Reference : The inhibitor thiomandelic acid binds to both metal ions in metallo-beta-lactamase an...
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
http://hdl.handle.net/2268/77926
The inhibitor thiomandelic acid binds to both metal ions in metallo-beta-lactamase and induces positive cooperativity in metal binding.
English
Damblon, Christian mailto [Université de Liège - ULg > Département de chimie (sciences) > Chimie biologique structurale >]
Jensen, Mikael [> > > >]
Ababou, Abdessamad [> > > >]
Barsukov, Igor [> > > >]
Papamicael, Cyril [> > > >]
Schofield, Christopher J [> > > >]
Olsen, Lars [> > > >]
Bauer, Rogert [> > > >]
Roberts, Gordon C K [> > > >]
2003
Journal of Biological Chemistry
American Society for Biochemistry and Molecular Biology
278
31
29240-51
Yes (verified by ORBi)
International
0021-9258
1083-351X
Baltimore
MD
[en] Bacillus cereus/enzymology ; Binding Sites ; Cadmium ; Magnetic Resonance Spectroscopy ; Mandelic Acids/chemistry/metabolism ; Metals/metabolism ; Models, Molecular ; Molecular Structure ; Spectrum Analysis ; Stereoisomerism ; Sulfhydryl Compounds/chemistry/metabolism ; beta-Lactamases/chemistry/metabolism
[en] Thiomandelic acid is a simple, broad spectrum, and reasonably potent inhibitor of metallo-beta-lactamases, enzymes that mediate resistance to beta-lactam antibiotics. We report studies by NMR and perturbed angular correlation (PAC) spectroscopy of the mode of binding of the R and S enantiomers of thiomandelic acid, focusing on their interaction with the two metal ions in cadmium-substituted Bacillus cereus metallo-beta-lactamase. The 113Cd resonances are specifically assigned to the metals in the two individual sites on the protein by using 113Cd-edited 1H NMR spectra. Each enantiomer of thiomandelate produces large downfield shifts of both 113Cd resonances and changes in the PAC spectra, which indicate that they bind such that the thiol of the inhibitor bridges between the two metals. For R-thiomandelate, this is unambiguously confirmed by the observation of scalar coupling between Halpha of the inhibitor and both cadmium ions. The NMR and PAC spectra reveal that the two chiral forms of the inhibitor differ in the details of their coordination geometry. The complex with R-thiomandelate, but not that with the S-enantiomer, shows evidence in the PAC spectra of a dynamic process in the nanosecond time regime, the possible nature of which is discussed. The thiomandelate complex of the mononuclear enzyme can be detected only at low metal to enzyme stoichiometry; the relative populations of mononuclear and binuclear enzyme as a function of cadmium concentration provide clear evidence for positive cooperativity in metal ion binding in the presence of the inhibitor, in contrast to the negative cooperativity observed in the free enzyme.
http://hdl.handle.net/2268/77926
10.1074/jbc.M301562200

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