title: Adenovirus serotype 5 hexon is critical for virus infection of hepatocytes in vivo.
abstract: Human species C adenovirus serotype 5 (Ad5) is the most common viral vector used in clinical studies worldwide. Ad5 vectors infect liver cells in vivo with high efficiency via a poorly defined mechanism, which involves virus binding to vitamin K-dependent blood coagulation factors. Here, we report that the major Ad5 capsid protein, hexon, binds human coagulation factor X (FX) with an affinity of 229 pM. This affinity is 40-fold stronger than the reported affinity of Ad5 fiber for the cellular receptor coxsackievirus and adenovirus receptor, CAR. Cryoelectron microscopy and single-particle image reconstruction revealed that the FX attachment site is localized to the central depression at the top of the hexon trimer. Hexon-mutated virus bearing a large insertion in hexon showed markedly reduced FX binding in vitro and failed to deliver a transgene to hepatocytes in vivo. This study describes the mechanism of FX binding to Ad5 and demonstrates the critical role of hexon for virus infection of hepatocytes in vivo.
authors.affiliation: Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA 98195-7720, USA.
authors.forename: O
authors.initials: O
authors.lastname: Kalyuzhniy
authors.forename: N C
authors.initials: NC
authors.lastname: Di Paolo
authors.forename: M
authors.initials: M
authors.lastname: Silvestry
authors.forename: S E
authors.initials: SE
authors.lastname: Hofherr
authors.forename: M A
authors.initials: MA
authors.lastname: Barry
authors.forename: P L
authors.initials: PL
authors.lastname: Stewart
authors.forename: D M
authors.initials: DM
authors.lastname: Shayakhmetov
mesh_terms: D000258:Adenovirus Infections, Human; D000260:Adenoviruses, Human / Q000737:chemistry* / Q000472:pathogenicity; D001665:Binding Sites; D036022:Capsid Proteins / Q000378:metabolism* / Q000502:physiology; D002478:Cells, Cultured; D020285:Cryoelectron Microscopy; D005170:Factor X / Q000378:metabolism*; D022781:Hepatocytes / Q000821:virology*; D006801:Humans; D011485:Protein Binding; D053585:Virus Attachment
chemical_list: D036022:Capsid Proteins; C018315:hexon capsid protein, Adenovirus; D005170:Factor X