34:36 GMT
In article <CM3CDp.AAp at> Jason Lei,
leij at writes:
>One graduate student in our lab had problem in using pGex for making
>fusion protein.  She only saw the right size (~64 kD) once; all other
>trials revealed only a size (~50 kD) of seemingly degraded product.
>She wondered if there are general guidelines (or source of such 
>guidelines) for making proteins by GST fusion.
>By the way, she tried both DH5a and JM105 (cultured overnight in 2XYT 
>with or without IPTG induction) with the same results.  She certainly
>would appreciate any ideas on this problem or guidelines for using pGex.
The recommended strain for pGex is DH5a.  I presume she has read the
Pharmacia handbook which comes with pGex and provides troubleshooting
guidelines.  Every fusion protein is different - that's the guideline I
follow -you have to play around to find the right conditions.  I would
suggest using  a protease-deficient strain if proteolysis is a problem.

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