Abstract
β-Lactamases inactivate β-lactam antibiotics by hydrolysis of their endocyclic β-lactam bond and are a major cause of antibiotic resistance in pathogenic bacteria. The zinc dependent metallo-β-lactamase enzymes are of particular concern since they are located on highly transmissible plasmids and have a broad spectrum of activity against almost all β-lactam antibiotics. We present here essentially complete (>96 %) backbone and sidechain sequence-specific NMR resonance assignments for the Bacillus cereus subclass B1 metallo-β-lactamase, BcII, and for its complex with R-thiomandelic acid, a broad spectrum inhibitor of metallo-β-lactamases. These assignments have been used as the basis for determination of the solution structures of the enzyme and its inhibitor complex and can also be used in a rapid screen for other metallo-β-lactamase inhibitors.
Highlights
Abstract b-Lactamases inactivate b-lactam antibiotics by hydrolysis of their endocyclic b-lactam bond and are a major cause of antibiotic resistance in pathogenic bacteria
The zinc dependent metallo-b-lactamase enzymes are of particular concern since they are located on highly transmissible plasmids and have a broad spectrum of activity against almost all b-lactam antibiotics
We present here essentially complete ([96 %) backbone and sidechain sequence-specific NMR resonance assignments for the Bacillus cereus subclass B1 metallo-b-lactamase, BcII, and for its complex with R-thiomandelic acid, a broad spectrum inhibitor of metallo-b-lactamases
Summary
The b-lactamases, enzymes which inactivate b-lactam antibiotics by hydrolysis of their endocyclic b-lactam bond, are a major cause of resistance to these antibiotics in pathogenic bacteria (Frere et al 1999). The rapid increase in this resistance is a major clinical and public health concern, as these antibiotics have long been crucial in the treatment of serious bacterial infections. R-thiomandelic acid has been identified (Mollard et al 2001; Damblon et al 2003) as a potent and promising MBL inhibitor with a Ki of 0.09 lM towards the MBL from Bacillus cereus, BcII, a representative of the subclass B1 of MBLs which includes the clinically important enzymes of the IMP and VIM families and the recently identified NDM-1 enzyme. The complete backbone and sidechain resonance assignments for the BcII MBL (227 amino-acid residues) and its complex with R-thiomandelate are presented in this communication. The solution structures of BcII and of the BcII–thiomandelate complex, the product of these assignments, are reported elsewhere (Karsisiotis, A.I., Damblon, C.F. and Roberts, G.C.K., submitted for publication). The only other example of sequence specific assignments for an MBL is of the CcrA enzyme from Bacteroides fragilis (Scrofani et al 1998) (BMRB 4102) where the majority of HN, N, CA, CB, CO and HA resonances were assigned
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