View source for 7ssa


==Cryo-EM structure of pioneer factor Cbf1 bound to the nucleosome==
<StructureSection load='7ssa' size='340' side='right'caption='[[7ssa]], [[Resolution|resolution]] 3.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7ssa]] is a 12 chain structure with sequence from [https://en.wikipedia.org/wiki/Saccharomyces_cerevisiae_S288C Saccharomyces cerevisiae S288C], [https://en.wikipedia.org/wiki/Xenopus_laevis Xenopus laevis] 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=7SSA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7SSA 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]] 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=7ssa FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7ssa OCA], [https://pdbe.org/7ssa PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7ssa RCSB], [https://www.ebi.ac.uk/pdbsum/7ssa PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7ssa ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/H32_XENLA H32_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.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Nucleosomes drastically limit transcription factor (TF) occupancy, while pioneer transcription factors (PFs) somehow circumvent this nucleosome barrier. In this study, we compare nucleosome binding of two conserved S. cerevisiae basic helix-loop-helix (bHLH) TFs, Cbf1 and Pho4. A cryo-EM structure of Cbf1 in complex with the nucleosome reveals that the Cbf1 HLH region can electrostatically interact with exposed histone residues within a partially unwrapped nucleosome. Single-molecule fluorescence studies show that the Cbf1 HLH region facilitates efficient nucleosome invasion by slowing its dissociation rate relative to DNA through interactions with histones, whereas the Pho4 HLH region does not. In vivo studies show that this enhanced binding provided by the Cbf1 HLH region enables nucleosome invasion and ensuing repositioning. These structural, single-molecule, and in vivo studies reveal the mechanistic basis of dissociation rate compensation by PFs and how this translates to facilitating chromatin opening inside cells.

Basic helix-loop-helix pioneer factors interact with the histone octamer to invade nucleosomes and generate nucleosome-depleted regions.,Donovan BT, Chen H, Eek P, Meng Z, Jipa C, Tan S, Bai L, Poirier MG Mol Cell. 2023 Apr 20;83(8):1251-1263.e6. doi: 10.1016/j.molcel.2023.03.006. Epub , 2023 Mar 29. PMID:36996811<ref>PMID:36996811</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7ssa" style="background-color:#fffaf0;"></div>

==See Also==
*[[Histone 3D structures|Histone 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Saccharomyces cerevisiae S288C]]
[[Category: Synthetic construct]]
[[Category: Xenopus laevis]]
[[Category: Eek P]]
[[Category: Tan S]]