Cloning and expression in Escherichia coli of mercuric ion resistance coding genes from Zymomonas mobilis

https://doi.org/10.1016/0168-1656(91)90065-4Get rights and content

Abstract

From a genomic library of Zymomonas mobilis prepared in Escherichia coli, two clones (carrying pZH4 and pZH5) resistant to the mercuric ion were isolated. On partial restriction analysis these two clones appeared to have the same 2.9 kb insert. Mercuric reductase activity was assayed from the Escherichia coli clone carrying pZH5 and it was Hg2+-inducible, NADH dependent and also required 2-mercaptoethanol for its activity. The plasmid pZH5 encoded three polypeptides, mercuric reductase (merA; 65 kDa), a transport protein (merT 18-17 kDa) and merC (15 kDa) as analysed by SDS-PAGE. Southern blot analysis showed the positive signal for the total DNA prepared from Hgr Z. mobilis but not with the Hgs strain which was cured for a plasmid (30 kb). These results were also confirmed by isolating this plasmid from Hgr Z. mobilis and transforming into E. coli. Moreover the plasmid pZH5 also hybridized with the mer probes derived from Tn21.

References (42)

  • T.J. Foster

    Plasmid-determined resistance to antimicrobial drugs and toxic metal ions in bacteria

    Microbiol. Rev.

    (1983)
  • T.J. Foster et al.

    Transposon A-generated mutation in the mercuric resistance genes of plasmid R100

    J. Bacteriol.

    (1979)
  • W.J. Jackson et al.

    Polypeptides encoded by the mer operon

    J. Bacteriol.

    (1982)
  • W.J. Jackson et al.

    Biochemical characterization of HgCl2-inducible polypeptides encoded by the mer operon of plasmid R100

    J. Bacteriol.

    (1982)
  • U.K. Laemmli

    Cleavage of structural proteins during the assembly of the head of bacteriophage T4

    Nature (London)

    (1970)
  • T. Maniatis et al.
  • M.T. Maynard et al.

    Purification and antigenic properties of intracellular invertase from Streptococcus mutans

    Infect. Immun.

    (1979)
  • J. Miller

    Experiments in Molecular Genetics

    (1972)
  • H. Nakahara et al.

    Hypersensitivity to Hg2+ and hyperbinding activity associated with cloned fragments of the mercurial resistance operon of plasmid NR1

    J. Bacteriol.

    (1979)
  • N. Ni'Bhrian et al.

    Tn5 insertion mutations in the mercuric ion resistance genes derived from plasmid R100

    J. Bacteriol.

    (1983)
  • N. Ni'Bhrian et al.

    Polypeptides specified by the mercuric resistance (mer) operon of plasmid R100

    Gene

    (1986)
  • View full text