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  • The binding sites of cadmium to reduced form of glutathione [Elektronski vir]
    Glušič, Martina, 1983- ; Grdadolnik, Jože
    Plants, like all living organisms, have evolved a suite of mechanism that control and respond to the uptake and accumulation of both essential and nonessential heavy metals. These mechanisms include ... the chelation and sequestration of heavy metals by particular ligands. Glutathione (GSH; ?-glutamyl-cysteinyl-glycine) is the most abundant low-molecular-weight thiol-containing compound in the cells and the thiol group acts as a ligand for heavy metal sequestration. In principle, the glutathione has eight possible binding sites but, it is well known, that Cd2+ prefers donor sites like thiol groups rather than donors such as carboxyl or carbonyl groups. However, it is still unclear how the carboxyl groups in the side chain and the peptide backbone contribute to the high affinity and selectivity toward metal cations. The present study concerns identification of the favoured complexation site of Cd2+ with reduced form of GSH by vibrational (Raman and FTIR) spectroscopy. For better characterization of the binding sites and due to the presence of similar functional groups (thiol, carboxylic acid, amino groups, ...) as GSH, we also used model systems such as penicillamine and N-acetylcysteine. GSH and other two thiol-containing compounds exist in a great number of protonated forms. Futhermore, the extent of metal-ligand interactions are also considerably influenced by the protonation stage of the ligand. Deprotonated thiol group is the best candidate to sequestrate the cadmium ion, but deprotonation requires drastic alkaline conditions that hardly occur in nature. We show that complexation of Cd2+ with GSH also happens considerably high at physiological conditions and that the thiol group plays a critical role for binding Cd2+.
    Vir: Sixth International Conference on Advanced Vibrational Spectroscopy [Elektronski vir] : Sonoma County, California 12-17 June 2011 (Str. [1])
    Vrsta gradiva - prispevek na konferenci
    Leto - 2011
    Jezik - angleški
    COBISS.SI-ID - 5083162

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