1QVN

Structure of SP4160 Bound to IL-2 V69A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Free: 0.308 
  • R-Value Work: 0.258 
  • R-Value Observed: 0.261 

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Ligand Structure Quality Assessment 


This is version 1.4 of the entry. See complete history


Literature

Hot-spot mimicry of a cytokine receptor by a small molecule.

Thanos, C.D.DeLano, W.L.Wells, J.A.

(2006) Proc Natl Acad Sci U S A 103: 15422-15427

  • DOI: https://doi.org/10.1073/pnas.0607058103
  • Primary Citation of Related Structures:  
    1QVN

  • PubMed Abstract: 

    Protein-protein complexes remain enticing, but extremely challenging, targets for small-molecule drug discovery. In a rare example described earlier, a high-affinity small molecule, SP4206 (Kd approximately 70 nM), was found to block binding of the IL-2alpha receptor (IL-2Ralpha) to IL-2 (Kd approximately 10 nM). Recently, the structure of the IL-2/IL-2Ralpha complex was solved [Rickert, M., Wang, X., Boulanger, M. J., Goriatcheva, N., Garcia, K. C. (2005) Science 308:1477-1480]. Using structural and functional analysis, we compare how SP4206 mimics the 83-fold larger IL-2Ralpha in binding IL-2. The binding free energy per contact atom (ligand efficiency) for SP4206 is about twice that of the receptor because of a smaller, but overlapping, contact epitope that insinuates into grooves and cavities not accessed by the receptor. Despite its independent design, the small molecule has a similar, but more localized, charge distribution compared with IL-2Ralpha. Mutational studies show that SP4206 targets virtually the same critical "hot-spot" residues on IL-2 that drive binding of IL-2Ralpha. Moreover, a mutation that enhances binding to the IL-2Ralpha near these hot spots also enhances binding to SP4206. Although the protein and small molecule do bind the same hot spot, they trap very different conformations of IL-2 because of its flexible nature. Our studies suggest that precise structural mimics of receptors are not required for high-affinity binding of small molecules, and they show that there are multiple solutions to tight binding at shared and adaptive hot spots.


  • Organizational Affiliation

    Sunesis Pharmaceuticals, 341 Oyster Point Boulevard, South San Francisco, CA 94080, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Interleukin-2
A, B, C, D
132Homo sapiensMutation(s): 1 
Gene Names: IL2
UniProt & NIH Common Fund Data Resources
Find proteins for P60568 (Homo sapiens)
Explore P60568 
Go to UniProtKB:  P60568
PHAROS:  P60568
GTEx:  ENSG00000109471 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP60568
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Free: 0.308 
  • R-Value Work: 0.258 
  • R-Value Observed: 0.261 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 53.514α = 90
b = 85.134β = 90
c = 122.141γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
CCP4data scaling
AMoREphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-04-05
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2013-01-09
    Changes: Database references
  • Version 1.4: 2021-10-27
    Changes: Database references, Derived calculations