Article (Scientific journals)
A Tripeptide Deletion in the Class C beta-Lactamase FOX-4 Enzyme Impairs Cefoxitin Hydrolysis and Slightly Increases Susceptibility to beta-Lactamase Inhibitors
Mallo, Susana; Pérez-Llarena, Francisco J.; Kerff, Frédéric et al.
2010In Journal of Antimicrobial Chemotherapy, 65 (6), p. 1187-94
Peer Reviewed verified by ORBi
 

Files


Full Text
2010_Mallo-FOX4_R2_loop.pdf
Publisher postprint (365.52 kB)
Request a copy

All documents in ORBi are protected by a user license.

Send to



Details



Abstract :
[en] OBJECTIVES: A natural variant of the AmpC enzyme from Escherichia coli HKY28 with a tripeptide deletion (Gly-286/Ser-287/Asp-288) was recently described. The isolate produced an inhibitor-sensitive AmpC beta-lactamase variant that also conferred higher than usual levels of resistance to ceftazidime in the E. coli host. To demonstrate whether this is true in other class C beta-lactamase enzymes, we deleted the equivalent tripeptide in the FOX-4 plasmid-mediated class C beta-lactamase. METHODS: By site-directed mutagenesis, we deleted the tripeptide Gly-306/Asn-307/Ser-308 of FOX-4, thus generating FOX-4(DeltaGNS). The enzymes (FOX-4 wild-type and DeltaGNS) were purified and kinetic parameters (kcat, Km, kcat/Km) as well as IC50 values of several beta-lactams were assessed. Modelling studies were also performed. RESULTS: FOX-4(DeltaGNS) did not increase the catalytic efficiency towards ceftazidime, although it conferred a slight increase in the susceptibility to beta-lactamase inhibitors. There was also a noteworthy decrease in the cefoxitin MIC with the FOX-4(DeltaGNS) mutant (from 512 to 16 mg/L) as well as a 10-fold decrease in kcat/Km towards imipenem, which revealed specific structural features. CONCLUSIONS: Although deletions in the R2-loop are able to extend the substrate spectrum of class C enzymes, the present results do not confirm this hypothesis in FOX-4. The FOX-4 R2 site would already be wide enough to accommodate antibiotic molecules, and thus any amino acid replacement or deletion at this location would not affect the hydrolytic efficiency towards beta-lactams and would have a less drastic effect on the susceptibility to beta-lactamase inhibitors.
Research Center/Unit :
CIP - Centre d'Ingénierie des Protéines - ULiège
Disciplines :
Biochemistry, biophysics & molecular biology
Author, co-author :
Mallo, Susana
Pérez-Llarena, Francisco J.
Kerff, Frédéric  ;  Université de Liège - ULiège > Centre d'ingénierie des protéines
Fernández-Moreira, Esteban
Soares, Nelson C.
Galleni, Moreno ;  Université de Liège - ULiège > Département des sciences de la vie > Macromolécules biologiques
Bou, German
Language :
English
Title :
A Tripeptide Deletion in the Class C beta-Lactamase FOX-4 Enzyme Impairs Cefoxitin Hydrolysis and Slightly Increases Susceptibility to beta-Lactamase Inhibitors
Publication date :
June 2010
Journal title :
Journal of Antimicrobial Chemotherapy
ISSN :
0305-7453
eISSN :
1460-2091
Publisher :
Oxford University Press, London, United Kingdom
Volume :
65
Issue :
6
Pages :
1187-94
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 26 February 2010

Statistics


Number of views
119 (7 by ULiège)
Number of downloads
2 (1 by ULiège)

Scopus citations®
 
10
Scopus citations®
without self-citations
5
OpenCitations
 
9

Bibliography


Similar publications



Contact ORBi