An expanded family of fungalysin extracellular metallopeptidases of Coprinopsis cinerea.

Abstract Proteolytic enzymes, particularly secreted proteases of fungal origin, are among the most important of industrial enzymes, yet the biochemical properties and substrate specificities of these proteins have been difficult to characterize. Genomic sequencing offers a powerful tool to identify potentially novel proteases. The genome of the model basidiomycete Coprinopsiscinereus was found to have an unusually high number of metalloproteases that closely match the M36 peptidase family known as fungalysins. The eight predicted C. cinereus fungalysins divide into two groups upon comparison with fungalysins from other fungi. One member, CcMEP1, is most similar to the single representative fungalysins from the basidiomycetes Phanerochaete chrysosporium, Cryptococcus neoformans, and Ustilagomaydis , and to the fungalysin type-protein from Aspergillus fumigatus. The remaining seven C. cinereus predicted fungalysins form a group with similarity to three predicted M36 peptidases of Laccariabicolor. All eight of the C. cinereus enzymes contain both the signature M36 Pfam domain and the FTPpropeptide domain. All contain large propeptides with considerable sequence conservation near a proposed cleavage site. The predicted mature enzymes range in size from 37–46 kDa and have isoelectric points that are mildly acidic to neutral. The proximity of these genes to telomeres and/or to transposable elementsmay have contributed to the expansion of this gene family in C. cinereus .