Precursor of all the viral capsid proteins. Capsid protein 1, together with capsid proteins 2 and 3, form an icosahedral capsid protecting the viral RNA genome. The icosahedral capsid has a pseudo-T=3 symmetry with a diameter of approximately 300 Angstroms, and is composed of 60 copies of each CP1, CP2, and CP3. CP1 is situated at the 12 fivefold axes, whereas CP2 and CP3 are located at the quasi-sixfold axes. All these proteins contain a beta-sheet structure called beta-barrel jelly roll. Capsid protein 4 is a tstructural component of the icosahedral capsid protecting the genomic RNA. It may play an important role in capsid assembly. Capsid protein 2, together with capsid proteins 1 and 3, form an icosahedral capsid protecting the viral RNA genome. The icosahedral capsid has a pseudo-T=3 symmetry with a diameter of approximately 300 Angstroms, and is composed of 60 copies of each CP1, CP2, and CP3. CP1 is situated at the 12 fivefold axes, whereas CP2 and CP3 are located at the quasi-sixfold axes. All these proteins contain a beta-sheet structure called beta-barrel jelly roll. Capsid protein 3, together with capsid proteins 1 and 2, form an icosahedral capsid protecting the viral RNA genome. The icosahedral capsid has a pseudo-T=3 symmetry with a diameter of approximately 300 Angstroms, and is composed of 60 copies of each CP1, CP2, and CP3. CP1 is situated at the 12 fivefold axes, whereas CP2 and CP3 are located at the quasi-sixfold axes. All these proteins contain a beta-sheet structure called beta-barrel jelly roll. Specific enzymatic cleavages in vivo yield mature proteins. Belongs to the picornaviruses polyprotein family. Translation initiates on an Ala codon through an unusual Internal Ribosome Entry Site (IRES). Icosahedral capsid structure