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Extracellular peptidase in the fungal pathogen Pseudallescheria boydii

Bianca Alcântara da Silva1, André Luis Souza dos Santos, Eliana Barreto-Bergter

  • 1Departamento de Microbiologia Geral, Instituto de Microbiologia Prof. Paulo de Góes (IMPPG), Centro de Ciências da Saúde (CCS), Bloco I, Universidade Federal do Rio de Janeiro (UFRJ), Ilha do Fundão, Brazil.

Current Microbiology
|June 16, 2006
PubMed

Insights

Researchers identified a novel 28-kDa extracellular metallopeptidase from Pseudallescheria boydii, a fungus causing human infections. This enzyme

Area of Science:

  • Medical Mycology
  • Enzymology
  • Biochemistry

Background:

  • Pseudallescheria boydii is an opportunistic fungal pathogen causing invasive infections in humans.
  • Fungal secreted enzymes play crucial roles in pathogenesis and host-pathogen interactions.
  • The enzymatic repertoire of P. boydii, particularly extracellular peptidases, remains largely uncharacterized.

Purpose of the Study:

  • To identify and characterize extracellular proteolytic activities secreted by Pseudallescheria boydii.
  • To investigate the enzymatic properties and potential classification of a prominent secreted peptidase.

Main Methods:

  • Utilized sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with bovine serum albumin (BSA) as a substrate.
  • Detected proteolytic activity in the extracellular environment of P. boydii grown in Sabouraud-dextrose medium.
  • Assessed peptidase activity under varying pH conditions and in the presence of specific enzyme inhibitors (1,10-phenanthroline, EDTA, EGTA, E-64, PMSF, pepstatin A).

Main Results:

  • A 28-kDa extracellular peptidase activity was identified and detected throughout the 13-day growth period, peaking on day 7.
  • The enzyme exhibited optimal activity at acidic pH (5.5).
  • Activity was completely inhibited by 1,10-phenanthroline, a zinc-metallopeptidase inhibitor, but unaffected by inhibitors of cysteine, serine, or aspartyl peptidases, and minimally affected by EDTA/EGTA.

Conclusions:

  • This study reports the first characterization of an extracellular metallopeptidase from the human opportunistic fungal pathogen Pseudallescheria boydii.
  • The identified 28-kDa peptidase is likely a zinc-dependent metallopeptidase, suggesting a potential role in P. boydii pathogenesis.

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