I am attempting to purify a protein complex of two proteins. The Protein A
and Protein B have been co-expressed in media containing N15-Cys. Protein
A has a 6-histadine tag. I am able to purify this complex via a Ni-NTA
column with good results. I now have the Protein A-labled/B-labled
Protein A must be co-expressed as it does not express well alone.
Have you tried separating A+B on the Nickel column by flowing 2M urea to help
tickle off protein B. The amount will vary depending on the affinity. In my
case (~50nM) requires about 1000-1700ml of 20mM Tris, 2M urea pH 7.5. Then
