View source for 9wxf


==cryo-electron microscopy structure of Dandelion==
<StructureSection load='9wxf' size='340' side='right'caption='[[9wxf]], [[Resolution|resolution]] 3.33&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9wxf]] is a 12 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9WXF OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9WXF FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.33&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=9wxf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9wxf OCA], [https://pdbe.org/9wxf PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9wxf RCSB], [https://www.ebi.ac.uk/pdbsum/9wxf PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9wxf ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The evolutionary arms race between bacteria and phages has driven the diversification of prokaryotic antiviral defense mechanisms, with nucleic acid degradation emerging as a central strategy. Here, we investigate a Higher Eukaryotes and Prokaryotes Nucleotide-binding (HEPN) domain-containing defense system from Escherichia coli that mediates RNase-dependent abortive infection. In contrast to canonical immune systems, where oligomerization triggers signaling, this system adopts a dodecameric autoinhibited architecture, with RNase activity unleashed upon oligomer dissociation. This activation mechanism is reminiscent of the dispersal of dandelion seeds, and we therefore term this defense system "Dandelion." We further identify the phage single-stranded DNA-binding (SSB) protein as a trigger for the Dandelion system, and phylogenetic analysis of SSB proteins uncovers the specificity underlying phage resistance. Our findings reveal a counterintuitive paradigm in bacterial immunity-âoligomer disassembly as an activation switch, which challenges the long-standing dogma that protein oligomerization activates immune signaling.

Oligomer disassembly activates an HEPN-containing bacterial defense system.,Tang Y, Liu T, Xiong C, Chen Q, Yu Y Mol Cell. 2026 Jul 2;86(13):2560-2571.e5. doi: 10.1016/j.molcel.2026.06.008. Epub , 2026 Jun 25. PMID:42349403<ref>PMID:42349403</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 9wxf" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Chen Q]]
[[Category: Tang Y]]
[[Category: Yu Y]]