Forms the portal vertex of the capsid. This portal plays critical roles in head assembly, genome packaging, neck/tail attachment, and genome ejection. The portal protein multimerizes as a single ring-shaped homododecamer arranged around a central channel. Homododecamer. Interacts with major capsid protein. Interacts with the tail tube proteins gp11 and gp12. Interacts with the terminase large subunit. Interacts with the internal virion protein gp14. Belongs to the podoviridae portal protein family.