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Updated: Jan 22, 2026

Orthogonal Protein Purification Facilitated by a Small Bispecific Affinity Tag
Published on: January 16, 2012
Uncapping the N-terminus of a ubiquitous His-tag peptide enhances its Cu2+ binding affinity
J Wątły1, A Hecel, R Wieczorek
1Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 14, 50383, Wroclaw, Poland. magdalena.rowinska-zyrek@chem.uni.wroc.pl.
Abstract:
Metal complexes with an N-terminally free and N-terminally acetylated polyhistidine region of Echis ocellatus venom, with an interesting His-rich motif present in numerous metal binding proteins from all kingdoms of life (DHDHDHHHHHHPGSSV-NH2 and Ac-DHDHDHHHHHHPGSSV-NH2) show the role of the free amino group in the thermodynamic enhancement of Cu2+, Ni2+ and Zn2+ binding. In the studied sequences, Cu2+ can be coordinated by different sets of imidazole rings, and a 3-10 helix is detected in close proximity of Cu2+ binding sites. The complexes are more stable than those with a typical His6-tag, despite a similar copper(ii) coordination mode in both cases.
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