9vh1

cryoEM structure of ptuA-ptuB complex in Retron-Eco7 anti-phage system

spinqualitylabelsall models 9vh1, resolution 3.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9vh1 is a 3 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.4Å Ligands: ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ATP78_ECOLX Probable ATPase component of antiviral defense system retron Ec78, composed of a non-coding RNA (ncRNA), a reverse transcriptase (RT), this protein and a putative HNH endonuclease. Expression of retron Ec78 confers protection against bacteriophage T5. At multiplicity of infection (MOI) of 0.02 cultures slow growth when infected with T5 but do not collapse, at MOI 2 cultures enter growth stasis. Publication Abstract from PubMed Retrons are bacterial antiphage defense systems comprising a reverse transcriptase (RT), a non-coding RNA (ncRNA), and cognate effector proteins. The RT synthesizes multicopy single-stranded DNA (msDNA) from the ncRNA template to detect phage invasion. This study focuses on Retron-Eco7, which integrates retron-based sensing with the effector module of Septu-a characterized antiphage system in which the PtuAB complex mediates nuclease-dependent defense. However, the activation mechanism of this hybrid system remains unclear. Here, we determined cryo-electron microscopy structures of the RT-msDNA-PtuAB quaternary complex and the PtuAB binary complex in Retron-Eco7. Structural analyses reveal that the DNA stem-loop of msDNA extensively interacts with PtuA subunits via electrostatic interactions. We establish Retron-Eco7 as a novel toxin-antitoxin system, in which RT-msDNA acts as the antitoxin, directly binding and neutralizing the PtuAB toxin. Furthermore, we identified a phage-encoded flap endonuclease as a trigger for Retron-Eco7 activation, which cleaves msDNA to release the PtuAB toxin. Our findings demonstrate the diversity in bacterial retron defense systems and uncover a novel activation mechanism of the Septu-derived retron toxin-antitoxin system. Phage nuclease-mediated defense activation of the bacterial Retron-Eco7 toxin-antitoxin system.,Dai Z, Liu C, Wang Y, Chen X, Fu X, Yang K, Zhu R, Jia X, Chen Y, Tao P, Guan Z, Zou T Nucleic Acids Res. 2025 Nov 13;53(21):gkaf1173. doi: 10.1093/nar/gkaf1173. PMID:41277685 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

Proteopedia Page Contributors and Editors (what is this?)

OCA