title: A glutathione S-transferase from Proteus mirabilis involved in heavy metal resistance and its potential application in removal of Hg²⁺.
abstract: Glutathione S-transferases (GSTs) are a family of multifunctional proteins playing important roles in detoxification of harmful physiological and xenobiotic compounds in organisms. In our study, a gene encoding a GST from Proteus mirabilis strain V7, gstPm-4, was cloned and conditionally expressed in Escherichia coli strain BL21(DE3). The purified GstPm-4 protein, with an estimated molecular mass of approximately 23kDa, was able to conjugate 1-chloro-2,4-dinitrobenzene and bind to the GSH-affinity matrix. Real-time reverse transcriptase PCR suggested that mRNA level of gstPm-4 was increased in the presence of CdCl2, CuCl2, HgCl2 and PbCl2, respectively. Correspondingly, overexpression of gstPm-4 in the genetically engineered bacterium Top10/pLacpGst exhibited higher heavy metal resistance compared to the control Top10/pLacP3. Another genetically engineered bacterium Top10/pBATGst, in which the DNA encoding GstPm-4 protein was fused with the DNA encoding Pfa1-based auto surface display system, was built. Top10/pBATGst could constitutively express the chimeric GstPm-4 and anchor it onto the cell surface subsequently. Almost 100% of the Hg(2+) within the range of 0.1-100 nM was adsorbed by Top10/pBATGst, and 80% of the bounded Hg(2+) could be desorbed from bacterial cells when pH was adjusted to 6.0. Thus, Top10/pBATGst can be potentially used for efficient treatment of Hg(2+)-contaminated aquatic environment.
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, YICCAS, Yantai, Shandong 264003, PR China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Zhang
authors.forename: Kun
authors.initials: K
authors.lastname: Yin
authors.forename: Bowei
authors.initials: B
authors.lastname: Li
authors.forename: Lingxin
authors.initials: L
authors.lastname: Chen
mesh_terms: D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D005982:Glutathione Transferase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D019216:Metals, Heavy / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D011513:Proteus mirabilis / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D019216:Metals, Heavy; D005982:Glutathione Transferase
keywords: Adsorption; Glutathione S-transferase; Heavy metal; Proteus mirabilis; Surface display