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Primary structure of OXA-3 and phylogeny of oxacillin-hydrolyzing class D beta-lactamases

F Sanschagrin1, F Couture, R C Levesque

  • 1Département de Microbiologie, Faculté de Médecine, Université Laval, Ste-Foy, Québec, Canada.

Antimicrobial Agents and Chemotherapy
|April 1, 1995
PubMed

Insights

Researchers sequenced the blaOXA-3 gene in Pseudomonas aeruginosa, revealing conserved motifs in class D beta-lactamases. Phylogenetic analysis identified five distinct evolutionary groups within this enzyme class.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Enzymology

Background:

  • Pseudomonas aeruginosa is an opportunistic pathogen.
  • Beta-lactamases are enzymes that confer resistance to beta-lactam antibiotics.
  • OXA-type beta-lactamases are a significant group of resistance enzymes.

Purpose of the Study:

  • To determine the nucleotide sequence of the blaOXA-3 gene.
  • To analyze the structural and functional characteristics of the OXA-3 enzyme.
  • To investigate the evolutionary relationships among class D beta-lactamases.

Main Methods:

  • Nucleotide sequencing of the blaOXA-3 gene.
  • Bioinformatic analysis including sequence alignment and dendrogram construction.
  • Comparison with known beta-lactamase sequences.

Main Results:

  • The blaOXA-3 gene encodes a 275-amino acid protein (OXA-3 enzyme).
  • Conserved amino acids and motifs characteristic of penicillin-recognizing proteins and class D beta-lactamases were identified.
  • Phylogenetic analysis revealed five distinct groups of class D beta-lactamases.

Conclusions:

  • The identified conserved motifs may play roles in oxacillinase structure and function.
  • OXA-3 shares conserved features with other class D beta-lactamases.
  • Significant evolutionary divergence exists among class D beta-lactamases.

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