View source for 7lsy


==NHEJ Short-range synaptic complex==
<StructureSection load='7lsy' size='340' side='right'caption='[[7lsy]], [[Resolution|resolution]] 8.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7lsy]] is a 17 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7LSY OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7LSY 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]] 8.4&#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=7lsy FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7lsy OCA], [https://pdbe.org/7lsy PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7lsy RCSB], [https://www.ebi.ac.uk/pdbsum/7lsy PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7lsy ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/XRCC6_HUMAN XRCC6_HUMAN] Single stranded DNA-dependent ATP-dependent helicase. Has a role in chromosome translocation. The DNA helicase II complex binds preferentially to fork-like ends of double-stranded DNA in a cell cycle-dependent manner. It works in the 3'-5' direction. Binding to DNA may be mediated by XRCC6. Involved in DNA non-homologous end joining (NHEJ) required for double-strand break repair and V(D)J recombination. The XRCC5/6 dimer acts as regulatory subunit of the DNA-dependent protein kinase complex DNA-PK by increasing the affinity of the catalytic subunit PRKDC to DNA by 100-fold. The XRCC5/6 dimer is probably involved in stabilizing broken DNA ends and bringing them together. The assembly of the DNA-PK complex to DNA ends is required for the NHEJ ligation step. Required for osteocalcin gene expression. Probably also acts as a 5'-deoxyribose-5-phosphate lyase (5'-dRP lyase), by catalyzing the beta-elimination of the 5' deoxyribose-5-phosphate at an abasic site near double-strand breaks. 5'-dRP lyase activity allows to 'clean' the termini of abasic sites, a class of nucleotide damage commonly associated with strand breaks, before such broken ends can be joined. The XRCC5/6 dimer together with APEX1 acts as a negative regulator of transcription.<ref>PMID:2466842</ref> <ref>PMID:8621488</ref> <ref>PMID:7957065</ref> <ref>PMID:9742108</ref> <ref>PMID:12145306</ref> <ref>PMID:20493174</ref> <ref>PMID:20383123</ref> 
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== Publication Abstract from PubMed ==
DNA double-strand breaks (DSBs) are a highly cytotoxic form of DNA damage and the incorrect repair of DSBs is linked to carcinogenesis(1,2). The conserved error-prone non-homologous end joining (NHEJ) pathway has a key role in determining the effects of DSB-inducing agents that are used to treat cancer as well as the generation of the diversity in antibodies and T cell receptors(2,3). Here we applied single-particle cryo-electron microscopy to visualize two key DNA-protein complexes that are formed by human NHEJ factors. The Ku70/80 heterodimer (Ku), the catalytic subunit of the DNA-dependent protein kinase (DNA-PKcs), DNA ligase IV (LigIV), XRCC4 and XLF form a long-range synaptic complex, in which the DNA ends are held approximately 115 A apart. Two DNA end-bound subcomplexes comprising Ku and DNA-PKcs are linked by interactions between the DNA-PKcs subunits and a scaffold comprising LigIV, XRCC4, XLF, XRCC4 and LigIV. The relative orientation of the DNA-PKcs molecules suggests a mechanism for autophosphorylation in trans, which leads to the dissociation of DNA-PKcs and the transition into the short-range synaptic complex. Within this complex, the Ku-bound DNA ends are aligned for processing and ligation by the XLF-anchored scaffold, and a single catalytic domain of LigIV is stably associated with a nick between the two Ku molecules, which suggests that the joining of both strands of a DSB involves both LigIV molecules.

Structural basis of long-range to short-range synaptic transition in NHEJ.,Chen S, Lee L, Naila T, Fishbain S, Wang A, Tomkinson AE, Lees-Miller SP, He Y Nature. 2021 May;593(7858):294-298. doi: 10.1038/s41586-021-03458-7. Epub 2021 , Apr 14. PMID:33854234<ref>PMID:33854234</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 7lsy" style="background-color:#fffaf0;"></div>

==See Also==
*[[DNA ligase 3D structures|DNA ligase 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Chen S]]
[[Category: He Y]]