title: Structure and interactions of the CS domain of human H/ACA RNP assembly protein Shq1.
abstract: Shq1 is an essential protein involved in the early steps of biogenesis and assembly of H/ACA ribonucleoprotein particles (RNPs). Shq1 binds to dyskerin (Cbf5 in yeast) at an early step of H/ACA RNP assembly and is subsequently displaced by the H/ACA RNA. Shq1 contains an N-terminal CS and a C-terminal Shq1-specific domain (SSD). Dyskerin harbors many mutations associated with dyskeratosis congenita. Structures of yeast Shq1 SSD bound to Cbf5 revealed that only a subset of these mutations is in the SSD binding site, implicating another subset in the putative CS binding site. Here, we present the crystal structure of human Shq1 CS (hCS) and the nuclear magnetic resonance (NMR) and crystal structures of hCS containing a serine substitution for proline 22 that is associated with some prostate cancers. The structure of hCS is similar to yeast Shq1 CS domain (yCS) and consists of two β-sheets that form an immunoglobulin-like β-sandwich fold. The N-terminal affinity tag sequence AHHHHHH associates with a neighboring protein in the crystal lattice to form an extra β-strand. Deletion of this tag was required to get spectra suitable for NMR structure determination, while the tag was required for crystallization. NMR chemical shift perturbation (CSP) experiments with peptides derived from putative CS binding sites on dyskerin and Cbf5 revealed a conserved surface on CS important for Cbf5/dyskerin binding. A HADDOCK (high-ambiguity-driven protein-protein docking) model of a Shq1-Cbf5 complex that defines the position of CS domain in the pre-H/ACA RNP was calculated using the CSP data.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA.
authors.forename: Mahavir
authors.initials: M
authors.lastname: Singh
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA.
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Wang
authors.affiliation: University of California Los Angeles-Department of Energy (UCLA-DOE) Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095, USA.
authors.forename: Duilio
authors.initials: D
authors.lastname: Cascio
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA; University of California Los Angeles-Department of Energy (UCLA-DOE) Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095, USA. Electronic address: feigon@mbi.ucla.edu.
authors.forename: Juli
authors.initials: J
authors.lastname: Feigon
mesh_terms: D019943:Amino Acid Substitution / Q000235:genetics; D001665:Binding Sites / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D019871:Dyskeratosis Congenita / Q000235:genetics; D006801:Humans; D006836:Hydro-Lyases / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000235:genetics; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017411:Ribonucleoproteins, Small Nuclear / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D020718:Ribonucleoproteins, Small Nucleolar / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*
chemical_list: D002352:Carrier Proteins; D018797:Cell Cycle Proteins; C112148:DKC1 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D017411:Ribonucleoproteins, Small Nuclear; D020718:Ribonucleoproteins, Small Nucleolar; C542388:SHQ1 protein, human; D029701:Saccharomyces cerevisiae Proteins; D006836:Hydro-Lyases; C082278:CBF5 protein, S cerevisiae
keywords: NMR; X-ray crystal structure; chemical shift perturbation; dyskerin and Cbf5; telomerase