3FWQ

Inactive conformation of human protein kinase CK2 catalytic subunit


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.233 
  • R-Value Work: 0.170 
  • R-Value Observed: 0.173 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

First inactive conformation of CK2 alpha, the catalytic subunit of protein kinase CK2

Raaf, J.Issinger, O.G.Niefind, K.

(2009) J Mol Biol 386: 1212-1221

  • DOI: https://doi.org/10.1016/j.jmb.2009.01.033
  • Primary Citation of Related Structures:  
    3FWQ

  • PubMed Abstract: 

    The Ser/Thr kinase casein kinase 2 (CK2) is a heterotetrameric enzyme composed of two catalytic chains (CK2alpha, catalytic subunit of CK2) attached to a dimer of two noncatalytic subunits (CK2beta, noncatalytic subunit of CK2). CK2alpha belongs to the superfamily of eukaryotic protein kinases (EPKs). To function as regulatory key components, EPKs normally exist in inactive ground states and are activated only upon specific signals. Typically, this activation is accompanied by large conformational changes in helix alpha C and in the activation segment, leading to a characteristic arrangement of catalytic key elements. For CK2alpha, however, no strict physiological control of activity is known. Accordingly, CK2alpha was found so far exclusively in the characteristic conformation of active EPKs, which is, in this case, additionally stabilized by a unique intramolecular contact between the N-terminal segment on one side, and helix alpha C and the activation segment on the other side. We report here the structure of a C-terminally truncated variant of human CK2alpha in which the enzyme adopts a decidedly inactive conformation for the first time. In this CK2alpha structure, those regulatory key regions still are in their active positions. Yet the glycine-rich ATP-binding loop, which is normally part of the canonical anti-parallel beta-sheet, has collapsed into the ATP-binding site so that ATP is excluded from binding; specifically, the side chain of Arg47 occupies the ribose region of the ATP site and Tyr50, the space required by the triphospho moiety. We discuss some factors that may support or disfavor this inactive conformation, among them coordination of small molecules at a remote cavity at the CK2alpha/CK2beta interaction region and binding of a CK2beta dimer. The latter stabilizes the glycine-rich loop in the extended active conformation known from the majority of CK2alpha structures. Thus, the novel inactive conformation for the first time provides a structural basis for the stimulatory impact of CK2beta on CK2alpha.


  • Organizational Affiliation

    Universität zu Köln, Institut für Biochemie, Zülpicher Str. 47, D-50674 Köln, Germany.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Casein kinase II subunit alpha
A, B
335Homo sapiensMutation(s): 0 
EC: 2.7.11.1
UniProt & NIH Common Fund Data Resources
Find proteins for P68400 (Homo sapiens)
Explore P68400 
Go to UniProtKB:  P68400
PHAROS:  P68400
GTEx:  ENSG00000101266 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP68400
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download Ideal Coordinates CCD File 
E [auth A]SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
GOL
Query on GOL

Download Ideal Coordinates CCD File 
C [auth A],
D [auth A],
I [auth B]
GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
CL
Query on CL

Download Ideal Coordinates CCD File 
F [auth A],
G [auth A],
H [auth A],
J [auth B],
K [auth B]
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.233 
  • R-Value Work: 0.170 
  • R-Value Observed: 0.173 
  • Space Group: P 43
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 71.324α = 90
b = 71.324β = 90
c = 125.681γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
AMoREphasing
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-02-17
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Non-polymer description, Version format compliance
  • Version 1.2: 2012-04-04
    Changes: Database references
  • Version 1.3: 2023-11-01
    Changes: Data collection, Database references, Derived calculations, Refinement description