3n84
From Proteopedia
Crystal Structure of the Grb2 SH2 Domain in Complex with a 23-Membered Macrocyclic Ligand Having the Sequence pYVNVP
Structural highlights
Function[GRB2_HUMAN] Adapter protein that provides a critical link between cell surface growth factor receptors and the Ras signaling pathway.[1] [2] [3] Isoform 2 does not bind to phosphorylated epidermal growth factor receptor (EGFR) but inhibits EGF-induced transactivation of a RAS-responsive element. Isoform 2 acts as a dominant negative protein over GRB2 and by suppressing proliferative signals, may trigger active programmed cell death.[4] [5] [6] Publication Abstract from PubMedThe thermodynamic and structural effects of macrocyclization as a tactic for stabilizing the biologically-active conformation of Grb2 SH2 binding peptides were investigated using isothermal titration calorimetry and x-ray crystallography. 23-Membered macrocycles containing the sequence pYVN were slightly more potent than their linear controls; however, preorganization did not necessarily eventuate in a more favorable binding entropy. Structures of complexes of macrocycle 7 and its acyclic control 8 are similar except for differences in relative orientations of corresponding atoms in the linking moieties of 7 and 8. There are no differences in the number of direct or water-mediated protein-ligand contacts that might account for the less favorable binding enthalpy of 7; however, an intramolecular hydrogen bond between the pY and pY+3 residues in 8 that is absent in 7 may be a factor. These studies highlight the difficulties associated with correlating energetics and structure in protein-ligand interactions. Thermodynamic and Structural Effects of Macrocyclization as a Constraining Method in Protein-Ligand Interactions.,Delorbe JE, Clements JH, Whiddon BB, Martin SF ACS Med Chem Lett. 2010 Nov 11;1(8):448-452. PMID:21116482[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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