Structure and function of archaeal box C/D sRNP core proteins

Nat Struct Biol. 2003 Apr;10(4):256-63. doi: 10.1038/nsb905.


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.

MeSH terms

  • Amino Acid Sequence
  • Archaeal Proteins / chemistry*
  • Archaeal Proteins / genetics
  • Archaeal Proteins / metabolism*
  • Archaeoglobus fulgidus / genetics
  • Archaeoglobus fulgidus / metabolism
  • Binding Sites
  • Chromosomal Proteins, Non-Histone / chemistry
  • Chromosomal Proteins, Non-Histone / metabolism
  • Crystallography, X-Ray
  • Dimerization
  • Electrophoretic Mobility Shift Assay
  • Macromolecular Substances
  • Models, Molecular
  • Molecular Sequence Data
  • Molecular Structure
  • Nuclear Proteins*
  • Protein Structure, Tertiary
  • RNA Editing
  • RNA, Archaeal / chemistry*
  • RNA, Archaeal / genetics
  • RNA, Archaeal / metabolism*
  • RNA, Small Nucleolar / chemistry
  • RNA, Small Nucleolar / genetics
  • RNA, Small Nucleolar / metabolism
  • RNA, Small Untranslated
  • Ribonucleoproteins, Small Nucleolar / chemistry
  • Ribonucleoproteins, Small Nucleolar / genetics
  • Ribonucleoproteins, Small Nucleolar / metabolism*
  • Sequence Homology, Amino Acid
  • Static Electricity


  • Archaeal Proteins
  • Chromosomal Proteins, Non-Histone
  • Macromolecular Substances
  • Nuclear Proteins
  • RNA, Archaeal
  • RNA, Small Nucleolar
  • Ribonucleoproteins, Small Nucleolar
  • fibrillarin
  • RNA, Small Untranslated

Associated data

  • PDB/1NT2