8HRB

Structure of tetradecameric RdrA ring in RNA-loading state

Summary for 8HRB

• Entry DOI: 10.2210/pdb8hrb/pdb
• EMDB information: 34966
• Descriptor: Archaeal ATPase, RNA (5'-R(*GP*UP*CP*CP*AP*GP*CP*GP*UP*CP*AP*UP*CP*GP*CP*UP*GP*GP*AP*C)-3'), ADENOSINE-5'-TRIPHOSPHATE (3 entities in total)
• Functional Keywords: cryoelectron microscopy, adenosine triphosphatase, immune system
• Biological source: Escherichia coli; More
• Total number of polymer chains: 20
• Total formula weight: 1542161.76

Authors

Gao, Y. (deposition date: 2022-12-15, release date: 2023-02-01, Last modification date: 2023-08-16)

Primary citation

Gao, Y.,Luo, X.,Li, P.,Li, Z.,Ye, F.,Liu, S.,Gao, P.
Molecular basis of RADAR anti-phage supramolecular assemblies.
Cell, 186:999-1012.e20, 2023

PubMed Abstract: Adenosine-to-inosine RNA editing has been proposed to be involved in a bacterial anti-phage defense system called RADAR. RADAR contains an adenosine triphosphatase (RdrA) and an adenosine deaminase (RdrB). Here, we report cryo-EM structures of RdrA, RdrB, and currently identified RdrA-RdrB complexes in the presence or absence of RNA and ATP. RdrB assembles into a dodecameric cage with catalytic pockets facing outward, while RdrA adopts both autoinhibited tetradecameric and activation-competent heptameric rings. Structural and functional data suggest a model in which RNA is loaded through the bottom section of the RdrA ring and translocated along its inner channel, a process likely coupled with ATP-binding status. Intriguingly, up to twelve RdrA rings can dock one RdrB cage with precise alignments between deaminase catalytic pockets and RNA-translocation channels, indicative of enzymatic coupling of RNA translocation and deamination. Our data uncover an interesting mechanism of enzymatic coupling and anti-phage defense through supramolecular assemblies.

PubMed: 36764292
DOI: 10.1016/j.cell.2023.01.026

Experimental method

ELECTRON MICROSCOPY (3.78 Å)