School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China.
PLoS One. 2012;7(8):e41956. doi: 10.1371/journal.pone.0041956. Epub 2012 Aug 2.
The influenza glycoprotein hemagglutinin (HA) plays crucial roles in the early stage of virus infection, including receptor binding and membrane fusion. Therefore, HA is a potential target for developing anti-influenza drugs. Recently, we characterized a novel inhibitor of highly pathogenic H5N1 influenza virus, CL-385319, which specifically inhibits HA-mediated viral entry. Studies presented here identified the critical binding residues for CL-385319, which clustered in the stem region of the HA trimer by site-directed mutagenesis. Extensive computational simulations, including molecular docking, molecular dynamics simulations, molecular mechanics generalized Born surface area (MM_GBSA) calculations, charge density and Laplacian calculations, have been carried out to uncover the detailed molecular mechanism that underlies the binding of CL-385319 to H5N1 influenza virus HA. It was found that the recognition and binding of CL-385319 to HA proceeds by a process of "induced fit" whereby the binding pocket is formed during their interaction. Occupation of this pocket by CL-385319 stabilizes the neutral pH structure of hemagglutinin, thus inhibiting the conformational rearrangements required for membrane fusion. This "induced fit" pocket may be a target for structure-based design of more potent influenza fusion inhibitors.
流感糖蛋白血凝素（HA）在病毒感染的早期阶段发挥着至关重要的作用，包括受体结合和膜融合。因此，HA 是开发抗流感药物的潜在靶点。最近，我们鉴定了一种新型的高致病性 H5N1 流感病毒抑制剂 CL-385319，它特异性抑制 HA 介导的病毒进入。本研究确定了 CL-385319 的关键结合残基，这些残基通过定点突变聚集在 HA 三聚体的茎部区域。我们进行了广泛的计算模拟，包括分子对接、分子动力学模拟、分子力学广义 Born 表面积（MM_GBSA）计算、电荷密度和拉普拉斯计算，以揭示 CL-385319 与 H5N1 流感病毒 HA 结合的详细分子机制。研究发现，CL-385319 识别和结合 HA 是通过“诱导契合”过程进行的，在相互作用过程中形成了结合口袋。CL-385319 占据这个口袋稳定了血凝素在中性 pH 下的结构，从而抑制了膜融合所需的构象重排。这个“诱导契合”口袋可能是基于结构设计更有效的流感融合抑制剂的靶点。
