Aichi virus 1 (AiV-1) is a human pathogen causing diarrhea, abdominal pain, nausea, vomiting, and fever. AiV-1 is identified in environmental screening studies with higher frequency and greater abundance than other human enteric viruses. Accordingly, 80 to 95% of adults worldwide have suffered from AiV-1 infections (1).
The structure of AiV-1 virion has been determined at 2.1 Å resolution (2). The surface of the virion has a unique topology distinct from other viruses from the Picornaviridae family (2) (3). Consequently, antiviral compounds that were developed against related enteroviruses are unlikely to be effective against AiV-1. Besides, AiV-1 empty particle doesn’t contain pores that might serve as channels for genome release; this mechanism being probably due to a local and reversible reorganization of the capsid.
Beyond biological considerations, the study of icosahedral particles by X-ray crystallography or cryo-electron microscopy approaches will be discussed. Whereas noncrystallographic symmetry averaging of electron density allowed to solve AiV-1 structure from data affected by perfect hemihedral twinning (4), icosahedral symmetry averaging coming along with data-processing reduces the investigation of viral genome packaging mechanism.
1. Kitajima M, Gerba CP. Aichi virus 1: environmental occurrence and behavior. Pathog Basel Switz. 19 mai 2015;4(2):25668.
2. Sabin C, Füzik T, Škubník K, Pálková L, Lindberg AM, Plevka P. Structure of Aichi virus 1 and its empty particle: clues towards kobuvirus genome release mechanism. J Virol. 28 sept 2016;JVI.01601-16.
3. Zhu L, Wang X, Ren J, Kotecha A, Walter TS, Yuan S, et al. Structure of human Aichi virus and implications for receptor binding. Nat Microbiol. 5 sept 2016;1:16150.
4. Sabin C, Plevka P. The use of noncrystallographic symmetry averaging to solve structures from data affected by perfect hemihedral twinning. Acta Crystallogr Sect F Struct Biol Commun. 16 févr 2016;72(Pt 3):18897.