9P4K

The structure of Retron Eco8-SSB complex

9P4K の概要

• エントリーDOI: 10.2210/pdb9p4k/pdb
• EMDBエントリー: 71272
• 分子名称: Retron Eco8 OLD nuclease, Retron Eco8 reverse transcriptase, msdDNA, ... (4 entities in total)
• 機能のキーワード: anti-phage, bacterial immunity, retron, dna, rna, reverse transcription, transferase-hydrolase-dna-rna complex, transferase/hydrolase/dna/rna
• 由来する生物種: Escherichia coli; 詳細
• タンパク質・核酸の鎖数: 16
• 化学式量合計: 722800.66

構造登録者

Yu, C.,Wang, C.,Fu, T. (登録日: 2025-06-17, 公開日: 2025-11-12, 最終更新日: 2025-12-03)

主引用文献

Yu, C.,Wang, C.,Forman, T.,Xie, J.,Major, S.,Fang, M.X.,Voyer, J.E.,Pogliano, J.,Fu, T.M.
Phage SSB detection by retron Eco8 msDNA unleashes nuclease-mediated immunity.
Mol.Cell, 85:4243-, 2025

PubMed Abstract: Retrons are antiphage defense systems that synthesize multicopy single-stranded DNA (msDNA) and are being adapted for genome engineering. The Escherichia coli retron Eco8 system comprises a reverse transcriptase (RT), an msDNA, and an overcoming lysogenization defect (OLD)-family nuclease (Eco8-OLD), reminiscent of Gabija. Here, we present the cryo-electron microscopy structure of the Eco8 supramolecular complex, a symmetric 4:4:4 assembly of RT, Eco8-OLD, and msDNA (a hybrid of msrRNA and msdDNA). The msDNA anchors RT and Eco8-OLD into a compact architecture that traps Eco8-OLD in an autoinhibited conformation. Upon phage infection, phage single-stranded DNA-binding proteins (SSBs) bind msdDNA, inducing conformational rearrangements that relieve Eco8-OLD autoinhibition and activate its non-specific DNA nuclease activity. This structural transition enables Eco8 to mount a robust antiphage response by restricting phage genome amplification. Our findings reveal a previously unrecognized mechanism of retron activation and highlight the central role of msDNA as a molecular switch in controlling retron-mediated antiphage defense.

PubMed: 41172989
DOI: 10.1016/j.molcel.2025.10.007

実験手法

ELECTRON MICROSCOPY (3.07 Å)