Department of Chemistry, Kookmin University, Seoul 136-702, Korea.
J Microbiol Biotechnol. 2013 Mar;23(3):329-34. doi: 10.4014/jmb.1210.10053.
Uridinediphospho-N-acetylglucosamine enolpyruvyl transferase (MurA, E.C. 2.5.1.7) is an essential bacterial enzyme that catalyzes the first step of the cell wall biosynthetic pathway, which involves the transfer of an enolpyruvyl group from phosphoenolpyruvate to uridinediphospho-Nacetylglucosamine. In this study, novel inhibitors of Haemophilus influenzae MurA (Hi MurA) were identified using high-throughput screening of a chemical library from the Korea Chemical Bank. The identified compounds contain a quinoline moiety and have much lower effective inhibitory concentrations (IC(50)) than fosfomycin, a wellknown inhibitor of MurA. These inhibitors appear to covalently modify the sulfhydryl group of the active site cysteine (C117), since the C117D mutant Hi MurA was not inhibited by these compounds and excess dithiothreitol abolished their inhibitory activities. The increased mass value of Hi MurA after treatment with the identified inhibitor further confirmed that the active-site cysteine residue of Hi MurA is covalently modified by the inhibitor.
尿苷二磷酸-N-乙酰葡萄糖胺烯醇丙酮酸基转移酶（MurA，EC 2.5.1.7）是一种必需的细菌酶，它催化细胞壁生物合成途径的第一步，其中涉及将烯醇丙酮酸基从磷酸烯醇丙酮酸转移到尿苷二磷酸-N-乙酰葡萄糖胺。在这项研究中，使用来自韩国化学银行的化学文库进行高通量筛选，鉴定出流感嗜血杆菌 MurA（Hi MurA）的新型抑制剂。鉴定出的化合物含有喹啉部分，其有效抑制浓度（IC50）比 MurA 的已知抑制剂磷霉素低得多。这些抑制剂似乎使活性位点半胱氨酸（C117）的巯基共价修饰，因为 C117D 突变体 Hi MurA 不受这些化合物的抑制，并且过量的二硫苏糖醇消除了它们的抑制活性。用鉴定出的抑制剂处理后 Hi MurA 的增加的质量值进一步证实 Hi MurA 的活性位点半胱氨酸残基被抑制剂共价修饰。
