Self assembles to form an icosahedral capsid, about 50 nm in diameter, nm, composed of 420 subunits of the viral capsid protein. The capsid encapsulates the genomic dsDNA. Following virus entry into host cell, provides nuclear import of the viral genome. Virus particles do not enter the nucleus, but dock at the nuclear membrane through the interaction with host importins (By similarity). Interacts (via nuclear localization signal) with host importin alpha. Belongs to the caulimoviridae capsid protein family.