How to disrupt tetrameric coiled coil proteins?

[harkness at acs.ucalgsry.ca]

We work with a heterodimeric protein which interacts through a coiled coil
domain. During the final purification by gel filtration the protein
appears to 
agregate into greater than dimer forms. I am looking for something to
include in the gel filtration buffer which will disrupt trimer and
tetramer structures and allow purification of the dimeric form?

Any help is greatly appreciated.

Steven Szarka, Ph.D.
Dept. of Biological Sciences
University of Calgary
Calgary, AB, Canada

sjszarka at acs.ucalgary.ca