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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, Vol. 385, Issue 6705, Page 188-194, Year 2024 |
Publish date | Jul 12, 2024 |
![]() | 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. In this study, we used cryogenic electron microscopy to determine the mechanistic ...Seventh-pandemic strains contain two pathogenicity islands that encode the DNA defense modules DdmABC and DdmDE. In this study, we used cryogenic electron microscopy to determine the mechanistic basis for plasmid defense by DdmDE. The helicase-nuclease DdmD adopts an autoinhibited dimeric architecture. The prokaryotic Argonaute protein DdmE uses a DNA guide to target plasmid DNA. The 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 nontarget DNA strand. In vitro studies indicate 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. |
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Methods | EM (single particle) |
Resolution | 2.55 Å |
Structure data | EMDB-50090, PDB-9ezx: |
Source |
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![]() | IMMUNE SYSTEM / Helicase / Nuclease / Complex / Effector |