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Title | Structural Snapshots of 26S Proteasome Reveal Tetraubiquitin-Induced Conformations. |
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Journal, issue, pages | Mol Cell, Vol. 73, Issue 6, Page 1150-11161.e6, Year 2019 |
Publish date | Mar 21, 2019 |
Authors | Zhanyu Ding / Cong Xu / Indrajit Sahu / Yifan Wang / Zhenglin Fu / Min Huang / Catherine C L Wong / Michael H Glickman / Yao Cong / |
PubMed Abstract | The 26S proteasome is the ATP-dependent protease responsible for regulating the proteome of eukaryotic cells through degradation of mainly ubiquitin-tagged substrates. In order to understand how ...The 26S proteasome is the ATP-dependent protease responsible for regulating the proteome of eukaryotic cells through degradation of mainly ubiquitin-tagged substrates. In order to understand how proteasome responds to ubiquitin signal, we resolved an ensemble of cryo-EM structures of proteasome in the presence of K48-Ub, with three of them resolved at near-atomic resolution. We identified a conformation with stabilized ubiquitin receptors and a previously unreported orientation of the lid, assigned as a Ub-accepted state C1-b. We determined another structure C3-b with localized K48-Ub to the toroid region of Rpn1, assigned as a substrate-processing state. Our structures indicate that tetraUb induced conformational changes in proteasome could initiate substrate degradation. We also propose a CP gate-opening mechanism involving the propagation of the motion of the lid to the gate through the Rpn6-α2 interaction. Our results enabled us to put forward a model of a functional cycle for proteasomes induced by tetraUb and nucleotide. |
External links | Mol Cell / PubMed:30792173 |
Methods | EM (single particle) |
Resolution | 3.8 - 7.5 Å |
Structure data | EMDB-9769, PDB-6j2c: EMDB-9770, PDB-6j2n: EMDB-9771, PDB-6j2q: |
Source |
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Keywords | HYDROLASE / Proteasome / K48-Ub4 / Ub-bound / cryo-EM |