9W2P

ShosT_apo from E. coli KTE181

Summary for 9W2P

• Entry DOI: 10.2210/pdb9w2p/pdb
• Descriptor: ShosT, SULFATE ION (3 entities in total)
• Functional Keywords: prtase, two-domain architecture, monomer, immune system
• Biological source: Escherichia coli KTE181
• Total number of polymer chains: 3
• Total formula weight: 148650.29

Authors

Yang, R.,He, L.,Li, F. (deposition date: 2025-07-28, release date: 2026-04-22)

Primary citation

Yang, R.,He, L.,Wu, Z.,Wang, R.,Guo, H.,Yuan, R.,Su, H.,Chen, G.,Li, F.
The molecular mechanisms of the ShosTA system in mediating anti-phage defense.
Nucleic Acids Res., 54:-, 2026

PubMed Abstract: The ShosTA system, a two-component toxin-antitoxin (TA) system consisting of the ShosT and ShosA proteins, has recently been shown to mediate anti-phage defense. However, the molecular mechanisms underlying this system's role in anti-phage defense remain elusive. Here, we first confirmed that ShosT functions as the toxic component that induces cell death, while ShosA acts as the antitoxin to neutralize these toxic effects. We then solved the crystal structures of apo-ShosT, ShosA, and the ShosT-PRPP (phosphoribosyl pyrophosphate) complex. The structural data reveal that while ShosT contains a PRTase (phosphoribosyl-transferase) domain, it possesses unique noncanonical features; furthermore, we demonstrate that its binding to PRPP is indispensable for its toxic activity. ShosA is a DprA-like protein that functions as a homodimer. Both its ssDNA-binding and dimerization abilities are essential for its antitoxin activity. Further biochemical and structural studies demonstrate that ShosA directly binds to RecA, an interaction that is essential for neutralizing ShosT. The ShosA-RecA interaction is sensitive to the presence of ssDNA, implying that ShosTA-mediated abortive infection (Abi) may be triggered by the invading phage DNA. Our studies uncovered the mechanisms of ShosT inducing cell death and ShosA antagonizing the toxic effects of ShosT in anti-phage defense.

PubMed: 41784268
DOI: 10.1093/nar/gkag197

Experimental method

X-RAY DIFFRACTION (2.02 Å)