胰酶酶切将轮状病毒VP4蛋白酶切成VP8和VP5可活化轮状病毒。在轮状病毒的感染过程中，VP8与唾液酸受体结合后，与VP5抗原区分离，暴露出原被VP8头部区域掩盖的膜融合区，进而介导轮状病毒入胞。在这一过程中，VP8与VP5抗原区相互作用机制以及解离机制目前尚不清楚。申请人在前期研究中，通过对轮状病毒冰冻电镜结构分析发现VP8和VP5抗原区存在相互作用；同时，酶切获得的VP8蛋白和截短表达的VP8蛋白与VP5蛋白之间均存在相互作用，并在此基础上建立了分析二者相互作用的方法。在前期工作的基础上，本课题拟通过结构分析发现VP8和VP5抗原区相互作用可能关键氨基酸，并通过缺失突变和定点突变进行验证；同时，分析受体结合和理化因素对VP8和VP5抗原区相互作用的影响。通过以上研究以期阐明轮状病毒感染过程中VP8和VP5抗原区相互作用及解离的可能机制。

Trypsin primes rotavirus for efficient infectivity by cleaving the spike protein VP4 into VP8* and VP5*. After binding to the sialic acid receptor, the VP8* heads must dissociate from the tip of VP5 to expose the hydrophobic membrane fusion region, which will mediate the penetration of rotavirus. However, the binding and dissociation mechanism between VP8 and VP5 was still not known. In our previous studies, by analyzing the cryo-EM structure of rotavirus, the applicant found that there was interaction between VP8 and VP5. In addition, both trypsin digested VP8 and N-terminal truncated VP8 can bind to VP5 antigen as analyzed by a direct binding assay. In this project, the key amino acids participated in VP8 and VP5 interaction analyzed by structural analysis will be verified by N-terminal deletion and site-directed mutation. In addition, the impact of receptor binding and physicochemical factors on VP8 and VP5 interaction will also be studied. Thus, elucidating the mechanism among VP5-VP8 interaction and the possible dissociation mechanism of VP8 and VP5 during rotavirus infection.