https://phaidra.vetmeduni.ac.at/o:5072 Aviadenovirus structure: A highly thermostable capsid in the absence of stabilizing proteins Pérez-Illana, Marta Marta Pérez-Illana Schachner, Anna Anna Schachner 0000-0002-1736-8421 University of Veterinary Medicine Vienna Hernando-Pérez, Mercedes Mercedes Hernando-Pérez Condezo, Gabriela N. Gabriela N. Condezo Paradela, Alberto Alberto Paradela Martínez, Marta Marta Martínez Marabini, Roberto Roberto Marabini Hess, Michael Michael Hess 0000-0002-6991-0120 University of Veterinary Medicine Vienna San Martín, Carmen Carmen San Martín 0000-0001-9799-175X Public Library of Science journal article open access eng High-resolution structural studies have mainly focused on two out of the six adenovirus genera: mastadenoviruses and atadenoviruses. Here we report the high-resolution structure of an aviadenovirus, the poultry pathogen fowl adenovirus serotype 4 (FAdV-C4). FAdV-C4 virions are highly thermostable, despite lacking minor coat and core proteins shown to stabilize the mast- and atadenovirus particles, having no genus-specific cementing proteins, and packaging a 25% longer genome. Unique structural features of the FAdV-C4 hexon include a large insertion at the trimer equatorial region, and a long N-terminal tail. Protein IIIa conformation is closer to atadenoviruses than to mastadenoviruses, while protein VIII diverges from all previously reported structures. We interpret these differences in light of adenovirus evolution. Finally, we discuss the possible role of core composition in determining capsid stability properties. These results enlarge our view on the structural diversity of adenoviruses, and provide useful information to counteract fowl pathogens or use non-human adenoviruses as vectors. Viral Structure Protein Interactions Monomers Bird Genomics Protein Structure Virions Adenoviruses Viral Packaging http://creativecommons.org/licenses/by/4.0/ https://phaidra.vetmeduni.ac.at/api/object/o:5072/download 10.1371/journal.ppat.1013553 https://phaidra.vetmeduni.ac.at/o:605 application/pdf PLOS Pathogens issn:1553-7374 VoR PLOS Pathogens 21 10 3.13 MB 2025