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  • 1
    Online Resource
    Online Resource
    Biochemical and Structural Characterization of the Subclass B1 Metallo-β-Lactamase VIM-4
    American Society for Microbiology ; 2011
    In:  Antimicrobial Agents and Chemotherapy Vol. 55, No. 3 ( 2011-03), p. 1248-1255
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 55, No. 3 ( 2011-03), p. 1248-1255
    Abstract: The metallo-β-lactamase VIM-4, mainly found in Pseudomonas aeruginosa or Acinetobacter baumannii , was produced in Escherichia coli and characterized by biochemical and X-ray techniques. A detailed kinetic study performed in the presence of Zn 2+ at concentrations ranging from 0.4 to 100 μM showed that VIM-4 exhibits a kinetic profile similar to the profiles of VIM-2 and VIM-1. However, VIM-4 is more active than VIM-1 against benzylpenicillin, cephalothin, nitrocefin, and imipenem and is less active than VIM-2 against ampicillin and meropenem. The crystal structure of the dizinc form of VIM-4 was solved at 1.9 Å. The sole difference between VIM-4 and VIM-1 is found at residue 228, which is Ser in VIM-1 and Arg in VIM-4. This substitution has a major impact on the VIM-4 catalytic efficiency compared to that of VIM-1. In contrast, the differences between VIM-2 and VIM-4 seem to be due to a different position of the flapping loop and two substitutions in loop 2. Study of the thermal stability and the activity of the holo- and apo-VIM-4 enzymes revealed that Zn 2+ ions have a pronounced stabilizing effect on the enzyme and are necessary for preserving the structure.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/AAC.01486-09
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2011
    detail.hit.zdb_id: 1496156-8
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  • 2
    Online Resource
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    A Standard Numbering Scheme for Class C β-Lactamases
    American Society for Microbiology ; 2020
    In:  Antimicrobial Agents and Chemotherapy Vol. 64, No. 3 ( 2020-02-21)
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 64, No. 3 ( 2020-02-21)
    Abstract: Unlike for classes A and B, a standardized amino acid numbering scheme has not been proposed for the class C (AmpC) β-lactamases, which complicates communication in the field. Here, we propose a scheme developed through a collaborative approach that considers both sequence and structure, preserves traditional numbering of catalytically important residues (Ser 64 , Lys 67 , Tyr 150 , and Lys 315 ), is adaptable to new variants or enzymes yet to be discovered and includes a variation for genetic and epidemiological applications.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/AAC.01841-19
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2020
    detail.hit.zdb_id: 1496156-8
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  • 3
    Online Resource
    Online Resource
    Purification and Biochemical Characterization of the VIM-1 Metallo-β-Lactamase
    American Society for Microbiology ; 2000
    In:  Antimicrobial Agents and Chemotherapy Vol. 44, No. 11 ( 2000-11), p. 3003-3007
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 44, No. 11 ( 2000-11), p. 3003-3007
    Abstract: VIM-1 is a new group 3 metallo-β-lactamase recently detected in carbapenem-resistant nosocomial isolates of Pseudomonas aeruginosa from the Mediterranean area. In this work, VIM-1 was purified from an Escherichia coli strain carrying the cloned bla VIM-1 gene by means of an anion-exchange chromatography step followed by a gel permeation chromatography step. The purified enzyme exhibited a molecular mass of 26 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and an acidic pI of 5.1 in analytical isoelectric focusing. Amino-terminal sequencing showed that mature VIM-1 results from the removal of a 26-amino-acid signal peptide from the precursor. VIM-1 hydrolyzes a broad array of β-lactam compounds, including penicillins, narrow- to expanded-spectrum cephalosporins, carbapenems, and mechanism-based serine-β-lactamase inactivators. Only monobactams escape hydrolysis. The highest catalytic constant/ K m ratios ( 〉 10 6 M −1 · s −1 ) were observed with carbenicillin, azlocillin, some cephalosporins (cephaloridine, cephalothin, cefuroxime, cefepime, and cefpirome), imipenem, and biapenem. Kinetic parameters showed remarkable variability with different β-lactams and also within the various penam, cephem, and carbapenem compounds, resulting in no clear preference of the enzyme for any of these β-lactam subfamilies. Significant differences were observed with some substrates between the kinetic parameters of VIM-1 and those of other metallo-β-lactamases. Inactivation assays carried out with various chelating agents (EDTA, 1,10- o -phenanthroline, and pyridine-2,6-dicarboxylic acid) indicated that formation of a ternary enzyme-metal-chelator complex precedes metal removal from the zinc center of the protein and revealed notable differences in the inactivation parameters of VIM-1 with different agents.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/AAC.44.11.3003-3007.2000
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2000
    detail.hit.zdb_id: 1496156-8
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  • 4
    Online Resource
    Online Resource
    Overproduction and Biochemical Characterization of the Chryseobacterium meningosepticum BlaB Metallo-β-Lactamase
    American Society for Microbiology ; 2002
    In:  Antimicrobial Agents and Chemotherapy Vol. 46, No. 6 ( 2002-06), p. 1921-1927
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 46, No. 6 ( 2002-06), p. 1921-1927
    Abstract: The BlaB metallo-β-lactamase of Chryseobacterium meningosepticum CCUG4310 was overproduced in Escherichia coli by means of a T7 promoter-based expression system. The overproducing system, scaled up in a 15-liter fermentor, yielded approximately 10 mg of BlaB protein per liter, mostly released in the culture supernatant. The enzyme was purified by two ion-exchange chromatographic steps with an overall yield of 66%. Analysis of the kinetic parameters revealed efficient activities ( k cat / K m ratios of 〉 10 6 M −1 s −1 ) toward most penam and carbapenem compounds, with the exception of the 6-α-methoxypenam derivative temocillin and of biapenem, which were poorer substrates. Hydrolysis of cephalosporins was overall less efficient, with a remarkable variability that was largely due to variable affinities of the BlaB enzyme for different compounds. BlaB was also able to hydrolyze serine-β-lactamase inhibitors, including β-iodopenicillanate, sulbactam and, although less efficiently, tazobactam.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/AAC.46.6.1921-1927.2002
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2002
    detail.hit.zdb_id: 1496156-8
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  • 5
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    Online Resource
    Postgenomic Scan of Metallo-β-Lactamase Homologues in Rhizobacteria: Identification and Characterization of BJP-1, a Subclass B3 Ortholog from Bradyrhizobium japonicum
    American Society for Microbiology ; 2006
    In:  Antimicrobial Agents and Chemotherapy Vol. 50, No. 6 ( 2006-06), p. 1973-1981
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 50, No. 6 ( 2006-06), p. 1973-1981
    Abstract: The diffusion of metallo-β-lactamases (MBLs) among clinically important human pathogens represents a therapeutic issue of increasing importance. However, the origin of these resistance determinants is largely unknown, although an important number of proteins belonging to the MBL superfamily have been identified in microbial genomes. In this work, we analyzed the distribution and function of genes encoding MBL-like proteins in the class Rhizobiales . Among 12 released complete genomes of members of the class Rhizobiales , a total of 57 open reading frames (ORFs) were found to have the MBL conserved motif and identity scores with MBLs ranging from 8 to 40%. On the basis of the best identity scores with known MBLs, four ORFs were cloned into Escherichia coli for heterologous expression. Among their products, one (blr6230) encoded by the Bradyrhizobium japonicum USDA110 genome, named BJP-1, hydrolyzed β-lactams when expressed in E. coli . BJP-1 enzyme is most closely related to the CAU-1 enzyme from Caulobacter vibrioides (40% amino acid sequence identity), a member of subclass B3 MBLs. A kinetic analysis revealed that BJP-1 efficiently hydrolyzed most β-lactam substrates, except aztreonam, ticarcillin, and temocillin, with the highest catalytic efficiency measured with meropenem. Compared to other MBLs, BJP-1 was less sensitive to inactivation by chelating agents.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/AAC.01551-05
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2006
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  • 6
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    Online Resource
    Biochemical Characterization of the THIN-B Metallo-β-Lactamase of Janthinobacterium lividum
    American Society for Microbiology ; 2004
    In:  Antimicrobial Agents and Chemotherapy Vol. 48, No. 12 ( 2004-12), p. 4778-4783
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 48, No. 12 ( 2004-12), p. 4778-4783
    Abstract: The THIN-B metallo-β-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.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/AAC.48.12.4778-4783.2004
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2004
    detail.hit.zdb_id: 1496156-8
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  • 7
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    Online Resource
    Functional Diversity among Metallo-β-Lactamases: Characterization of the CAR-1 Enzyme of Erwinia carotovora
    American Society for Microbiology ; 2008
    In:  Antimicrobial Agents and Chemotherapy Vol. 52, No. 7 ( 2008-07), p. 2473-2479
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 52, No. 7 ( 2008-07), p. 2473-2479
    Abstract: Metallo-β-lactamases (MBLs) are zinc-dependent bacterial enzymes characterized by an efficient hydrolysis of carbapenems and a lack of sensitivity to commercially available β-lactamase inactivators. Apart from the acquired subclass B1 enzymes, which exhibit increasing clinical importance and whose evolutionary origin remains unclear, most MBLs are encoded by resident genes found in the genomes of organisms belonging to at least three distinct phyla. Using genome database mining, we identified an open reading frame (ORF) (ECA2849) encoding an MBL-like protein in the sequenced genome of Erwinia carotovora , an important plant pathogen. Although no detectable β-lactamase activity could be found in E. carotovora , a recombinant Escherichia coli strain in which the ECA2849 ORF was cloned showed decreased susceptibility to several β-lactams, while carbapenem MICs were surprisingly poorly affected. The enzyme, named CAR-1, was purified by means of ion-exchange chromatography steps, and its characterization revealed unique structural and functional features. This new MBL was able to efficiently hydrolyze cephalothin, cefuroxime, and cefotaxime and, to a lesser extent, penicillins and the other cephalosporins but only poorly hydrolyzed meropenem, while imipenem was not recognized. CAR-1 is the first example of a functional naturally occurring MBL in the family Enterobacteriaceae (order Enterobacteriales ) and highlights the extraordinary structural and functional diversity exhibited by MBLs.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/AAC.01062-07
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2008
    detail.hit.zdb_id: 1496156-8
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  • 8
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    Online Resource
    IND-6, a Highly Divergent IND-Type Metallo-β-Lactamase from Chryseobacterium indologenes Strain 597 Isolated in Burkina Faso
    American Society for Microbiology ; 2009
    In:  Antimicrobial Agents and Chemotherapy Vol. 53, No. 10 ( 2009-10), p. 4320-4326
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 53, No. 10 ( 2009-10), p. 4320-4326
    Abstract: The genus Chryseobacterium and other genera belonging to the family Flavobacteriaceae include organisms that can behave as human pathogens and are known to cause different kinds of infections. Several species of Flavobacteriaceae , including Chryseobacterium indologenes , are naturally resistant to β-lactam antibiotics (including carbapenems), due to the production of a resident metallo-β-lactamase. Although C. indologenes presently constitutes a limited clinical threat, the incidence of infections caused by this organism is increasing in some settings, where isolates that exhibit multidrug resistance phenotypes (including resistance to aminoglycosides and quinolones) have been detected. Here, we report the identification and characterization of a new IND-type variant from a C. indologenes isolate from Burkina Faso that is resistant to β-lactams and aminoglycosides. The levels of sequence identity of the new variant to other IND-type metallo-β-lactamases range between 72 and 90% (for IND-4 and IND-5, respectively). The purified enzyme exhibited N-terminal heterogeneity and a posttranslational modification consisting of the presence of a pyroglutamate residue at the N terminus. IND-6 shows a broad substrate profile, with overall higher turnover rates than IND-5 and higher activities than IND-2 and IND-5 against ceftazidime and cefepime.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/AAC.01607-08
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2009
    detail.hit.zdb_id: 1496156-8
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  • 9
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    Online Resource
    CAU-1, a Subclass B3 Metallo-β-Lactamase of Low Substrate Affinity Encoded by an Ortholog Present in the Caulobacter crescentus Chromosome
    American Society for Microbiology ; 2002
    In:  Antimicrobial Agents and Chemotherapy Vol. 46, No. 6 ( 2002-06), p. 1823-1830
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 46, No. 6 ( 2002-06), p. 1823-1830
    Abstract: The sequenced chromosome of Caulobacter crescentus CB15 encodes a hypothetical protein that exhibits significant similarity (30 to 35% identical residues) to metallo-β-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-β-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 β-lactams were poor overall ( K m values were always 〉 100 μM and often 〉 400 μM). 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 β-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-β-lactamase in a member of the α subdivision of the class Proteobacteria .
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/AAC.46.6.1823-1830.2002
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2002
    detail.hit.zdb_id: 1496156-8
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  • 10
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    Online Resource
    Mutational Analysis of VIM-2 Reveals an Essential Determinant for Metallo-β-Lactamase Stability and Folding
    American Society for Microbiology ; 2010
    In:  Antimicrobial Agents and Chemotherapy Vol. 54, No. 8 ( 2010-08), p. 3197-3204
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 54, No. 8 ( 2010-08), p. 3197-3204
    Abstract: Metallo-β-lactamase (MBL)-producing bacteria are emerging worldwide and represent a formidable threat to the efficacy of relevant β-lactams, including carbapenems, expanded-spectrum cephalosporins, and β-lactamase inactivator/β-lactam combinations. VIM-2 is currently the most widespread MBL and represents a primary target for MBL inhibitor research, the clinical need for which is expected to further increase in the future. Using a saturation mutagenesis approach, we probed the importance of four residues (Phe-61, Ala-64, Tyr-67, and Trp-87) located close to the VIM-2 active site and putatively relevant to the enzyme activity based on structural knowledge of the enzyme and on structure-activity relationships of the subclass B1 MBLs. The ampicillin MIC values shown by the various mutants were affected very differently depending on the randomized amino acid position. Position 64 appeared to be rather tolerant to substitution, and kinetic studies showed that the A64W mutation did not significantly affect substrate hydrolysis or binding, representing an important difference from IMP-type enzymes. Phe-61 and Tyr-67 could be replaced with several amino acids without the ampicillin MIC being significantly affected, but in contrast, Trp-87 was found to be critical for ampicillin resistance. Further kinetic and biochemical analyses of W87A and W87F variants showed that this residue is apparently important for the structure and proper folding of the enzyme but, surprisingly, not for its catalytic activity. These data support the critical role of residue 87 in the stability and folding of VIM-2 and might have strong implications for MBL inhibitor design, as this residue would represent an ideal target for interaction with small molecules.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/AAC.01336-09
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2010
    detail.hit.zdb_id: 1496156-8
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    SSG: 15,3
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