The fungal product terreic acid is a covalent inhibitor of the bacterial cell wall biosynthetic enzyme UDP-N-acetylglucosamine 1-carboxyvinyltransferase (MurA) .
The fungal product terreic acid is a covalent inhibitor of the bacterial cell wall biosynthetic enzyme UDP-N-acetylglucosamine 1-carboxyvinyltransferase (MurA) .
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DOI：
10.1021/bi100365b
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发表时间：
2010-05-18
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：
Han, Huijong;Yang, Yan;Olesen, Sanne H.;Becker, Andreas;Betzi, Stephane;Schonbrunn, Ernst
土酸是由真菌土曲霉产生的具有抗生素特性的代谢产物。我们发现土酸是一种共价抑制细菌细胞壁生物合成酶MurA的抑制剂。cloxacin和E.大肠杆菌中的表达。MurA死端复合物与terreic酸的晶体结构显示，奎宁环共价连接到Cys 115的巯基，Cys 115是抗生素磷霉素的分子靶点。动力学表征表明，灭活需要底物UNAG（UDP-N-乙酰葡糖胺）的存在，灭活速率常数为kinact = 130 M− 1 s −1。虽然失活的机制是相似的，磷霉素是大约50倍，比terreic酸的效力，和这两种抑制剂的共价修饰的结构后果是根本不同的。MurA-磷霉素复合物以封闭的酶构象存在，其中Cys 115-磷霉素加合物埋在活性位点中。相反，与terreic酸的死端复合物是开放的，不含UNAG，并且具有暴露于溶剂的Cys 115-terreic酸加合物。看来，土酸反应与Cys 115在封闭的，二元状态的酶，但所产生的Cys 115土酸加合物施加空间位阻的活性位点。因此，含有Cys 115的环重排，酶打开并释放UNAG。土酸和磷霉素对MurA灭活的不同动力学和结构特征反映了非共价结合潜力的重要性，即使对于共价抑制剂，也是如此，以确保灭活效率和特异性。
Terreic acid is a metabolite with antibiotic properties produced by the fungus Aspergillus terreus. We found that terreic acid is a covalent inhibitor of the bacterial cell wall biosynthetic enzyme MurA from E. cloacae and E. coli in-vitro. The crystal structure of the MurA dead-end complex with terreic acid revealed that the quinine ring is covalently attached to the thiol group of Cys115, the molecular target of the antibiotic fosfomycin. Kinetic characterization established that the inactivation requires the presence of substrate UNAG (UDP-N-acetylglucosamine), proceeding with an inactivation rate constant of kinact = 130 M−1s−1. Although the mechanisms of inactivation are similar, fosfomycin is approximately 50 times more potent than terreic acid, and the structural consequences of covalent modification by these two inhibitors are fundamentally different. The MurA-fosfomycin complex exists in the closed enzyme conformation, with the Cys115-fosfomycin adduct buried in the active site. In contrast, the dead-end complex with terreic acid is open, free of UNAG, and has the Cys115-terreic acid adduct solvent–exposed. It appears that terreic acid reacts with Cys115 in the closed, binary state of the enzyme, but that the resulting Cys115-terreic acid adduct imposes steric clashes in the active site. As a consequence, the loop containing Cys115 rearranges, the enzyme opens and UNAG is released. The differential kinetic and structural characteristics of MurA inactivation by terreic acid and fosfomycin reflect the importance of non-covalent binding potential, even for covalent inhibitors, to ensure inactivation efficiency and specificity.
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影响因子：
15
作者：
SHEEHAN, JC;LAWSON, WB;GAUL, RJ
通讯作者：
GAUL, RJ
影响因子：
5.7
作者：
Schonbrunn, E;Sack, S;Mandelkow, E
通讯作者：
Mandelkow, E
DOI：
10.1111/j.1432-1033.1993.tb18442.x
发表时间：
1993-12-15
期刊：
EUROPEAN JOURNAL OF BIOCHEMISTRY
影响因子：
--
作者：
WANKE, C;AMRHEIN, N
通讯作者：
AMRHEIN, N
影响因子：
4.8
作者：
Eschenburg, S;Priestman, MA;Schönbrunn, E
通讯作者：
Schönbrunn, E
影响因子：
2.7
作者：
Bachelier, Anke;Mayer, Ralf;Klein, Christian D.
通讯作者：
Klein, Christian D.