Mechanism of Respiratory Syncytial Virus Fusion

描述(申请人提供)：呼吸道合胞病毒(RSV)感染仍然是婴儿和老年人的一个重要医疗问题。感染需要病毒膜与靶细胞膜的融合，靶细胞膜将病毒基因组送入靶细胞细胞质。病毒融合(F)蛋白是RSV的三种糖蛋白之一，它发挥着这一作用。它 从两个相关病毒的晶体结构来看，一个在触发前，一个在触发后，F蛋白在结构上经历了巨大的变化，完成了膜融合。基于这些结构，已经建立了RSV F蛋白的前触发和后触发模型。使用预触发模型，已经识别了最有可能附着到目标细胞和/或用于触发的位置。这些位点上的氨基酸突变为丙氨酸将检验它们在细胞-细胞融合中的重要性。对于在不阻止F蛋白到达细胞表面的情况下阻止融合的突变，将对其附着和触发能力进行生化研究。在这些研究中，首次产生了F蛋白的可溶性(SF)形式的预触发形式，并被证明是由摩尔分数的降低触发的。降低分子量导致F蛋白触发的可能性也将被调查，因为它的机制可能提供新的抗病毒药物靶点。总体而言，这些研究将导致识别F蛋白中可用于快速筛选新的抗病毒化合物和开发新的疫苗的功能结构域。

DESCRIPTION (provided by applicant): Respiratory syncytial virus (RSV) infection remains an important medical problem for infants and the elderly. Infection requires the fusion of the vira membrane with the target cell membrane, which delivers the viral genome into the target cell cytoplasm. The viral fusion (F) protein, one of the three RSV glycoproteins, performs this role. It is clear from the crystal structures of two related viruses, one in the pre-triggered and one in th post-triggered form, that the F protein undergoes massive changes in structure to accomplish membrane fusion. Based on these structures, models of the pre-triggered and post-triggered RSV F protein have been generated. Using the pre-triggered model, the most likely sites for attachment to target cells and/or for triggering have been identified. Mutation of the amino acids in these sites to alanine will test their importance in cell-cell fusion. Mutations that prevent fuion without preventing the F protein from reaching the cell surface will be studied biochemically for their attachment and triggering abilities. For these studies, a soluble (sF) version of the F proten in its pre-triggered form has been produced for the first time, and shown to be triggered by a reduction in molarity. The possibility that reduced molarity causes F protein triggering will also be investigated since its mechanism may provide novel antiviral drug targets. Overall, these studies will result in the identification of functional domains in the F protein that can be used t rapidly screen for novel antiviral compounds and to develop novel vaccines.