8j4u

Publication Abstract from PubMed

In 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.