Immobilized metal affinity chromatography, or IMAC, has been employed for many applications making use of its versatile interaction with aromatic nitrogens and phosphates. To this end, NTA matrices have been loaded with a broad range of transition metals, as optimized for the individual interaction. Cube Biotech offers a selection of NTA based ligands for IMAC that cover more specialized purposes. All Magnetic Beads are delivered as a 25% suspension. Contact us for alternative options.
Applications that can be addressed with our Special IMAC MagBeads:
Purification of zinc-finger or copper-binding proteins (Zn, Cu)
Purification of his-tagged proteins with different specificity (Zn, Cu,)
Immobilized metal affinity chromatography, or IMAC for short, has been employed for many applications. Its Versatile applications range covering interaction with aromatic nitrogens and phosphates makes it one of the most practical methods in biology. We loaded our NTA ligand with multiple different metals for differnt affinities. Most commonly used alternative transition metals are copper (Cu), iron (Fe), and zinc (Zn). gallium (Ga), aluminium (Al), and zirconium (Zr) are sometimes used, but they are not in our standard stock. But do not worry. contact us and we can create them for you. Or you use one of our unloaded NTA or IDA MagBeads and load them yourselves with the metal ions that you desire. The loading protocols are provided on their respective pages.
Applications that can be addressed with IMAC from our standard sortiment.
When purifying his-tagged zinc-finger proteins which require a bound zinc ion for activity, it is often advisable to use Zn-IMAC instead of Ni-IMAC materials. Zinc matrices provide a high specificity for his-tagged protein purification (see Fig. 1) and an exchange of zinc bound to the active site of the protein by nickel is avoided (2). At the same time, non-tagged zinc-finger proteins can be purified using zinc IMAC matrices, simply by their affinity to this metal (1). Similar approaches have been done to enrich copper-binding proteins by Cu-IMAC, in particular with plant extracts (3).
Fig. 1: Affinity and specificity of metal ions commonly used for IMAC. Loading an IMAC resin with different metal ions can adjust the affinity and specificity to optimize the purity and yield of a purified protein.
Different metal ions confer different binding affinity and specificity
Loading different metal ions to a resin results in differing affinity and specificity for a his-tagged protein. Generally, cobalt exhibits the higest binding specificity of commonly used IMAC metal ions, leading to relatively low yields but high purity. Copper, at the other end of the spectrum, has a high affinity leading to high yields but unspecific binding. In searching for the optimal resin to purify a protein, it is recommended to explore different chelating ligands (IDA or NTA) and different metal ions.