DNA recognition by beta-sheets in the Arc repressor-operator crystal structure

Nature. 1994 Feb 24;367(6465):754-7. doi: 10.1038/367754a0.


Transcription of the ant gene during lytic growth of bacteriophage P22 (ref. 1) is regulated by the cooperative binding of two Arc repressor dimers to a 21-base-pair operator site. Here we report the co-crystal structure of this Arc tetramer-operator complex at 2.6 A resolution. As expected from genetic and structural studies and from the co-crystal structure of the homologous Escherichia coli MetJ repressor, each Arc dimer uses an antiparallel beta-sheet to recognize bases in the major groove. However, the Arc and MetJ complexes differ in several important ways: the beta-sheet-DNA interactions of Arc are far less symmetrical; DNA binding by Arc is accompanied by important conformational changes in the beta-sheet; and Arc uses a different part of its protein surface for dimer-dimer interactions.

Publication types

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

MeSH terms

  • Base Sequence
  • Crystallography, X-Ray
  • DNA / metabolism*
  • Models, Molecular
  • Molecular Sequence Data
  • Operator Regions, Genetic
  • Protein Structure, Secondary
  • Repressor Proteins / chemistry*
  • Viral Proteins / chemistry*
  • Viral Regulatory and Accessory Proteins


  • Repressor Proteins
  • Viral Proteins
  • Viral Regulatory and Accessory Proteins
  • phage repressor proteins
  • DNA