+検索条件
-Structure paper
タイトル | Structural insights into dsRNA processing by Drosophila Dicer-2-Loqs-PD. |
---|---|
ジャーナル・号・ページ | Nature, Vol. 607, Issue 7918, Page 399-406, Year 2022 |
掲載日 | 2022年6月29日 |
著者 | Shichen Su / Jia Wang / Ting Deng / Xun Yuan / Jinqiu He / Nan Liu / Xiaomin Li / Ying Huang / Hong-Wei Wang / Jinbiao Ma / |
PubMed 要旨 | Small interfering RNAs (siRNAs) are the key components for RNA interference (RNAi), a conserved RNA-silencing mechanism in many eukaryotes. In Drosophila, an RNase III enzyme Dicer-2 (Dcr-2), aided ...Small interfering RNAs (siRNAs) are the key components for RNA interference (RNAi), a conserved RNA-silencing mechanism in many eukaryotes. In Drosophila, an RNase III enzyme Dicer-2 (Dcr-2), aided by its cofactor Loquacious-PD (Loqs-PD), has an important role in generating 21 bp siRNA duplexes from long double-stranded RNAs (dsRNAs). ATP hydrolysis by the helicase domain of Dcr-2 is critical to the successful processing of a long dsRNA into consecutive siRNA duplexes. Here we report the cryo-electron microscopy structures of Dcr-2-Loqs-PD in the apo state and in multiple states in which it is processing a 50 bp dsRNA substrate. The structures elucidated interactions between Dcr-2 and Loqs-PD, and substantial conformational changes of Dcr-2 during a dsRNA-processing cycle. The N-terminal helicase and domain of unknown function 283 (DUF283) domains undergo conformational changes after initial dsRNA binding, forming an ATP-binding pocket and a 5'-phosphate-binding pocket. The overall conformation of Dcr-2-Loqs-PD is relatively rigid during translocating along the dsRNA in the presence of ATP, whereas the interactions between the DUF283 and RIIIDb domains prevent non-specific cleavage during translocation by blocking the access of dsRNA to the RNase active centre. Additional ATP-dependent conformational changes are required to form an active dicing state and precisely cleave the dsRNA into a 21 bp siRNA duplex as confirmed by the structure in the post-dicing state. Collectively, this study revealed the molecular mechanism for the full cycle of ATP-dependent dsRNA processing by Dcr-2-Loqs-PD. |
リンク | Nature / PubMed:35768513 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 3.12 - 4.55 Å |
構造データ | EMDB-32236, PDB-7w0a: EMDB-32237, PDB-7w0b: EMDB-32238, PDB-7w0c: EMDB-32239, PDB-7w0d: EMDB-32240, PDB-7w0e: EMDB-32241, PDB-7w0f: |
化合物 | ChemComp-MG: ChemComp-ADP: |
由来 |
|
キーワード | RNA BINDING PROTEIN / Ribonuclease |