Download MendeleyCryo-EM structure of the RADAR supramolecular anti-phage defense complex.
Duncan-Lowey, B., Tal, N., Johnson, A.G., Rawson, S., Mayer, M.L., Doron, S., Millman, A., Melamed, S., Fedorenko, T., Kacen, A., Brandis, A., Mehlman, T., Amitai, G., Sorek, R., Kranzusch, P.J.(2023) Cell 186: 987
- PubMed: 36764290
- DOI: https://doi.org/10.1016/j.cell.2023.01.012
- Primary Citation of Related Structures:
8FNT, 8FNU, 8FNV, 8FNW - PubMed Abstract:
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.
Organizational Affiliation:
Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
