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Accueil > Publications > Recherche par années > Années 2000 > 2001

Mollard, C ; Moali, C ; Papamicael, C ; Damblon, C ; Vessilier, S ; Amicosante, G ; Schofield, CJ ; Galleni, M ; Frère, JM ; Roberts, GCK

Thiomandelic acid, a broad spectrum inhibitor of zinc ß-lactamases - Kinetic and spectroscopic studies

Journal of Biological Chemistry 276 (48) 45015-45023

par Administrateur - publié le

Abstract :

Resistance to ß -lactam antibiotics mediated by metallo-ß -lactamases is an increasingly worrying clinical problem. Candidate inhibitors include mercaptocarboxylic acids, and we report studies of a simple such compound, thiomandelic acid. A series of 35 analogues were synthesized and examined as metallo-ß -lactamase inhibitors. The K-i values (Bacillus cereus enzyme) are 0.09 muM for R-thiomandelic acid and 1.28 muM for the S-isomer. Structure-activity relationships show that the thiol is essential for activity and the carboxylate increases potency ; the affinity is greatest when these groups are close together. Thioesters of thiomandelic acid are substrates for the enzyme, liberating thiomandelic acid, suggesting a starting point for the design of "pro-drugs." Importantly, thiomandelic acid is a broad spectrum inhibitor of metallo-ß -lactamases, with a submicromolar K-i value for all nine enzymes tested, except the Aeromonas hydrophila enzyme ; such a wide spectrum of activity is unprecedented. The binding of thiomandelic acid to the B. cereus enzyme was studied by NMR ; the results are consistent with the idea that the inhibitor thiol binds to both zinc ions, while its carboxylate binds to Arg(91). Amide chemical shift perturbations for residues 30-40 (the ß (3)-ß (4) loop) suggest that this small inhibitor induces a movement of this loop of the kind seen for other larger inhibitors.