Metallochaperone

Article By:

Culotta, Valeria Cizewski Department of Environmental Health Sciences, Johns Hopkins University School of Public Health, Baltimore, Maryland.

Last reviewed:September 2021

DOI:https://doi.org/10.1036/1097-8542.757592

A type of protein that shuttles metal ions to specific sites within a cell. Metallochaperones are molecular facilitators that transport metal ions to target proteins (see illustration). The target sites for metal delivery include a number of metalloenzymes, or proteins that bind metal ions, such as copper, zinc, or iron. These ions are subsequently used as cofactors to carry out essential biochemical reactions. It was long thought that metalloenzymes could acquire their metal ion without the assistance of an accessory metallochaperone. The metal ion was believed to freely diffuse within the cell until it contacted its metalloenzyme target, at which point the metal ion inserted itself into the protein. However, several discoveries in the late 1990s led to a radical change in the thinking of how metalloenzymes acquire their metal ion. The insertion of the metal is now known to require an auxiliary protein, which is termed the metallochaperone. Metallochaperones escort the ion to a specific intracellular location and facilitate the incorporation of the metal into designated metalloenzymes. See also: Biochemistry; Bioinorganic chemistry; Enzyme; Ion; Protein

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