title: Crystal structure of U2 snRNP SF3b components: Hsh49p in complex with Cus1p-binding domain.
abstract: Spliceosomal proteins Hsh49p and Cus1p are components of SF3b, which together with SF3a, Msl1p/Lea1p, Sm proteins, and U2 snRNA, form U2 snRNP, which plays a crucial role in pre-mRNA splicing. Hsh49p, comprising two RRMs, forms a heterodimer with Cus1p. We determined the crystal structures ofSaccharomyces cerevisiaefull-length Hsh49p as well as its RRM1 in complex with a minimal binding region of Cus1p (residues 290-368). The structures show that the Cus1 fragment binds to the α-helical surface of Hsh49p RRM1, opposite the four-stranded β-sheet, leaving the canonical RNA-binding surface available to bind RNA. Hsh49p binds the 5' end region of U2 snRNA via RRM1. Its affinity is increased in complex with Cus1(290-368)p, partly because an extended RNA-binding surface forms across the protein-protein interface. The Hsh49p RRM1-Cus1(290-368)p structure fits well into cryo-EM density of the Bactspliceosome, corroborating the biological relevance of our crystal structure.
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom.
authors.forename: Anne-Marie M
authors.initials: AM
authors.lastname: van Roon
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom.
authors.forename: Chris
authors.identifier: 0000-0001-8492-8305
authors.initials: C
authors.lastname: Oubridge
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom.
authors.forename: Eiji
authors.initials: E
authors.lastname: Obayashi
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom.
authors.forename: Benedetta
authors.initials: B
authors.lastname: Sposito
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Newman
authors.affiliation: Equipe Labellisée La Ligue, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé et de la Recherche Médicale (INSERM), U964/Université de Strasbourg, 67404 Illkirch, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Séraphin
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom.
authors.forename: Kiyoshi
authors.identifier: 0000-0003-1785-6510
authors.initials: K
authors.lastname: Nagai
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D017124:Conserved Sequence; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000378:metabolism; D055232:Proline-Rich Protein Domains; D011485:Protein Binding; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D012313:RNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012342:RNA, Small Nuclear / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D017413:Ribonucleoprotein, U2 Small Nuclear / Q000737:chemistry* / Q000378:metabolism
chemical_list: D046912:Multiprotein Complexes; D012342:RNA, Small Nuclear; D016601:RNA-Binding Proteins; D017413:Ribonucleoprotein, U2 Small Nuclear; C405484:U2 small nuclear RNA; D012313:RNA
keywords: RNA binding; RRM; SF3b; U2 snRNP; splicing