Analysis of yggX and gshA mutants provides insights into the labile iron pool in Salmonella enterica.
Strains of Salmonella enterica lacking YggX and the cellular reductant glutathione exhibit defects similar to those resulting from iron deficiency and oxidative stress. Mutant strains are sensitive to hydrogen peroxide and superoxide, deregulate the expression of the Fur-regulated gene entB, and fail to grow on succinate medium. Suppression of some yggX gshA mutant phenotypes by the cell-permeable iron chelator deferoxamine allowed the conclusion that increased levels of cellular Fenton chemistry played a role in the growth defects. The data presented are consistent with a scenario in which glutathione acts as a physiological chelator of the labile iron pool and in which YggX acts upstream of the labile iron pool by preventing superoxide toxicity.
Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Dr., Madison, WI 53706, USA.
Michael P
MP
Thorgersen
Diana M
DM
Downs
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D005978:Glutathione / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007501:Iron / Q000378:metabolism*; D007506:Iron-Sulfur Proteins / Q000378:metabolism; D018384:Oxidative Stress; D012097:Repressor Proteins / Q000378:metabolism; D019779:Salmonella enterica / Q000235:genetics* / Q000378:metabolism*
D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D012097:Repressor Proteins; C432136:YggX protein, Salmonella enterica; C068477:ferric uptake regulating proteins, bacterial; D006861:Hydrogen Peroxide; D007501:Iron; D005978:Glutathione