Crystal Structure of the Grb2 SH2 Domain in Complex with a Cyclopropyl-constrained Ac-pY-Q-N-NH2 Tripeptide Mimic

Experimental Data Snapshot

  • Resolution: 2 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.229 

wwPDB Validation 3D Report Full Report

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Thermodynamic and Structural Effects of Conformational Constraints in Protein-Ligand Interactions. Entropic Paradoxy Associated with Ligand Preorganization.

Delorbe, J.E.Clements, J.H.Teresk, M.G.Benfield, A.P.Plake, H.R.Millspaugh, L.E.Martin, S.F.

(2009) J.Am.Chem.Soc. 131: 16758-16770

  • DOI: 10.1021/ja904698q
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Succinate- and cyclopropane-derived phosphotyrosine (pY) replacements were incorporated into a series of Grb2 SH2 binding ligands wherein the pY+1 residue was varied to determine explicitly how variations in ligand preorganization affect binding ener ...

    Succinate- and cyclopropane-derived phosphotyrosine (pY) replacements were incorporated into a series of Grb2 SH2 binding ligands wherein the pY+1 residue was varied to determine explicitly how variations in ligand preorganization affect binding energetics and structure. The complexes of these ligands with the Grb2 SH2 domain were examined in a series of thermodynamic and structural investigations using isothermal titration calorimetry and X-ray crystallography. The binding enthalpies for all ligands were favorable, and although binding entropies for all ligands having a hydrophobic residue at the pY+1 site were favorable, binding entropies for those having a hydrophilic residue at this site were unfavorable. Preorganized ligands generally bound with more favorable Gibbs energies than their flexible controls, but this increased affinity was the consequence of relatively more favorable binding enthalpies. Unexpectedly, binding entropies of the constrained ligands were uniformly disfavored relative to their flexible controls, demonstrating that the widely held belief that ligand preorganization should result in an entropic advantage is not necessarily true. Crystallographic studies of complexes of several flexible and constrained ligands having the same amino acid at the pY+1 position revealed extensive similarities, but there were some notable differences. There are a greater number of direct polar contacts in complexes of the constrained ligands that correlate qualitatively with their more favorable binding enthalpies and Gibbs energies. There are more single water-mediated contacts between the domain and the flexible ligand of each pair; although fixing water molecules at a protein-ligand interface is commonly viewed as entropically unfavorable, entropies for forming these complexes are favored relative to those of their constrained counterparts. Crystallographic b-factors in the complexes of constrained ligands are greater than those of their flexible counterparts, an observation that seems inconsistent with our finding that entropies for forming complexes of flexible ligands are relatively more favorable. This systematic study highlights the profound challenges and complexities associated with predicting how structural changes in a ligand will affect enthalpies, entropies, and structure in protein-ligand interactions.

    Related Citations: 
    • Ligand Preorganization May Be Accompanied by Entropic Penalties in Protein-Ligand Interactions
      Benfield, A.P.,Teresk, M.G.,Plake, H.R.,DeLorbe, J.E.,Millspaugh, L.E.,Martin, S.F.
      (2006) Angew.Chem.Int.Ed.Engl. 45: 6830

    Organizational Affiliation

    Department of Chemistry and Biochemistry, The Institute of Cellular and Molecular Biology, University of Texas, Austin, Texas 78712, USA.


Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Growth factor receptor-bound protein 2
A, C
117Homo sapiensMutation(s): 0 
Gene Names: GRB2 (ASH)
Find proteins for P62993 (Homo sapiens)
Go to Gene View: GRB2
Go to UniProtKB:  P62993
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
Query on AYQ

Download SDF File 
Download CCD File 
A, C
C21 H29 N6 O10 P
 Ligand Interaction
Biologically Interesting Molecules 1 Unique
IDChainsNameType/Class2D Diagram3D Interactions
PRD_000633 (AYQ)
Query on PRD_000633


External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
Experimental Data & Validation

Experimental Data

  • Resolution: 2 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.229 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 40.384α = 90.00
b = 63.955β = 90.00
c = 92.725γ = 90.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
DENZOdata reduction
HKL-2000data scaling
HKL-2000data reduction
CrystalCleardata collection
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report or Ramachandran Plots

Entry History 

Deposition Data

  • Deposited Date: 2009-08-11 
  • Released Date: 2009-11-17 
  • Deposition Author(s): Clements, J.H.

Revision History 

  • Version 1.0: 2009-11-17
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Atomic model, Database references, Derived calculations, Non-polymer description, Structure summary, Version format compliance
  • Version 1.2: 2012-12-12
    Type: Other
  • Version 1.3: 2017-11-01
    Type: Refinement description