Crystal structure of the P93A monomer mutant of S. cerevisiae Cks1

Experimental Data Snapshot

  • Resolution: 2.59 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.217 

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The structure of a monomeric mutant cks protein reveals multiple functions for a conserved hinge-region proline.

Balog, E.R.Saetern, O.C.Finch, W.Hoeft, C.O.Thai, V.Harvey, S.L.Kellogg, D.R.Rubin, S.M.

(2011) J Mol Biol 411: 520-528

  • DOI: https://doi.org/10.1016/j.jmb.2011.05.045
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Cks (cyclin-dependent kinase subunit) proteins are essential eukaryotic cell cycle regulatory proteins that physically associate with cyclin-dependent kinases (Cdks) to modulate their activity. Cks proteins have also been studied for their ability to form domain-swapped dimers by exchanging β-strands. Domain swapping is mediated by a conserved β-hinge region containing two proline residues. Previous structural studies indicate that Cks in its dimer form is unable to bind Cdk, suggesting that the monomer-dimer equilibrium of Cks may have an effect on Cks-mediated Cdk regulation. We present the crystal structure of a proline-to-alanine mutant Saccharomyces cerevisiae Cks protein (Cks1 P93A) that preferentially adopts the monomer conformation but surprisingly fails to bind Cdk. Comparison of the Cks1 P93A structure to that of other Cks proteins reveals that Pro93 is critical for stabilizing a multiple β-turn structure in the hinge region that properly positions an essential Cdk-binding residue. Additionally, we find that these β-turn formations, conserved in Cks homologs, have implications for the mechanism and preferentiality of strand exchange. Together, our observations suggest that the conservation of Cks hinge-region prolines reflects their functions in forming a Cdk binding interface and that the ability of these prolines to control partitioning between monomer and dimer is a consequence of the β-turn networks within the hinge.

  • Organizational Affiliation

    Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Cyclin-dependent kinases regulatory subunit
A, B
117Saccharomyces cerevisiaeMutation(s): 1 
Gene Names: CKS1YBR135WYBR1011
Find proteins for P20486 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Explore P20486 
Go to UniProtKB:  P20486
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP20486
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on FLC

Download Ideal Coordinates CCD File 
C6 H5 O7
Experimental Data & Validation

Experimental Data

  • Resolution: 2.59 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.217 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 89.522α = 90
b = 89.522β = 90
c = 93.157γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
DENZOdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-06-29
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2011-08-10
    Changes: Database references
  • Version 1.3: 2024-02-21
    Changes: Data collection, Database references, Derived calculations