View source for 5mz6


==Cryo-EM structure of a Separase-Securin complex from Caenorhabditis elegans at 3.8 A resolution==
<SX load='5mz6' size='340' side='right' viewer='molstar' caption='[[5mz6]], [[Resolution|resolution]] 3.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5mz6]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Caenorhabditis_elegans Caenorhabditis elegans]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5MZ6 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5MZ6 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]] 3.8&#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=5mz6 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5mz6 OCA], [https://pdbe.org/5mz6 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5mz6 RCSB], [https://www.ebi.ac.uk/pdbsum/5mz6 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5mz6 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/SEP1_CAEEL SEP1_CAEEL] Cysteine protease, which plays a central role in homologous chromosome separation during meiosis I and in sister chromatid separation during embryonic mitosis (PubMed:11728305, PubMed:12498686, PubMed:20116245, PubMed:21878498). Promotes chromosome/sister chromatid segregation by cleaving the scc-1 (mitosis) and rec-8 (meiosis) subunits of the cohesin complex at the onset of anaphase (Probable). May cleave histone H3-like protein cpar-1 during meiosis I metaphase-anaphase transition (PubMed:25919583). Promotes cortical granule exocytosis after oocyte fertilization during the first meiotic anaphase (PubMed:17913784, PubMed:21878498). Essential for embryonic cytokinesis by regulating rab-11-positive vesicle trafficking at the plasma membrane at the cleavage furrow and midbody (PubMed:20116245). Regulates centriole segregation during spermatocyte meiosis (PubMed:23401519). Required for embryonic anterior-posterior axis formation (PubMed:11832245).<ref>PMID:11728305</ref> <ref>PMID:11832245</ref> <ref>PMID:12498686</ref> <ref>PMID:17913784</ref> <ref>PMID:20116245</ref> <ref>PMID:21878498</ref> <ref>PMID:23401519</ref> <ref>PMID:25919583</ref> 
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== Publication Abstract from PubMed ==
Separase is a caspase-family protease that initiates chromatid segregation by cleaving the kleisin subunits (Scc1 and Rec8) of cohesin, and regulates centrosome duplication and mitotic spindle function through cleavage of kendrin and Slk19. To understand the mechanisms of securin regulation of separase, we used single-particle cryo-electron microscopy (cryo-EM) to determine a near-atomic-resolution structure of the Caenorhabditis elegans separase-securin complex. Separase adopts a triangular-shaped bilobal architecture comprising an N-terminal tetratricopeptide repeat (TPR)-like alpha-solenoid domain docked onto the conserved C-terminal protease domain. Securin engages separase in an extended antiparallel conformation, interacting with both lobes. It inhibits separase by interacting with the catalytic site through a pseudosubstrate mechanism, thus revealing that in the inhibited separase-securin complex, the catalytic site adopts a conformation compatible with substrate binding. Securin is protected from cleavage because an aliphatic side chain at the P1 position represses protease activity by disrupting the organization of catalytic site residues.

Cryo-EM structure of a metazoan separase-securin complex at near-atomic resolution.,Boland A, Martin TG, Zhang Z, Yang J, Bai XC, Chang L, Scheres SH, Barford D Nat Struct Mol Biol. 2017 Mar 6. doi: 10.1038/nsmb.3386. PMID:28263324<ref>PMID:28263324</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 5mz6" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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[[Category: Caenorhabditis elegans]]
[[Category: Large Structures]]
[[Category: Bai XC]]
[[Category: Barford D]]
[[Category: Boland A]]
[[Category: Chang L]]
[[Category: Martin TG]]
[[Category: Scheres SHW]]
[[Category: Yang J]]
[[Category: Zhang Z]]