Primary Citation of Related Structures: 3N7Y, 3N84, 3N8M
PubMed Abstract:
The 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 ...
The 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.
Organizational Affiliation:
Department of Chemistry and Biochemistry, The Institute of Cellular and Molecular Biology, and The Texas Institute of Drug and Diagnostic Development, The University of Texas, Austin, Texas 78712, USA.
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