View source for 5hnk


==Crystal structure of T5Fen in complex intact substrate and metal ions.==
<StructureSection load='5hnk' size='340' side='right'caption='[[5hnk]], [[Resolution|resolution]] 2.22&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5hnk]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_virus_T5 Escherichia virus T5] 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=5HNK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5HNK 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]] 2.22&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</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=5hnk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5hnk OCA], [https://pdbe.org/5hnk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5hnk RCSB], [https://www.ebi.ac.uk/pdbsum/5hnk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5hnk ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/FEN_BPT5 FEN_BPT5] Catalyzes both the 5'-exonucleolytic and structure-specific endonucleolytic hydrolysis of DNA branched nucleic acid molecules and probably plays a role in viral genome replication (PubMed:9874768, PubMed:15077103, PubMed:10364212). Active on flap (branched duplex DNA containing a free single-stranded 5'-end), 5'overhangs and pseudo-Y structures (PubMed:9874768, PubMed:15077103, PubMed:10364212). The substrates require a free, single-stranded 5' end, with endonucleolytic hydrolysis occurring at the junction of double- and single-stranded DNA (PubMed:9874768). This function may be used for example to trim such branched molecules generated by Okazaki fragments synthesis during replication.[HAMAP-Rule:MF_04140]<ref>PMID:10364212</ref> <ref>PMID:15077103</ref> <ref>PMID:9874768</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Maintenance of genome integrity requires that branched nucleic acid molecules be accurately processed to produce double-helical DNA. Flap endonucleases are essential enzymes that trim such branched molecules generated by Okazaki-fragment synthesis during replication. Here, we report crystal structures of bacteriophage T5 flap endonuclease in complexes with intact DNA substrates and products, at resolutions of 1.9-2.2 A. They reveal single-stranded DNA threading through a hole in the enzyme, which is enclosed by an inverted V-shaped helical arch straddling the active site. Residues lining the hole induce an unusual barb-like conformation in the DNA substrate, thereby juxtaposing the scissile phosphate and essential catalytic metal ions. A series of complexes and biochemical analyses show how the substrate's single-stranded branch approaches, threads through and finally emerges on the far side of the enzyme. Our studies suggest that substrate recognition involves an unusual 'fly-casting, thread, bend and barb' mechanism.

Direct observation of DNA threading in flap endonuclease complexes.,AlMalki FA, Flemming CS, Zhang J, Feng M, Sedelnikova SE, Ceska T, Rafferty JB, Sayers JR, Artymiuk PJ Nat Struct Mol Biol. 2016 Jun 6. doi: 10.1038/nsmb.3241. PMID:27273516<ref>PMID:27273516</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 5hnk" style="background-color:#fffaf0;"></div>

==See Also==
*[[Exonuclease 3D structures|Exonuclease 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia virus T5]]
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Almalki FA]]
[[Category: Artymiuk PJ]]
[[Category: Feng M]]
[[Category: Rafferty JB]]
[[Category: Sayers JR]]
[[Category: Sedelnikova SE]]
[[Category: Zhang J]]