Database of articles cited by EMDB/PDB/SASBDB data

Keywords
Structure methods	All X-ray diffraction NMR electron microscopy small angle scattering neutron diffraction fiber diffraction powder diffraction infrared spectroscopy EPR fluorescence transfer theoretical model Hybrid
Author
Journal
IF	>30 >20 >10 >5 all

Title	Kiwa is a membrane-embedded defense supercomplex activated at phage attachment sites.
Journal, issue, pages	Cell, Vol. 188, Issue 21, Page 5862-5877.e23, Year 2025
Publish date	Oct 16, 2025
Authors	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 Abstract	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.
External links	Cell / PubMed:40730155 / PubMed Central
Methods	EM (single particle) / X-ray diffraction
Resolution	3.6 - 4.28 Å
Structure data	48556 9mrg EMDB-48556, PDB-9mrg: Cryo-EM structure of KwaA tetramer with C2 symmetry Method: EM (single particle) / Resolution: 3.69 Å 48562 9mrr EMDB-48562, PDB-9mrr: Cryo-EM structure of KwaA with C4 symmetry Method: EM (single particle) / Resolution: 4.28 Å 48564 9mrx EMDB-48564, PDB-9mrx: Cryo-EM structure of KwaA-KwaB complex Method: EM (single particle) / Resolution: 3.75 Å 49973 9o0i EMDB-49973, PDB-9o0i: Cryo-EM structure of Local KwaA-KwaB complex Method: EM (single particle) / Resolution: 3.86 Å PDB-9mtn: Crystal structure of KwaB Method: X-RAY DIFFRACTION / Resolution: 3.92 Å PDB-9nyu: Crystal structure of KwaB dimer Method: X-RAY DIFFRACTION / Resolution: 3.6 Å
Chemicals	ChemComp-AV0: Lauryl Maltose Neopentyl Glycol
Source	escherichia coli (E. coli)
Keywords	IMMUNE SYSTEM / Anti-phage / Kiwa / tetramer / KwaA tetramer / C4 / anti-phage defense / KwaA-KwaB complex / KwaB dimer / Kiwa system / ANTIVIRAL PROTEIN / Antiphage