9I2F

Cryo-EM structure of retron Eco2 (Ec67)

9I2F の概要

• エントリーDOI: 10.2210/pdb9i2f/pdb
• 関連するPDBエントリー: 9I2G 9S1F
• EMDBエントリー: 52583
• 分子名称: msDNA (67-MER), Retron Ec67 protein, RNA (132-MER) (3 entities in total)
• 機能のキーワード: retron, reverse transcriptase, dna, rna, toprim, rnaseh, msdna, antiviral protein
• 由来する生物種: Escherichia coli NCTC 86; 詳細
• タンパク質・核酸の鎖数: 9
• 化学式量合計: 394881.71

構造登録者

Jasnauskaite, M.,Miksys, A.,Skorupskaite, A.,Malinauskaite, L.,Pausch, P. (登録日: 2025-01-20, 公開日: 2026-02-04, 最終更新日: 2026-02-25)

主引用文献

Jasnauskaite, M.,Juozapaitis, J.,Liegute, T.,Grigaitis, R.,Skorupskaite, A.,Steinchen, W.,Miksys, A.,Truncaite, L.,Kazlauskaite, K.,Torres Jimenez, M.F.,Khochare, S.,Dudas, G.,Bange, G.,Malinauskaite, L.,Songailiene, I.,Pausch, P.
Structure and mechanism of antiphage retron Eco2.
Nat.Struct.Mol.Biol., 33:330-340, 2026

PubMed Abstract: Retrons are prokaryotic reverse transcriptase systems that produce multicopy single-stranded DNA (msDNA), yet the principles by which they mediate antiviral defense remain largely unresolved. Here we investigate the mechanism of Escherichia coli Eco2, a minimal retron composed of a single reverse transcriptase-nuclease fusion protein. Cryogenic electron microscopy and hydrogen/deuterium exchange mass spectrometry reveal the structures and dynamics of a trimeric nucleoprotein complex assembled within a branched msDNA scaffold, which cages the TOPRIM nucleases. We show that the phage-encoded endonuclease DenB initiates msDNA degradation, thereby unblocking the nuclease active sites. Activated Eco2 cuts transfer RNAs, resulting in translational shutdown for antiphage defense. We further identify ribosomal protein S1 as a putative RNA chaperone that associates with the msDNA precursor. These findings provide insights into the molecular mechanisms of minimal retrons and establish a structural basis for engineering of Eco2.

PubMed: 41709047
DOI: 10.1038/s41594-026-01754-2

実験手法

ELECTRON MICROSCOPY (2.8 Å)