Related Experiment Video
Updated: May 30, 2025

Expression, Purification, and Antimicrobial Activity of S100A12
Published on: May 13, 2017
Calprotectin's Protein Structure Shields Ni-N(His) Bonds from Competing Agents
Zhuojian Lu1, Jingyuan Nie1, Ziling Wang2
1State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
Abstract:
The Ni-N(His) coordination bond, formed between the nickel ion and histidine residues, is essential for recombinant protein purification, especially in Ni-NTA-based systems for selectively binding polyhistidine-tagged (Histag) proteins. While previous studies have explored its bond strength in a synthetic Ni-NTA-Histag system, the influence of the surrounding protein structure remains less understood. In this study, we used atomic force microscopy-based single-molecule force spectroscopy (AFM-SMFS) to quantify the Ni-N(His) bond strength in calprotectin, a biologically relevant protein system. Our results demonstrate that the Ni-N(His) bond in protein exhibits a rupture force of ∼56 pN. Notably, kinetic analysis revealed a significantly lower off-rate compared to the synthetic system, suggesting that the protein environment plays a crucial role in stabilizing the bond. Moreover, we found that the bond is less susceptible to displacement by competing agents, such as imidazole, and experiences only a modest decrease in stability under acidic conditions, compared to the dramatic weakening seen in a synthetic system. These findings highlight the role of protein structure in protecting the mechanical and kinetic stability of the Ni-N(His) bond, offering insights into understanding the metal-ligand interactions in proteins in general.
Related Concept Videos
Protein Folding
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
Protein Organization
The primary structure of a protein is its amino acid sequence....
Covalently Linked Protein Regulators
These groups modify specific amino acids in a protein....
Protein and Protein Structure
A protein's shape is critical to its function. For example, an enzyme...
Conservation of Protein Domains Over Different Proteins
A limited set of protein domains often duplicate and recombine during evolution. These domains can be organized in different combinations to...
Protein-protein Interfaces

