Self-assembles to form the virion icosahedral capsid with a T=1 symmetry. This very small capsid (17-22 nm in diameter) allows the virus to be very stable in the environment and resistant to some disinfectants, including detergents. Essential for the initial attachment to heparan sulfate moities and chondroitin sulfate B of the host cell surface proteoglycans. After attachment, the virus is endocytosed and traffics to the nucleus. The capsid protein binds and transports the viral genome and Rep across the nuclear envelope (By similarity).