Molecular mechanism of plasmid elimination by the DdmDE defense system
Molecular mechanism of plasmid elimination by the DdmDE defense system
Abstract Seventh pandemic Vibrio cholerae strains contain two hallmark pathogenicity islands that encode the DNA defense modules DdmABC and DdmDE. Here we use cryo-EM to reveal the mechanistic basis for plasmid defense by DdmDE. A cryo-EM structure of the DdmD helicase-nuclease reveals that 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. Finally, 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 architecture and mechanism of DdmDE systems in plasmid elimination.
Adams D.W.、Jinek M.、Loeff L.、Chanez C.、Righi L.、Stutzmann S.、Blokesch M.
Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, ¨|cole Polytechnique F¨|d¨|rale de LausanneDepartment of Biochemistry, University of ZurichDepartment of Biochemistry, University of ZurichDepartment of Biochemistry, University of ZurichLaboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, ¨|cole Polytechnique F¨|d¨|rale de LausanneLaboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, ¨|cole Polytechnique F¨|d¨|rale de LausanneLaboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, ¨|cole Polytechnique F¨|d¨|rale de Lausanne
分子生物学微生物学
Adams D.W.,Jinek M.,Loeff L.,Chanez C.,Righi L.,Stutzmann S.,Blokesch M..Molecular mechanism of plasmid elimination by the DdmDE defense system[EB/OL].(2025-03-28)[2025-06-21].https://www.biorxiv.org/content/10.1101/2024.05.10.593530.点此复制
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