Chelation of Cadmium Ions by Phytochelatin Synthase: Role of the Cystein-rich C-Terminal

VESTERGAARD Mun'delanji, MATSUMOTO Sachiko, NISHIKORI Shingo, SHIRAKI Kentaro, HIRATA Kazumasa, TAKAGI Masahiro

doi:10.2116/analsci.24.277

Chelation of Cadmium Ions by Phytochelatin Synthase: Role of the Cystein-rich C-Terminal

DOI PDF Web Site Web Site Web Site 被引用文献1件参考文献56件

VESTERGAARD Mun'delanji

School of Materials Science, Japan Advanced Institute of Science and Technology
MATSUMOTO Sachiko

School of Materials Science, Japan Advanced Institute of Science and Technology
NISHIKORI Shingo

Division of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University
SHIRAKI Kentaro

Institute of Applied Physics, University of Tsukuba
HIRATA Kazumasa

Department of Environmental Bioengineering Laboratory, Graduate School of Pharmaceutical Sciences, Osaka University
TAKAGI Masahiro

School of Materials Science, Japan Advanced Institute of Science and Technology

この論文をさがす

抄録

The interactions between Cd²⁺ and the C-terminal region of phytochelatin (PC) synthase using recombinant wild-type and mutant PC synthase were studied. We show that site-directed mutagenesis of Cys residues at C³⁵⁸C³⁵⁹XXXC³⁶³XXC³⁶⁶ motif decreases the number of Cd²⁺ and other heavy metal ions interacting with the enzyme, and that the motif binds the metals discriminatingly. The optimum binding ratio of PC synthase to Cd²⁺ was also determined. The findings indicate that Cys exists as a free SH residue and that it is involved in the regulation of PC enzyme activity by transferring the metals into closer proximity with the catalytic domain. These results are important in understanding heavy metal detoxification mechanisms in higher plants, a step towards phytoremediated-applications.