Capsid protein self-assembles to form an icosahedral capsid with a T=3 symmetry, about 26 nm in diameter, and consisting of 89 capsid proteins dimers (178 capsid proteins). Involved in viral genome encapsidation through the interaction between a capsid protein dimer and the multiple packaging signals present in the RNA genome. Binding of the capsid proteins to the viral RNA induces a conformational change required for efficient T=3 shell formation. The capsid contains also 1 copy of the A2 maturation protein. Acts as a translational repressor of viral replicase synthesis late in infection. This latter function is the result of capsid protein interaction with an RNA hairpin which contains the replicase ribosome-binding site. Homodimer. The capsid protein dimer binds to the viral RNA via an operator hairpin, but also many other RNA sequences in the viral genome. The shell is composed of 89 dimers of the capsid protein and 1 copy of the maturation protein.