The metallo-beta-lactamase GOB is a mono-Zn(II) enzyme with a novel active site

JORGELINA MORAN-BARRIO; JAVIER MARCELO GONZALEZ; ADRIANA LIMANSKY; ALEJANDRO J. VILA

JOURNAL OF BIOLOGICAL CHEMISTRY

AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

Año: 2007 vol. 282 p. 18286 - 18293

0021-9258

 Metallo-ß-lactamases (MßLs) are zinc-dependent enzymes able to hydrolyze and inactivate most ß-lactam antibiotics. The large diversity of active site structures and metal content among MßLs from different sources has limited the design of a pan-MßL inhibitor. Here we report the biochemical and biophysical characterization of a novel MßL, GOB-18, from a clinical isolate of a Gram-negative opportunistic pathogen, Elizabethkingia meningoseptica. Different spectroscopic techniques, three-dimensional modeling, and mutagenesis experiments, reveal that the Zn(II) ion is bound to Asp120, His121, His263, and a solvent molecule, i.e. in the canonical Zn2 site of dinuclear MßLs. Contrasting all other related MßLs, GOB-18 is fully active against a broad range of ß-lactam substrates using a single Zn(II) ion in this site. These data further enlarge the structural diversity of MßLs.