Characterization of genes encoding two manganese peroxidases from the lignin-degrading fungus Dichomitus squalens

Genes encoding two manganese peroxidases from the white-rot basidiomycete D ichomitus squalens were cloned and sequenced. The mnp1 and mnp2 genes encod e mature proteins of 369 and 365 amino acids, respectively. The amino acids involved in peroxidase function, those forming the Mn-II binding site, and those forming the five disulfide bonds in other Mn peroxidases are conserv ed in these sequences. Both predicted D. squalens proteins contain multiple acidic residues in their C-terminal sequences, which may be involved in ad ditional metal binding. Both genes contain seven small introns, the locatio ns of which align with each other. The promoters of both D, squalens genes contain putative AP-2 sites, which may be involved in their regulation by n utrient nitrogen. Southern blot analysis of genomic PCR fragments suggests that these sequences represent separate genes rather than allelic variants. (C) 1999 Elsevier Science B.V. All rights reserved.