Zinc uptake, oxidative stress and the FNR-like proteins of Lactococcus lactis

Colin Scott, Helen Rawsthorne, Manisha Upadhyay, Claire A. Shearman, Michael J. Gasson, John R. Guest, Jeffrey Green*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)


Lactococcus lactis ssp. cremoris MG1363 contains two FNR homologues, FlpA and FlpB, encoded by the distal genes of two paralogous operons (orfXA/B-orfYA/B-flpA/B). An flpA flpB double mutant strain is hypersensitive to hydrogen peroxide and has a depleted intracellular Zn(II) pool. The phenotypes of the flp mutant strains suggest that FlpA and FlpB control the expression of high and low affinity ATP-dependent Zn(II) uptake systems, respectively. Plate tests revealed that expression from a orfXB::lac reporter was activated by Cd(II), consistent with other Zn(II)-regulated systems. The link between a failure to acquire Zn(II) and hypersensitivity to oxidative stress suggests that Zn(II) may be required to protect vulnerable protein thiols from oxidation.

Original languageEnglish
Pages (from-to)85-89
Number of pages5
JournalFEMS Microbiology Letters
Issue number1
Publication statusPublished - 1 Nov 2000
Externally publishedYes


  • lactic acid bacterium
  • zinc
  • oxidative stress
  • FNR-like protein
  • cadmium
  • thiol protection


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