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-Structure paper
| タイトル | Molecular mechanism of Eco8-mediated anti-phage defense. |
|---|---|
| ジャーナル・号・ページ | Mol Cell, Vol. 85, Issue 22, Page 4229-44242.e4, Year 2025 |
| 掲載日 | 2025年11月20日 |
著者 | Linggang Yuan / Liqiao Xu / Bing Wu / Qingyang Liu / Yue Yao / Xiaoting Hua / Yu Feng / ![]() |
| PubMed 要旨 | Escherichia coli Eco8 is an anti-phage defense system consisting of a reverse transcriptase, a class 3 overcoming lysogenization defect (OLD) nuclease, and a DNA-RNA chimera called multi-copy single- ...Escherichia coli Eco8 is an anti-phage defense system consisting of a reverse transcriptase, a class 3 overcoming lysogenization defect (OLD) nuclease, and a DNA-RNA chimera called multi-copy single-stranded DNA (msDNA). Genetic and biochemical data suggest that Eco8-mediated anti-phage defense is triggered by the phage single-stranded DNA (ssDNA)-binding proteins, but the underlying structural basis remains unknown. Here, we demonstrate that the DNA cleavage and ATP hydrolysis activities of the OLD nuclease are critical for Eco8-mediated anti-phage defense. We also determine the cryoelectron microscopy (cryo-EM) structures of Eco8 alone and in complex with the T7 phage ssDNA-binding protein. Structural analysis reveals that the reverse transcriptase, msDNA, and OLD nuclease form a megacomplex with a 4:4:4 stoichiometry. The T7 phage ssDNA-binding protein unwinds the msDNA and transforms Eco8 into an ATP-dependent DNA-degrading machinery. This study not only elucidates the molecular mechanism of Eco8-mediated anti-phage defense but also validates that msDNA serves as a sensor of phage DNA-modifying/binding proteins. |
リンク | Mol Cell / PubMed:41172990 |
| 手法 | EM (単粒子) |
| 解像度 | 3.2 - 3.3 Å |
| 構造データ | EMDB-63268, PDB-9lp9: EMDB-63269, PDB-9lpa: |
| 化合物 | ![]() ChemComp-ATP: |
| 由来 |
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キーワード | ANTITOXIN/DNA/RNA / retron / multi-copy single-stranded DNA / Eco8 / anti-phage defense / OLD-family endonuclease / reverse transcriptase / ANTITOXIN-DNA-RNA complex |
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