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-Structure paper
Title | Molecular mechanism of plasmid elimination by the DdmDE defense system. |
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Journal, issue, pages | Science, Page eadq0534, Year 2024 |
Publish date | Jun 13, 2024 |
Authors | Luuk Loeff / David W Adams / Christelle Chanez / Sandrine Stutzmann / Laurie Righi / Melanie Blokesch / Martin Jinek / |
PubMed Abstract | Seventh pandemic strains contain two pathogenicity islands that encode the DNA defense modules DdmABC and DdmDE. Here we use cryogenic electron microscopy to reveal the mechanistic basis for plasmid ...Seventh pandemic strains contain two pathogenicity islands that encode the DNA defense modules DdmABC and DdmDE. Here we use cryogenic electron microscopy to reveal the mechanistic basis for plasmid defense by DdmDE. A structure of the DdmD helicase-nuclease reveals it adopts an auto-inhibited dimeric architecture. The prokaryotic Argonaute protein DdmE uses a DNA guide to target plasmid DNA. A structure of the DdmDE complex, validated by in vivo mutational studies, shows that DNA binding by DdmE triggers disassembly of the DdmD dimer and loading of monomeric DdmD onto the non-target DNA strand. In vitro studies reveal that DdmD translocates in the 5'-to-3' direction, while partially degrading the plasmid DNA. These findings provide critical insights into the mechanism of DdmDE systems in plasmid elimination. |
External links | Science / PubMed:38870273 |
Methods | EM (single particle) |
Resolution | 2.55 Å |
Structure data | EMDB-50090, PDB-9ezx: |
Source |
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Keywords | IMMUNE SYSTEM / Helicase / Nuclease / Complex / Effector |