View source for 6mr8


==D276G DNA polymerase beta substrate complex with templating adenine and incoming Fapy-dGTP analog==
<StructureSection load='6mr8' size='340' side='right'caption='[[6mr8]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6mr8]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] 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=6MR8 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6MR8 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]] 1.897&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=GKS:1-[2-amino-5-(formylamino)-6-oxo-1,6-dihydropyrimidin-4-yl]-2,5-anhydro-1,3-dideoxy-6-O-[(R)-hydroxy{[(R)-hydroxy(phosphonooxy)phosphoryl]oxy}phosphoryl]-D-ribo-hexitol'>GKS</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=6mr8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6mr8 OCA], [https://pdbe.org/6mr8 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6mr8 RCSB], [https://www.ebi.ac.uk/pdbsum/6mr8 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6mr8 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/DPOLB_HUMAN DPOLB_HUMAN] Repair polymerase that plays a key role in base-excision repair. Has 5'-deoxyribose-5-phosphate lyase (dRP lyase) activity that removes the 5' sugar phosphate and also acts as a DNA polymerase that adds one nucleotide to the 3' end of the arising single-nucleotide gap. Conducts 'gap-filling' DNA synthesis in a stepwise distributive fashion rather than in a processive fashion as for other DNA polymerases.<ref>PMID:9207062</ref> <ref>PMID:9572863</ref> <ref>PMID:11805079</ref> <ref>PMID:21362556</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
4,6-Diamino-5-formamidopyrimidine (Fapy*dG) is an abundant form of oxidative DNA damage that is mutagenic and contributes to the pathogenesis of human disease. When Fapy*dG is in its nucleotide triphosphate form, Fapy*dGTP, it is inefficiently cleansed from the nucleotide pool by the responsible enzyme in Escherichia coli MutT and its mammalian homolog MTH1. Therefore, under oxidative stress conditions, Fapy*dGTP could become a pro-mutagenic substrate for insertion into the genome by DNA polymerases. Here, we evaluated insertion kinetics and high-resolution ternary complex crystal structures of a configurationally stable Fapy*dGTP analog, beta-C-Fapy*dGTP, with DNA polymerase beta. The crystallographic snapshots and kinetic data indicate that binding of beta-C-Fapy*dGTP impedes enzyme closure, thus hindering insertion. The structures reveal that an active site residue, Asp276, positions beta-C-Fapy*dGTP so that it distorts the geometry of critical catalytic atoms. Removal of this guardian side chain permits enzyme closure and increases the efficiency of beta-C-Fapy*dG insertion opposite dC. These results highlight the stringent requirements necessary to achieve a closed DNA polymerase active site poised for efficient nucleotide incorporation and illustrate how DNA polymerase beta has evolved to hinder Fapy*dGTP insertion.

A guardian residue hinders insertion of a Fapy*dGTP analog by modulating the open-closed DNA polymerase transition.,Smith MR, Shock DD, Beard WA, Greenberg MM, Freudenthal BD, Wilson SH Nucleic Acids Res. 2019 Jan 16. pii: 5289696. doi: 10.1093/nar/gkz002. PMID:30649431<ref>PMID:30649431</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6mr8" style="background-color:#fffaf0;"></div>

==See Also==
*[[DNA polymerase 3D structures|DNA polymerase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Beard WA]]
[[Category: Freudenthal BD]]
[[Category: Smith MR]]
[[Category: Wilson SH]]