STRUCTURE AND REGULATION OF MANGANESE PEROXIDASE GENE FROM PHANEROCHAETE-CHRYSOSPORIUM

Manganese peroxidase (MnP) is one of two lignin-degrading enzymes secreted by the white-rot basidiomycete Phanerochaete chrysosporium. MnP is an H2 O2-dependent heme peroxidase. The enzyme oxidizes Mn(II) to Mn(III), which in turn oxidizes the terminal phenolic substrates. Several cDNAs encoding MnP isozymes have been isolated and characterized. A cDNA prove was used to isolate and characterize a gene encoding MnP. Comparison of the cDNA and genomic sequences reveal 6 introns, all containing less than 72 base pairs. The appearance of MnP activity in the extracellular medium depends on the presence of Mn. In addition, MnP mRNA is only detected in cells grown in the presence of Mn. If Mn is added to 4-day-old nitrogen-limited Mn-deficient cultures, extracellular MnP activity appears within 6 hours and MnP mRNA appears within 1 hour. These results indicate that Mn is involved in the transcriptional regulation of the MnP gene.