TY - JOUR A1 - Rademacher, Corinna A1 - Hoffmann, Marie-Christine A1 - Lackmann, Jan-Wilm A1 - Moser, Roman A1 - Pfänder, Yvonne A1 - Leimkühler, Silke A1 - Narberhaus, Franz A1 - Masepohl, Bernd T1 - Tellurite resistance gene trgB confers copper tolerance to Rhodobacter capsulatus JF - BioMetals : an international journal on the role of metal ions in biology, biochemistry and medicine N2 - 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 trgB-lacZ 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. KW - Copper KW - Tellurite KW - Nudix hydrolase KW - Metal homeostasis KW - Rhodobacter Y1 - 2012 U6 - https://doi.org/10.1007/s10534-012-9566-2 SN - 0966-0844 VL - 25 IS - 5 SP - 995 EP - 1008 PB - Springer CY - Dordrecht ER -