Molecular homology among the structural proteins of densonucleosis virus from silkworm, Bombyx mori.

Similarities among the four structural proteins of Bombyx densonucleosis virus (DNV) were examined by four independent techniques, peptide mapping, immunodiffusion tests, amino acid analysis and enzyme linked immunosorbent (ELISA) technique. The peptide maps produced by Staphylococcus aureus V8 protease, or chymotrypsin indicated the existence of sequence homology among the proteins. The results of immunodiffusion tests revealed that these four structural proteins share common antigens. The amino acid compositions of these proteins were also very similar to each other. However, the amount of amino acid residues (e.g., serine) in VP3 was not always sufficient to account for the amount found in the smaller structural protein, VP2. These results indicate that the four structural proteins of Bombyx DNV probably originate, at least partially, from a common DNA sequence, and that VP2 is not a direct cleavage product of VP3.