Coordination of Bi3+ to metal-free metallothionein: Spectroscopy and density functional calculation of structure, coordination, and electronic excitations
- 物理技术－已发表论文 
Understanding the structure of mammal Bi-containing metallothionein-2 (Bi-MT2) is of great physiological significance due to the importance of Bi-MT2 in alleviating adverse effect of anti-cancer drugs. A unique feature of rabbit liver Bi-MT2 is the metal-oxygen bond (Bi - O), which is absent in well-characterized Zn-MT2 and Cd-MT2. However, the ligand contributing to the Bi - O bonding in Bi-MT2 remains unidentified. In this study, the coordination of Bi3+ to rabbit liver metal-free metallothionein was investigated using both experimental and theoretical methods. UV-visible and circular dichroism spectra indicate that Bi-MT2 has a different secondary structure from those of Zn-MT2 and Cd-MT2. Three possible Bi3+ coordination structures in Bi-7-MT2 and relative binding free energies were calculated using the density functional theory. Absorption spectra corresponding to these coordination structures were evaluated by time-dependent density functional theory. Our computation results are consistent with the UV-vis spectroscopic data and strongly suggest that the carboxyl group in the aspartic acid residues contributes to the Bi - O bond formation. (C) 2012 Elsevier Inc. All rights reserved.
CitationJOURNAL OF INORGANIC BIOCHEMISTRY，2012,113,：9-14