His tagged protein expression

Bill Geese wjgeese at tempest.ocis.temple.edu
Thu Aug 6 12:36:08 EST 1998

Refer to Biotechniques (either June 98 or July 98 I forget exactly.)
There is an article which deals with Ni++ induced
his-protein oligomerization.
Hope this helps


On Thu, 6 Aug 1998, Mayank Bhalla wrote:

> Hi,
> I am trying to express a 15 kDa protozoan protein as a His tag fusion in
> Qiagen's pQE30 vector. My problem is that the protein is being expressed
> as a trimer (possibly!?) as the over expressed protein appears to be about
> 45 kDa on the SDS-PAGE. This high molecular weight protein gets purified
> on the Ni-NTA resin supplied by Qiagen. 
> Can any one offer ideas so as to why it may be happening and what can I do
> to get the protein of the right size? I have confirmed the construct by
> sequencing the whole of the insert and the junctions.
> Any help will be greatly appreciated.
> Many thanks
> Mayank

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