title: Identification and functional analysis of VP3, the guanylyltransferase of Banna virus (genus Seadornavirus, family Reoviridae).
abstract: Banna virus (BAV) particles contain seven structural proteins: VP4 and VP9 form an outer-capsid layer, whilst the virus core contains three major proteins (VP2, VP8 and VP10) and two minor proteins (VP1 and VP3). Sequence analysis showed that VP3 contains motifs [Kx(I/V/L)S] and (Hx(n)H) that have previously been identified in the guanylyltransferases of other reoviruses. Incubation of purified BAV-Ch core particles with [alpha-32P]GTP resulted in exclusive covalent labelling of VP3, demonstrating autoguanylation activity (which is considered indicative of guanylyltransferase activity). Recombinant VP3 prepared in a cell-free expression system was also guanylated under similar reaction conditions, and products were synthesized (in the presence of non-radiolabelled GDP) that co-migrated with GMP, GDP and GpppG during TLC. This reaction, which required magnesium ions for optimum activity, demonstrates that VP3 possesses nucleoside triphosphatase (GTPase) activity and is the BAV guanylyltransferase (RNA 'capping' enzyme).
authors.affiliation: Unité des Virus Emergents: EFS Alpes-Méditerranée and Faculté de Médecine de Marseille, Université de la Méditerranée, 27 Boulevard Jean Moulin, 13005 Marseille cedex 5, France.
authors.forename: Fauziah Mohd
authors.initials: FM
authors.lastname: Jaafar
authors.affiliation: Unité des Virus Emergents: EFS Alpes-Méditerranée and Faculté de Médecine de Marseille, Université de la Méditerranée, 27 Boulevard Jean Moulin, 13005 Marseille cedex 5, France.
authors.forename: Houssam
authors.initials: H
authors.lastname: Attoui
authors.affiliation: Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK.
authors.forename: Peter P C
authors.initials: PPC
authors.lastname: Mertens
authors.affiliation: Unité des Virus Emergents: EFS Alpes-Méditerranée and Faculté de Médecine de Marseille, Université de la Méditerranée, 27 Boulevard Jean Moulin, 13005 Marseille cedex 5, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: de Micco
authors.affiliation: Maladies Virales Émergentes et Systèmes d'Information UR034, Institut de Recherche pour le Développement, Marseille, France.|Unité des Virus Emergents: EFS Alpes-Méditerranée and Faculté de Médecine de Marseille, Université de la Méditerranée, 27 Boulevard Jean Moulin, 13005 Marseille cedex 5, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: de Lamballerie
mesh_terms: D000595:Amino Acid Sequence; D018162:Coltivirus / Q000201:enzymology*; D020558:GTP Phosphohydrolases / Q000378:metabolism; D008780:Methyltransferases; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes; D009713:Nucleotidyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014758:Viral Core Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins
chemical_list: D009097:Multienzyme Complexes; D011994:Recombinant Proteins; D014758:Viral Core Proteins; D014764:Viral Proteins; D008780:Methyltransferases; D009713:Nucleotidyltransferases; C020842:guanylyltransferase; D010744:Phosphoric Monoester Hydrolases; C027731:capping enzyme, vaccinia virus; D020558:GTP Phosphohydrolases