View source for 3kxb


==Structural characterization of H3K56Q nucleosomes and nucleosomal arrays==
<StructureSection load='3kxb' size='340' side='right'caption='[[3kxb]], [[Resolution|resolution]] 3.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3kxb]] is a 10 chain structure with sequence from [https://en.wikipedia.org/wiki/Xenopus_laevis Xenopus laevis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3KXB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3KXB 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]] 3.2&#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=3kxb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3kxb OCA], [https://pdbe.org/3kxb PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3kxb RCSB], [https://www.ebi.ac.uk/pdbsum/3kxb PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3kxb ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/H4_XENLA H4_XENLA] Core component of nucleosome. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/kx/3kxb_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=3kxb ConSurf].
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== Publication Abstract from PubMed ==
The post-translational modification of histones is a key mechanism for the modulation of DNA accessibility. Acetylated lysine 56 in histone H3 is associated with nucleosome assembly during replication and DNA repair, and is thus likely to predominate in regions of chromatin containing nucleosome-free regions. Here we show by X-ray crystallography that mutation of H3 lysine 56 to glutamine (to mimic acetylation) or glutamate (to cause a charge reversal) has no detectable effects on the structure of the nucleosome. At the level of higher order chromatin structure, the K to Q substitution has no effect on the folding of model nucleosomal arrays in cis, regardless of the degree of nucleosome density. In contrast, defects in array-array interactions in trans ('oligomerization') are selectively observed for mutant H3 lysine 56 arrays that contain nucleosome-free regions. Our data suggests that H3K56 acetylation is one of the molecular mechanisms employed to keep chromatin with nucleosome-free regions accessible to the DNA replication and repair machinery.

Structural characterization of H3K56Q nucleosomes and nucleosomal arrays.,Watanabe S, Resch M, Lilyestrom W, Clark N, Hansen JC, Peterson C, Luger K Biochim Biophys Acta. 2010 May-Jun;1799(5-6):480-6. Epub 2010 Jan 25. PMID:20100606<ref>PMID:20100606</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 3kxb" style="background-color:#fffaf0;"></div>

==See Also==
*[[Histone 3D structures|Histone 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Xenopus laevis]]
[[Category: Clark NJ]]
[[Category: Lilyestrom WG]]