Genetic engineering of Escherichia coli for enhanced uptake and bioaccumulation of mercury.
Synthetic phytochelatins (ECs) are a new class of metal-binding peptides with a repetitive metal-binding motif, (Glu-Cys)(n)Gly, which were shown to bind heavy metals more effectively than metallothioneins. However, the limited uptake across the cell membrane is often the rate-limiting factor for the intracellular bioaccumulation of heavy metals by genetically engineered organisms expressing these metal-binding peptides. In this paper, two potential solutions were investigated to overcome this uptake limitation either by coexpressing an Hg(2+) transport system with (Glu-Cys)(20)Gly (EC20) or by directly expressing EC20 on the cell surface. Both approaches were equally effective in increasing the bioaccumulation of Hg(2+). Since the available transport systems are presently limited to only a few heavy metals, our results suggest that bioaccumulation by bacterial sorbents with surface-expressed metal-binding peptides may be useful as a universal strategy for the cleanup of heavy metal contamination.
Bae
W
W
Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, USA.
Mehra
R K
RK
Mulchandani
A
A
Chen
W
W
D002614:Chelating Agents / Q000138:chemical synthesis / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D005818:Genetic Engineering / Q000379:methods*; D005978:Glutathione; D008628:Mercury / Q000378:metabolism*; D008667:Metalloproteins / Q000138:chemical synthesis / Q000235:genetics* / Q000378:metabolism*; D054811:Phytochelatins; D010940:Plant Proteins / Q000138:chemical synthesis / Q000235:genetics* / Q000378:metabolism*
D002614:Chelating Agents; D008667:Metalloproteins; D010940:Plant Proteins; D054811:Phytochelatins; D008628:Mercury; D005978:Glutathione