9P4J
The structure of Retron Eco8 in Apo state
Summary for 9P4J
| Entry DOI | 10.2210/pdb9p4j/pdb |
| EMDB information | 71271 |
| Descriptor | Retron Eco8 OLD nuclease, Retron Eco8 reverse transcriptase, msrRNA, ... (4 entities in total) |
| Functional Keywords | anti-phage, bacterial immunity, retron, dna, rna, reverse transcription, transferase-hydrolase-dna-rna complex, transferase/hydrolase/dna/rna |
| Biological source | Escherichia coli More |
| Total number of polymer chains | 16 |
| Total formula weight | 722800.66 |
| Authors | |
| Primary citation | 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, 2025 Cited by 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: 41172989DOI: 10.1016/j.molcel.2025.10.007 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (2.68 Å) |
Structure validation
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