Oxidative stress and disruption of labile iron generate specific auxotrophic requirements in Salmonella enterica.
The response of a cell to integrated stresses was investigated using environmental and/or genetic perturbations that disrupted labile iron homeostasis and increased oxidative stress. The effects of the perturbations were monitored as nutritional requirements, and were traced to specific enzymic targets. A yggX gshA cyaY mutant strain required exogenous thiamine and methionine for growth. The thiamine requirement, which had previously been linked to the Fe-S cluster proteins ThiH and ThiC, was responsive to oxidative stress and was not directly affected by manipulation of the iron pool. The methionine requirement was associated with the activity of sulfite reductase, an enzyme that appeared responsive to disruption of labile iron homeostasis. The results are incorporated in a model to suggest how the activity of iron-containing enzymes not directly sensitive to oxygen can be decreased by oxidation of the labile iron pool.
Thorgersen
Michael P
MP
Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA.
Downs
Diana M
DM
Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA.
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003035:Cobalt / Q000378:metabolism; D003470:Culture Media; D015964:Gene Expression Regulation, Bacterial; D018869:Heat-Shock Response; D006706:Homeostasis; D007501:Iron / Q000378:metabolism*; D007506:Iron-Sulfur Proteins / Q000235:genetics / Q000378:metabolism; D008715:Methionine / Q000378:metabolism*; D009154:Mutation; D018384:Oxidative Stress; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000235:genetics / Q000378:metabolism; D012486:Salmonella typhimurium / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D013831:Thiamine / Q000378:metabolism*
D001426:Bacterial Proteins; D003470:Culture Media; D007506:Iron-Sulfur Proteins; D003035:Cobalt; D008715:Methionine; D007501:Iron; D050862:Oxidoreductases Acting on Sulfur Group Donors; D013831:Thiamine