The Corynebacterium glutamicum mycothiol peroxidase is a reactive oxygen species‐scavenging enzyme that shows promiscuity in thiol redox control. Issue 6 (11th April 2015)

• Record Type: Journal Article
• Authors: Pedre, Brandán; Van Molle, Inge; Villadangos, Almudena F.; Wahni, Khadija; Vertommen, Didier; Turell, Lucía; Erdogan, Huriye; Mateos, Luis M.; Messens, Joris
• Is Part Of: Molecular microbiology. Volume 96:Issue 6(2015)
• Page Start: 1176
• Page End: 1191
• Publication Date: 2015-04-11
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.12998
• Languages: English
• ISSNs: 0950-382X

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>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). <italic>C</italic><italic>orynebacterium glutamicum</italic> 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 H₂O₂ 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 H₂O₂ stress, and its gene expression is clearly induced upon H₂O₂ challenge. These findings add a new dimension to the redox control and the functioning of CysGPxs in general.</p> </abstract>