Limits of versatility of versatile peroxidase

Doriv Knop, Dana Levinson, Arik Makovitzki, Avi Agami, Elad Lerer, Avishai Mimran, Oded Yarden, Yitzhak Hadar*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

Although Mn2+ is the most abundant substrate of versatile peroxidases (VPs), repression of Pleurotus ostreatus vp1 expression occurred in Mn2+-sufficient medium. This seems to be a biological contradiction. The aim of this study was to explore the mechanism of direct oxidation by VP1 under Mn2+-deficient conditions, as it was found to be the predominant enzyme during fungal growth in the presence of synthetic and natural substrates. The native VP1 was purified and characterized using three substrates, Mn2+, Orange II (OII), and Reactive Black 5 (RB5), each oxidized by a different active site in the enzyme. While the pH optimum for Mn2+ oxidation is 5, the optimum pH for direct oxidation of both dyes was found to be 3. Indeed, effective in vivo decolorization occurred in media without addition of Mn2+ only under acidic conditions. We have determined that Mn2+ inhibits in vitro the direct oxidation of both OII and RB5 while RB5 stabilizes both Mn2+ and OII oxidation. Furthermore, OII was found to inhibit the oxidation of both Mn2+ and RB5. In addition, we could demonstrate that VP1 can cleave OII in two different modes. Under Mn2+-mediated oxidation conditions, VP1 was able to cleave the azo bond only in asymmetric mode, while under the optimum conditions for direct oxidation (absence of Mn2+ at pH 3) both symmetric and asymmetric cleavages occurred. We concluded that the oxidation mechanism of aromatic compounds by VP1 is controlled by Mn2+ and pH levels both in the growth medium and in the reaction mixture.

Original languageAmerican English
Pages (from-to)4070-4080
Number of pages11
JournalApplied and Environmental Microbiology
Volume82
Issue number14
DOIs
StatePublished - 2016

Bibliographical note

Publisher Copyright:
© 2016, American Society for Microbiology.

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