Cloning and expression of a new manganese peroxidase from Irpex lacteus F17 and its application in decolorization of reactive black 5

• Irpex lacteus F17 was identified for manganese peroxidase (MnP) production.
• A novel gene (imnp) encoding MnP from this fungus was cloned and sequenced.
• The MnP was deemed to be a new member of short-type of hybrid MnPs.
• The cDNA of imnp was successfully expressed in Escherichia coli Rosetta (DE3).
• The recombinant MnP shows a promising biotechnological potential.

A novel gene (imnp) encoding manganese peroxidase (MnP) from a new and local white-rot fungus, Irpex lacteus F17, was cloned and sequenced. It contains a coding region of 1632 bp, eleven exons and ten introns. The deduced protein, Il-MnP, contains 333 amino acids, with a signal peptide of 26 amino acids. It shows conserved motifs that also exist in other fungal MnPs, including a Mn2+-binding site, Ca2+-binding sites, and eight cysteines. Based on a phylogenetic tree analysis, Il-MnP was deemed to be a new member of the short-type hybrid manganese peroxidases belonging to the class II fungal heme peroxidase subclass/subfamily A.2. Furthermore, the cDNA encoding the mature protein sequence was cloned into the expression vector pET28a and successfully expressed in Escherichia coli Rosetta (DE3). The recombinant protein was refolded and purified to homogeneity, and then partially characterized. Kinetic properties of the recombinant MnP differed from native MnP produced by I. lacteus F17, whereas the spectrum of substrates oxidized by both enzymes was similar. Other attractive features of the recombinant enzyme were its high stability at extreme pH values (from pH 3.5 to 9) and its ability to decolorize a high redox potential azo dye, reactive black 5. The results indicate that this enzyme has a promising biotechnological potential.

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