8BTP image
Entry Detail
PDB ID:
8BTP
EMDB ID:
Keywords:
Title:
Helical structure of BcThsA in complex with 1''-3'gc(etheno)ADPR
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2022-11-29
Release Date:
2024-02-21
Method Details:
Experimental Method:
Resolution:
2.75 Å
Aggregation State:
HELICAL ARRAY
Reconstruction Method:
HELICAL
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:NAD(+) hydrolase ThsA
Mutations:N112A
Chain IDs:A, B, C, D, E, F, G, H, I, J, K, L
Chain Length:479
Number of Molecules:12
Biological Source:Bacillus cereus MSX-D12
Primary Citation
Activation of Thoeris antiviral system via SIR2 effector filament assembly.
Nature 627 431 436 (2024)
PMID: 38383786 DOI: 10.1038/s41586-024-07092-x

Abstact

To survive bacteriophage (phage) infections, bacteria developed numerous anti-phage defence systems1-7. Some of them (for example, type III CRISPR-Cas, CBASS, Pycsar and Thoeris) consist of two modules: a sensor responsible for infection recognition and an effector that stops viral replication by destroying key cellular components8-12. In the Thoeris system, a Toll/interleukin-1 receptor (TIR)-domain protein, ThsB, acts as a sensor that synthesizes an isomer of cyclic ADP ribose, 1''-3' glycocyclic ADP ribose (gcADPR), which is bound in the Smf/DprA-LOG (SLOG) domain of the ThsA effector and activates the silent information regulator 2 (SIR2)-domain-mediated hydrolysis of a key cell metabolite, NAD+ (refs. 12-14). Although the structure of ThsA has been solved15, the ThsA activation mechanism remained incompletely understood. Here we show that 1''-3' gcADPR, synthesized in vitro by the dimeric ThsB' protein, binds to the ThsA SLOG domain, thereby activating ThsA by triggering helical filament assembly of ThsA tetramers. The cryogenic electron microscopy (cryo-EM) structure of activated ThsA revealed that filament assembly stabilizes the active conformation of the ThsA SIR2 domain, enabling rapid NAD+ depletion. Furthermore, we demonstrate that filament formation enables a switch-like response of ThsA to the 1''-3' gcADPR signal.

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