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Title: Thermodynamic parameters for binding of some halogenated inhibitors of human protein kinase CK2

Highlights: • Two new compounds being potential human CK2a inhibitors are studied. • Their IC50 values were determined in vitro. • The heats of binding and kbind were estimated using DSC. • The increased stability of protein–ligand complexes was followed by fluorescence. • Methylated TBBt derivative (MeBr3Br) is almost as active as TBBt. - Abstract: The interaction of human CK2α with a series of tetrabromobenzotriazole (TBBt) and tetrabromobenzimidazole (TBBz) analogs, in which one of the bromine atoms proximal to the triazole/imidazole ring is replaced by a methyl group, was studied by biochemical (IC{sub 50}) and biophysical methods (thermal stability of protein–ligand complex monitored by DSC and fluorescence). Two newly synthesized tri-bromo derivatives display inhibitory activity comparable to that of the reference compounds, TBBt and TBBz, respectively. DSC analysis of the stability of protein–ligand complexes shows that the heat of ligand binding (H{sub bind}) is driven by intermolecular electrostatic interactions involving the triazole/imidazole ring, as indicated by a strong correlation between H{sub bind} and ligand pK{sub a}. Screening, based on fluorescence-monitored thermal unfolding of protein–ligand complexes, gave comparable results, clearly identifying ligands that most strongly bind to the protein. Overall results, additionally supported by molecular modeling, confirm that a balance ofmore » hydrophobic and electrostatic interactions contribute predominantly, relative to possible intermolecular halogen bonding, in binding of the ligands to the CK2α ATP-binding site.« less
Authors:
;  [1] ;  [1] ;  [2] ; ;  [3] ;  [1] ;  [1]
  1. Institute of Biochemistry and Biophysics PAS, Warszawa (Poland)
  2. (Poland)
  3. Warsaw University of Technology, Faculty of Chemistry, Warszawa (Poland)
Publication Date:
OSTI Identifier:
22416880
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemical and Biophysical Research Communications; Journal Volume: 456; Journal Issue: 1; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ATP; BIOCHEMISTRY; BONDING; BROMINE; CALORIMETRY; COMPARATIVE EVALUATIONS; COMPLEXES; CORRELATIONS; FLUORESCENCE; HUMAN POPULATIONS; IMIDAZOLES; IN VITRO; LIGANDS; PHOSPHOTRANSFERASES; PROTEINS; SCREENING