Partial characterization of the proteins of human papilloma viruses (HPV) 1-3

The protein compositions of full and empty particles of human papilloma viruses 1, 2, and 3 were compared by SDS-gel electrophoresis. The protein patterns revealed a considerable variation in the relative concentrations of three major proteins (VP2, 3, and 4) in individual preparations. In some cases, "heavy" and "light" full particles prepared from the same wart showed a similar variability in the concentrations of VP2, 3, and 4. The different protein patterns were interpreted as resulting from conversion of VP2 into VP3 and 4. The molecular relationship of these three proteins was confirmed by BrCN cleavage which led to corresponding oligopeptides. Electron micrographs of empty particles revealed that the only detectable protein components VP3 and 4 are present in typical capsomeres.