Protein-protein contacts in the glucocorticoid receptor homodimer influence its DNA binding properties

J Biol Chem. 1990 Feb 25;265(6):3535-42.

Abstract

We have investigated the influence of the N-terminal domain of the 94-kDa glucocorticoid receptor on the DNA:receptor interaction. An alpha-chymotrypsin-induced 39-kDa receptor fragment, containing the hormone and DNA binding domains, binds DNA with a reduced specificity compared to the intact 94-kDa receptor. Various footprinting assays did not reveal any qualitative differences when comparing the DNA contact points made by the two different receptor entities. Like the intact receptor, the 39-kDa receptor fragment binds as a dimer to DNA. Glutaraldehyde cross-linking demonstrated a difference in the protein:protein contacts of the two homodimers. Furthermore, the dimeric 94-kDa receptor did not recognize a half-DNA site, while the dissociated 94-kDa receptor dimer and the dimeric 39-kDa receptor fragment allowed binding to such a site. These results suggest that the loss of the N-terminal domain of the receptor affects the steric arrangement and/or rigidity of the two DNA binding domains of the receptor homodimer, resulting in a decreased DNA binding specificity of the 39-kDa receptor fragment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Composition
  • Base Sequence
  • Binding Sites
  • Chymotrypsin
  • DNA / metabolism*
  • DNA-Binding Proteins / metabolism*
  • Exodeoxyribonucleases
  • Liver / metabolism*
  • Macromolecular Substances
  • Models, Molecular
  • Molecular Sequence Data
  • Molecular Weight
  • Nucleic Acid Conformation
  • Nucleotide Mapping
  • Peptide Fragments / isolation & purification
  • Peptide Fragments / metabolism
  • Rats
  • Receptors, Glucocorticoid / isolation & purification
  • Receptors, Glucocorticoid / metabolism*
  • Triamcinolone Acetonide / metabolism

Substances

  • DNA-Binding Proteins
  • Macromolecular Substances
  • Peptide Fragments
  • Receptors, Glucocorticoid
  • DNA
  • Exodeoxyribonucleases
  • exodeoxyribonuclease III
  • Chymotrypsin
  • Triamcinolone Acetonide