The crystal structure of the human hepatitis B virus capsid

Hepatitis B is a small enveloped DNA virus that poses a major hazard to hum an health. The crystal structure of the T = 4 capsid has been solved at 3.3 Angstrom resolution, revealing a largely helical protein fold that is unus ual for icosahedral viruses. The monomer fold is stabilized by a hydrophobi c core that is highly conserved among human viral variants. Association of two amphipathic alpha-helical hairpins results in formation of a dimer with a four-helix bundle as the major central feature. The capsid is assembled from dimers via interactions involving a highly conserved region near the C terminus of the truncated protein used for crystallization. The major immu nodominant region lies at the tips of the alpha-helical hairpins that form spikes on the capsid surface.