Poliovirus type 3 capsid (None in widespread canonical use; sometimes abbreviated as PV3 capsid in scientific literature.)

The poliovirus type 3 capsid is a protein shell that encases the RNA genome of poliovirus type 3. It is composed of 60 copies each of four viral proteins (VP1, VP2, VP3, and VP4) organized with icosahedral symmetry[1][7]. The capsid mediates critical processes in the viral life cycle including host cell receptor binding, structural transitions for genome release, and immune recognition. Antigenic sites on the capsid surface account for differences in immune response and are key to vaccine effectiveness[3]. Structural studies have detailed the complex topography of the external surface, which features a "mesa" at fivefold axes, canyons (the receptor-binding site), and propeller-like protrusions[1][4]. The capsid is a validated antiviral target: several drugs bind a hydrophobic pocket within VP1, stabilizing the capsid and preventing the conformational changes necessary for viral uncoating and infection[8]. The capsid is the basis for vaccination strategies, with amino acid variations influencing both antigenicity and thermostability of different strains[3][4].

Other names

Poliovirus type 3 viral capsidPV3 capsidPoliovirus type 3 capsid protein complexSabin 3 capsid (for vaccine strain)type 3 poliovirus capsid

Capsid-binding drugs insert into the hydrophobic pocket of the capsid (typically VP1 pocket), inhibit conformational transitions required for viral uncoating, prevent genome release and thus block viral replication[8][1].