View source for 30mn


==PLD-fold vaccinia virus endonuclease K4 with DNA==
<StructureSection load='30mn' size='340' side='right'caption='[[30mn]], [[Resolution|resolution]] 2.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[30mn]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Vaccinia_virus Vaccinia virus] 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=30MN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=30MN FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 2.6&#8491;</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=30mn FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=30mn OCA], [https://pdbe.org/30mn PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=30mn RCSB], [https://www.ebi.ac.uk/pdbsum/30mn PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=30mn ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/PG042_VACCC PG042_VACCC] DNA nicking enzyme that cleaves extruded cruciform DNA at its tip. Probably nicks viral hairpins.[UniProtKB:P18377]
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== Publication Abstract from PubMed ==
Vaccinia virus (VACV) is an orthopoxvirus closely related to mpox virus, which started global outbreaks in 2022. Poxvirus genomes are flanked by short, inverted complementary hairpin telomeres that feature mismatched bases and insertions essential for viral replication. In this context, a role of the late protein K4 has been proposed. K4 is present in the virion, is apparently non-essential and has a phospholipase D (PLD)-fold as has VACV F13 protein. It also shares fold and nuclease activity with its closest homologue, mammalian PLD3. We established an endonuclease activity against ssDNA and hairpin loops and bubbles in a dsDNA context while RNA is resistant to cleavage. The 2.4 A cryo-EM structure of K4 shows an unusual octameric assembly, also present in solution. At low concentration, tetramers and dimers similar to the one of hPLD3 are also present. Despite its nuclease activity, in K4 a C-terminal extension blocks the DNA binding pockets. Using an inactive mutant, fortuitously, a DNA 19mer bound simultaneously to 2 sites of the octamer where it displaced the C-termini. DNA binding uses similar residues as the hPLD3 5'-exonuclease, despite different activities and orientations of the DNA. The role of K4 and the control of its activity by the observed auto-inhibition remain enigmatic.

High-resolution Structure of the Vaccinia Virus Phospholipase D-fold Endonuclease K4.,Groger H, Trouba C, Barbaste J, Lacroix G, Schoehn G, Burmeister WP, Tarbouriech N J Mol Biol. 2026 Jul 29;438(21):169961. doi: 10.1016/j.jmb.2026.169961. PMID:42526583<ref>PMID:42526583</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 30mn" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Vaccinia virus]]
[[Category: Burmeister WP]]
[[Category: Groger H]]
[[Category: Tarbouriech N]]