Magnetic and metal binding structural analysis of Mn, Zn-metallothionein-green fluorescence fusion protein

• Main Author: 陳廷楷
• Other Authors: Chang, Chia-Ching
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/81179322002365943617

碩士 === 國立交通大學 === 生物科技學系 === 100 === Metallothionein-green fluorescence fusion protein (MT-GFP) is a zinc binding protein, which binds seven divalent transition metal ions through its 20 conserved cysteines and forms two metal binding clusters with Zinc-Blende structure. In this study, Mn2+ ions has substituted for Zn2+ at M3, M4 metal binding sites in the β-domain of MT-GFP. We found this Mn, Zn binding protein exhibits weak ferromagnetic properties at temperature range from 10K to 300K by SQUID measurement. By micro-Raman spectroscopy analysis, the Zn-S and Mn-S bending modes can be observed clearly at 288 cm-1 and 355 cm-1, respectively. These evidences indicate that the Zn2+ and Mn2+ ions are bound with Cys residues of MT-GFP. Extended X-ray absorption fine structure (EXAFS) analysis also indicats Mn2+ ions bond to MT-GFP via the Mn-S bond of Cys. The conformation of Mn,Zn-MT-GFP can be characterized by TEM and the its intermolecular interactions can be determined by its electron diffraction pattern.