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) (PubMed:27671640, PubMed:19913556). Involved in viral genome encapsidation through the interaction between a capsid protein dimer and the multiple packaging signals present in the RNA genome (PubMed:8943226, PubMed:27671640). Binding of the capsid proteins to the viral RNA induces a conformational change required for efficient T=3 shell formation (PubMed:19913556). The capsid contains also 1 copy of the A2 maturation protein (PubMed:27671640). 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 (PubMed:16531233). The homodimers binds to the viral RNA via an operator hairpin, but also to many other RNA sequences in the viral genome; this interaction probably shifts the virus from the replicative to the assembly phase and ensures specific encapsidation of the viral genome (PubMed:8943226, PubMed:16531233). Interacts with the maturation protein A2 (PubMed:28111107, PubMed:29078304). The shell is composed of 89 dimers of the capsid protein, one of them being sequestered inside the virion, and 1 copy of the maturation protein. Icosahedral capsid structure