Biotechnology Letters

, Volume 35, Issue 8, pp 1253–1258 | Cite as

Optimizing cadmium and mercury specificity of CadR-based E. coli biosensors by redesign of CadR

  • Hu-Chun TaoEmail author
  • Zhi-Wen Peng
  • Peng-Song Li
  • Tai-An Yu
  • Jie Su
Original Research Paper


The metalloprotein, CadR, was redesigned to optimize cadmium and mercury specificity of CadR-based E. coli biosensors. By truncating 10 and 21 amino acids from the C-terminal extension of CadR, CadR-TC10 and CadR-TC21 were obtained, respectively. The genes cadR, cadR-TC10 and cadR-TC21 were used as sensing elements to construct green fluorescent protein based E.coli biosensors. Induction at 30 °C for 4 h in supplemented M9 medium was the optimized condition for the biosensor. Compared with CadR-based biosensor, there was a clear decline in induction coefficient for CadR-TC21-based biosensor (decreased by 86 % in Zn(II), 44 % in Hg(II), and only 37 % in Cd(II)). While in CadR-TC10-based biosensor, the induction coefficient decreased by 95 % in Zn(II), 70 % in Hg(II), and 67 % in Cd(II). Improved performances of CadR mutants based E. coli biosensors indicated that truncating C-terminal extension of CadR could improve the specificity.


Cadmium CadR Mercury Specificity Whole cell biosensor 



This research was supported by Shenzhen Municipal Government under a grant for Key Lab Construction (CXB201111240110A). We thank Yu-Jie Liang for help in fluorescent assay and Priscilla Young for English language editing.

Supplementary material

10529_2013_1216_MOESM1_ESM.docx (1.1 mb)
Supplementary material 1 (DOCX 1165 kb)


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Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Hu-Chun Tao
    • 1
    Email author
  • Zhi-Wen Peng
    • 1
  • Peng-Song Li
    • 1
  • Tai-An Yu
    • 1
  • Jie Su
    • 1
  1. 1.Key Laboratory for Heavy Metal Pollution Control and ReutilizationSchool of Environment and Energy, Peking University Shenzhen Graduate SchoolShenzhenChina

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