A novel inhibitor that suspends the induced fit mechanism of UDP-N-acetylglucosamine enolpyruvyl transferase (MurA)
A novel inhibitor that suspends the induced fit mechanism of UDP-N-acetylglucosamine enolpyruvyl transferase (MurA)
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DOI：
10.1074/jbc.m414412200
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发表时间：
2005-04-08
影响因子：
4.8
通讯作者：
Schönbrunn, E
中科院分区：
文献类型：
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作者：
Eschenburg, S;Priestman, MA;Schönbrunn, E
MurA （udp - n -乙酰氨基葡萄糖烯醇丙酮基转移酶，EC 2.5.1.7）催化了细菌细胞壁合成的第一步。它是天然存在的广谱抗生素磷霉素的靶标。磷霉素是一种环氧化物，是一种相对较差的药物，因为越来越多的细菌已经对磷霉素产生了耐药性。因此，迫切需要通过不同的分子作用模式开发针对MurA的新型药物。我们已经确定了一个新的支架有效的MurA抑制剂，衍生物的5-磺氧基-邻氨基苯酸，使用高通量筛选。T6361和T6362是MurA的竞争性抑制剂，相对于第一底物udp - n -乙酰氨基葡萄糖（UNAG），其K-i为16 μ m。2.6埃分辨率的T6361配合物以及荧光数据显示，该抑制剂靶向一个环，Pro（112）到Pro(121)，这对酶在催化过程中的结构变化至关重要。因此，这类新的MurA抑制剂不是活性位点导向的，而是阻碍了从开放（未配体）到封闭（unag配体）酶形式的转变。这些结果为MurA的存在提供了证据。UNAG碰撞配合物可以被不同于基态酶促反应类似物的小分子特异性靶向。
MurA (UDP-N-acetylglucosamine enolpyruvyl transferase, EC 2.5.1.7) catalyzes the first committed step in the synthesis of the bacterial cell wall. It is the target of the naturally occurring, broad-spectrum antibiotic fosfomycin. Fosfomycin, an epoxide, is a relatively poor drug because an ever-increasing number of bacteria have developed resistance to fosfomycin. Thus, there is a critical need for the development of novel drugs that target MurA by a different molecular mode of action. We have identified a new scaffold of potent MurA inhibitors, derivatives of 5-sulfonoxy-anthranilic acid, using high-throughput screening. T6361 and T6362 are competitive inhibitors of MurA with respect to the first substrate, UDP-N-acetylglucosamine (UNAG), with a K-i of 16 mu M. The crystal structure of the MurA.T6361 complex at 2.6 angstrom resolution, together with fluorescence data, revealed that the inhibitor targets a loop, Pro(112) to Pro(121), that is crucial for the structural changes of the enzyme during catalysis. Thus, this new class of MurA inhibitors is not active site-directed but instead obstructs the transition from the open (unliganded) to the closed (UNAG-liganded) enzyme form. The results provide evidence for the existence of a MurA.UNAG collision complex that may be specifically targeted by small molecules different from ground-state analogs of the enzymatic reaction.