Nanomolar inhibitors of AmpC beta-lactamase

J Am Chem Soc. 2003 Jan 22;125(3):685-95. doi: 10.1021/ja0288338.


beta-lactamases are the most widespread resistance mechanism to beta-lactam antibiotics, such as the penicillins and the cephalosporins. In an effort to combat these enzymes, a combination of stereoselective organic synthesis, enzymology, microbiology, and X-ray crystallography was used to design and evaluate new carboxyphenyl-glycylboronic acid transition-state analogue inhibitors of the class C beta-lactamase AmpC. The new compounds improve inhibition by over 2 orders of magnitude compared to analogous glycylboronic acids, with K(i) values as low as 1 nM. On the basis of the differential binding of different analogues, the introduced carboxylate alone contributes about 2.1 kcal/mol in affinity. This carboxylate corresponds to the ubiquitous C3(4)' carboxylate of beta-lactams, and this energy represents the first thermodynamic measurement of the importance of this group in molecular recognition by class C beta-lactamases. The structures of AmpC in complex with two of these inhibitors were determined by X-ray crystallography at 1.72 and 1.83 A resolution. These structures suggest a structural basis for the high affinity of the new compounds and provide templates for further design. The highest affinity inhibitor was 5 orders of magnitude more selective for AmpC than for characteristic serine proteases, such as chymotrypsin. This inhibitor reversed the resistance of clinical pathogens to the third generation cephalosporin ceftazidime; it may serve as a lead compound for drug discovery to combat bacterial resistance to beta-lactam antibiotics.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Bacterial Proteins*
  • Boron Compounds / chemical synthesis
  • Boron Compounds / chemistry
  • Boron Compounds / metabolism
  • Boron Compounds / pharmacology
  • Boronic Acids / chemical synthesis
  • Boronic Acids / chemistry*
  • Boronic Acids / metabolism
  • Boronic Acids / pharmacology*
  • Ceftazidime / pharmacology
  • Crystallography, X-Ray
  • Drug Synergism
  • Enzyme Inhibitors / chemical synthesis
  • Enzyme Inhibitors / chemistry*
  • Enzyme Inhibitors / metabolism
  • Enzyme Inhibitors / pharmacology*
  • Kinetics
  • Microbial Sensitivity Tests
  • Models, Chemical
  • Molecular Conformation
  • Substrate Specificity
  • beta-Lactamase Inhibitors*
  • beta-Lactamases / metabolism


  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Boron Compounds
  • Boronic Acids
  • Enzyme Inhibitors
  • beta-Lactamase Inhibitors
  • methaneboronic acid
  • Ceftazidime
  • AmpC beta-lactamases
  • beta-Lactamases