Recognition and Resistance in TEM -Lactamase
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- 作者：Xiaojun Wang ; George Minasov ; Jesú ; s Blá ; zquez ; Emilia Caselli ; Fabio Prati ; and Brian K. Shoichet
- 刊名：Biochemistry
- 出版年：2003
- 出版时间：July 22, 2003
- 年：2003
- 卷：42
- 期：28
- 页码：8434 - 8444
- 全文大小：873K
- 年卷期：v.42,no.28(July 22, 2003)
- ISSN：1520-4995
文摘
Developing antimicrobials that are less likely to engender resistance has become an importantdesign criterion as more and more drugs fall victim to resistance mutations. One hypothesis is that themore closely an inhibitor resembles a substrate, the more difficult it will be to develop resistant mutationsthat can at once disfavor the inhibitor and still recognize the substrate. To investigate this hypothesis, 10transition-state analogues, of greater or lesser similarity to substrates, were tested for inhibition of TEM-1
-lactamase, the most widespread resistance enzyme to penicillin antibiotics. The inhibitors were alsotested against four characteristic mutant enzymes: TEM-30, TEM-32, TEM-52, and TEM-64. The inhibitormost similar to the substrate, compound 10, was the most potent inhibitor of the WT enzyme, with a Kivalue of 64 nM. Conversely, compound 10 was the most susceptible to the TEM-30 (R244S) mutant, forwhich inhibition dropped by over 100-fold. The other inhibitors were relatively impervious to the TEM-30 mutant enzyme. To understand recognition and resistance to these transition-state analogues, thestructures of four of these inhibitors in complex with TEM-1 were determined by X-ray crystallography.These structures suggest a structural basis for distinguishing inhibitors that mimic the acylation transitionstate and those that mimic the deacylation transition state; they also suggest how TEM-30 reduces theaffinity of compound 10. In cell culture, this inhibitor reversed the resistance of bacteria to ampicillin,reducing minimum inhibitory concentrations of this penicillin by between 4- and 64-fold, depending onthe strain of bacteria. Notwithstanding this activity, the resistance of TEM-30, which is already extant inthe clinic, suggests that there can be resistance liabilities with substrate-based design.
-lactamase, the most widespread resistance enzyme to penicillin antibiotics. The inhibitors were alsotested against four characteristic mutant enzymes: TEM-30, TEM-32, TEM-52, and TEM-64. The inhibitormost similar to the substrate, compound 10, was the most potent inhibitor of the WT enzyme, with a Kivalue of 64 nM. Conversely, compound 10 was the most susceptible to the TEM-30 (R244S) mutant, forwhich inhibition dropped by over 100-fold. The other inhibitors were relatively impervious to the TEM-30 mutant enzyme. To understand recognition and resistance to these transition-state analogues, thestructures of four of these inhibitors in complex with TEM-1 were determined by X-ray crystallography.These structures suggest a structural basis for distinguishing inhibitors that mimic the acylation transitionstate and those that mimic the deacylation transition state; they also suggest how TEM-30 reduces theaffinity of compound 10. In cell culture, this inhibitor reversed the resistance of bacteria to ampicillin,reducing minimum inhibitory concentrations of this penicillin by between 4- and 64-fold, depending onthe strain of bacteria. Notwithstanding this activity, the resistance of TEM-30, which is already extant inthe clinic, suggests that there can be resistance liabilities with substrate-based design.