title: Crystal structure and functional analysis of the SARS-coronavirus RNA cap 2'-O-methyltransferase nsp10/nsp16 complex.
abstract: Cellular and viral S-adenosylmethionine-dependent methyltransferases are involved in many regulated processes such as metabolism, detoxification, signal transduction, chromatin remodeling, nucleic acid processing, and mRNA capping. The Severe Acute Respiratory Syndrome coronavirus nsp16 protein is a S-adenosylmethionine-dependent (nucleoside-2'-O)-methyltransferase only active in the presence of its activating partner nsp10. We report the nsp10/nsp16 complex structure at 2.0 Å resolution, which shows nsp10 bound to nsp16 through a ∼930 Å² surface area in nsp10. Functional assays identify key residues involved in nsp10/nsp16 association, and in RNA binding or catalysis, the latter likely through a SN2-like mechanism. We present two other crystal structures, the inhibitor Sinefungin bound in the S-adenosylmethionine binding pocket and the tighter complex nsp10(Y96F)/nsp16, providing the first structural insight into the regulation of RNA capping enzymes in +RNA viruses.
authors.affiliation: Centre National de la Recherche Scientifique and Université de la Méditerranée, UMR 6098, Architecture et Fonction des Macromolécules Biologiques, Marseille, France. etienne.decroly@afmb.univ-mrs.fr
authors.forename: Etienne
authors.initials: E
authors.lastname: Decroly
authors.forename: Claire
authors.initials: C
authors.lastname: Debarnot
authors.forename: François
authors.initials: F
authors.lastname: Ferron
authors.forename: Mickael
authors.initials: M
authors.lastname: Bouvet
authors.forename: Bruno
authors.initials: B
authors.lastname: Coutard
authors.forename: Isabelle
authors.initials: I
authors.lastname: Imbert
authors.forename: Laure
authors.initials: L
authors.lastname: Gluais
authors.forename: Nicolas
authors.initials: N
authors.lastname: Papageorgiou
authors.forename: Andrew
authors.initials: A
authors.lastname: Sharff
authors.forename: Gérard
authors.initials: G
authors.lastname: Bricogne
authors.forename: Miguel
authors.initials: M
authors.lastname: Ortiz-Lombardia
authors.forename: Julien
authors.initials: J
authors.lastname: Lescar
authors.forename: Bruno
authors.initials: B
authors.lastname: Canard
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000378:metabolism; D003460:Crystallization; D008274:Magnesium / Q000378:metabolism; D008780:Methyltransferases / Q000737:chemistry* / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D010957:Plasmids; D011485:Protein Binding; D012315:RNA Caps / Q000378:metabolism*; D012367:RNA, Viral / Q000378:metabolism*; D012436:S-Adenosylmethionine / Q000378:metabolism; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics*; D017361:Viral Nonstructural Proteins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: C558878:Nsp10 protein, SARS virus; D012315:RNA Caps; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins; D012436:S-Adenosylmethionine; D008780:Methyltransferases; C558879:Nsp16 protein, SARS virus; C052744:RNA 2'-O-methyltransferase; D008274:Magnesium; D000241:Adenosine; C006235:sinefungin