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-Structure paper
| タイトル | Kiwa is a membrane-embedded defense supercomplex activated at phage attachment sites. |
|---|---|
| ジャーナル・号・ページ | Cell, Vol. 188, Issue 21, Page 5862-5877.e23, Year 2025 |
| 掲載日 | 2025年10月16日 |
著者 | Zhiying Zhang / Thomas C Todeschini / Yi Wu / Roman Kogay / Ameena Naji / Joaquin Cardenas Rodriguez / Rupavidhya Mondi / Daniel Kaganovich / David W Taylor / Jack P K Bravo / Marianna Teplova / Triana Amen / Eugene V Koonin / Dinshaw J Patel / Franklin L Nobrega / ![]() |
| PubMed 要旨 | Bacteria and archaea deploy diverse antiviral defense systems, many of which remain mechanistically uncharacterized. Here, we characterize Kiwa, a widespread two-component system composed of the ...Bacteria and archaea deploy diverse antiviral defense systems, many of which remain mechanistically uncharacterized. Here, we characterize Kiwa, a widespread two-component system composed of the transmembrane sensor KwaA and the DNA-binding effector KwaB. Cryogenic electron microscopy (cryo-EM) analysis reveals that KwaA and KwaB assemble into a large, membrane-associated supercomplex. Upon phage binding, KwaA senses infection at the membrane, leading to KwaB binding of ejected phage DNA and inhibition of replication and late transcription, without inducing host cell death. Although KwaB can bind DNA independently, its antiviral activity requires association with KwaA, suggesting spatial or conformational regulation. We show that the phage-encoded DNA-mimic protein Gam directly binds and inhibits KwaB but that co-expression with the Gam-targeted RecBCD system restores protection by Kiwa. Our findings support a model in which Kiwa coordinates membrane-associated detection of phage infection with downstream DNA binding by its effector, forming a spatially coordinated antiviral mechanism. |
リンク | Cell / PubMed:40730155 / PubMed Central |
| 手法 | EM (単粒子) / X線回折 |
| 解像度 | 3.6 - 4.28 Å |
| 構造データ | EMDB-48556, PDB-9mrg: EMDB-48562, PDB-9mrr: EMDB-48564, PDB-9mrx: EMDB-49973, PDB-9o0i: ![]() PDB-9mtn: ![]() PDB-9nyu: |
| 化合物 | ![]() ChemComp-AV0: |
| 由来 |
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キーワード | IMMUNE SYSTEM / Anti-phage / Kiwa / tetramer / KwaA tetramer / C4 / anti-phage defense / KwaA-KwaB complex / KwaB dimer / Kiwa system / ANTIVIRAL PROTEIN / Antiphage |
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