BioMetals

, Volume 25, Issue 5, pp 995–1008

Tellurite resistance gene trgB confers copper tolerance to Rhodobacter capsulatus

  • Corinna Rademacher
  • Marie-Christine Hoffmann
  • Jan-Wilm Lackmann
  • Roman Moser
  • Yvonne Pfänder
  • Silke Leimkühler
  • Franz Narberhaus
  • Bernd Masepohl
Article

DOI: 10.1007/s10534-012-9566-2

Cite this article as:
Rademacher, C., Hoffmann, MC., Lackmann, JW. et al. Biometals (2012) 25: 995. doi:10.1007/s10534-012-9566-2

Abstract

To identify copper homeostasis genes in Rhodobacter capsulatus, we performed random transposon Tn5 mutagenesis. Screening of more than 10,000 Tn5 mutants identified tellurite resistance gene trgB as a so far unrecognized major copper tolerance determinant. The trgB gene is flanked by tellurite resistance gene trgA and cysteine synthase gene cysK2. While growth of trgA mutants was only moderately restricted by tellurite, trgB and cysK2 mutants were severely affected by tellurite, which implies that viability under tellurite stress requires increased cysteine levels. Mutational analyses revealed that trgB was the only gene in this chromosomal region conferring cross-tolerance towards copper. Expression of the monocistronic trgB gene required promoter elements overlapping the trgA coding region as shown by nested deletions. Neither copper nor tellurite affected trgB transcription as demonstrated by reverse transcriptase PCR and trgBlacZ fusions. Addition of tellurite or copper gave rise to increased cellular tellurium and copper concentrations, respectively, as determined by inductively coupled plasma-optical emission spectroscopy. By contrast, cellular iron concentrations remained fairly constant irrespective of tellurite or copper addition. This is the first study demonstrating a direct link between copper and tellurite response in bacteria.

Keywords

Copper Tellurite Nudix hydrolase Metal homeostasis Rhodobacter 

Copyright information

© Springer Science+Business Media, LLC. 2012

Authors and Affiliations

  • Corinna Rademacher
    • 1
  • Marie-Christine Hoffmann
    • 1
  • Jan-Wilm Lackmann
    • 1
  • Roman Moser
    • 1
  • Yvonne Pfänder
    • 1
  • Silke Leimkühler
    • 2
  • Franz Narberhaus
    • 1
  • Bernd Masepohl
    • 1
  1. 1.Biologie der Mikroorganismen, Fakultät für Biologie und BiotechnologieRuhr-Universität BochumBochumGermany
  2. 2.Molekulare Enzymologie, Institut für Biochemie und BiologieUniversität PotsdamPotsdamGermany

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