EMD-2494

Single-particle
23.0 Å
EMD-2494 Deposition: 23/10/2013
Map released: 25/12/2013
Last modified: 17/02/2016
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-2494

Substrate Recruitment Pathways in the Yeast Exosome by Electron Microscopy

EMD-2494

Single-particle
23.0 Å
EMD-2494 Deposition: 23/10/2013
Map released: 25/12/2013
Last modified: 17/02/2016
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Saccharomyces cerevisiae, synthetic construct
Sample: Rrp44-Exosome incubated with RNA14

Deposition Authors: Liu J-J, Bratkowski MA, Liu XQ, Niu C-Y, Ke AL, Wang H-W
Visualization of distinct substrate-recruitment pathways in the yeast exosome by EM.
Liu JJ, Bratkowski MA, Liu X, Niu CY, Ke A, Wang HW
(2014) Nat. Struct. Mol. Biol. , 21 , 95 - 102
Abstract:
The eukaryotic exosome is a multisubunit complex typically composed of a catalytically inactive core and the Rrp44 protein, which contains 3'-to-5' exo- and endo-RNase activities. RNA substrates have been shown to be recruited through the core to reach Rrp44's exo-RNase (EXO) site. Using single-particle EM and biochemical analysis, we provide visual evidence that two distinct substrate-recruitment pathways exist. In the through-core route, channeling of the single-stranded substrates from the core to Rrp44 induces a characteristic conformational change in Rrp44. In the alternative direct-access route, this conformational change does not take place, and the RNA substrate is visualized to avoid the core and enter Rrp44's EXO site directly. Our results provide mechanistic explanations for several RNA processing scenarios by the eukaryotic exosome and indicate substrate-specific modes of degradation by this complex.