title: Biochemical characterization of the THIN-B metallo-beta-lactamase of Janthinobacterium lividum.
abstract: The THIN-B metallo-beta-lactamase, a subclass B3 enzyme produced by the environmental species Janthinobacterium lividum, was overproduced in Escherichia coli by means of a T7-based expression system. The enzyme was purified (>95%) by two ion-exchange chromatography steps and subjected to biochemical analysis. The native THIN-B enzyme is a monomeric protein of 31 kDa. It exhibits the highest catalytic efficiencies with carbapenem substrates and cephalosporins, except for cephaloridine, which acts as a poor inactivator. Individual rate constants for inactivation by chelators were measured, suggesting that inactivation occurred by a mechanism involving formation of a ternary complex.
authors.affiliation: Dipartimento di Biologia Molecolare, Laboratorio di Fisiologia e Biotecnologia dei Microrganismi, Università di Siena, Siena, Italy.
authors.forename: Jean-Denis
authors.initials: JD
authors.lastname: Docquier
authors.forename: Teresa
authors.initials: T
authors.lastname: Lopizzo
authors.forename: Sabrina
authors.initials: S
authors.lastname: Liberatori
authors.forename: Manuela
authors.initials: M
authors.lastname: Prenna
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Thaller
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Frère
authors.forename: Gian Maria
authors.initials: GM
authors.lastname: Rossolini
mesh_terms: D000595:Amino Acid Sequence; D002511:Cephalosporins / Q000378:metabolism; D002614:Chelating Agents / Q000494:pharmacology; D002852:Chromatography, Ion Exchange; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D007700:Kinetics; D008969:Molecular Sequence Data; D020560:Proteobacteria / Q000201:enzymology* / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013438:Sulfhydryl Compounds / Q000378:metabolism; D014357:Trypsin / Q000737:chemistry; D001618:beta-Lactamases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D002511:Cephalosporins; D002614:Chelating Agents; D003470:Culture Media; D004791:Enzyme Inhibitors; D011994:Recombinant Proteins; D013438:Sulfhydryl Compounds; D014357:Trypsin; C425147:beta-lactamase THIN-B; D001618:beta-Lactamases