5V03

A positive allosteric modulator binding pocket in SK2 ion channels is shared by Riluzole and CyPPA


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.58 Å
  • R-Value Free: 0.220 
  • R-Value Work: 0.194 
  • R-Value Observed: 0.196 

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Ligand Structure Quality Assessment 


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Literature

An Intracellular Allosteric Modulator Binding Pocket in SK2 Ion Channels Is Shared by Multiple Chemotypes.

Cho, L.T.Alexandrou, A.J.Torella, R.Knafels, J.Hobbs, J.Taylor, T.Loucif, A.Konopacka, A.Bell, S.Stevens, E.B.Pandit, J.Horst, R.Withka, J.M.Pryde, D.C.Liu, S.Young, G.T.

(2018) Structure 26: 533-544.e3

  • DOI: 10.1016/j.str.2018.02.017
  • Primary Citation of Related Structures:  
    5V02, 5V03

  • PubMed Abstract: 
  • Small conductance potassium (SK) ion channels define neuronal firing rates by conducting the after-hyperpolarization current. They are key targets in developing therapies where neuronal firing rates are dysfunctional, such as in epilepsy, Parkinson's, and amyotrophic lateral sclerosis (ALS) ...

    Small conductance potassium (SK) ion channels define neuronal firing rates by conducting the after-hyperpolarization current. They are key targets in developing therapies where neuronal firing rates are dysfunctional, such as in epilepsy, Parkinson's, and amyotrophic lateral sclerosis (ALS). Here, we characterize a binding pocket situated at the intracellular interface of SK2 and calmodulin, which we show to be shared by multiple small-molecule chemotypes. Crystallization of this complex revealed that riluzole (approved for ALS) and an analog of the anti-ataxic agent (4-chloro-phenyl)-[2-(3,5-dimethyl-pyrazol-1-yl)-pyrimidin-4-yl]-amine (CyPPA) bind to and allosterically modulate via this site. Solution-state nuclear magnetic resonance demonstrates that riluzole, NS309, and CyPPA analogs bind at this bipartite pocket. We demonstrate, by patch-clamp electrophysiology, that both classes of ligand interact with overlapping but distinct residues within this pocket. These data define a clinically important site, laying the foundations for further studies of the mechanism of action of riluzole and related molecules.


    Organizational Affiliation

    Pfizer Neuroscience and Pain Research Unit, Granta Park, Great Abington, Cambridge CB21 6GS, UK. Electronic address: gareth.8.young@gsk.com.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Small conductance calcium-activated potassium channel protein 2A [auth B]102Homo sapiensMutation(s): 0 
Gene Names: KCNN2
UniProt & NIH Common Fund Data Resources
Find proteins for Q9H2S1 (Homo sapiens)
Explore Q9H2S1 
Go to UniProtKB:  Q9H2S1
PHAROS:  Q9H2S1
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
CalmodulinB [auth R]149Homo sapiensMutation(s): 0 
Gene Names: 
CALM1CALMCAMCAM1CALM2CAM2CAMBCALM3CALML2CAM3...
CALM1CALMCAMCAM1CALM2CAM2CAMBCALM3CALML2CAM3CAMCCAMIII

UniProt & NIH Common Fund Data Resources
Find proteins for P0DP23 (Homo sapiens)
Explore P0DP23 
Go to UniProtKB:  P0DP23
PHAROS:  P0DP23
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
658 (Subject of Investigation/LOI)
Query on 658

Download Ideal Coordinates CCD File 
D [auth R]N-(4-chlorophenyl)-2-(3,5-dimethyl-1H-pyrazol-1-yl)pyrimidin-4-amine
C15 H14 Cl N5
MYCRDMLFNQGDBT-UHFFFAOYSA-N
 Ligand Interaction
SO4
Query on SO4

Download Ideal Coordinates CCD File 
C [auth B]SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
CA
Query on CA

Download Ideal Coordinates CCD File 
E [auth R], F [auth R]CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.58 Å
  • R-Value Free: 0.220 
  • R-Value Work: 0.194 
  • R-Value Observed: 0.196 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 77.092α = 90
b = 66.882β = 93.95
c = 65.381γ = 90
Software Package:
Software NamePurpose
BUSTERrefinement
XDSdata reduction
Aimlessdata scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment  



Entry History 

Deposition Data

  • Deposited Date: 2017-02-28 
  • Released Date: 2018-03-07 
  • Deposition Author(s): Liu, S.

Revision History  (Full details and data files)

  • Version 1.0: 2018-03-07
    Type: Initial release
  • Version 1.1: 2018-04-25
    Changes: Data collection, Database references