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AmpC beta-lactamase in complex with an m.carboxyphenylglycylboronic acid bearing the cephalothin R1 side chainAmpC beta-lactamase in complex with an m.carboxyphenylglycylboronic acid bearing the cephalothin R1 side chain
Structural highlights
FunctionAMPC_ECOLI This protein is a serine beta-lactamase with a substrate specificity for cephalosporins. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedbeta-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. Nanomolar inhibitors of AmpC beta-lactamase.,Morandi F, Caselli E, Morandi S, Focia PJ, Blazquez J, Shoichet BK, Prati F J Am Chem Soc. 2003 Jan 22;125(3):685-95. PMID:12526668[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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