9EZG

Crystal structure of human Casein Kinase II subunit alpha (CK2a1) in complex with 5-((4-((2-aminoethyl)(ethyl)amino)-3-(4H-1,2,4-triazol-4-yl)phenyl)amino)-7-(cyclopropylamino)pyrazolo[1,5-a]pyrimidine-3-carbonitrile


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.18 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.209 
  • R-Value Observed: 0.211 

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Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history


Literature

More than an Amide Bioisostere: Discovery of 1,2,4-Triazole-containing Pyrazolo[1,5- a ]pyrimidine Host CSNK2 Inhibitors for Combatting beta-Coronavirus Replication.

Ong, H.W.Yang, X.Smith, J.L.Dickmander, R.J.Brown, J.W.Havener, T.M.Taft-Benz, S.Howell, S.Sanders, M.K.Capener, J.L.Counago, R.M.Chang, E.Kramer, A.Moorman, N.J.Heise, M.Axtman, A.D.Drewry, D.H.Willson, T.M.

(2024) J Med Chem 67: 12261-12313

  • DOI: https://doi.org/10.1021/acs.jmedchem.4c00962
  • Primary Citation of Related Structures:  
    8P06, 8P07, 9EZG

  • PubMed Abstract: 

    The pyrazolo[1,5- a ]pyrimidine scaffold is a promising scaffold to develop potent and selective CSNK2 inhibitors with antiviral activity against β-coronaviruses. Herein, we describe the discovery of a 1,2,4-triazole group to substitute a key amide group for CSNK2 binding present in many potent pyrazolo[1,5- a ]pyrimidine inhibitors. Crystallographic evidence demonstrates that the 1,2,4-triazole replaces the amide in forming key hydrogen bonds with Lys68 and a water molecule buried in the ATP-binding pocket. This isosteric replacement improves potency and metabolic stability at a cost of solubility. Optimization for potency, solubility, and metabolic stability led to the discovery of the potent and selective CSNK2 inhibitor 53 . Despite excellent in vitro metabolic stability, rapid decline in plasma concentration of 53 in vivo was observed and may be attributed to lung accumulation, although in vivo pharmacological effect was not observed. Further optimization of this novel chemotype may validate CSNK2 as an antiviral target in vivo.


  • Organizational Affiliation

    Rapidly Emerging Antiviral Drug Development Initiative (READDI), Chapel Hill, North Carolina 27599, United States.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Casein kinase II subunit alpha
A, B
338Homo sapiensMutation(s): 0 
Gene Names: CSNK2A1CK2A1
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
Expand
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
A1H8C (Subject of Investigation/LOI)
Query on A1H8C

Download Ideal Coordinates CCD File 
M [auth A],
U [auth B]
5-[[4-[2-azanylethyl(ethyl)amino]-3-(1,2,4-triazol-4-yl)phenyl]amino]-7-(cyclopropylamino)pyrazolo[1,5-a]pyrimidine-3-carbonitrile
C22 H25 N11
VVIQQTQLDDARAW-UHFFFAOYSA-N
SO4
Query on SO4

Download Ideal Coordinates CCD File 
C [auth A]
D [auth A]
E [auth A]
F [auth A]
G [auth A]
C [auth A],
D [auth A],
E [auth A],
F [auth A],
G [auth A],
H [auth A],
I [auth A],
J [auth A],
K [auth A],
L [auth A],
N [auth B],
O [auth B],
P [auth B],
Q [auth B],
R [auth B],
S [auth B],
T [auth B]
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
EDO
Query on EDO

Download Ideal Coordinates CCD File 
V [auth B]1,2-ETHANEDIOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.18 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.209 
  • R-Value Observed: 0.211 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 127.799α = 90
b = 127.799β = 90
c = 124.73γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
Aimlessdata scaling
XDSdata reduction
MOLREPphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Innovative Medicines InitiativeSwitzerland875510

Revision History  (Full details and data files)

  • Version 1.0: 2024-07-31
    Type: Initial release
  • Version 1.1: 2024-08-07
    Changes: Database references