Crystal structure of the ACVR1 (ALK2) kinase in complex with an Quinazolinone based ALK2 inhibitor with a 4-morpholinophenyl solvent accessible group.

Experimental Data Snapshot

  • Resolution: 2.20 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.175 

wwPDB Validation   3D Report Full Report

Ligand Structure Quality Assessment 

This is version 1.4 of the entry. See complete history


Novel Quinazolinone Inhibitors of ALK2 Flip between Alternate Binding Modes: Structure-Activity Relationship, Structural Characterization, Kinase Profiling, and Cellular Proof of Concept.

Hudson, L.Mui, J.Vazquez, S.Carvalho, D.M.Williams, E.Jones, C.Bullock, A.N.Hoelder, S.

(2018) J Med Chem 61: 7261-7272

  • DOI: https://doi.org/10.1021/acs.jmedchem.8b00782
  • Primary Citation of Related Structures:  
    6GI6, 6GIN, 6GIP

  • PubMed Abstract: 

    Structure-activity relationship and crystallographic data revealed that quinazolinone-containing fragments flip between two distinct modes of binding to activin receptor-like kinase-2 (ALK2). We explored both binding modes to discover potent inhibitors and characterized the chemical modifications that triggered the flip in binding mode. We report kinase selectivity and demonstrate that compounds of this series modulate ALK2 in cancer cells. These inhibitors are attractive starting points for the discovery of more advanced ALK2 inhibitors.

  • Organizational Affiliation

    Laboratori de Química Farmacèutica (Unitat Associada al CSIC), Facultat de Farmàcia i Ciències de l'Alimentació, and Institute of Biomedicine (IBUB) , Universitat de Barcelona , Av. Joan XXIII s/n , Barcelona E-08028 , Spain.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Activin receptor type-1
A, B
301Homo sapiensMutation(s): 1 
Gene Names: ACVR1ACVRLK2
UniProt & NIH Common Fund Data Resources
Find proteins for Q04771 (Homo sapiens)
Explore Q04771 
Go to UniProtKB:  Q04771
GTEx:  ENSG00000115170 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ04771
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
IR2 (Subject of Investigation/LOI)
Query on IR2

Download Ideal Coordinates CCD File 
C [auth A],
J [auth B]
C27 H22 N4 O2
Query on SO4

Download Ideal Coordinates CCD File 
D [auth A]
E [auth A]
F [auth A]
K [auth B]
L [auth B]
D [auth A],
E [auth A],
F [auth A],
K [auth B],
L [auth B],
M [auth B]
O4 S
Query on EDO

Download Ideal Coordinates CCD File 
G [auth A],
H [auth A],
I [auth A],
N [auth B]
C2 H6 O2
Binding Affinity Annotations 
IDSourceBinding Affinity
IR2 BindingDB:  6GIN Kd: 330 (nM) from 1 assay(s)
IC50: 32 (nM) from 1 assay(s)
Binding MOAD:  6GIN IC50: 32 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 2.20 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.175 
  • Space Group: P 2 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 59.08α = 90
b = 86.39β = 90
c = 139.29γ = 90
Software Package:
Software NamePurpose
iMOSFLMdata reduction
Aimlessdata scaling

Structure Validation

View Full Validation Report

Ligand Structure Quality Assessment 

Entry History 

Revision History  (Full details and data files)

  • Version 1.0: 2018-05-23
    Type: Initial release
  • Version 1.1: 2018-08-22
    Changes: Data collection, Database references
  • Version 1.2: 2018-09-05
    Changes: Data collection, Database references
  • Version 1.3: 2019-04-03
    Changes: Data collection, Source and taxonomy
  • Version 1.4: 2024-01-17
    Changes: Data collection, Database references, Refinement description