Lighting E. coli cells as biological sensors for Cd2+

Abstract

Whole cells of E. coli expressing a chimeric cadmium-binding peptide fused to green fluorescent protein (CdBPGFP) were prepared and applied for the determination of cadmium. Construction of the structural gene was performed by inserting two synthetic oligonucleotides coding for four repeats of a Cd-binding peptide (His-Ser-Gln-Lys-Val-Phe) into the 5′-end of the GFPuv gene. Similarly, a hexahistidine-green fluorescent protein (his6GFPuv) was prepared and used as a reference in the determinations of heavy metals. The lowest concentrations of Cd, which activated the fluorescence, were 0.5 μM, 50 μM, and 0.5 mM for cells carrying CdBP4GFP, his6GFP and native GFP, respectively.