Hepatitis B core antigen forms oligomers and complexes with the p gene product in hepatitis B virus core particles

The nucleocapsid core of hepatitis B virus (HBV) is composed of the hepatitis B core antigen (HBcAg), a viral genome, a polymerase and a protein covalently linked to the 5'-end of the minus DNA strand. The interactions among the constituents are still very limited. By using the in vitro phosphorylation method, it was found that the p gene product formed complexes with HBcAg in the core particles through non-covalent linkage. After complete digestion of the HBV genome, the complexes between the HBcAg and p gene product remained intact. These results indicate that the HBcAg and p gene product are not complexed through the HBV genome. Also, it was found that the 21 kD HBcAg formed oligomers through disulfide linkages in the extracellular viral particles.