One His, two His…the emerging roles of histidine in cellular nickel trafficking

• Published in: Journal of inorganic biochemistry 2024-10, Vol.259, p.112668, Article 112668
• Main Authors: Chivers, Peter T., Basak, Priyanka, Maroney, Michael J.
• Format: Article
• Language: English
• Subjects: Histidine; Homeostasis; Low molecular weight ligands; Maturation; Nickel-trafficking; Speciation
• ISSN: 0162-0134; 1873-3344; 1873-3344
• DOI: 10.1016/j.jinorgbio.2024.112668

Biological environments present a complex array of metal-binding ligands. Metal-binding proteins have been the overwhelming focus of study because of their important and well-defined biological roles. Consequently, the presence of functional low molecular weight (LMW) metal-ligand complexes has been overlooked in terms of their roles in metallobiochemistry, particularly within cells. Recent studies in microbial systems have illuminated the different roles of L-histidine in nickel uptake, gene expression, and metalloenzyme maturation. In this focused critical review, these roles are surveyed in the context of the coordination chemistry of Ni(II) ions and the amino acid histidine, and the physico-chemical properties of nickel complexes of histidine. These complexes are fundamentally important to cellular metal homeostasis and further work is needed to fully define their contributions. The different roles of L-histidine in nickel uptake, gene expression, and metalloenzyme maturation are reviewed in the context of the coordination chemistry of L-His and the physico-chemical properties of nickel complexes of L-His. [Display omitted] •Low molecular weight metal complexes play important roles in many physiological processes.•L-His is a component of cytosolic metal buffers with which other biomolecules compete.•At cellular Ni and L-His concentrations, Ni(His)+ and Ni(His)2 both play roles.•Ternary complexes are important for buffering, homeostasis, and enzyme maturation.