Chemical interactions of mercury species and some transition and noble metals towards metallothionein (Zn7MT-2) evaluated using SEC/ICP-MS, RP-HPLC/ESI-MS and MALDI-TOF-MS

Abstract

The chemical affinities of three submetallomes ("Mn, Co, Ni, Cu, Cd"; "Pd, Pt, Au"; and "Hg, CH3Hg, C 2H5Hg-THI") towards metallothionein-2 (Zn 7MT-2) in a physiological solution environment were evaluated using SEC/ICP-MS together with RP-HPLC/ESI-IT-MS and MALDI-TOF-MS, and followed the order: "Zn2+ < Cu2+, Cd2+ > Ni 2+ > Mn2+, Co2+"; "Pd2+ > Au3+ > Pt2+"; and "Hg2+ > CH3Hg+ > C2H5Hg-THI". Besides these, the structural change and composition of the CH 3Hg-MT-2 complexes formed during the CH3Hg+ titration process were further investigated using CD spectroscopy, RP-HPLC/ESI-MS and MALDI-TOF-MS, indicating that linear and more hydrophobic (CH3Hg)xMT-2 (x = 12, 13, 14, 15, 16, 17, 18, 19 and 20) were formed. This information is important in understanding the interactions of the metals with Zn7MT-2 and their corresponding biological functions and toxicities. © 2013 The Royal Society of Chemistry.