Bioadsorption of cadmium ion by cell surface-engineered yeasts displaying metallothionein and hexa-His.
The Cd(2+)-chelating abilities of yeast metallothionein (YMT) and hexa-His displayed on the yeast-cell surface were compared. Display of YMT and hexa-His by alpha-agglutinin-based cell-surface engineering was confirmed by immunofluorescent labeling. Surface-engineered yeast cells with YMT and hexa-His fused in tandem showed superior cell-surface adsorption and recovery of Cd2+ under EDTA treatment on the cell surface than hexa-His-displaying cells. YMT was demonstrated to be more effective than hexa-His for the adsorption of Cd2+. Yeast cells displaying YMT and/or hexa-His exhibited a higher potential for the adsorption of Cd2+ than Escherichia coli cells displaying these molecules. In order to investigate the effect of the displayed YMT and hexa-His on sensitivity to toxic Cd2+, growth in Cd(2+)-containing liquid medium was monitored. Unlike hexa-His-displaying cells, cells displaying YMT and hexa-His fused in tandem induced resistance to Cd2+ through active and enhanced adsorption of toxic Cd2+. These results indicate that YMT-displaying yeast cells are a unique bioadsorbent with a functional chelating ability superior to that of E. coli.
Kuroda
K
K
Laboratory of Applied Biological Chemistry, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Yoshida, Sakyo-ku, 606-8501 Kyoto, Japan.
Ueda
M
M
D000327:Adsorption; D002104:Cadmium / Q000378:metabolism* / Q000633:toxicity; D002462:Cell Membrane / Q000378:metabolism*; D003470:Culture Media; D003545:Cysteine; D004492:Edetic Acid / Q000494:pharmacology; D005818:Genetic Engineering / Q000379:methods; D006639:Histidine; D008668:Metallothionein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
D003470:Culture Media; D002104:Cadmium; D006639:Histidine; D008668:Metallothionein; D004492:Edetic Acid; D003545:Cysteine