7NJ1

CryoEM structure of the human Separase-Securin complex


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 2.90 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structural basis of human separase regulation by securin and CDK1-cyclin B1.

Yu, J.Raia, P.Ghent, C.M.Raisch, T.Sadian, Y.Cavadini, S.Sabale, P.M.Barford, D.Raunser, S.Morgan, D.O.Boland, A.

(2021) Nature 596: 138-142

  • DOI: https://doi.org/10.1038/s41586-021-03764-0
  • Primary Citation of Related Structures:  
    7NJ0, 7NJ1

  • PubMed Abstract: 

    In early mitosis, the duplicated chromosomes are held together by the ring-shaped cohesin complex 1 . Separation of chromosomes during anaphase is triggered by separase-a large cysteine endopeptidase that cleaves the cohesin subunit SCC1 (also known as RAD21 2-4 ). Separase is activated by degradation of its inhibitors, securin 5 and cyclin B 6 , but the molecular mechanisms of separase regulation are not clear. Here we used cryogenic electron microscopy to determine the structures of human separase in complex with either securin or CDK1-cyclin B1-CKS1. In both complexes, separase is inhibited by pseudosubstrate motifs that block substrate binding at the catalytic site and at nearby docking sites. As in Caenorhabditis elegans 7 and yeast 8 , human securin contains its own pseudosubstrate motifs. By contrast, CDK1-cyclin B1 inhibits separase by deploying pseudosubstrate motifs from intrinsically disordered loops in separase itself. One autoinhibitory loop is oriented by CDK1-cyclin B1 to block the catalytic sites of both separase and CDK1 9,10 . Another autoinhibitory loop blocks substrate docking in a cleft adjacent to the separase catalytic site. A third separase loop contains a phosphoserine 6 that promotes complex assembly by binding to a conserved phosphate-binding pocket in cyclin B1. Our study reveals the diverse array of mechanisms by which securin and CDK1-cyclin B1 bind and inhibit separase, providing the molecular basis for the robust control of chromosome segregation.


  • Organizational Affiliation

    Department of Molecular Biology, University of Geneva, Geneva, Switzerland.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Separin2,160Homo sapiensMutation(s): 0 
Gene Names: ESPL1ESP1KIAA0165
EC: 3.4.22.49
UniProt & NIH Common Fund Data Resources
Find proteins for Q14674 (Homo sapiens)
Explore Q14674 
Go to UniProtKB:  Q14674
PHAROS:  Q14674
GTEx:  ENSG00000135476 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ14674
Sequence Annotations
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Securin202Homo sapiensMutation(s): 0 
Gene Names: PTTG1EAP1PTTGTUTR1
UniProt & NIH Common Fund Data Resources
Find proteins for O95997 (Homo sapiens)
Explore O95997 
Go to UniProtKB:  O95997
PHAROS:  O95997
GTEx:  ENSG00000164611 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO95997
Sequence Annotations
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 2.90 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 
EM Software:
TaskSoftware PackageVersion
RECONSTRUCTIONRELION

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Swiss National Science FoundationSwitzerland310030_185235
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesR35-GM118053

Revision History  (Full details and data files)

  • Version 1.0: 2021-08-04
    Type: Initial release
  • Version 1.1: 2021-08-18
    Changes: Database references
  • Version 1.2: 2024-10-23
    Changes: Data collection, Structure summary