Principle

Protino® Ni-TED products enable fast and convenient purification of recombinant polyhistidine-tagged proteins by immobilized metal ion affinity chromatography (IMAC). Protino® Ni-TED is a dry silica-based resin precharged with Ni²⁺ ions. Binding of protein is based on the interaction between the polyhistidine tag of the recombinant protein and immobilized Ni²⁺ ions. The chelating group of Protino® Ni-TED is based on TED (tris-carboxymethyl ethylene diamine), a strong pentadentate metal chelator. TED occupies five of the six binding sites in the coordination sphere of the Ni²⁺ ion, the remaining coordination site of Ni²⁺ is available for protein binding. Compared to TED, other chelating groups such as NTA (nitrilotriacetic acid) have four binding sites available for the Ni²⁺ ion, the remaining two sites of Ni²⁺ are available for protein binding:

TED – (5 bonds) – Ni²⁺ – (1 bond) – protein
NTA – (4 bonds) – Ni²⁺ – (2 bonds) – protein

The additional chelation site of TED with Ni²⁺ minimizes metal leaching during purification and increases specificity for polyhistidine-tagged proteins. Furthermore due to fewer side chains of the silica material in comparison to traditional resins based on agarose, the non specific binding of non-histidine tagged proteins is highly reduced. As a result target protein of excellent purity is eluted from the column.

Features

* Binding capacity will vary for each polyhistidin-tagged protein