Structure and mechanism of antiphage retron Eco2 - PubMed
3 days ago
- #Retrons
- #Antiphage Defense
- #Eco2 Mechanism
- Retrons are prokaryotic reverse transcriptase systems producing multicopy single-stranded DNA (msDNA) for antiviral defense.
- Escherichia coli Eco2 is a minimal retron with a reverse transcriptase-nuclease fusion protein.
- Cryogenic electron microscopy and hydrogen/deuterium exchange mass spectrometry reveal trimeric nucleoprotein complex structures within msDNA scaffolds.
- Phage-encoded endonuclease DenB initiates msDNA degradation, activating Eco2's nuclease sites.
- Activated Eco2 cuts transfer RNAs, leading to translational shutdown as an antiphage defense mechanism.
- Ribosomal protein S1 is identified as a putative RNA chaperone associated with msDNA precursor.
- Findings provide insights into minimal retron mechanisms and a structural basis for Eco2 engineering.