Article (Scientific journals)
The structure of the di-zinc subclass B2 metallo-beta-lactamase CphA reveals that the second inhibitory zinc ion binds in the "histidine" site.
Bebrone, Carine; Delbrück, Heinrich; Kupper, Michaël et al.
2009In Antimicrobial Agents and Chemotherapy
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Abstract :
[en] Bacteria can defend themselves against beta-lactam antibiotics through the expression of class B beta-lactamases, which cleave the beta-lactam amide bond and render the molecule harmless. There are three subclasses of class B beta-lactamases (B1, B2 and B3), all of which require Zn(2+) for activity and can bind either one or two zinc ions. Whereas the B1 and B3 metallo-beta-lactamases are most active as di-zinc enzymes, subclass B2 enzymes such as Aeromonas hydrophila CphA are inhibited by the binding of a second zinc ion. We crystallized A. hydrophila CphA in order to determine the binding site of the inhibitory zinc ion. X-ray data from zinc-saturated crystals allowed us to solve the crystal structures of the di-zinc forms of the wild-type enzyme and N220G mutant. The first zinc ion binds in the "cysteine" site, as previously determined for the mono-zinc form of the enzyme. The second zinc ion occupies a slightly modified "histidine" site, where the conserved His118 and His196 residues act as metal ligands. This atypical coordination sphere probably explains the rather high dissociation constant for the second zinc ion compared to those observed in enzymes of subclasses B1 and B3. Inhibition by the second zinc ion results from immobilization of the catalytically-important His118 and His196 residues, as well as the folding of the Gly232-Asn233 loop into a position that covers the active site.
Disciplines :
Biochemistry, biophysics & molecular biology
Author, co-author :
Bebrone, Carine ;  Université de Liège - ULiège > Centre d'ingénierie des protéines
Delbrück, Heinrich;  Rheinisch - Westfälische Technische Hochschule Aachen - RWTH > Institut für Molekulare Biotechnologie > Bioanlytics
Kupper, Michaël;  Rheinisch - Westfälische Technische Hochschule Aachen - RWTH > Institut für Molekulare Biotechnologie > Bioanalytics
Schlömer, Philipp;  Rheinisch - Westfälische Technische Hochschule Aachen - RWTH > Institut für Molekulare Biotechnologie > Bioanalytics
Willmann, Charlotte;  Rheinisch - Westfälische Technische Hochschule Aachen - RWTH
Frère, Jean-Marie ;  Université de Liège - ULiège > Centre d'ingénierie des protéines
Fisher, Rainer;  Rheinisch - Westfälische Technische Hochschule Aachen - RWTH
Galleni, Moreno ;  Université de Liège - ULiège > Département des sciences de la vie > Macromolécules biologiques
Hoffmann, Kurt;  Rheinisch - Westfälische Technische Hochschule Aachen - RWTH > Institut für Molekulare Biotechnologie > Bioanalytics
Language :
English
Title :
The structure of the di-zinc subclass B2 metallo-beta-lactamase CphA reveals that the second inhibitory zinc ion binds in the "histidine" site.
Publication date :
2009
Journal title :
Antimicrobial Agents and Chemotherapy
ISSN :
0066-4804
eISSN :
1098-6596
Publisher :
American Society for Microbiology (ASM), Washington, United States - District of Columbia
Peer reviewed :
Peer Reviewed verified by ORBi
Funders :
F.R.S.-FNRS - Fonds de la Recherche Scientifique [BE]
Available on ORBi :
since 18 October 2009

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