title: Large surface proteins of hepatitis B virus containing the pre-s sequence.
abstract: The sequence of hepatitis B virus DNA contains an open reading frame which codes for a not-yet-identified protein of at least 389 amino acids. Only the products starting at the third (GP33/GP36) or the fourth (P24/GP27) initiation signal have been characterized as components of the viral surface antigen. We found a larger protein, P39, and its glycosylated form, GP42, in hepatitis B virus particles and viral surface antigen filaments. Immunological cross-reactions showed that P39/GP42 is partially homologous to P24/GP27 and GP33/GP36. The unique portion of its sequence bound monoclonal antibodies which had been induced by immunization with hepatitis B virus particles. Proteolytic cleavage patterns and subtype-specific size differences suggested that the sequence of P39 starts with the first initiation signal of the open reading frame. Its amino-terminal part (pre-s coded) is exposed at the viral surface and, probably, is highly immunogenic. A model is presented of how the open reading frame for the viral envelope leads to defined amounts of three different proteins.
mesh_terms: D000911:Antibodies, Monoclonal; D001483:Base Sequence; D004279:DNA, Viral / Q000235:genetics; D005796:Genes; D005814:Genes, Viral; D006514:Hepatitis B Surface Antigens / Q000235:genetics* / Q000302:isolation & purification; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D008970:Molecular Weight; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D000911:Antibodies, Monoclonal; D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D012333:RNA, Messenger