Zn-NTA is a term that refers to a zinc Ion that has been coupled Nitrilotriacetic acid (NTA). Zn-NTA can then be coupled to agarose or magnetic beads for Immobilized Metal Chelate Affinity Chromatography, short IMAC. This is a purification method for two purposes.
- The purification of his tagged proteins
- The enrichment of zinc finger proteins
Cube Biotech offers multiple different Cu-NTA based products for your specific assay.
Overview of Cube Biotech's Cu-NTA products for protein purification.
Features
| Usage |
Specific binding and purification of 6x his-tagged proteins |
| Specifity |
Affinity to His-tagged proteins and zinc finger proteins |
| Bead size |
- 40 µm (agarose resin)
- 30 µm (magnetic beads)
|
| Binding capacity |
Depending on the application |
| Metal Ion capacity |
>12 µeqv Zn2+/mL. |
| Chelator stability |
Stable in buffer containing 10 mM DTT and 1 mM EDTA |
| Bead Ligand |
Cu-NTA |
Zn-NTA products by Cube Biotech were successfully used in the following publications:
| Protein | Year | Author | Product |
|---|
| HrpII |
2017 |
Bauer W.S., Richardson K.A., Adams N.M., Ricks K.M., Gasperino D.J., Ghionea S.J., Rosen M., Nichols K.P., Weigl B.H., Haselton F.R., Wright D.W., 1 |
Cu-NTA MagBeads |
Purification of zinc-finger proteins
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 (3). At the same time, non-tagged zinc-finger proteins can be purified using zinc IMAC matrices, simply by their affinity to this metal (2).
Different metal ions confer different binding affinity and specificity
Depending on the chelating metal ion the results of a His tag protein purification may change. The coupled metal ion influences the balance between protein affinity to the His tagged protein and the specificity of the purification. Copper as the chelating ion is the choice with the highest affinity. Using Copper-NTA will lead to the highest protein yield.
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.
References
- Bauer, Westley S et al. “Rapid concentration and elution of malarial antigen histidine-rich protein II using solid phase Zn(II) resin in a simple flow-through pipette tip format.” Biomicrofluidics vol. 11,3 034115. 2 Jun. 2017, doi:10.1063/1.4984788
- Vorácková, I. et al. Purification of proteins containing zinc finger domains using immobilized metal ion affinity chromatography. Protein Expr. Purif. (2011) 79(1):88-95.
- Block et. al. Immobilized-metal affinity chromatography (IMAC) a review. Methods Enzymol. (2009), 463:439-73.
