Overexpression, purification, and characterization of the cloned metallo-β-lactamase L1 from Stenotrophomonas maltophilia

Michael W. Crowder, Timothy R. Walsh, Linda Banovic, Margaret Pettit, James Spencer

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The metallo-β-lactamase L1 from Stenotrophomonas maltophilia was cloned, overexpressed, and characterized by spectrometric and biochemical techniques. Results of metal analyses were consistent with the cloned enzyme having 2 mol of tightly bound Zn(II) per monomer. Gel filtration chromatography demonstrated that the cloned enzyme exists as a tightly held tetramer with a molecular mass of ca. 115 kDa, and matrix-assisted laser desorption ionization and time-of-flight mass spectrometry indicated a monomeric molecular mass of 28.8 kDa. Steady-state kinetic studies with a number of diverse penicillin and cephalosporin antibiotics demonstrated that L1 effectively hydrolyzes all tested compounds, with k(cat)/K(m) values ranging between 0.002 and 5.5 μM-1 s-1. These characteristics of the recombinant enzyme are contrasted to those previously reported for metallo- β-lactamases isolated directly from S. maltophilia.

Original languageEnglish (US)
Pages (from-to)921-926
Number of pages6
JournalAntimicrobial Agents and Chemotherapy
Issue number4
StatePublished - Apr 1 1998


ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)
  • Infectious Diseases

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