Heterogeneity, molecular weight and stability of an oncogenic papovavirus of the Syrian hamster.

Sedimentation, isopycnic density gradient and molecular weight studies of an oncogenic papovavirus of the Syrian hamster have been performed. The sedimentation coefficient of 223 S, the buoyant density of 1.340 g/ml, and the molecular weight of 27.5 X 10(6) are in close correspondence with those of SV 40 (simian virus 40) and polyoma viruses. Deviating from these members of the papovavirus group, a sedimentation heterogeneity resulting in the presence of dimers and higher virion oligomers up to pentamers besides heterogeneous material of viral origin was demonstrated by sedimentation velocity. Also, a microheterogeneity of the buoyant density of the virus was demonstrable which is discussed to reflect this virion association. The stability of hamster papovavirus was examined after exposure to alkaline pH and the virus destabilizing agents dithiothreitol and ethyleneglycol-bis-N,N'-tetraacetic acid. In neutral conditions a nucleoprotein complex of 170 S was demonstrated. Further disintegration of this complex with increasing pH resulted in its conversion to nucleoprotein complexes of 125 S and 90 S in analogy to SV 40 and polyoma viruses.