Differential inhibition of class I and class II 5-enolpyruvylshikimate-3-phosphate synthases by tetrahedral reaction intermediate analogues.
Differential inhibition of class I and class II 5-enolpyruvylshikimate-3-phosphate synthases by tetrahedral reaction intermediate analogues.
复制标题
四面体反应中间体类似物对 I 类和 II 类 5-烯醇丙酮莽草酸-3-磷酸合酶的差异抑制。
DOI：
10.1021/bi701095u
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发表时间：
2007
期刊：
影响因子：
2.9
通讯作者：
Schonbrunn,Ernst
中科院分区：
文献类型：
--
作者：
Funke,Todd;Healy-Fried,MarthaL;Han,Huijong;Alberg,DavidG;Bartlett,PaulA;Schonbrunn,Ernst
莽草酸途径酶5-烯醇式莽草酸-3-磷酸合酶（EPSP合酶或EPSPS）最为人所知的是除草剂草甘膦的靶标。EPSPS也被认为是开发新型抗生素的有吸引力的靶标，因为许多微生物的致病性取决于莽草酸途径的功能。在这里，我们已经调查了稳定的氟化或膦酸酯为基础的类似物的四面体反应中间体（TI）的抑制效力在一个平行的研究，利用I类（草甘膦敏感）和II类（草甘膦耐受）EPSPS。TI的（R）-二氟甲基和（R）-膦酸酯类似物是迄今为止描述的最有效的EPSPS抑制剂。然而，我们发现II类EPSPS对这些TI类似物的抑制作用的敏感性降低了400倍。X-射线晶体学数据显示，抑制剂与大肠杆菌的代表性I类EPSPS结合后观察到的活性位点残基的构象变化在土壤杆菌属的原型II类酶中不发生。菌株CP 4。似乎因为II类EPSPS的活性位点不具有适应这些TI类似物的灵活性，所以类似物本身经历构象变化，导致不太有利的抑制性质。由于病原微生物如金黄色葡萄球菌利用II类EPSPS，我们的结论是，合理的设计新的EPSPS抑制剂的潜力，作为广谱抗生素应基于II类EPSP酶的活性位点结构。
The shikimate pathway enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSP synthase or EPSPS) is best known as the target of the herbicide glyphosate. EPSPS is also considered an attractive target for the development of novel antibiotics since the pathogenicity of many microorganisms depends on the functionality of the shikimate pathway. Here, we have investigated the inhibitory potency of stable fluorinated or phosphonate-based analogues of the tetrahedral reaction intermediate (TI) in a parallel study utilizing class I (glyphosate-sensitive) and class II (glyphosate-tolerant) EPSPS. The (R)-difluoromethyl and (R)-phosphonate analogues of the TI are the most potent inhibitors of EPSPS described to date. However, we found that class II EPSPS are up to 400 times less sensitive to inhibition by these TI analogues. X-ray crystallographic data revealed that the conformational changes of active site residues observed upon inhibitor binding to the representative class I EPSPS fromEscherichia colido not occur in the prototypical class II enzyme fromAgrobacteriumsp. strain CP4. It appears that because the active sites of class II EPSPS do not possess the flexibility to accommodate these TI analogues, the analogues themselves undergo conformational changes, resulting in less favorable inhibitory properties. Since pathogenic microorganisms such asStaphylococcus aureusutilize class II EPSPS, we conclude that the rational design of novel EPSPS inhibitors with potential as broad-spectrum antibiotics should be based on the active site structures of class II EPSP synthases.