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Tandem oligomeric expression of metallothionein enhance heavy metal tolerance and bioaccumulation in Escherichia coli.

  • Wenli Ma
    ,
  • Xuefen Li
    ,
  • Qi Wang
    ,
  • Zhumei Ren
    ,
  • James Crabbe
    ,
  • Lan Wang
Research Output: Contribution to journal Article Peer-review

Open access

Abstract

Metallothioneins (MTs) are a family of low molecular weight, cysteine-rich, metal-binding proteins, which play important roles in metal homeostasis and heavy metal detoxification. In our previous study, a novel full length MT cDNA was successfully cloned from the freshwater crab (Sinopotamon henanense). In the present study, tandem repeats of two and three copies of the crab MT gene were integrated by overlap extension PCR (SOEPCR) and expressed in Escherichia coli. The SUMO fusion expression system was adopted to increase the stability and solubility of the recombinant MT proteins. The recombinant proteins were purified and their metal-binding abilities were further analyzed by the ultraviolet absorption spectral scan. Furthermore, the metal tolerance and bioaccumulation of E. coli cells expressing oligomeric MTs were determined. Results showed that the recombinant plasmids pET28a-SUMO-2MT and pET28a-SUMO-3MT were successfully constructed. SDS-PAGE analysis showed that the SUMO-2MT and SUMO-3MT were expressed mainly in the soluble forms. Oligomeric MTs expression significantly enhanced Cu, Cd or Zn tolerance and accumulation in E. coli in the order: SUMO-3MT˃SUMO-2MT˃SUMO-MT˃control. Cells harboring pET28a-SUMO -3MT exhibited the highest Cu, Cd or Zn bioaccumulation at 5.8-fold, 3.1-fold or 6.7-fold higher than that of the control cells. Our research could lay a foundation for large-scale preparation of MTs and provide a scientific basis for bioremediation of heavy metal pollution by oligomeric MTs.

Publication Information

Output type

Research Output: Contribution to journal Article Peer-review

Original language

English

Pages from-to (Number of pages)

Pages 301-307

Journal (Volume, Issue Number)

Ecotoxicology and Environmental Safety (Volume 181)

Publication milestones

  • Accepted/In press - 07/06/2019
  • Published - 13/06/2019

Publication status

Published - 13/06/2019

ISSN

0147-6513

External Publication IDs

  • handle.net: 10547/623349
  • Scopus: 85067184074

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