Capsid protein that self-assembles to form the pseudo-hexameric capsomers of the icosahedral capsid (By similarity). The capsid is constructed of 2760 pseudo-hexameric capsomers and 12 pentameric capsomers, with a T=277 symmetry, about 200 nm in diameter (By similarity). The capsid encapsulates the DNA-containing nucleoid, the core shell and the inner membrane (By similarity). Plays an essential role in virion assembly (By similarity). Involved in virus attachment to the host cell (By similarity). Homotrimer (By similarity). The membrane-bound form, but not the cytosolic one, assembles into large complexes (By similarity). Interacts with the minor capsid proteins M1249L and p17; these interactions form a rigid zipper structure that stabilizes the capsomers (By similarity). Present in the outer part of the capsid shell (By similarity). Localizes to the viral factory at 16 hpi (By similarity). Expressed in the late phase of the viral replicative cycle. Belongs to the NCLDV major capsid protein family.