9WIW

Crystal structure of a Escherichia phage UPEC07 protein

Summary for 9WIW

• Entry DOI: 10.2210/pdb9wiw/pdb
• Descriptor: Endoribonuclease, SULFATE ION (3 entities in total)
• Functional Keywords: helix, dimer, sponge protein, anti typeiv thoeris, antimicrobial protein
• Biological source: Escherichia phage T4
• Total number of polymer chains: 1
• Total formula weight: 13068.47

Authors

Wang, H.,Feng, Y.,Wei, L.L. (deposition date: 2025-08-29, release date: 2026-03-04, Last modification date: 2026-09-16)

Primary citation

Chen, Y.,Wei, L.,Han, Z.,Zhao, R.,Zeng, Z.,Liu, Y.,Zhang, P.,Tan, K.,Fan, Y.,Sheng, L.,Wang, H.,Pinilla-Redondo, R.,Feng, Y.,Han, W.
A phage-encoded sponge protein suppresses bacterial TIR-Caspase immune signaling.
Nat Commun, 17:-, 2026

PubMed Abstract: Triggering immune response through generation of signal molecules is a common immune strategy across all domains of life. In the bacterial type IV Thoeris anti-phage system, a Toll/interleukin-1 receptor (TIR)-domain protein produces adenosine 5'-diphosphate-cyclo[N7:1"]-ribose (N7-cADPR) as the immune signal to activate a Caspase-like effector. Here, we identified an inhibitor of type IV Thoeris through a phage mating assay that allows a sensitive phage to acquire anti-defense genes from related resistant phages. The inhibitor (hereafter TadIV-1) functions as a sponge that sequesters the N7-cADPR signal to inhibit Caspase activation. Structural analyses of TadIV-1 indicate a distinctive signal binding mechanism, wherein the binding pocket comprises its N-terminal flexible loop. In addition, phages lacking TadIV-1 can escape type IV Thoeris sensing through mutation in the capsid vertex protein. Collectively, this work expands the phage anti-defense arsenal with a unique immune signal sequestration mechanism and provides insights into phage invasion recognition mechanism of type IV Thoeris.

PubMed: 41968157
DOI: 10.1038/s41467-026-71527-4

Experimental method

X-RAY DIFFRACTION (2.56 Å)