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ZapA, a possible virulence factor from Proteus mirabilis exhibits broad protease substrate specificity

M A Anéas1, F C Portaro, I Lebrun

  • 1Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes, 1374, 05508-900 São Paulo, SP, Brazil.

Brazilian Journal of Medical and Biological Research = Revista Brasileira De Pesquisas Medicas E Biologicas
|October 23, 2001
PubMed

Insights

Proteus mirabilis metalloprotease ZapA shows broad substrate specificity, cleaving bioactive peptides and insulin. Interestingly, native IgA remained resistant to ZapA hydrolysis, despite its known IgA-degrading activity.

Area of Science:

  • Microbiology
  • Enzymology
  • Proteomics

Background:

  • Proteus mirabilis is an opportunistic pathogen.
  • ZapA is a metalloprotease secreted by P. mirabilis and is considered a virulence factor due to its IgA-degrading activity.
  • The substrate specificity of ZapA is not fully characterized.

Purpose of the Study:

  • To characterize the substrate specificity of the metalloprotease ZapA.
  • To identify novel cleavage sites for ZapA.
  • To compare the activity of native and recombinant ZapA.

Main Methods:

  • Utilized fluorescent peptides derived from bioactive peptides and oxidized beta-chain of insulin.
  • Determined enzyme specificity through cleavage assays.
  • Analyzed catalytic efficiencies of ZapA.

Main Results:

  • ZapA cleaved bradykinin- and dynorphin-derived peptides at Phe-Ser and Phe-Leu bonds, respectively.
  • A novel cleavage site (Val-Asn) was identified in the beta-chain of insulin.
  • Both native and recombinant ZapA exhibited broad substrate specificity, acting on various amino acid types.
  • Native IgA was resistant to hydrolysis by ZapA.

Conclusions:

  • ZapA possesses broad substrate specificity, cleaving various peptide bonds.
  • The previously attributed IgA-degrading activity of ZapA requires further investigation as native IgA was found resistant.
  • Understanding ZapA's specificity provides insights into P. mirabilis pathogenesis.

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