Open AccessZinc uptake, oxidative stress and the FNR‐like proteins of Lactococcus lactis
Author(s) -
Scott Colin,
Rawsthorne Helen,
Upadhyay Manisha,
Shearman Claire A.,
Gasson Michael J.,
Guest John R.,
Green Jeffrey
Publication year - 2000
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2000.tb09363.x
Subject(s) - lactococcus lactis , mutant , operon , oxidative stress , hydrogen peroxide , intracellular , biology , oxidative phosphorylation , biochemistry , gene , zinc , strain (injury) , microbiology and biotechnology , bacteria , streptococcaceae , chemistry , genetics , lactic acid , organic chemistry , anatomy
Lactococcus lactis ssp. cremoris MG1363 contains two FNR homologues, FlpA and FlpB, encoded by the distal genes of two paralogous operons ( orfX A/B ‐orfY A/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 orfX B ::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.