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==Structures of DHBN domain of Gallus gallus BLM helicase==
<StructureSection load='5lut' size='340' side='right'caption='[[5lut]], [[Resolution|resolution]] 2.72&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5lut]] is a 11 chain structure with sequence from [https://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5LUT OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5LUT FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.72&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</scene>, <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</scene></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=5lut FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5lut OCA], [https://pdbe.org/5lut PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5lut RCSB], [https://www.ebi.ac.uk/pdbsum/5lut PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5lut ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/BLM_CHICK BLM_CHICK] ATP-dependent DNA helicase that unwinds single- and double-stranded DNA in a 3'-5' direction (PubMed:28228481). Participates in DNA replication and repair (By similarity). Involved in 5'-end resection of DNA during double-strand break (DSB) repair (By similarity). Negatively regulates sister chromatid exchange (SCE) (By similarity). Stimulates DNA 4-way junction branch migration and DNA Holliday junction dissolution (By similarity). Binds DNA (PubMed:28228481). Binds single-stranded DNA (ssDNA), forked duplex DNA and DNA Holliday junction (By similarity).[UniProtKB:P54132]<ref>PMID:28228481</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Helicases play a critical role in processes such as replication or recombination by unwinding double-stranded DNA; mutations of these genes can therefore have devastating biological consequences. In human, mutations in genes of three members of the RecQ family helicases (blm, wrn and recq4) give rise to three strikingly distinctive clinical phenotypes: Bloom syndrome, Werner syndrome and Rothmund-Thomson syndrome, respectively. However, the molecular basis for these varying phenotypic outcomes is unclear, in part because a full mechanistic description of helicase activity is lacking. As the helicase core domains are highly conserved, it has been postulated that functional differences among family members might be explained by significant differences in the N-terminal domains, but these domains are poorly characterized. To help fill this gap, we now describe bioinformatics, biochemical, and structural data for three vertebrate BLM proteins. We pair high resolution crystal structures with SAXS analysis to describe an internal, highly conserved sequence we term the Dimerization Helical Bundle in N-terminal domain (DHBN). We show that, despite the N-terminal domain being loosely structured and potentially lacking a defined three dimensional structure in general, the DHBN exists as a dimeric structure required for higher order oligomer assembly. Interestingly, the unwinding amplitude and rate decrease as BLM is assembled from dimer into hexamer, and also, the stable DHBN dimer can be dissociated upon ATP hydrolysis. Thus, the structural and biochemical characterizations of N-terminal domains will provide new insights into how the N-terminal domain affects the structural and functional organization of the full BLM molecule.

A Helical Bundle in the N-terminal Domain of the BLM Helicase Mediates Dimer and Potentially Hexamer Formation.,Shi J, Chen WF, Zhang B, Fan SH, Ai X, Liu NN, Rety S, Xi XG J Biol Chem. 2017 Feb 22. pii: jbc.M116.761510. doi: 10.1074/jbc.M116.761510. PMID:28228481<ref>PMID:28228481</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5lut" style="background-color:#fffaf0;"></div>

==See Also==
*[[Helicase 3D structures|Helicase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Gallus gallus]]
[[Category: Large Structures]]
[[Category: Ai X]]
[[Category: Chen W-F]]
[[Category: Fan S-H]]
[[Category: Liu N-N]]
[[Category: Rety S]]
[[Category: Shi J]]
[[Category: Xi X-G]]
[[Category: Zhang B]]