View source for 3kmj


==Crystal structure of vSET under condition B==
<StructureSection load='3kmj' size='340' side='right'caption='[[3kmj]], [[Resolution|resolution]] 1.85&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3kmj]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Paramecium_bursaria_Chlorella_virus_1 Paramecium bursaria Chlorella virus 1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3KMJ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3KMJ 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]] 1.85&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=3kmj FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3kmj OCA], [https://pdbe.org/3kmj PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3kmj RCSB], [https://www.ebi.ac.uk/pdbsum/3kmj PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3kmj ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/O41094_PBCV1 O41094_PBCV1] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Histone modifications are regarded as the most indispensible phenomena in epigenetics. Of these modifications, lysine methylation is of the greatest complexity and importance as site- and state-specific lysine methylation exerts a plethora of effects on chromatin structure and gene transcription. Notably, paramecium bursaria chlorella viruses encode a conserved SET domain methyltransferase, termed vSET, that functions to suppress host transcription by methylating histone H3 at lysine 27 (H3K27), a mark for eukaryotic gene silencing. Unlike mammalian lysine methyltransferases (KMTs), vSET functions only as a dimer, but the underlying mechanism has remained elusive. In this study, we demonstrate that dimeric vSET operates with negative cooperativity between the two active sites and engages in H3K27 methylation one site at a time. New atomic structures of vSET in the free form and a ternary complex with S-adenosyl homocysteine and a histone H3 peptide and biochemical analyses reveal the molecular origin for the negative cooperativity and explain the substrate specificity of H3K27 methyltransferases. Our study suggests a "walking" mechanism, by which vSET acts all by itself to globally methylate host H3K27, which is accomplished by the mammalian EZH2 KMT only in the context of the Polycomb repressive complex.

Dimerization of a viral SET protein endows its function.,Wei H, Zhou MM Proc Natl Acad Sci U S A. 2010 Oct 26;107(43):18433-8. Epub 2010 Oct 11. PMID:20937900<ref>PMID:20937900</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3kmj" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Paramecium bursaria Chlorella virus 1]]
[[Category: Wei H]]
[[Category: Zhou MM]]