Norwalk virus VP1 capsid protein (VP1)

The Norwalk virus VP1 capsid protein is the major structural protein of the Norwalk virus (a genogroup I human norovirus), forming the icosahedral T=3 symmetry capsid with 180 copies organized as 90 dimers, approximately 38-410 Å in diameter. It consists of an N-terminal arm (NTA), shell domain (S, residues ~41-213, eight-stranded β-barrel forming the inner shell), and protruding domain (P, residues ~222-540, divided into P1 and P2 subdomains, forming surface spikes). The S and P domains are linked by a flexible hinge (~residues 213-222), enabling conformational changes between 'resting' (P domain close to S) and 'raised/rising' (P elevated) states, influenced by divalent ions (e.g., Cd2+) at P domain dimer interfaces for stability. The P2 subdomain mediates strain-specific glycan binding for cell attachment. VP1 self-assembles into virus-like particles (VLPs); co-expression with minor protein VP2 enhances stability but VP2 is internal and low-copy. Flexibility aids replication, antigen presentation, and vaccine design challenges due to antigenic variation.

Other names

major capsid protein