7ajt

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Cryo-EM structure of the 90S-exosome super-complex (state Pre-A1-exosome)

Structural highlights

7ajt is a 12 chain structure with sequence from Saccharomyces cerevisiae S288C. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:Electron Microscopy, Resolution 4.6Å
Ligands:GTP, MG, ZN
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

NAT10_YEAST RNA cytidine acetyltransferase with specificity toward both 18S rRNA and tRNAs. Catalyzes the formation of N(4)-acetylcytidine (ac4C) at positions 1280 and 1773 in 18S rRNA. Required for early nucleolar cleavages of precursor rRNA at sites A0, A1 and A2 during 18S rRNA synthesis (PubMed:25086048, PubMed:25653167). Catalyzes the formation of ac4C at position 12 in serine and leucine tRNAs. Requires the tRNA-binding adapter protein TAN1 for full tRNA acetyltransferase activity but not for 18S rRNA acetylation (PubMed:25653167).[HAMAP-Rule:MF_03211][1] [2]

Publication Abstract from PubMed

Ribosome assembly is catalyzed by numerous trans-acting factors and coupled with irreversible pre-rRNA processing, driving the pathway toward mature ribosomal subunits. One decisive step early in this progression is removal of the 5' external transcribed spacer (5'-ETS), an RNA extension at the 18S rRNA that is integrated into the huge 90S pre-ribosome structure. Upon endo-nucleolytic cleavage at an internal site, A(1), the 5'-ETS is separated from the 18S rRNA and degraded. Here we present biochemical and cryo-electron microscopy analyses that depict the RNA exosome, a major 3'-5' exoribonuclease complex, in a super-complex with the 90S pre-ribosome. The exosome is docked to the 90S through its co-factor Mtr4 helicase, a processive RNA duplex-dismantling helicase, which strategically positions the exosome at the base of 5'-ETS helices H9-H9', which are dislodged in our 90S-exosome structures. These findings suggest a direct role of the exosome in structural remodeling of the 90S pre-ribosome to drive eukaryotic ribosome synthesis.

Structure of the Maturing 90S Pre-ribosome in Association with the RNA Exosome.,Lau B, Cheng J, Flemming D, La Venuta G, Berninghausen O, Beckmann R, Hurt E Mol Cell. 2021 Jan 21;81(2):293-303.e4. doi: 10.1016/j.molcel.2020.11.009. Epub , 2020 Dec 15. PMID:33326748[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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Citations
5 reviews cite this structure
RNA folding and functions of RNA helicases in ribosome biogenesis.
Mitterer et al. (2022)
4 more
17 other articles
No citations found

See Also

References

  1. ↑ Ito S, Akamatsu Y, Noma A, Kimura S, Miyauchi K, Ikeuchi Y, Suzuki T, Suzuki T. A single acetylation of 18 S rRNA is essential for biogenesis of the small ribosomal subunit in Saccharomyces cerevisiae. J Biol Chem. 2014 Sep 19;289(38):26201-12. doi: 10.1074/jbc.M114.593996. Epub, 2014 Aug 1. PMID:25086048 doi:http://dx.doi.org/10.1074/jbc.M114.593996
  2. ↑ Sharma S, Langhendries JL, Watzinger P, Kotter P, Entian KD, Lafontaine DL. Yeast Kre33 and human NAT10 are conserved 18S rRNA cytosine acetyltransferases that modify tRNAs assisted by the adaptor Tan1/THUMPD1. Nucleic Acids Res. 2015 Feb 27;43(4):2242-58. doi: 10.1093/nar/gkv075. Epub 2015 , Feb 4. PMID:25653167 doi:http://dx.doi.org/10.1093/nar/gkv075
  3. ↑ Lau B, Cheng J, Flemming D, La Venuta G, Berninghausen O, Beckmann R, Hurt E. Structure of the Maturing 90S Pre-ribosome in Association with the RNA Exosome. Mol Cell. 2021 Jan 21;81(2):293-303.e4. PMID:33326748 doi:10.1016/j.molcel.2020.11.009

Contents


PDB ID 7ajt

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OCA

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