Structural and functional homology of parvovirus and papovavirus polypeptides.

We have compared the sequences of the putative polypeptides of the human pathogenic B19 parvovirus with protein sequences in the National Bethesda Research Foundation Library, and have discovered a significant homology between a B19 parvovirus non-structural (NS) protein and the T antigens of polyomaviruses and simian virus 40 (SV40) and the putative E1 proteins of papillomaviruses. The region of highest homology with the papovavirus proteins corresponds to the region that is most highly conserved in the NS1 proteins of several other parvoviruses. Studies with the T antigen of both polyomaviruses and SV40 have implicated this region as having an ATPase activity and nucleotide-binding function.