[Study on the induction of pco promoters from Escherichia coli with copper and other metal ions].
Two copper inducible promoters in the pco determinant of Escherichia coli were studied by determining the luciferase activity of report vector pUCD615. The results showed that in the absence of pBIN19pco, providing copper resistance genes in trans, the maximum induction for both PpcoA lux fusions was observed at 5 mmol/L CuSO4 and PpcoA box was a stronger promoter than PpcoA long. There were two peaks in the bioluminescences of both PpcoE-lux fusions induced with increasing copper concentration, the first peak was observed at about 0.5 mmol/L CuSO4, the second peak, also the maximum induction, was observed at about 5 mmol/L CuSO4, and PpcoE long was a stronger promoter than PpcoE box. The results indicated that the PpcoE promoter was a much stronger promoter than PpcoA promoter. The results also showed that the copper box was very important and essential to pco promoters, since both of the Ppco short-lux fusions failed to show any luciferase activity when they were induced with copper. In the presence of pBIN19pco, the maximum inductions of all of the Ppco-lux fragments were observed at 6 mmol/L CuSO4 and they were much higher than those observed in the absence of pBIN19pco, and the results also indicated that the cells were able to resistant to much higher copper concentration in the presence of pBIN19pco than in the absence of that. Zn2+ and Ni2+ could be inducers for all of the fragments and Zn2+ was a better inducer than Ni2+, and Cd2+ and Ag+ did not induce the pco system.
Liu
Z P
ZP
Institute of Microbiology, Chinese Academy of Sciences, Beijing.
Brown
N L
NL
D001483:Base Sequence; D003300:Copper / Q000494:pharmacology*; D004926:Escherichia coli / Q000235:genetics*; D008163:Luminescent Measurements; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic
D003300:Copper