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Structure of HerA-Sir2 complex from Escherichia coli Nezha systemStructure of HerA-Sir2 complex from Escherichia coli Nezha system
Structural highlights
FunctionPublication Abstract from PubMedIn response to the persistent exposure to phage infection, bacteria have evolved diverse antiviral defense mechanisms. In this study, we report a bacterial two-component defense system consisting of a Sir2 NADase and a HerA helicase. Cryo-electron microscopy reveals that Sir2 and HerA assemble into a approximately 1 MDa supramolecular octadecamer. Unexpectedly, this complex exhibits various enzymatic activities, including ATPase, NADase, helicase, and nuclease, which work together in a sophisticated manner to fulfill the antiphage function. Therefore, we name this defense system "Nezha" after a divine warrior in Chinese mythology who employs multiple weapons to defeat enemies. Our findings demonstrate that Nezha could sense phage infections, self-activate to arrest cell growth, eliminate phage genomes, and subsequently deactivate to allow for cell recovery. Collectively, Nezha represents a paradigm of sophisticated and multifaceted strategies bacteria use to defend against viral infections. Multiple enzymatic activities of a Sir2-HerA system cooperate for anti-phage defense.,Tang D, Chen Y, Chen H, Jia T, Chen Q, Yu Y Mol Cell. 2023 Dec 21;83(24):4600-4613.e6. doi: 10.1016/j.molcel.2023.11.010. , Epub 2023 Dec 13. PMID:38096825[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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