HIS TAG - Metal affinity column

[Sandra & Thomas Haselhorst]

Hi there, 

I am trying to express a ~20 kDa protein in E.coli LB and M9 minimal
media. I have got good expression and I want to purify this
recombinant protein with a metal affinity (TALON) column. But my
protein doesn't bind to the matrix at all. I only find my protein in
the through flow and elution of the metal column with 150 mM Imidazole
results in  several other bands. But not my protein. Is there anything
wrong with the matrix, vector etc. ?? I am not sure where to start to
solve this problem ...

Thanks

Tommy