View source for 9svk


==cryo-EM structure of LwHicAB-crRNA==
<StructureSection load='9svk' size='340' side='right'caption='[[9svk]], [[Resolution|resolution]] 3.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9svk]] is a 14 chain structure with sequence from [https://en.wikipedia.org/wiki/Leptotrichia_wadei_F0279 Leptotrichia wadei F0279]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9SVK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9SVK 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]] 3.4&#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=9svk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9svk OCA], [https://pdbe.org/9svk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9svk RCSB], [https://www.ebi.ac.uk/pdbsum/9svk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9svk ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/U2RCH0_LEPWF U2RCH0_LEPWF] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
CRISPR-Cas and toxin-antitoxin systems can serve as antiviral defense mechanisms in prokaryotes. In typical toxin-antitoxin systems, toxin activation can limit phage propagation by inducing growth arrest or reduced cellular fitness, while the antitoxin neutralizes toxin activity. Here, we study potential functional synergy between a CRISPR-Cas13a system and a type II toxin-antitoxin module (HicAB) from a Leptotrichia bacterium, when heterologously expressed in E. coli, as well as in biochemical and structural analyses. We show that the antitoxin HicB exhibits toxic properties, and Cas13a directly activates HicB, triggering growth inhibition and conferring protection against bacteriophages. Structural analyses reveal that Cas13a binding promotes the spatial proximity of HicB tetramers, likely enabling its activation. The toxin HicA competitively binds to HicB, thereby inhibiting Cas13a-mediated HicB activation. Importantly, both CRISPR RNA and HicB independently suppress HicA toxicity. Structural evidence indicates that CRISPR RNA forms a hetero-tetradecameric complex with HicAB, occluding HicA's active site and neutralizing its toxic function. Thus, our findings indicate functional synergy between distinct bacterial immune strategies.

Potential role of a CRISPR-Cas-activated toxin-antitoxin system in bacterial immunity.,Chen J, Huang L, Chen H, Li X, Lin X, Guo C, Liu X, Fu G, Chen Y, Liu L Nat Commun. 2026 Jun 26;17(1):7995. doi: 10.1038/s41467-026-74930-z. PMID:42362581<ref>PMID:42362581</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 9svk" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Leptotrichia wadei F0279]]
[[Category: Jiyun C]]
[[Category: Liang L]]
[[Category: Xueyan L]]