Biochemical characterization of the naturally occurring oxacillinase OXA-50 of Pseudomonas aeruginosa.

ABSTRACT: The bla(OXA-50) gene (formerly known as the PA5514 gene) is an oxacillinase gene identified in silico in the genome of Pseudomonas aeruginosa PAO1. By using a mutant strain of P. aeruginosa PAO1 that had an inactivated bla(AmpC) cephalosporinase gene, the bla(OXA-50) gene was shown to be expressed constitutively in P. aeruginosa. This beta-lactamase gene was cloned onto a multicopy plasmid and expressed in P. aeruginosa and Escherichia coli. It conferred decreased susceptibility to ampicillin and ticarcillin and, interestingly, to moxalactam and meropenem in P. aeruginosa but not in E. coli. Overexpression and purification enabled us to determine the molecular mass (25 kDa), the pI value (8.6), and the hydrolysis spectrum of the OXA-50 beta-lactamase. It is a narrow-spectrum oxacillinase t

SUBMITTER: Girlich D 

PROVIDER: S-EPMC415580 | biostudies-literature | 2004 Jun

REPOSITORIES: biostudies-literature