Norovirus GII.4 capsid protein (VP1)

The Norovirus GII.4 capsid protein (VP1) is the principal structural protein forming the shell of GII.4 norovirus particles, responsible for the majority of epidemic and pandemic viral gastroenteritis cases worldwide. VP1 self-assembles into an icosahedral capsid (typically with T=3 symmetry), using 180 copies that organize into 90 dimers, creating a protective shell and displaying surface protrusions involved in host cell attachment. The VP1 protein features two major domains: the shell (S) domain forming the virion's inner scaffold, and the protruding (P) domain forming external features crucial for interaction with host histo-blood group antigens (HBGAs). These interactions mediate cell entry and determine host susceptibility, while the exposed P2 subdomain is a hotspot for antigenic variation, facilitating immune escape and driving the emergence of new pandemic variants. No small-molecule drugs currently target VP1, but it is the major antigen in vaccine development, as virus-like particles (VLPs) mimicking its structure elicit protective antibody responses in humans. The extensive antigenic diversity of GII.4 VP1 poses challenges to vaccine efficacy, necessitating continual surveillance and antigenic updating similar to influenza vaccines.

Other names

Major capsid protein VP1GII.4 capsid proteinNorovirus VP1Norovirus major structural protein

None for direct-acting drugs; for vaccines, the mechanism is induction of neutralizing antibodies targeting VP1, preventing virion binding and entry into host cells