4DA5

Choline Kinase alpha acts through a double-displacement kinetic mechanism involving enzyme isomerisation, as determined through enzyme and inhibitor kinetics and structural biology


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.199 

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This is version 1.2 of the entry. See complete history


Literature

Kinetic and mechanistic characterisation of Choline Kinase-alpha.

Hudson, C.S.Knegtel, R.M.Brown, K.Charlton, P.A.Pollard, J.R.

(2013) Biochim Biophys Acta 1834: 1107-1116

  • DOI: https://doi.org/10.1016/j.bbapap.2013.02.008
  • Primary Citation of Related Structures:  
    4DA5

  • PubMed Abstract: 

    Choline Kinase is a key component of the Kennedy pathway that converts choline into a number of structural and signalling lipids that are essential for cell growth and survival. One member of the family, Choline Kinase-α (ChoKα) is frequently up-regulated in human cancers, and expression of ChoKα is sufficient to transform cells. Consequently ChoKα has been studied as a potential target for therapeutic agents in cancer research. Despite great interest in the enzyme, mechanistic studies have not been reported. In this study, a combination of initial velocity and product inhibition studies, together with the kinetic and structural characterisation of a novel ChoKα inhibitor is used to support a mechanism of action for human ChoKα. Substrate and inhibition kinetics are consistent with an iso double displacement mechanism, in which the γ-phosphate from ATP is transferred to choline in two distinct steps via a phospho-enzyme intermediate. Co-crystal structures, and existing site-specific mutation studies, support an important role for Asp306, in stabilising the phospho-enzyme intermediate. The kinetics also indicate a distinct kinetic (isomerisation) step associated with product release, which may be attributed to a conformational change in the protein to disrupt an interaction between Asp306 and the phosphocholine product, facilitating product release. This study describes a mechanism for ChoKα that is unusual amongst kinases, and highlights the availability of different enzyme states that can be exploited for drug discovery.


  • Organizational Affiliation

    Vertex Pharmaceuticals (Europe) Limited, Oxfordshire, UK.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Choline kinase alpha
A, B
457Homo sapiensMutation(s): 0 
Gene Names: CHKACHKCKI
EC: 2.7.1.32 (PDB Primary Data), 2.7.1.82 (PDB Primary Data)
UniProt & NIH Common Fund Data Resources
Find proteins for P35790 (Homo sapiens)
Explore P35790 
Go to UniProtKB:  P35790
PHAROS:  P35790
GTEx:  ENSG00000110721 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP35790
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.199 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 55.84α = 90
b = 121.69β = 90
c = 131.73γ = 90
Software Package:
Software NamePurpose
DNAdata collection
AMoREphasing
BUSTERrefinement
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-04-17
    Type: Initial release
  • Version 1.1: 2013-08-28
    Changes: Database references
  • Version 1.2: 2024-02-28
    Changes: Data collection, Database references, Derived calculations