Structure of His-Tag complex

Darren Tyson tysondr at
Thu May 8 12:04:20 EST 1997

Thorsten Schmidt wrote:
> Dear reader!
> The His-Tag-System is widely used for protein purification.
> (Novagene, Quiagen ...)
> Using a special expression vector, a "His-Tag", a repeat of six Histidines,
> is added to the target protein.
> A special resin is then loaded with nickel-ions.
> When one loads the column with a protein mixture only
> the target protein forms with its histidines a complex with the nickel and
> the resin.
> After washing steps the protein can be eluted with a buffer containing
> Imidazole.
> I want to know the exact structure of this complex and the reason, why
> it is possible to elute the protein with Imidazole.
> Can you help me, perhaps tell me a reference?
> Thank you very much in advance for your answer
> Thorsten


QIAGEN's web site has plenty of information available regarding
purification of His-tagged proteins.  In particular, they have an online
version of the QIAexpressionist which is a great resource for the theory
behind the expression and purification of recombinant His-tagged
proteins.  The URL is

Hope this helps,

Darren Tyson
Ph.D. Candidate in Cell & Molecular Biology
Saint Louis University

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