+Search query
-Structure paper
| Title | Anti-phage defense mechanism involving phage-encoded DNA binding protein and bacterial reverse transcriptase DRT4. |
|---|---|
| Journal, issue, pages | Nat Commun, Vol. 17, Issue 1, Page 289, Year 2025 |
| Publish date | Dec 2, 2025 |
Authors | Yong Wang / Hao Wu / Jinyue Li / Qiyin An / Zhenhua Tian / Zengqin Deng / ![]() |
| PubMed Abstract | Prokaryotic defense-associated reverse transcriptase (DRT) systems confer host resistance to viral infection through DNA synthesis; however, the molecular mechanisms underlying their function remain ...Prokaryotic defense-associated reverse transcriptase (DRT) systems confer host resistance to viral infection through DNA synthesis; however, the molecular mechanisms underlying their function remain poorly understood. Here, we demonstrate that DRT4, a single-gene anti-phage defense system, synthesizes single-stranded DNA (ssDNA) products of random sequences in a template-independent manner. High-resolution cryo-EM structures of DRT4 in multiple functional states elucidate its oligomeric architecture, catalytic metal ion coordination, and substrate/DNA product binding, offering mechanistic insights into its promiscuous polymerization activity. Structural and biochemical analyses further identify a conserved tyrosine residue that acts as the priming site for the initiation of DNA synthesis. Upon phage infection, a phage-encoded DNA-binding protein, ORF55, protects the 3' end of the DRT4-synthesized ssDNA from host exonuclease degradation, likely resulting in toxic ssDNA accumulation that leads to cell death. Remarkably, ORF55 also activates DRT6, a structural homolog of DRT4, suggesting a conserved activation mechanism among related DRT systems. These findings provide structural and mechanistic insights into DRT4-mediated antiviral defense, establishing a distinct paradigm for antiviral reverse transcriptase in bacterial immunity. |
External links | Nat Commun / PubMed:41330908 / PubMed Central |
| Methods | EM (single particle) |
| Resolution | 2.27 - 2.93 Å |
| Structure data | EMDB-64990, PDB-9vdo: EMDB-64991, PDB-9vdp: EMDB-64992, PDB-9vdv: |
| Chemicals | ![]() ChemComp-DCP: ![]() ChemComp-MN: |
| Source |
|
Keywords | DNA BINDING PROTEIN/DNA / UG15 / DRT4 / Reverse transcriptases / UG/Abi system / DNA BINDING PROTEIN-DNA complex |
Movie
Controller
Structure viewers
About Yorodumi Papers



Authors
External links








Keywords