Primary structure of OXA-3 and phylogeny of oxacillin-hydrolyzing class D beta-lactamases.
We determined the nucleotide sequence of the blaOXA-3(pMG25) gene from Pseudomonas aeruginosa. The bla structural gene encoded a protein of 275 amino acids representing one monomer of 31,879 Da for the OXA-3 enzyme. Comparisons between the OXA-3 nucleotide and amino acid sequences and those of class A, B, C, and D beta-lactamases were performed. An alignment of the eight known class D beta-lactamases including OXA-3 demonstrated the presence of conserved amino acids. In addition, conserved motifs composed of identical amino acids typical of penicillin-recognizing proteins and specific class D motifs were identified. These conserved motifs were considered for possible roles in the structure and function of oxacillinases. On the basis of the alignment and identity scores, a dendrogram was constructed. The phylogenetic data obtained revealed five groups of class D beta-lactamases with large evolutionary distances between each group.
Sanschagrin
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Département de Microbiologie, Faculté de Médecine, Université Laval, Ste-Foy, Québec, Canada.
Couture
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Levesque
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D000595:Amino Acid Sequence; D001483:Base Sequence; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D010802:Phylogeny; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D001618:beta-Lactamases / Q000737:chemistry* / Q000235:genetics
C039404:beta-lactamase OXA-2; D001618:beta-Lactamases