Sensitivity to potassium tellurite of Escherichia coli cells deficient in CSD, CsdB and IscS cysteine desulfurases

Diana M. Rojas, Claudio C. Vásquez

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


The csdA, csdB and iscS genes encoding for cysteine desulfurase enzymatic activities in Escherichia coli were independently inactivated and potassium tellurite sensitivity, determined for each of the resulting mutant clones, was found to be iscS > csdB > csdA. Structural genes encoding for each of the wild-type cysteine desulfurases were cloned into a vector containing the regulated ara promoter and further introduced into the mutant strains. Desulfurase-deficient cells transformed with homolog or paralog desulfurase genes and grown in arabinose-amended media restored their basal tellurite resistance. While csdB gene complemented the auxotrophy of csdB and iscS mutants for nicotinic acid, the iscS gene only complemented the auxotrophy of iscS cells for thiamine. Introduction of the csdA gene into the desulfurase-deficient strains did not change tellurite resistance or nutritional requirement patterns of the recipient cells. Complementation analysis could not be performed under anaerobic conditions because the three mutants did not show tellurite hypersensitivity. These results indicate that oxidative stress is involved in tellurite toxicity in E. coli.

Original languageEnglish
Pages (from-to)465-471
Number of pages7
JournalResearch in Microbiology
Issue number4
Publication statusPublished - May 2005
Externally publishedYes


  • CSD
  • CsdB
  • Desulfurase
  • IscS
  • Potassium tellurite

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology


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