Structural snapshots of OxyR reveal the peroxidatic mechanism of H2O2 sensing.

B Pedre, D Young, D Charlier, Á Mourenza, leonardo Rosado, L Marcos-Pascual, K Wahni, Edo Martens, de la Rubia A G, VV Belousov, LM Mateos, J Messens

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Hydrogen peroxide (H 2O 2) is a strong oxidant capable of oxidizing cysteinyl thiolates, yet only a few cysteine-containing proteins have exceptional reactivity toward H 2O 2. One such example is the prokaryotic transcription factor OxyR, which controls the antioxidant response in bacteria, and which specifically and rapidly reduces H 2O 2. In this study, we present crystallographic evidence for the H 2O 2-sensing mechanism and H 2O 2-dependent structural transition of Corynebacterium glutamicum OxyR by capturing the reduced and H 2O 2-bound structures of a serine mutant of the peroxidatic cysteine, and the full-length crystal structure of disulfide-bonded oxidized OxyR. In the H 2O 2-bound structure, we pinpoint the key residues for the peroxidatic reduction of H 2O 2, and relate this to mutational assays showing that the conserved active-site residues T107 and R278 are critical for effective H 2O 2 reduction. Furthermore, we propose an allosteric mode of structural change, whereby a localized conformational change arising from H 2O 2induced intramolecular disulfide formation drives a structural shift at the dimerization interface of OxyR, leading to overall changes in quaternary structure and an altered DNA-binding topology and affinity at the catalase promoter region. This study provides molecular insights into the overall OxyR transcription mechanism regulated by H 2O 2.

Original languageEnglish
Pages (from-to)E11623-E11632
JournalProceedings of the National Academy of Sciences of the United States of America
Volume115
Issue number50
DOIs
Publication statusPublished - 11 Dec 2018

Bibliographical note

Copyright © 2018 the Author(s). Published by PNAS.

Keywords

  • Amino Acid Substitution
  • Bacterial Proteins/chemistry
  • Binding Sites/genetics
  • Catalase/chemistry
  • Corynebacterium glutamicum/genetics
  • Crystallography, X-Ray
  • Genes, Bacterial
  • Hydrogen Peroxide/metabolism
  • Kinetics
  • Mutagenesis, Site-Directed
  • Oxidation-Reduction
  • Protein Structure, Quaternary
  • Transcription Factors/chemistry
  • Transcription, Genetic

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