A lipid modified ubiquitin is packaged into particles of several envelopedviruses

An anti-ubiquitin cross-reactive protein which migrates more slowly (6.5 kD a) by SDS-PAGE than ubiquitin was identified in African swine fever virus p articles. This protein was extracted into the detergent phase in Triton X-1 14 phase separations, showing that it is hydrophobic, and was radiolabelled with both [H-3]palmitic acid and [P-32]orthophosphate. This indicates that the protein has a similar structure to the membrane associated phosphatidy l ubiquitin described in baculovirus particles. A similar molecule was foun d in vaccinia virus and herpes simplex virus particles, suggesting that it may be a component of uninfected cell membranes, which is incorporated into membrane layers in virions during morphogenesis. (C) 1999 Federation of Eu ropean Biochemical Societies.