View source for 9vnq


==Bacillus Subtilis Ku core homodimer complexed with double strand DNA==
<StructureSection load='9vnq' size='340' side='right'caption='[[9vnq]], [[Resolution|resolution]] 2.74&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9vnq]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacillus_subtilis Bacillus subtilis] and [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9VNQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9VNQ 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]] 2.74&#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=9vnq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9vnq OCA], [https://pdbe.org/9vnq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9vnq RCSB], [https://www.ebi.ac.uk/pdbsum/9vnq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9vnq ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/KU_BACSU KU_BACSU] With LigD forms a non-homologous end joining (NHEJ) DNA repair enzyme, which repairs dsDNA breaks with reduced fidelity. Binds linear dsDNA with 5'- and 3'- overhangs but not closed circular dsDNA nor ssDNA. Recruits and stimulates the ligase activity of LigD (By similarity). Probably involved in DNA repair during spore germination.[HAMAP-Rule:MF_01875]<ref>PMID:16497325</ref> 
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== Publication Abstract from PubMed ==
DNA double-strand breaks (DSBs) pose a severe threat to genomic integrity, and cells rely on two major pathways for repair: homologous recombination and non-homologous end joining (NHEJ). While eukaryotic NHEJ requires a multi-component assembly including the Ku70/80 heterodimer, bacterial NHEJ operates with a simpler toolkit comprising a Ku homodimer and the multifunctional LigD. Despite this simplicity, the mechanism by which broken DNA ends are bridged together has remained unclear in bacterial NHEJ. Here, we present a cryo-electron microscopy structure of the Bacillus subtilis Ku (bsKu)-DNA complex at 2.74 A resolution, capturing two blunt DNA ends bridged by a Ku protein alone. Supported by further biochemical assays, we propose an integrated model in which oligomeric arrays of Ku homodimers bridge and stabilize two DNA ends, facilitating efficient DSB repair in Bacillus subtilis. This work reveals a bsKu-mediated DNA bridging mechanism distinct from the eukaryotic system and provides critical structural insight into prokaryotic DNA repair.

Structure of Bacillus subtilis Ku-mediated DNA synaptic complex.,Kim WJ, Kim J, Jo M, Kim Y, Kim MS Nucleic Acids Res. 2025 Oct 21:gkaf1036. doi: 10.1093/nar/gkaf1036. PMID:41118517<ref>PMID:41118517</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
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</StructureSection>
[[Category: Bacillus subtilis]]
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Kim MS]]
[[Category: Kim WJ]]