1. Academic Validation
  2. Sedolisins, a new class of secreted proteases from Aspergillus fumigatus with endoprotease or tripeptidyl-peptidase activity at acidic pHs

Sedolisins, a new class of secreted proteases from Aspergillus fumigatus with endoprotease or tripeptidyl-peptidase activity at acidic pHs

  • Appl Environ Microbiol. 2006 Mar;72(3):1739-48. doi: 10.1128/AEM.72.3.1739-1748.2006.
Utz Reichard 1 Barbara Léchenne Abdul R Asif Frank Streit Eric Grouzmann Olivier Jousson Michel Monod
Affiliations

Affiliation

  • 1 Department of Medical Microbiology, University Hospital of Göttingen, Kreuzbergring 57, D-37075 Göttingen, Germany. ureicha@gwdg.de
Abstract

The secreted proteolytic activity of Aspergillus fumigatus is of potential importance as a virulence factor and in the industrial hydrolysis of protein sources. The A. fumigatus genome contains sequences that could encode a five-member gene family that produces proteases in the sedolisin family (MEROPS S53). Four putative secreted sedolisins with a predicted 17- to 20-amino-acid signal sequence were identified and termed SedA to SedD. SedA produced heterologously in Pichia pastoris was an acidic endoprotease. Heterologously produced SedB, SedC, and SedD were tripeptidyl-peptidases (TPP) with a common specificity for tripeptide-p-nitroanilide substrates at acidic pHs. Purified SedB hydrolyzed the peptide Ala-Pro-Gly-Asp-Arg-Ile-Tyr-Val-His-Pro-Phe to Arg-Pro-Gly, Asp-Arg-Ile, and Tyr-Val-His-Pro-Phe, thereby confirming TPP activity of the Enzyme. SedB, SedC, and SedD were detected by Western blotting in culture supernatants of A. fumigatus grown in a medium containing hemoglobin as the sole nitrogen source. A degradation product of SedA also was observed. A search for genes encoding sedolisin homologues in other Fungal genomes indicates that sedolisin gene families are widespread among filamentous ascomycetes.

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