Cryo-EM Structure of the African Swine Fever Virus

Abstract

African swine fever virus (ASFV) is a large double-stranded DNA virus with an icosahedral multilayered structure. ASFV causes a lethal swine hemorrhagic disease and is currently responsible for widespread damage to the pork industry in Asia. Neither vaccines nor antivirals are available and the molecular characterization of the ASFV particle is outstanding. Here, we describe the cryogenic electron microscopy (cryo-EM) structure of the icosahedral capsid of ASFV at 4.6-Å. The ASFV particle consists of 8,280 copies of the major capsid protein p72, 60 copies of the penton protein, and at least 8,340minor capsid proteins, of which there might be 3 different types. Like other nucleocytoplasmic large DNA viruses, the minor capsid proteins form a hexagonal network below the outer capsid shell, functioning as stabilizers by "gluing" neighboring capsomers together. Our findings provide a comprehensive molecular model of the ASFV capsid architecture that will contribute to the future development of countermeasures, including vaccines.