Dear Dee,
Some proteins with chaperone-like activity (perhaps your B?) can only
bind to partially folded proteins.
Probably A folds to a molten globule structure after 1-2 days. You can
check by spectroscopic techniques (ANS or Trp fluorescence, CD).
Hope that helps.
Cheers,
Clement
On 10/22/13 11:10 AM, Xiaodi Yu wrote:
Dear All:
I have a general question about protein- protein interactions. I have
two proteins, A and B. A is a disordered protein while B is a well
folded protein. The binding between A and B has been approved by
GST-pull down assay previously. The strange thing is I cannot get them
bind if protein A were just freshly prepared. However, if I kept these
two proteins separately for one or two days at 4 degree and then did
the GST-pull down assay again, I can observe very strong interaction
between A and B.
Protein A doesn't contain any cys residue. I have already test certain
chemicals which might affect the interactions, for example, DTT and
EDTA. These chemicals seems to have no effect on the binding.
Although A is a disordered protein, does it need such long time to
find its proper conformation?
Do any people have similar experience? Any suggestions are greatly
appreciated.
Thanks,
Dee
