The emergence of escape-mutants of influenza hemagglutinin (HA) following vaccination compels the yearly re-formulation of flu vaccines. Since binding the sialic acid receptor remains in all cases essential for infection, small-molecule inhibitors of HA binding to sialic acid could be interesting therapeutic complements or alternatives to immuno-prophylaxis in the control of flu epidemics. In this work, we made use of NMR spectroscopy to study the interaction between a derivative of sialic acid (the Neu5Ac-α-(2,6)-Gal-β-(1-4)-GlcNAc trisaccharide) and HAs (H1 and H5) from human and avian strains of influenza virus, directly expressed on the surface of stable transfected 293 T human cells. The HAs were shown to retain their native trimeric conformation and binding properties. Exploiting the magnetization transfer between the proteins and the ligand, we obtained evidence of the binding event and mapped the (non-identical) sugar epitopes recognized by the two HA species. The rapid and reliable method for screening sialic acid-related HA ligands we have developed could yield useful information for an efficient drug design.

中文翻译：

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Neu5Ac-α-（2,6）-Gal-β-（1-4）-GlcNAc与在转染的人细胞中表达的流感病毒血凝素的NMR相互作用研究

接种疫苗后，流感血凝素（HA）逃逸突变体的出现迫使每年重新配制流感疫苗。由于在所有情况下，结合唾液酸受体仍然是感染必不可少的，因此，HA结合唾液酸的小分子抑制剂可能是控制流感流行的有趣的治疗补充方法或免疫预防方法的替代方法。在这项工作中，我们利用NMR光谱研究了唾液酸衍生物（Neu5Ac-α-（2,6）-Gal-β-（1-4）-GlcNAc三糖）与HAs（H1和H5）来自人和禽流感病毒株，直接在稳定转染的293 T人细胞表面表达。已显示HA保留其天然三聚体构象和结合​​特性。利用蛋白质和配体之间的磁化传递，我们获得了结合事件的证据，并绘制了两个HA物种识别的（不同）糖表位。我们开发的一种快速可靠的筛选唾液酸相关HA配体的方法可以为有效的药物设计提供有用的信息。