The Corynebacterium glutamicum mycothiol peroxidase is a reactive oxygen species-scavenging enzyme that shows promiscuity in thiol redox control.

TitleThe Corynebacterium glutamicum mycothiol peroxidase is a reactive oxygen species-scavenging enzyme that shows promiscuity in thiol redox control.
Publication TypeJournal Article
Year of Publication2015
AuthorsPedre, B., Van Molle I., Villadangos A. F., Wahni K., Vertommen D., Turell L., Erdogan H., Mateos L. M., and Messens J.
JournalMol Microbiol
Volume96
Issue6
Pagination1176-91
Date Published2015 Jun
ISSN1365-2958
KeywordsBacterial Proteins, Corynebacterium glutamicum, Cysteine, Disulfides, Glycopeptides, Hydrogen Peroxide, Inositol, Kinetics, Molecular Sequence Data, Oxidation-Reduction, Oxidative Stress, Oxidoreductases, Peroxidases, Reactive Oxygen Species, Sequence Analysis, Protein, Sulfhydryl Compounds, Thioredoxins
Abstract

Cysteine glutathione peroxidases (CysGPxs) control oxidative stress levels by reducing hydroperoxides at the expense of cysteine thiol (-SH) oxidation, and the recovery of their peroxidatic activity is generally accomplished by thioredoxin (Trx). Corynebacterium glutamicum mycothiol peroxidase (Mpx) is a member of the CysGPx family. We discovered that its recycling is controlled by both the Trx and the mycothiol (MSH) pathway. After H2 O2 reduction, a sulfenic acid (-SOH) is formed on the peroxidatic cysteine (Cys36), which then reacts with the resolving cysteine (Cys79), forming an intramolecular disulfide (S-S), which is reduced by Trx. Alternatively, the sulfenic acid reacts with MSH and forms a mixed disulfide. Mycoredoxin 1 (Mrx1) reduces the mixed disulfide, in which Mrx1 acts in combination with MSH and mycothiol disulfide reductase as a biological relevant monothiol reducing system. Remarkably, Trx can also take over the role of Mrx1 and reduce the Mpx-MSH mixed disulfide using a dithiol mechanism. Furthermore, Mpx is important for cellular survival under H2 O2 stress, and its gene expression is clearly induced upon H2 O2 challenge. These findings add a new dimension to the redox control and the functioning of CysGPxs in general.

DOI10.1111/mmi.12998
Alternate JournalMol. Microbiol.
PubMed ID25766783
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