Crystal structure of a conformation-selective casein kinase-1 inhibitor

J Biol Chem. 2000 Jun 30;275(26):20052-60. doi: 10.1074/jbc.M001713200.

Abstract

Members of the casein kinase-1 family of protein kinases play an essential role in cell regulation and disease pathogenesis. Unlike most protein kinases, they appear to function as constitutively active enzymes. As a result, selective pharmacological inhibitors can play an important role in dissection of casein kinase-1-dependent processes. To address this need, new small molecule inhibitors of casein kinase-1 acting through ATP-competitive and ATP-noncompetitive mechanisms were isolated on the basis of in vitro screening. Here we report the crystal structure of 3-[(2,4,6-trimethoxyphenyl) methylidenyl]-indolin-2-one (IC261), an ATP-competitive inhibitor with differential activity among casein kinase-1 isoforms, in complex with the catalytic domain of fission yeast casein kinase-1 refined to a crystallographic R-factor of 22.4% at 2.8 A resolution. The structure reveals that IC261 stabilizes casein kinase-1 in a conformation midway between nucleotide substrate liganded and nonliganded conformations. We propose that adoption of this conformation by casein kinase-1 family members stabilizes a delocalized network of side chain interactions and results in a decreased dissociation rate of inhibitor.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Casein Kinases
  • Computer Simulation
  • Crystallography, X-Ray
  • Enzyme Inhibitors / pharmacology
  • Humans
  • Hydrogen Bonding
  • Indoles / chemistry*
  • Indoles / pharmacology*
  • Inhibitory Concentration 50
  • Kinetics
  • Models, Molecular
  • Molecular Sequence Data
  • Mutation
  • Oxindoles
  • Peptide Library
  • Phloroglucinol / analogs & derivatives*
  • Phloroglucinol / chemistry
  • Phloroglucinol / pharmacology
  • Phosphotransferases / metabolism
  • Protein Binding / drug effects
  • Protein Conformation / drug effects
  • Protein Isoforms / chemistry
  • Protein Kinase Inhibitors*
  • Protein Structure, Tertiary
  • Schizosaccharomyces / enzymology
  • Static Electricity

Substances

  • Enzyme Inhibitors
  • IC 261
  • Indoles
  • Oxindoles
  • Peptide Library
  • Protein Isoforms
  • Protein Kinase Inhibitors
  • 2-oxindole
  • Phloroglucinol
  • Phosphotransferases
  • Casein Kinases

Associated data

  • PDB/1EH4