EMD-29323
Structure of RdrA from Escherichia coli RADAR defense system
EMD-29323
Single-particle2.52 Å
Deposition: 28/12/2022Map released: 01/02/2023
Last modified: 19/06/2024
Sample Organism:
Escherichia coli
Sample: E. coli RdrA complex
Fitted models: 8fnt (Avg. Q-score: 0.486)
Deposition Authors: Duncan-Lowey B, Johnson AG
,
Rawson S ,
Mayer ML,
Kranzusch PJ
Sample: E. coli RdrA complex
Fitted models: 8fnt (Avg. Q-score: 0.486)
Deposition Authors: Duncan-Lowey B, Johnson AG
,
Rawson S ,
Mayer ML,
Kranzusch PJ
Cryo-EM structure of the RADAR supramolecular anti-phage defense complex.
Duncan-Lowey B,
Tal N,
Johnson AG ,
Rawson S ,
Mayer ML,
Doron S,
Millman A,
Melamed S ,
Fedorenko T,
Kacen A,
Brandis A,
Mehlman T,
Amitai G,
Sorek R,
Kranzusch PJ
(2023) Cell , 186 , 987
,
Rawson S ,
Mayer ML,
Doron S,
Millman A,
Melamed S ,
Fedorenko T,
Kacen A,
Brandis A,
Mehlman T,
Amitai G,
Sorek R,
Kranzusch PJ
(2023) Cell , 186 , 987
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.
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.