View source for 4qzd


==Mouse Tdt, F405A mutant, in complex with a DSB substrate, C-C base pair==
<StructureSection load='4qzd' size='340' side='right'caption='[[4qzd]], [[Resolution|resolution]] 2.70&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4qzd]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Mus_musculus Mus musculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4QZD OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4QZD 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]] 2.7&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=DCT:2,3-DIDEOXYCYTIDINE+5-TRIPHOSPHATE'>DCT</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</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=4qzd FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4qzd OCA], [https://pdbe.org/4qzd PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4qzd RCSB], [https://www.ebi.ac.uk/pdbsum/4qzd PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4qzd ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/TDT_MOUSE TDT_MOUSE] Template-independent DNA polymerase which catalyzes the random addition of deoxynucleoside 5'-triphosphate to the 3'-end of a DNA initiator. One of the in vivo functions of this enzyme is the addition of nucleotides at the junction (N region) of rearranged Ig heavy chain and T-cell receptor gene segments during the maturation of B- and T-cells.
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== Publication Abstract from PubMed ==
Eukaryotic DNA polymerase mu of the PolX family can promote the association of the two 3'-protruding ends of a DNA double-strand break (DSB) being repaired (DNA synapsis) even in the absence of the core non-homologous end-joining (NHEJ) machinery. Here, we show that terminal deoxynucleotidyltransferase (TdT), a closely related PolX involved in V(D)J recombination, has the same property. We solved its crystal structure with an annealed DNA synapsis containing one micro-homology (MH) base pair and one nascent base pair. This structure reveals how the N-terminal domain and Loop 1 of Tdt cooperate for bridging the two DNA ends, providing a templating base in trans and limiting the MH search region to only two base pairs. A network of ordered water molecules is proposed to assist the incorporation of any nucleotide independently of the in trans templating base. These data are consistent with a recent model that explains the statistics of sequences synthesized in vivo by Tdt based solely on this dinucleotide step. Site-directed mutagenesis and functional tests suggest that this structural model is also valid for Pol mu during NHEJ.

Structural basis for a novel mechanism of DNA bridging and alignment in eukaryotic DSB DNA repair.,Gouge J, Rosario S, Romain F, Poitevin F, Beguin P, Delarue M EMBO J. 2015 Apr 15;34(8):1126-42. doi: 10.15252/embj.201489643. Epub 2015 Mar, 11. PMID:25762590<ref>PMID:25762590</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4qzd" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Mus musculus]]
[[Category: Delarue M]]
[[Category: Gouge J]]