title: Structure and function of archaeal box C/D sRNP core proteins.
abstract: Nop56p and Nop58p are two core proteins of the box C/D snoRNPs that interact concurrently with fibrillarin and snoRNAs to function in enzyme assembly and catalysis. Here we report the 2.9 A resolution co-crystal structure of an archaeal homolog of Nop56p/Nop58p, Nop5p, in complex with fibrillarin from Archaeoglobus fulgidus (AF) and the methyl donor S-adenosyl-L-methionine. The N-terminal domain of Nop5p forms a complementary surface to fibrillarin that serves to anchor the catalytic subunit and to stabilize cofactor binding. A coiled coil in Nop5p mediates dimerization of two fibrillarin-Nop5p heterodimers for optimal interactions with bipartite box C/D RNAs. Structural analysis and complementary biochemical data demonstrate that the conserved C-terminal domain of Nop5p harbors RNA-binding sites. A model of box C/D snoRNP assembly is proposed based on the presented structural and biochemical data.
authors.affiliation: Department of Chemistry and Biochemistry, Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306, USA.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Aittaleb
authors.forename: Rumana
authors.initials: R
authors.lastname: Rashid
authors.forename: Qiong
authors.initials: Q
authors.lastname: Chen
authors.forename: John R
authors.initials: JR
authors.lastname: Palmer
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Daniels
authors.forename: Hong
authors.initials: H
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D019611:Archaeoglobus fulgidus / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000378:metabolism; D018360:Crystallography, X-Ray; D019281:Dimerization; D024202:Electrophoretic Mobility Shift Assay; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009687:Nuclear Proteins; D017434:Protein Structure, Tertiary; D017393:RNA Editing; D019642:RNA, Archaeal / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020537:RNA, Small Nucleolar / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020718:Ribonucleoproteins, Small Nucleolar / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity; D058727:RNA, Small Untranslated
chemical_list: D019843:Archaeal Proteins; D002868:Chromosomal Proteins, Non-Histone; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D019642:RNA, Archaeal; D020537:RNA, Small Nucleolar; D020718:Ribonucleoproteins, Small Nucleolar; C047458:fibrillarin; D058727:RNA, Small Untranslated