4FL3

Structural and Biophysical Characterization of the Syk Activation Switch


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.180 

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Literature

Structural and biophysical characterization of the syk activation switch.

Gradler, U.Schwarz, D.Dresing, V.Musil, D.Bomke, J.Frech, M.Greiner, H.Jakel, S.Rysiok, T.Muller-Pompalla, D.Wegener, A.

(2013) J Mol Biol 425: 309-333

  • DOI: 10.1016/j.jmb.2012.11.007
  • Primary Citation of Related Structures:  
    4FL1, 4FL2, 4FL3

  • PubMed Abstract: 
  • Syk is an essential non-receptor tyrosine kinase in intracellular immunological signaling, and the control of Syk kinase function is considered as a valuable target for pharmacological intervention in autoimmune or inflammation diseases. Upon immune receptor stimulation, the kinase activity of Syk is regulated by binding of phosphorylated immune receptor tyrosine-based activating motifs (pITAMs) to the N-terminal tandem Src homology 2 (tSH2) domain and by autophosphorylation with consequences for the molecular structure of the Syk protein ...

    Syk is an essential non-receptor tyrosine kinase in intracellular immunological signaling, and the control of Syk kinase function is considered as a valuable target for pharmacological intervention in autoimmune or inflammation diseases. Upon immune receptor stimulation, the kinase activity of Syk is regulated by binding of phosphorylated immune receptor tyrosine-based activating motifs (pITAMs) to the N-terminal tandem Src homology 2 (tSH2) domain and by autophosphorylation with consequences for the molecular structure of the Syk protein. Here, we present the first crystal structures of full-length Syk (fl-Syk) as wild type and as Y348F,Y352F mutant forms in complex with AMP-PNP revealing an autoinhibited conformation. The comparison with the crystal structure of the truncated Syk kinase domain in complex with AMP-PNP taken together with ligand binding studies by surface plasmon resonance (SPR) suggests conformational differences in the ATP sites of autoinhibited and activated Syk forms. This hypothesis was corroborated by studying the thermodynamic and kinetic interaction of three published Syk inhibitors with isothermal titration calorimetry and SPR, respectively. We further demonstrate the modulation of inhibitor binding affinities in the presence of pITAM and discuss the observed differences of thermodynamic and kinetic signatures. The functional relevance of pITAM binding to fl-Syk was confirmed by a strong stimulation of in vitro autophosphorylation. A structural feedback mechanism on the kinase domain upon pITAM binding to the tSH2 domain is discussed in analogy of the related family kinase ZAP-70 (Zeta-chain-associated protein kinase 70). Surprisingly, we observed distinct conformations of the tSH2 domain and the activation switch including Tyr348 and Tyr352 in the interdomain linker of Syk in comparison to ZAP-70.


    Organizational Affiliation

    Merck KGaA, Merck Serono Research, Small Molecule Platform/MIB, Frankfurter Str. 250, 64293 Darmstadt, Germany. ulrich.graedler@merckgroup.com



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Tyrosine-protein kinase SYKA635Homo sapiensMutation(s): 2 
Gene Names: SYK
EC: 2.7.10.2
UniProt & NIH Common Fund Data Resources
Find proteins for P43405 (Homo sapiens)
Explore P43405 
Go to UniProtKB:  P43405
PHAROS:  P43405
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ANP (Subject of Investigation/LOI)
Query on ANP

Download Ideal Coordinates CCD File 
B [auth A]PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER
C10 H17 N6 O12 P3
PVKSNHVPLWYQGJ-KQYNXXCUSA-N
 Ligand Interaction
MG
Query on MG

Download Ideal Coordinates CCD File 
C [auth A]MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Binding Affinity Annotations 
IDSourceBinding Affinity
ANP PDBBind:  4FL3 Kd: 1.50e+5 (nM) from 1 assay(s)
Binding MOAD:  4FL3 Kd: 1.50e+5 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.180 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 62.735α = 90
b = 71.034β = 103.93
c = 76.333γ = 90
Software Package:
Software NamePurpose
XDSdata scaling
PHASERphasing
BUSTERrefinement
XDSdata reduction

Structure Validation

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Ligand Structure Quality Assessment  



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-11-28
    Type: Initial release
  • Version 1.1: 2013-02-13
    Changes: Database references