I'm dealing with two different protein(say, protein_a and protein_b) which stays in an interacting-oligomeric form in biological system.
I have so far successfully been able to purify both the proteins using IMAC(Ni-NTA) protocol.
Further TEM analysis of the purified protein is showing the presence of oligomeric form(for each of them separately) in the purified sample.

But, how can I be able to detect or show how the oligomers of protein_a and protein_b is interacting to produce a much larger macromolecular entity ? And how can I be able to quantify that interaction ?

Any ideas regarding this issue would be highly appreciated.

  • $\begingroup$ Are the oligomers of a defined size? Gel filtration chromatography or native PAGE could show an interaction and give an apparent Mr of the complex. $\endgroup$
    – canadianer
    Commented Aug 17, 2015 at 16:19
  • $\begingroup$ Previous data regarding oligomer size shows that protein_a forms ~600kd oligomer(using analytical ultra centrifugation), however protein_b's oligomer size not yet known. So, I'm not sure whether native PAGE could resolve such big mw. @canadianer $\endgroup$
    – diffracteD
    Commented Aug 17, 2015 at 17:19
  • $\begingroup$ Though I've never tried, there are native PAGE systems capable of resolving proteins upwards of 10000 kDa $\endgroup$
    – canadianer
    Commented Aug 17, 2015 at 17:41


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