title: Structure determination of feline calicivirus virus-like particles in the context of a pseudo-octahedral arrangement.
abstract: The vesivirus feline calicivirus (FCV) is a positive strand RNA virus encapsidated by an icosahedral T=3 shell formed by the viral VP1 protein. Upon its expression in the insect cell - baculovirus system in the context of vaccine development, two types of virus-like particles (VLPs) were formed, a majority built of 60 subunits (T=1) and a minority probably built of 180 subunits (T=3). The structure of the small particles was determined by x-ray crystallography at 0.8 nm resolution helped by cryo-electron microscopy in order to understand their formation. Cubic crystals belonged to space group P213. Their self-rotation function showed the presence of an octahedral pseudo-symmetry similar to the one described previously by Agerbandje and co-workers for human parvovirus VLPs. The crystal structure could be solved starting from the published VP1 structure in the context of the T=3 viral capsid. In contrast to viral capsids, where the capsomers are interlocked by the exchange of the N-terminal arm (NTA) domain, this domain is disordered in the T=1 capsid of the VLPs. Furthermore it is prone to proteolytic cleavage. The relative orientation of P (protrusion) and S (shell) domains is alerted so as to fit VP1 to the smaller T=1 particle whereas the intermolecular contacts around 2-fold, 3-fold and 5-fold axes are conserved. By consequence the surface of the VLP is very similar compared to the viral capsid and suggests a similar antigenicity. The knowledge of the structure of the VLPs will help to improve their stability, in respect to a use for vaccination.
authors: Unit of Virus Host Cell Interactions, Université Grenoble Alpes, Grenoble, France; Unit of Virus Host Cell Interactions, Unité Mixte Internationale 3265, Centre National de Recherche Scientifique, Grenoble, France.
authors: Wim P
authors: WP
authors: Burmeister
authors: Unit of Virus Host Cell Interactions, Université Grenoble Alpes, Grenoble, France; Unit of Virus Host Cell Interactions, Unité Mixte Internationale 3265, Centre National de Recherche Scientifique, Grenoble, France; Laboratoire de Virologie, Centre Hospitalo-Universitaire de Grenoble, Grenoble, France.
authors: Marlyse
authors: M
authors: Buisson
authors: Institut de Biologie Structurale Jean-Pierre Ebel, Commissariat d'Energie Atomique, Grenoble, France; Institut de Biologie Structurale Jean-Pierre Ebel, Centre National de Recherche Scientifique, Grenoble, France; Institut de Biologie Structurale Jean-Pierre Ebel, Université Grenoble Alpes, Grenoble, France.
authors: Leandro F
authors: LF
authors: Estrozi
authors: Institut de Biologie Structurale Jean-Pierre Ebel, Commissariat d'Energie Atomique, Grenoble, France; Institut de Biologie Structurale Jean-Pierre Ebel, Centre National de Recherche Scientifique, Grenoble, France; Institut de Biologie Structurale Jean-Pierre Ebel, Université Grenoble Alpes, Grenoble, France.
authors: Guy
authors: G
authors: Schoehn
authors: Lyon Gerland Laboratory, Merial R&D, Lyon, France.
authors: Olivier
authors: O
authors: Billet
authors: Lyon Gerland Laboratory, Merial R&D, Lyon, France.
authors: Zahia
authors: Z
authors: Hannas
authors: Lyon Gerland Laboratory, Merial R&D, Lyon, France.
authors: Cécile
authors: C
authors: Sigoillot
authors: Lyon Gerland Laboratory, Merial R&D, Lyon, France.
authors: Hervé
authors: H
authors: Poulet
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017927:Calicivirus, Feline / Q000235:genetics / Q000648:ultrastructure*; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics; D002415:Cats; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D016415:Sequence Alignment; D014771:Virion / Q000648:ultrastructure*
chemical_list: D036022:Capsid Proteins