ジャーナル: Cell / 年: 2023 タイトル: Cryo-EM structure of the RADAR supramolecular anti-phage defense complex. 著者: Brianna Duncan-Lowey / Nitzan Tal / Alex G Johnson / Shaun Rawson / Megan L Mayer / Shany Doron / Adi Millman / Sarah Melamed / Taya Fedorenko / Assaf Kacen / Alexander Brandis / Tevie ...著者: Brianna Duncan-Lowey / Nitzan Tal / Alex G Johnson / Shaun Rawson / Megan L Mayer / Shany Doron / Adi Millman / Sarah Melamed / Taya Fedorenko / Assaf Kacen / Alexander Brandis / Tevie Mehlman / Gil Amitai / Rotem Sorek / Philip J Kranzusch / 要旨: RADAR is a two-protein bacterial defense system that was reported to defend against phage by "editing" messenger RNA. Here, we determine cryo-EM structures of the RADAR defense complex, revealing ...RADAR is a two-protein bacterial defense system that was reported to defend against phage by "editing" messenger RNA. Here, we determine cryo-EM structures of the RADAR defense complex, revealing RdrA as a heptameric, two-layered AAA+ ATPase and RdrB as a dodecameric, hollow complex with twelve surface-exposed deaminase active sites. RdrA and RdrB join to form a giant assembly up to 10 MDa, with RdrA docked as a funnel over the RdrB active site. Surprisingly, our structures reveal an RdrB active site that targets mononucleotides. We show that RdrB catalyzes ATP-to-ITP conversion in vitro and induces the massive accumulation of inosine mononucleotides during phage infection in vivo, limiting phage replication. Our results define ATP mononucleotide deamination as a determinant of RADAR immunity and reveal supramolecular assembly of a nucleotide-modifying machine as a mechanism of anti-phage defense.