Work

Unveiling the Molecular Basis of Silver(I) Sequestration by Glutathione: Stoichiometry, Stability and Structure at Neutral pH

Year: 2026

Type: preprint

Abstract: The complexation of Ag(I) ions by reduced glutathione (GSH) at neutral pH was studied by UV-vis, CD and NMR spectroscopies and mass spectrometry, aided by DFT calculations. A tetrameric Ag 4 (GSH) 4 complex was found to be the sole species at these conditions, containing the octagonal Ag 4 S 4 ring with digonal S-Ag-S coordination mode. The pH-independent stability constant of this complex was determined by competitive titrations with excess of thiosulfate ions as KAg4(GSH)4 = 1.6 × 10 67 M -7 . Equilibrium calculations using this constant indicate that physiological millimolar GSH concentrations can sequester all substoichiometric Ag(I) ions, presumably preventing their toxicity towards cellular proteins. However, the ring structure of the complex is not compatible with the standard cellular heavy metal detoxication mechanism. These results provide a molecular basis for deciphering the role of glutathione in cellular silver toxicity and detoxication.

Source: ChemRxiv

DOI: 10.26434/chemrxiv.15010809/v1

Authors: Paulina Szczerba, Tshering Zangmo, Luisa Ronga, Joanna Szpunar, Kosma Szutkowski, Igor Zhukov, Wojciech Bal

Institutions: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Polish Academy of Sciences, Université de Pau et des Pays de l'Adour, Adam Mickiewicz University in Poznań

Language: English

Topic: Sulfur Compounds in Biology

Subfield: Biochemistry

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: green

Funders: Narodowa Agencja Wymiany Akademickiej, Université de Pau et des Pays de l'Adour

OpenAlex ID: W7223176883

Cites: 1

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