GST fusion proteins

[dalyt at HAL.HAHNEMANN.EDU]

February 1, 1993

This note concerns a problem that I am having with GST fusion proteins from
the pGEX/2T vector. During batch elution of either fusion protein or GST
alone, I am getting a stringy aggregate that turns out to be the fusion
protein or GST which ever the case may be. The elution conditions are: 5
bead vols. of 5 mM glutathione (reduced) in 50 mM Tris-HCl pH 8.0, freshly
prepared. I never saw this phenomenon when using the matrix in a column but
this may be because the aggregates would never have gotten out.

Have any of you pGEX users eluted with something other than glutathione? I
have considered trying low pH glycine buffer but will have to bring up the
pH through the pI of both GST and the fused protein. This may cause as much
of a problem as glutathione.

Any thoughts or suggestions would be appreciated.

Thanks.

Tom
___________________________________________________________________________
 THOMAS M. DALY                 /   / /   /   DEPT. OF MICROBOLOGY  MS 405
 Voice (215) 762-1903          /___/ /   /    HAHNEMANN UNIVERSITY
 Fax   (215) 762-8075         /   / /   /     BROAD & VINE STS.,
 DALYT at hal.hahnemann.edu     /   / /___/      PHILA., PA 19102
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