View source for 6qsz


==Crystal structure of the Sir4 H-BRCT domain in complex with Esc1 pS1450 peptide==
<StructureSection load='6qsz' size='340' side='right'caption='[[6qsz]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6qsz]] is a 16 chain structure with sequence from [https://en.wikipedia.org/wiki/Saccharomyces_cerevisiae_S288C Saccharomyces cerevisiae S288C]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6QSZ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6QSZ 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]] 2.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</scene>, <scene name='pdbligand=SEP:PHOSPHOSERINE'>SEP</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=6qsz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6qsz OCA], [https://pdbe.org/6qsz PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6qsz RCSB], [https://www.ebi.ac.uk/pdbsum/6qsz PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6qsz ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/SIR4_YEAST SIR4_YEAST] The proteins SIR1 through SIR4 are required for transcriptional repression of the silent mating type loci, HML and HMR. The proteins SIR2 through SIR4 repress mulitple loci by modulating chromatin structure. Involves the compaction of chromatin fiber into a more condensed form.<ref>PMID:18039933</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
In Saccharomyces cerevisiae, the silent information regulator (SIR) proteins Sir2/3/4 form a complex that suppresses transcription in subtelomeric regions and at the homothallic mating-type (HM) loci. Here, we identify a non-canonical BRCA1 C-terminal domain (H-BRCT) in Sir4, which is responsible for tethering telomeres to the nuclear periphery. We show that Sir4 H-BRCT and the closely related Dbf4 H-BRCT serve as selective phospho-epitope recognition domains that bind to a variety of phosphorylated target peptides. We present detailed structural information about the binding mode of established Sir4 interactors (Esc1, Ty5, Ubp10) and identify several novel interactors of Sir4 H-BRCT, including the E3 ubiquitin ligase Tom1. Based on these findings, we propose a phospho-peptide consensus motif for interaction with Sir4 H-BRCT and Dbf4 H-BRCT. Ablation of the Sir4 H-BRCT phospho-peptide interaction disrupts SIR-mediated repression and perinuclear localization. In conclusion, the Sir4 H-BRCT domain serves as a hub for recruitment of phosphorylated target proteins to heterochromatin to properly regulate silencing and nuclear order.

The Sir4 H-BRCT domain interacts with phospho-proteins to sequester and repress yeast heterochromatin.,Deshpande I, Keusch JJ, Challa K, Iesmantavicius V, Gasser SM, Gut H EMBO J. 2019 Oct 15;38(20):e101744. doi: 10.15252/embj.2019101744. Epub 2019 Sep , 12. PMID:31515872<ref>PMID:31515872</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6qsz" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Saccharomyces cerevisiae S288C]]
[[Category: Challa K]]
[[Category: Deshpande I]]
[[Category: Gasser SM]]
[[Category: Gut H]]
[[Category: Iesmantavicius V]]
[[Category: Keusch JJ]]