The pattern of tegument-capsid interaction in the herpes simplex virus type 1 virion is not influenced by the small hexon-associated protein VP26

Examination of the three-dimensional structure of intact herpes simplex vir us type 1 (HSV-1) virions had revealed that the icosahedrally symmetrical i nteraction between the tegument and capsid involves the pentons but not the hexons (Z. H. Zhou, D. H. Chen, J. Jakana, F. J. Rixon, and W. Chin, J. Vi rol. 73:3210-3218, 1999). To account for this, we postulated that the prese nce of the small capsid protein, VP26, on top of the hexons was masking pot ential binding sites and preventing tegument attachment. We have now tested this hypothesis by determining the structure of virions lacking VP26. Apar t from the obvious absence of VP26 from the capsids, the structures of the VP26 minus and wild-type virions were essentially identical. Notably, they showed the same tegument attachment patterns, thereby demonstrating that VP 26 is not responsible for the divergent tegument binding properties of pent ons and hexons.