Cu + /Ag + Competition in Type I Copper Proteins (T1Cu)

• Published in: Biomolecules (Basel, Switzerland) Vol. 13; no. 4; p. 681
• Main Authors: Kircheva, Nikoleta, Angelova, Silvia, Dobrev, Stefan, Petkova, Vladislava, Nikolova, Valya, Dudev, Todor
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01-04-2023; MDPI
• Subjects: Amino acid composition; Amino acids; azurin; Biotransformation; Calibration; Cations; ceruloplasmin; Competition; Computational chemistry; Copper; Copper - chemistry; DFT; Dielectric constant; Geometry; Heavy metals; Humans; Metal ions; Physiological aspects; plastocyanin; Preferences; Proteins; Silver; Silver - chemistry; Type I copper proteins; Bulgaria; ceruloplasmin; plastocyanin; silver; DFT; Type I copper proteins; azurin
• ISSN: 2218-273X; 2218-273X
• DOI: 10.3390/biom13040681

Due to the similarity in the basic coordination behavior of their mono-charged cations, silver biochemistry is known to be linked to that of copper in biological systems. Still, Cu
/
is an essential micronutrient in many organisms, while no known biological process requires silver. In human cells, copper regulation and trafficking is strictly controlled by complex systems including many cytosolic copper chaperones, whereas some bacteria exploit the so-called "blue copper" proteins. Therefore, evaluating the controlling factors of the competition between these two metal cations is of enormous interest. By employing the tools of computational chemistry, we aim to delineate the extent to which Ag
might be able to compete with the endogenous copper in its Type I (T1Cu) proteins, and where and if, alternatively, it is handled uniquely. The effect of the surrounding media (dielectric constant) and the type, number, and composition of amino acid residues are taken into account when modelling the reactions in the present study. The obtained results clearly indicate the susceptibility of the T1Cu proteins to a silver attack due to the favorable composition and geometry of the metal-binding centers, along with the similarity between the Ag
/Cu
-containing structures. Furthermore, by exploring intriguing questions of both metals' coordination chemistry, an important background for understanding the metabolism and biotransformation of silver in organisms is provided.