Path: utzoo!attcan!utgpu!watmath!iuvax!bionet!bionet-20.bio.net!SOKATCH.BURNS
From: SOKATCH.BURNS@BIONET-20.BIO.NET (P. Gayle Burns)
Newsgroups: bionet.molbio.methds-reagnts
Subject: affinity purification of DNA-binding proteins
Message-ID: <12486874925.28.SOKATCH.BURNS@BIONET-20.BIO.NET>
Date: 17 Apr 89 15:32:35 GMT
Sender: daemon@NET.BIO.NET
Lines: 15

Thanks! Yes, the Promega GRAB kit was the one I was thinking of.
The original method on which this kit is based is from Levens and Howley, Mol.
Cell Biol. Vol 5, 2307-2315 (1985).  Also see Gimble, Levens, and Max, Mol
Cell Biol Vol. 7, 1815-1822 (1987).
	Another affinity method that was brought to my attention is this:
The DNA fragment is affinity labeled with biotin-deoxynucleotide by filling in
the end using Klenow.  This binds to streptavidin-agarose (BRL) and you have
your affinity matrix! After binding of the repressor from a crude cell lysate,
the protein can be eluded by high salt concentration, inducer, or as a complex 
with the bound DNA fragment by restriction digestion. The authors claim a
3400-fold enrichment.  This method is by Leblond-Francillard, Dreyfus and
Rougeon, Eur. J. Biochem vol 166, 351-355 (1987). 
	I'd like to hear of successes and failures with these methods.
Gayle Burns
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