1.W.4. The Viral Portal Protein 4 (PPP4) Family
Members of this family from eukaryotic viruses form portals in the viral capsid through which viral DNA is translocated during DNA packaging. The protein assembles as a dodecamer at a single fivefold axis of the T=16 icosahedric capsid. It binds to the molecular motor that translocates the viral DNA, termed terminase (Newcomb et al. 2001).