THE ASPERGILLUS-FUMIGATUS MEPB GENE ENCODES AN 82 KDA INTRACELLULAR METALLOPROTEINASE STRUCTURALLY RELATED TO MAMMALIAN THIMET OLIGOPEPTIDASES

Aspergillus fumigatus produces an 82 kDa intracellular metalloproteina se that hydrolyses the Pt-peptide, 4-phenylarobenzyloxycarbonyl-Pro-Le u-Gly-Pro-Arg, a typical substrate of members of the thimet oligopepti dase family which is ubiquitously distributed across animal species. T he A. fumigatus mepB gene encoding this 82 kDa metalloproteinase was c loned and sequenced. Analysis of the deduced amino acid sequence of me pB showed that the MepB protein is a cytosolic zinc metalloproteinase of the thimet oligopeptidase family (M3) and as such is probably invol ved in the intracellular degradation of small peptides. An A. fumigatu s mutant that lacks the MepB Pz-peptidolytic activity was constructed by gene disruption at the mepB locus. Analysis of this mutant did not reveal any detectable phenotype.