HBsAg

Large envelope protein
Identifiers
OrganismHepatitis B virus genotype B2 (isolate Vietnam/9873/1997)
SymbolS
UniProtQ9QAB7
Search for
StructuresSwiss-model
DomainsInterPro
The genome organisation of HBV; the genes overlap. ORF S, in green, encodes HBsAg.
HBsAg under a transmission electron microscope: the protein self assembles into virus-like particles

HBsAg (also known as the Australia antigen) is the surface antigen of the hepatitis B virus (HBV). Its presence in blood indicates existing hepatitis B infection.