E. coli trp repressor forms a domain-swapped array in aqueous alcohol

Structure. 2004 Jun;12(6):1099-108. doi: 10.1016/j.str.2004.03.019.

Abstract

The E. coli trp repressor (trpR) homodimer recognizes its palindromic DNA binding site through a pair of flexible helix-turn-helix (HTH) motifs displayed on an intertwined helical core. Flexible N-terminal arms mediate association between dimers bound to tandem DNA sites. The 2.5 A X-ray structure of trpR crystallized in 30% (v/v) isopropanol reveals a substantial conformational rearrangement of HTH motifs and N-terminal arms, with the protein appearing in the unusual form of an ordered 3D domain-swapped supramolecular array. Small angle X-ray scattering measurements show that the self-association properties of trpR in solution are fundamentally altered by isopropanol.

Publication types

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

MeSH terms

  • 2-Propanol / chemistry
  • Alcohols / chemistry*
  • Amino Acid Motifs
  • Amino Acid Sequence
  • Animals
  • Bacterial Proteins / chemistry*
  • Binding Sites
  • Crystallography, X-Ray
  • Dimerization
  • Escherichia coli / metabolism*
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Repressor Proteins / chemistry*
  • Scattering, Radiation
  • X-Rays

Substances

  • Alcohols
  • Bacterial Proteins
  • Repressor Proteins
  • TRPR protein, E coli
  • 2-Propanol

Associated data

  • PDB/1M17