Ehmann David E, Demeritt Julie E, Hull Kenneth G, Fisher Stewart L
Department of Biochemistry, Infection Discovery, Cancer and Infection Research Area, AstraZeneca R&D Boston, 35 Gatehouse Drive, Waltham, MA 02451, USA.
Biochim Biophys Acta. 2004 May 6;1698(2):167-74. doi: 10.1016/j.bbapap.2003.11.006.
UDP-N-acetylmuramyl-l-alanine ligase (MurC) is an essential bacterial enzyme involved in peptidoglycan biosynthesis and a target for the discovery of novel antibacterial agents. As a result of a high-throughput screen (HTS) against a chemical library for inhibitors of MurC, a series of benzofuran acyl-sulfonamides was identified as potential leads. One of these compounds, Compound A, inhibited Escherichia coli MurC with an IC(50) of 2.3 microM. Compound A exhibited time-dependent, partially reversible inhibition of E. coli MurC. Kinetic studies revealed a mode of inhibition consistent with the compound acting competitively with the MurC substrates ATP and UDP-N-acetyl-muramic acid (UNAM) with a K(i) of 4.5 microM against ATP and 6.3 microM against UNAM. Fluorescence binding experiments yielded a K(d) of 3.1 microM for the compound binding to MurC. Compound A also exhibited high-affinity binding to bovine serum albumin (BSA) as evidenced by a severe reduction in MurC inhibition upon addition of BSA. This finding is consistent with the high lipophilicity of the compound. Advancement of this compound series for further drug development will require reduction of albumin binding.
UDP-N-乙酰胞壁酰-L-丙氨酸连接酶（MurC）是一种参与肽聚糖生物合成的必需细菌酶，也是新型抗菌剂发现的靶点。通过针对MurC抑制剂的化学文库进行高通量筛选（HTS），鉴定出一系列苯并呋喃酰基磺酰胺作为潜在先导化合物。其中一种化合物A对大肠杆菌MurC的抑制IC(50)为2.3 microM。化合物A对大肠杆菌MurC表现出时间依赖性、部分可逆的抑制作用。动力学研究揭示的抑制模式与该化合物与MurC底物ATP和UDP-N-乙酰胞壁酸（UNAM）竞争性作用一致，对ATP的K(i)为4.5 microM，对UNAM的K(i)为6.3 microM。荧光结合实验得出该化合物与MurC结合的K(d)为3.1 microM。化合物A对牛血清白蛋白（BSA）也表现出高亲和力结合，添加BSA后MurC抑制作用严重降低即证明了这一点。这一发现与该化合物的高亲脂性一致。推进该化合物系列用于进一步的药物开发需要降低白蛋白结合。
