Applied Microbiology and Biotechnology

, Volume 70, Issue 4, pp 458–463

Effective display of metallothionein tandem repeats on the bioadsorption of cadmium ion

Authors

  • Kouichi Kuroda
    • Division of Applied Life Sciences, Graduate School of AgricultureKyoto University
    • Division of Applied Life Sciences, Graduate School of AgricultureKyoto University
Applied Genetics and Molecular Biotechnology

DOI: 10.1007/s00253-005-0093-8

Cite this article as:
Kuroda, K. & Ueda, M. Appl Microbiol Biotechnol (2006) 70: 458. doi:10.1007/s00253-005-0093-8

Abstract

To increase the level of adsorption of heavy metal ions in surface-engineered yeasts, a yeast metallothionein (YMT) was tandemly fused and displayed by means of an α-agglutinin-based display system. The display of the YMT and its tandem repeats was examined by immunofluorescent labeling. The adsorption and recovery of Cd2+ on the cell surface was increasingly enhanced with increasing number of tandem repeats. All Cd2+-binding sites in the YMT tandem repeats were suggested to be completely occupied. To investigate the relationship between cell-surface adsorption and protection against heavy metal ion toxicity, the tolerance of these surface-engineered yeasts to Cd2+ was examined by growing in Cd2+-containing liquid medium. The rate of growth was found to be dependent on the number of displayed tandem repeats of YMT. These results suggest that the characteristics of surface-engineered yeasts as a bioadsorbent were dependent on the ability of the displayed proteins to bind metal ions, and the adsorption of heavy metal ions on the cell surface plays a major role in the ability of the cells to resist the toxic effects of metal ions.

Copyright information

© Springer-Verlag 2005