Format

Send to

Choose Destination
Proc Natl Acad Sci U S A. 2018 Dec 11;115(50):E11623-E11632. doi: 10.1073/pnas.1807954115. Epub 2018 Nov 21.

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

Author information

1
Center for Structural Biology, Vlaams Instituut voor Biotechnologie-Vrije Universiteit Brussel, B-1050 Brussels, Belgium.
2
Brussels Center for Redox Biology, Vrije Universiteit Brussel, B-1050 Brussels, Belgium.
3
Structural Biology Brussels, Vrije Universiteit Brussel, B-1050 Brussels, Belgium.
4
Research Group of Microbiology, Vrije Universiteit Brussel, B-1050 Brussels, Belgium.
5
Department of Molecular Biology, Area of Microbiology, University of León, 24071 León, Spain.
6
Department of Metabolism and Redox Biology, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117997, Russia.
7
Institute of Translational Medicine, Pirogov Russian National Research Medical University, Moscow 117997, Russia.
8
Institute for Cardiovascular Physiology, Georg August University Göttingen, 37073 Göttingen, Germany.
9
Department of Molecular Biology, Area of Microbiology, University of León, 24071 León, Spain; luis.mateos@unileon.es joris.messens@vib-vub.be.
10
Center for Structural Biology, Vlaams Instituut voor Biotechnologie-Vrije Universiteit Brussel, B-1050 Brussels, Belgium; luis.mateos@unileon.es joris.messens@vib-vub.be.

Abstract

Hydrogen peroxide (H2O2) is a strong oxidant capable of oxidizing cysteinyl thiolates, yet only a few cysteine-containing proteins have exceptional reactivity toward H2O2 One such example is the prokaryotic transcription factor OxyR, which controls the antioxidant response in bacteria, and which specifically and rapidly reduces H2O2 In this study, we present crystallographic evidence for the H2O2-sensing mechanism and H2O2-dependent structural transition of Corynebacterium glutamicum OxyR by capturing the reduced and H2O2-bound structures of a serine mutant of the peroxidatic cysteine, and the full-length crystal structure of disulfide-bonded oxidized OxyR. In the H2O2-bound structure, we pinpoint the key residues for the peroxidatic reduction of H2O2, and relate this to mutational assays showing that the conserved active-site residues T107 and R278 are critical for effective H2O2 reduction. Furthermore, we propose an allosteric mode of structural change, whereby a localized conformational change arising from H2O2-induced 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 H2O2.

KEYWORDS:

X-ray structure; hydrogen peroxide sensor; redox regulation; transcription factor

PMID:
30463959
PMCID:
PMC6294878
DOI:
10.1073/pnas.1807954115
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center