9NHC

Cryo-EM structure of SIWI-piRNA-target(49-nt)-GTSF1-Maelstrom complex

9NHC の概要

• エントリーDOI: 10.2210/pdb9nhc/pdb
• 関連するPDBエントリー: 9NHB
• EMDBエントリー: 49408
• 分子名称: Piwi-like protein Siwi, piRNA, target RNA (49-nt), ... (7 entities in total)
• 機能のキーワード: siwi, gtsf1, maelstrom, rna binding protein, rna binding protein-rna complex, rna binding protein/rna
• 由来する生物種: Bombyx mori (domestic silkworm); 詳細
• タンパク質・核酸の鎖数: 5
• 化学式量合計: 192703.74

構造登録者

Sarkar, S.,Gebert, L.F.R.,MacRae, I.J. (登録日: 2025-02-24, 公開日: 2025-09-17, 最終更新日: 2025-10-01)

主引用文献

De, D.,Sarkar, S.,Gebert, L.F.R.,Wiryaman, T.,Anzelon, T.A.,MacRae, I.J.
A conserved PIWI silencing complex detects piRNA-target engagement.
Mol.Cell, 85:3275-3287.e7, 2025

PubMed Abstract: In animal germ cells, PIWI proteins use piRNAs to detect active selfish genetic elements. Base-pairing to a piRNA defines transposon recognition, but how this interaction triggers a defensive response remains unclear. Here, we identify a transposon recognition complex composed of the silkworm proteins Siwi, GTSF1, and Maelstrom. Biochemical and cryo-electron microscopy (cryo-EM) analyses show that extended piRNA-target pairing locks Siwi in a conformation that recruits GTSF1 and Maelstrom. Extended piRNA-target pairing is recognized by the N-terminal helix of Maelstrom and the first zinc finger of GTSF1, which act together to hold Siwi in an endonucleolytically active state. The resulting activated complex, termed Siwi, rapidly cleaves target RNAs and recruits the piRNA biogenesis factor Spindle-E. Structural predictions reveal related complexes in animals ranging from humans to sponges, indicating PIWI assembly is a conserved transposon recognition mechanism employed broadly across the metazoan kingdom.

PubMed: 40912244
DOI: 10.1016/j.molcel.2025.08.010

実験手法

ELECTRON MICROSCOPY (3.6 Å)