Encapsidates the viral genome into characteristic twinned ('geminate') particles. Binds the genomic viral ssDNA and shuttles it into and out of the cell nucleus. Plays a role in protection of the genome from degradation, virus acquisition and transmission by insect vectors, infectivity, and systemic movement. The CP of monopartite geminiviruses is absolutely essential for virus movement (By similarity). Homomultimer. Interacts with the movement protein (By similarity). Binds to single-stranded and double-stranded viral DNA. It is actively transported into the host cell nucleus. It may be exported out of the nucleus through a nuclear export signal for cell-to-cell movement and spread (By similarity). Belongs to the geminiviridae capsid protein family.