8QCA

CryoEM structure of a S. Cerevisiae Ski2387 complex in the closed state bound to RNA

Summary for 8QCA

• Entry DOI: 10.2210/pdb8qca/pdb
• EMDB information: 18326
• Descriptor: Antiviral helicase SKI2, Superkiller protein 3, Antiviral protein SKI8, ... (5 entities in total)
• Functional Keywords: helicase, rna binding, rna degradation, hydrolase
• Biological source: Saccharomyces cerevisiae (baker's yeast); More
• Total number of polymer chains: 6
• Total formula weight: 436589.79

Authors

Keidel, A.,Koegel, A.,Reichelt, P.,Kowalinski, E.,Schaefer, I.B.,Conti, E. (deposition date: 2023-08-25, release date: 2023-11-15, Last modification date: 2023-11-29)

Primary citation

Keidel, A.,Kogel, A.,Reichelt, P.,Kowalinski, E.,Schafer, I.B.,Conti, E.
Concerted structural rearrangements enable RNA channeling into the cytoplasmic Ski238-Ski7-exosome assembly.
Mol.Cell, 83:4093-, 2023

PubMed Abstract: The Ski2-Ski3-Ski8 (Ski238) helicase complex directs cytoplasmic mRNAs toward the nucleolytic exosome complex for degradation. In yeast, the interaction between Ski238 and exosome requires the adaptor protein Ski7. We determined different cryo-EM structures of the Ski238 complex depicting the transition from a rigid autoinhibited closed conformation to a flexible active open conformation in which the Ski2 helicase module has detached from the rest of Ski238. The open conformation favors the interaction of the Ski3 subunit with exosome-bound Ski7, leading to the recruitment of the exosome. In the Ski238-Ski7-exosome holocomplex, the Ski2 helicase module binds the exosome cap, enabling the RNA to traverse from the helicase through the internal exosome channel to the Rrp44 exoribonuclease. Our study pinpoints how conformational changes within the Ski238 complex regulate exosome recruitment for RNA degradation. We also reveal the remarkable conservation of helicase-exosome RNA channeling mechanisms throughout eukaryotic nuclear and cytoplasmic exosome complexes.

PubMed: 37879335
DOI: 10.1016/j.molcel.2023.09.037

Experimental method

ELECTRON MICROSCOPY (2.84 Å)