Crystal structure of the African swine fever virus core shell protein p15

African swine fever virus (ASFV) is the causative agent of African swine fever, a highly fatal hemorrhagic disease of pigs, which has resulted in great economic losses to the global pork industry, especially in Asia. ASFV particles are comprised of multiple layers encompassing the genomic DNA. Though the capsid structure has been determined, very little is known about the structure of the core shell. The precursor polyprotein pp62 is the structural component of the core shell that gives rise to the p35 and p15 proteins. Herein, we describe the crystal structure of p15 at a resolution of 2.2 Å. The structure of p15 exhibits as a trimeric conformation that is mainly mediated by intermolecular disulfide bonds and supported by multiple hydrogen bond interactions. The button conformation on the surface of adjacent molecules may also play a role in trimeric formation of the ASFV p15. The center of the p15 trimer exhibits opposite electrostatic characteristics on each side. These findings benefit our understanding of ASFV core shell assembly and will aid in the design of antiviral drugs and vaccines. •Scientific questionNone of the structures of these core shell proteins have been reported, and the lack of information concerning the core shell architecture has restricted our understanding of ASFV virus assembly and vaccine design.•Evidence before this studyThe core shell is comprised of the products of two precursor polyproteins: pp220 and pp62.pp220 gives rise to p150, p37, p34, p14, and p5, while pp62 gives rise to p35, p15, and p8, after proteolytic processing by the ASFV-encoded pS273R protease of the SUMO-1-specific protease family.•New findingsIn this study, the crystal structure of p15 was determined at a resolution of 2.2 Å. The solved p15 structure presented as a trimer. The p15 trimer is formed via an intermolecular disulfide bond between C8 and C29 of two adjacent molecules. The center of the p15 trimer exhibits opposite electrostatic characteristics on each side.•Significance of the studyOur study provides the detail conformation of a core shell protein, p15, which is composed of an α-helix head and β-sheet tail. These findings benefit our understanding of the mechanisms of ASFV core shell assembly and will aid in the future design of anti-viral drugs or vaccines.