1qum

<table><tr><td colspan='2'>[[1qum]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/"bacillus_coli"_migula_1895 "bacillus coli" migula 1895]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QUM OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1QUM FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>

<tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=3DR:1,2-DIDEOXYRIBOFURANOSE-5-PHOSPHATE'>3DR</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[1qtw|1qtw]]</div></td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Deoxyribonuclease_IV_(phage-T(4)-induced) Deoxyribonuclease IV (phage-T(4)-induced)], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.21.2 3.1.21.2] </span></td></tr>

[[https://www.uniprot.org/uniprot/END4_ECOLI END4_ECOLI]] Endonuclease IV plays a role in DNA repair. It cleaves phosphodiester bonds at apurinic or apyrimidinic sites (AP sites) to produce new 5'-ends that are base-free deoxyribose 5-phosphate residues. It preferentially attacks modified AP sites created by bleomycin and neocarzinostatin.

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== Publication Abstract from PubMed ==

Endonuclease IV is the archetype for a conserved apurinic/apyrimidinic (AP) endonuclease family that primes DNA repair synthesis by cleaving the DNA backbone 5' of AP sites. The crystal structures of Endonuclease IV and its AP-DNA complex at 1.02 and 1.55 A resolution reveal how an alpha8beta8 TIM barrel fold can bind dsDNA. Enzyme loops intercalate side chains at the abasic site, compress the DNA backbone, bend the DNA approximately 90 degrees, and promote double-nucleotide flipping to sequester the extrahelical AP site in an enzyme pocket that excludes undamaged nucleotides. These structures suggest three Zn2+ ions directly participate in phosphodiester bond cleavage and prompt hypotheses that double-nucleotide flipping and sharp bending by AP endonucleases provide exquisite damage specificity while aiding subsequent base excision repair pathway progression.

Structure of the DNA repair enzyme endonuclease IV and its DNA complex: double-nucleotide flipping at abasic sites and three-metal-ion catalysis.,Hosfield DJ, Guan Y, Haas BJ, Cunningham RP, Tainer JA Cell. 1999 Aug 6;98(3):397-408. PMID:10458614<ref>PMID:10458614</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 1qum" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Bacillus coli migula 1895]]

[[Category: Cunningham, R P]]

[[Category: Guan, Y]]

[[Category: Haas, B J]]

[[Category: Hosfield, D J]]

[[Category: Tainer, J A]]

[[Category: Trinuclear zn cluster]]