Abstract
Background: Fungal DyP-type peroxidases have so far been described exclusively for basidiomycetes. Moreover, peroxidases from ascomycetes that oxidize Mn2+ ions are yet not known. Methods: We describe here the physicochemical, biocatalytic, and molecular characterization of a DyP-type peroxidase (DyP, EC 1.11.1.19) from an ascomycetous fungus. Results: The enzyme oxidizes classic peroxidase substrates such as 2,6-DMP but also veratryl alcohol and notably Mn2+ to Mn3+ ions, suggesting a physiological function of this DyP in lignin modification. The KM value (49 µM) indicates that Mn2+ ions bind with high affinity to the XgrDyP protein but their subsequent oxidation into reactive Mn3+ proceeds with moderate efficiency compared to MnPs and VPs. Mn2+ oxidation was most effective at an acidic pH (between 4.0 and 5.0) and a hypothetical surface exposed an Mn2+ binding site comprising three acidic amino acids (two aspartates and one glutamate) could be localized within the hypothetical XgrDyP structure. The oxidation of Mn2+ ions is seemingly supported by four aromatic amino acids that mediate an electron transfer from the surface to the heme center. Conclusions: Our findings shed new light on the possible involvement of DyP-type peroxidases in lignocellulose degradation, especially by fungi that lack prototypical ligninolytic class II peroxidases.
Highlights
IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
DyPs were recognized as a new family of heme peroxidases found in both fungi and bacteria
We describe for the first time an Mn2+ -oxidizing DyP-type peroxidase secreted by an ascomycetous fungus, a new strain of Xylaria grammica (IHIA82, GenBank accession number MK408621) collected from rotting plant debris in the Kakamega
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. DyPs were recognized as a new family of heme peroxidases found in both fungi and bacteria. There are features in the secondary and tertiary structure of DyPs that do not allow them to be classified into any of the known peroxidase groups of bacteria, fungi, or plants (class I, II, and III peroxidases/PODs, respectively). Sequence similarities to ligninolytic class II peroxidases are low (0.5–5%) and the typical heme-binding region, which is conserved among the whole catalase-peroxidase superfamily, does not contain the distal His [3,4,5]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
