Isoelectric Focussing of Zinc-Finger Proteins

[WILLARD at MVAX.WISTAR.UPENN.EDU]

Hi.

Does anyone know of a way to run IEF gels of DNA binding proteins, specifically
Zinc finger proteins?  I have attempted to run an IEF gel for the purpose
of assessing the ion exchange purification conditions of two different zinc
finger proteins - WT1 (four Zn fingers) and Mig1 (two zinc fingers).  I used
the Phast system from pharmacia, including their pre-cast IEF 3-9 gels.
Using silver staining, I could see that the proteins PRECIPITATED at the
point of application (no matter where they were applied on the gel).

This has been a major problem because I cannot determine whether or not
my sample is homogeneous - the possibility exists that there are multiple
isoforms.

Any suggestions would be greatly appreciated.

Thanks,
Rob Willard
Wistar Institute/Univ of Penn
Willard at WISTB.WISTAR.UPENN.EDU