The sequenced chromosome of Caulobacter crescentus CB15 encodes a hypothetical protein that exhibits significant similarity (30 to 35% identical residues) to metallo-beta-lactamases of subclass B3. An allelic variant of this gene (divergent by 3% of its nucleotides) was cloned in Escherichia coli from C. crescentus type strain DSM4727. Expression studies confirmed the metallo-beta-lactamase activity of its product, CAU-1. The enzyme produced in E. coli was purified by two ion-exchange chromatography steps. CAU-1 contains a 29-kDa polypeptide with an alkaline isoelectric pH (> 9), and unlike the L1 enzyme of Stenotrophomonas maltophilia, the native form is monomeric. Kinetic analysis revealed a preferential activity toward penicillins, carbapenems, and narrow-spectrum cephalosporins, while oxyimino cephalosporins were poorly or not hydrolyzed. Affinities for the various beta-lactams were poor overall (K(m) values were always > 100 microM and often > 400 microM). The interaction with divalent ion chelators appeared to occur by a mechanism similar to that prevailing in other members of subclass B3. In C. crescentus, the CAU-1 enzyme is produced independently of beta-lactam exposure and, interestingly, the bla(CAU) determinant is bracketed by three other genes, including two genes encoding enzymes involved in methionine biosynthesis and a gene encoding a putative transcriptional regulator, in an operon-like structure. The CAU-1 enzyme is the first example of a metallo-beta-lactamase in a member of the alpha subdivision of the class Proteobacteria:

Docquier, J., Pantanella, F., Giuliani, F., Thaller, M.c., Amicosante, G., Galleni, M., et al. (2002). CAU-1, a subclass B3 metallo-beta-lactamase of low substrate affinity encoded by an ortholog present in the Caulobacter crescentus chromosome. ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, 46(6), 1823-1830 [doi: 10.1128/AAC.46.6.1823-1830.2002].

CAU-1, a subclass B3 metallo-beta-lactamase of low substrate affinity encoded by an ortholog present in the Caulobacter crescentus chromosome

THALLER, MARIA CRISTINA;
2002-06-01

Abstract

The sequenced chromosome of Caulobacter crescentus CB15 encodes a hypothetical protein that exhibits significant similarity (30 to 35% identical residues) to metallo-beta-lactamases of subclass B3. An allelic variant of this gene (divergent by 3% of its nucleotides) was cloned in Escherichia coli from C. crescentus type strain DSM4727. Expression studies confirmed the metallo-beta-lactamase activity of its product, CAU-1. The enzyme produced in E. coli was purified by two ion-exchange chromatography steps. CAU-1 contains a 29-kDa polypeptide with an alkaline isoelectric pH (> 9), and unlike the L1 enzyme of Stenotrophomonas maltophilia, the native form is monomeric. Kinetic analysis revealed a preferential activity toward penicillins, carbapenems, and narrow-spectrum cephalosporins, while oxyimino cephalosporins were poorly or not hydrolyzed. Affinities for the various beta-lactams were poor overall (K(m) values were always > 100 microM and often > 400 microM). The interaction with divalent ion chelators appeared to occur by a mechanism similar to that prevailing in other members of subclass B3. In C. crescentus, the CAU-1 enzyme is produced independently of beta-lactam exposure and, interestingly, the bla(CAU) determinant is bracketed by three other genes, including two genes encoding enzymes involved in methionine biosynthesis and a gene encoding a putative transcriptional regulator, in an operon-like structure. The CAU-1 enzyme is the first example of a metallo-beta-lactamase in a member of the alpha subdivision of the class Proteobacteria:
giu-2002
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore BIO/19 - MICROBIOLOGIA GENERALE
Settore MED/07 - MICROBIOLOGIA E MICROBIOLOGIA CLINICA
English
Con Impact Factor ISI
Amino Acid Sequence; Anti-Bacterial Agents; Caulobacter; Chelating Agents; Chromatography, Gel; Chromosomes, Bacterial; Cloning, Molecular; DNA, Bacterial; Kinetics; Microbial Sensitivity Tests; Molecular Sequence Data; Recombinant Proteins; Spectrometry, Mass, Electrospray Ionization; beta-Lactams
Docquier, J., Pantanella, F., Giuliani, F., Thaller, M.c., Amicosante, G., Galleni, M., et al. (2002). CAU-1, a subclass B3 metallo-beta-lactamase of low substrate affinity encoded by an ortholog present in the Caulobacter crescentus chromosome. ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, 46(6), 1823-1830 [doi: 10.1128/AAC.46.6.1823-1830.2002].
Docquier, J; Pantanella, F; Giuliani, F; Thaller, Mc; Amicosante, G; Galleni, M; Frère, J; Bush, K; Rossolini, G
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/156167
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