To facilitate the purification of a recombinant protein expressed in
E.coli, a poly-histidine tag can be added to the N-terminal sequence of
the protein.
In this way, the protein can be retained on a matrix charged with Ni2+
ions which form complexes with the histidine residues, and therefore, a
specific elution can be carried out.
But, due to their amino acid content, some E.coli proteins are also bound
to the Ni-column, and disturb the purification of the recombinant protein.
Has anybody identified E.coli proteins which are retained during
purification using a Ni-column?
I would also be very interested in references describing this subset of
E.coli proteins.
