Herpes simplex virus 1 DNA packaging proteins encoded by UL6, UL15, UL17, UL28, and UL33 are located on the external surface of the viral capsid

Studies to localize the herpes simplex virus 1 portal protein encoded by U(L)6, the putative terminase components encoded by U(L)15, U(L)28, and U(L)33, the minor capsid proteins encoded by U(L)17, and the major scaffold protein ICP35 were conducted. ICP35 in B capsids was more resistant to trypsin digestion of intact capsids than pU(L)6, pU(L)15, pU(L)179 pU(L)28, or pU(L)33. ICP35 required sectioning of otherwise intact embedded capsids for immunoreactivity, whereas embedding and/or sectioning decreased the immunoreactivities of pU(L)6, pU(L)17, pU(L)28, and pU(L)33. Epitopes of pU(L)15 were recognized roughly equally well in both sectioned and unsectioned capsids. These data indicate that pU(L)69 pU(L)17, pU(L)28, pUL33, and at least some portion of pU(L)15 are located at the external surface of the capsid.