Aspergillus fumigatus is one of the aspergillosis-causing fungi. The fungus produces some extracellular proteolytic enzyme, such as a serine protease and a metalloprotease. It has been thought that the proteolytic enzymes play important roles during early infection. Elastin occupies about 28% of lung proteins and it was reported that the elastinolytic activity was essential for infectious capacity of A. fumigatus. The serine protease has elastin degradation activity. Thermolysin like high molecular weight metalloprotease can digest collagen and gelatin but cannot hydrolyze elastin. The defective mutant of two proteases, however, maintaines infectious capacity and the expression level of the low molecular weight metalloprotease (MEP20) becomes higher than that of the wild type. MEP20 has been thought to be concerned with elastin digestion. We cloned the gene encoding a low molecular weight metalloprotease of A. fumigatusfrom Japanese aspergillosis patient and the enzyme was expressed by using A. oryzae as a host. We compared the amino acid sequences of MEP20s of A. fumigatus from Japan, America and Europe. The identities of amino acid sequences were shown only 87%, 59% and 56% between the enzymes from Japanese and American strains, Japanese and European strains, and American and European strains, respectively. The identity between the amino acid sequences of MEP20 from Japanese A. fumigatus and deutelolysin from Japanese fermentative strain A. oryzae was also only 60%. Amino acid sequences of MEP20s showed the diversification of depending on the location in A. fumigatus. We will discuss the enzymatic profiles of low molecular weight metalloproteases.
Fungal Genet. Newsl. 50 (Supl):abstract
Full conference title:
22nd Fungal Genetics Conference
- Fungal Genetics Conference 22nd (2001)