Norovirus major capsid protein VP1 (genotype GI.1) (VP1)

The Norovirus VP1 capsid protein (genotype GI.1) is the primary structural component of the Norwalk virus, the prototype strain of the Norovirus genus. It is a approximately 60 kDa protein that self-assembles into an icosahedral capsid composed of 180 subunits (90 dimers) with T=3 symmetry. The protein is structurally divided into a conserved shell (S) domain and a variable protruding (P) domain, with the P2 subdomain being the most surface-exposed region containing the binding site for host histo-blood group antigens (HBGAs), which serve as essential attachment factors for infection. As the major antigen, VP1 is the primary target for vaccine development, including virus-like particles (VLPs) and viral-vectored vaccines designed to elicit blockade antibodies that prevent viral attachment to host cells. Therapeutic strategies also explore small-molecule inhibitors that competitively bind the HBGA pocket to block infection. Challenges in targeting VP1 include significant genetic diversity across genogroups and the rapid evolution of new variants, which can lead to immune escape and limited cross-genotype protection.

Other names

Major capsid proteinORF2 proteinNorwalk virus capsid proteinVP1 proteinCapsid protein VP1

Vaccines targeting VP1 elicit neutralizing antibodies (blockade antibodies) that prevent the virus from binding to host histo-blood group antigens (HBGAs) on intestinal epithelial cells. Small-molecule inhibitors act by competitively binding to the HBGA-binding pocket in the P2 subdomain of VP1, thereby blocking viral attachment and subsequent entry into the host cell.