Roles of metal ions and hydrogen peroxide in modulating the interaction of the Bacillus subtilis PerR peroxide regulon repressor with operator DNA

Mol Microbiol. 2001 Aug;41(4):849-59. doi: 10.1046/j.1365-2958.2001.02543.x.

Abstract

The inducible response to H(2)O(2) stress in Bacillus subtilis is under the control of PerR, one of three Fur homologues in this organism. PerR was purified in both an inactive, metal-dependent form and an active, metal-containing form as determined using DNA-binding assays. Active PerR contains both zinc and iron and is designated PerR:Zn,Fe. Added manganous ion competes for binding to the iron site and can restore DNA-binding activity to the metal-dependent form of PerR, presumably generating PerR:Zn,Mn. The DNA-binding activity of PerR:Zn,Fe is eliminated by exposure to H(2)O(2) whereas PerR:Zn,Mn is comparatively resistant. DNA-binding activity can be restored by a thiol-reducing agent, suggesting that redox-active cysteines are involved in peroxide sensing. Experiments using reporter fusions demonstrate that elevated levels of manganese repress PerR regulon genes and prevent their full induction by H(2)O(2). In contrast, in cells grown with iron supplementation, a PerR-repressed gene is completely derepressed by H(2)O(2). These results are consistent with the idea that the intracellular form of the PerR metalloprotein, and therefore its hydrogen peroxide sensitivity, can be altered by growth conditions.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacillus subtilis / drug effects
  • Bacillus subtilis / genetics*
  • Bacillus subtilis / growth & development
  • Bacillus subtilis / metabolism*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / isolation & purification
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Cations, Divalent / metabolism
  • Cations, Divalent / pharmacology
  • DNA Footprinting
  • DNA, Bacterial / genetics
  • DNA, Bacterial / metabolism*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Deoxyribonuclease I / metabolism
  • Gene Expression Regulation, Bacterial / drug effects
  • Hydrogen Peroxide / pharmacology*
  • Iron / metabolism
  • Iron / pharmacology
  • Manganese / metabolism
  • Manganese / pharmacology
  • Metals / metabolism
  • Metals / pharmacology*
  • Molecular Sequence Data
  • Mutation
  • Operator Regions, Genetic / genetics*
  • Oxidative Stress / drug effects
  • Oxidative Stress / genetics
  • Protein Binding / drug effects
  • Regulon / genetics*
  • Repressor Proteins / genetics
  • Repressor Proteins / isolation & purification
  • Repressor Proteins / metabolism*
  • Transcription Factors*
  • Zinc / metabolism

Substances

  • Bacterial Proteins
  • Cations, Divalent
  • DNA, Bacterial
  • DNA-Binding Proteins
  • Metals
  • Repressor Proteins
  • Transcription Factors
  • peroxide repressor proteins
  • Manganese
  • Hydrogen Peroxide
  • Iron
  • Deoxyribonuclease I
  • Zinc