Crystal structure of spleen tyrosine kinase complexed with a 2-substituted 7-azaindole

Experimental Data Snapshot

  • Resolution: 2.26 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.216 

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Ligand Structure Quality Assessment 

This is version 1.3 of the entry. See complete history


Structural insights for design of potent spleen tyrosine kinase inhibitors from crystallographic analysis of three inhibitor complexes.

Villasenor, A.G.Kondru, R.Ho, H.Wang, S.Papp, E.Shaw, D.Barnett, J.W.Browner, M.F.Kuglstatter, A.

(2009) Chem Biol Drug Des 73: 466-470

  • DOI: https://doi.org/10.1111/j.1747-0285.2009.00785.x
  • Primary Citation of Related Structures:  
    3FQE, 3FQH, 3FQS

  • PubMed Abstract: 

    Spleen tyrosine kinase is considered an attractive drug target for the treatment of allergic and antibody mediated autoimmune diseases. We have determined the co-crystal structures of spleen tyrosine kinase complexed with three known inhibitors: YM193306, a 7-azaindole derivative and R406. The cis-cyclohexyldiamino moiety of YM193306 is forming four hydrophobically shielded polar interactions with the spleen tyrosine kinase protein and is therefore crucial for the high potency of this inhibitor. Its primary amino group is inducing a conformational change of the spleen tyrosine kinase DFG Asp side chain. The crystal structure of the 7-azaindole derivative bound to spleen tyrosine kinase is the first demonstration of a 2-substituted 7-azaindole bound to a protein kinase. Its indole-amide substituent is tightly packed between the N- and C-terminal kinase lobes. The co-crystal structure of the spleen tyrosine kinase-R406 complex shows two main differences to the previously reported structure of spleen tyrosine kinase soaked with R406: (i) the side chain of the highly conserved Lys is disordered and not forming a hydrogen bond to R406 and (ii) the DFG Asp side chain is pointing away from and not towards R406. The novel protein-ligand interactions and protein conformational changes revealed in these structures guide the rational design and structure-based optimization of second-generation spleen tyrosine kinase inhibitors.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Tyrosine-protein kinase SYK
A, B
291Homo sapiensMutation(s): 0 
Gene Names: SYK
UniProt & NIH Common Fund Data Resources
Find proteins for P43405 (Homo sapiens)
Explore P43405 
Go to UniProtKB:  P43405
PHAROS:  P43405
GTEx:  ENSG00000165025 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP43405
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on 057

Download Ideal Coordinates CCD File 
C [auth A],
D [auth B]
C21 H22 N4 O2
Binding Affinity Annotations 
IDSourceBinding Affinity
057 BindingDB:  3FQH IC50: 570 (nM) from 1 assay(s)
Binding MOAD:  3FQH IC50: 570 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 2.26 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.216 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 40.156α = 80.78
b = 41.949β = 90.78
c = 87.604γ = 79.59
Software Package:
Software NamePurpose
ADSCdata collection
HKL-2000data reduction
HKL-2000data 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: 2009-03-10
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2019-07-24
    Changes: Data collection, Refinement description
  • Version 1.3: 2023-09-06
    Changes: Data collection, Database references, Derived calculations, Refinement description