NMR experiments reveal the molecular basis of receptor recognition by a calicivirus.

The analysis of virus-receptor interactions at atomic resolution is of fundamental importance to understand infection processes, and to establish novel anti-viral therapies. As an example, rabbit hemorrhagic disease virus (RHDV), a member of the Caliciviridae family and considered as an "emerging" virus, attaches to histo-blood group antigens (HBGA) on the surface of adult rabbit epithelial cells of the upper respiratory and digestive tracts. It appears that this attachment is a key step in the process of infection with RHDV. Here, we report NMR experiments that reveal the atomic details of the recognition of HBGAs and fragments thereof by RHDV virus-like particles (VLP). The experiments yield binding epitopes of several HBGAs and show that L-fucose is a minimal structural requirement for specific molecular recognition by the VLPs. As the methodology is general, these studies may pave the way for the development of novel anti-viral entry inhibitors.