• Register
X
Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

X

Leaving Community

Are you sure you want to leave this community? Leaving the community will revoke any permissions you have been granted in this community.

No
Yes

Structure of H/ACA RNP protein Nhp2p reveals cis/trans isomerization of a conserved proline at the RNA and Nop10 binding interface.

H/ACA small nucleolar and Cajal body ribonucleoproteins (RNPs) function in site-specific pseudouridylation of eukaryotic rRNA and snRNA, rRNA processing, and vertebrate telomerase biogenesis. Nhp2, one of four essential protein components of eukaryotic H/ACA RNPs, forms a core trimer with the pseudouridylase Cbf5 and Nop10 that binds to H/ACA RNAs specifically. Crystal structures of archaeal H/ACA RNPs have revealed how the protein components interact with each other and with the H/ACA RNA. However, in place of Nhp2p, archaeal H/ACA RNPs contain L7Ae, which binds specifically to an RNA K-loop motif absent from eukaryotic H/ACA RNPs, while Nhp2 binds a broader range of RNA structures. We report solution NMR studies of Saccharomyces cerevisiae Nhp2 (Nhp2p), which reveal that Nhp2p exhibits two major conformations in solution due to cis/trans isomerization of the evolutionarily conserved Pro83. The equivalent proline is in the cis conformation in all reported structures of L7Ae and other homologous proteins. Nhp2p has the expected α-β-α fold, but the solution structures of the major conformation of Nhp2p with trans Pro83 and of Nhp2p-S82W with cis Pro83 reveal that Pro83 cis/trans isomerization affects the positions of numerous residues at the Nop10 and RNA binding interface. An S82W substitution, which stabilizes the cis conformation, also stabilizes the association of Nhp2p with H/ACA snoRNPs expressed in vivo. We propose that Pro83 plays a key role in the assembly of the eukaryotic H/ACA RNP, with the cis conformation locking in a stable Cbf5-Nop10-Nhp2 ternary complex and positioning the protein backbone to interact with the H/ACA RNA.

Pubmed ID: 21708174

Authors

  • Koo BK
  • Park CJ
  • Fernandez CF
  • Chim N
  • Ding Y
  • Chanfreau G
  • Feigon J

Journal

Journal of molecular biology

Publication Data

September 2, 2011

Associated Grants

  • Agency: NIGMS NIH HHS, Id: GM37254
  • Agency: NIGMS NIH HHS, Id: GM48123
  • Agency: NIGMS NIH HHS, Id: GM61518
  • Agency: NIGMS NIH HHS, Id: R01 GM037254
  • Agency: NIGMS NIH HHS, Id: R01 GM037254-24
  • Agency: NIGMS NIH HHS, Id: R01 GM048123
  • Agency: NIGMS NIH HHS, Id: R01 GM048123-19
  • Agency: NIGMS NIH HHS, Id: R01 GM061518

Mesh Terms

  • Amino Acid Sequence
  • Amino Acid Substitution
  • Blotting, Western
  • Immunoprecipitation
  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Molecular Sequence Data
  • Nuclear Proteins
  • Proline
  • Protein Binding
  • Protein Conformation
  • RNA, Fungal
  • RNA, Small Nucleolar
  • RNA-Binding Proteins
  • Ribonucleoproteins, Small Nuclear
  • Ribonucleoproteins, Small Nucleolar
  • Saccharomyces cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Sequence Homology, Amino Acid
  • Stereoisomerism