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

National Natural Science Foundation of China [21035006, 21275120]; National Basic Research Program 973 Project [2009CB421605]The chemical affinities of three submetallomes ("Mn, Co, Ni, Cu, Cd''; "Pd, Pt, Au''; and "Hg, CH3Hg, C2H5Hg-THI'') towards metallothionein-2 (Zn7MT-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+ Ni2+ > Mn2+, Co2+''; "Pd2+ > Au3+ > Pt2+''; and "Hg2+ > CH3Hg+ > C2H5Hg-THI''. Besides these, the structural change and composition of the CH3Hg-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)(x)MT-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