Many gene-regulatory proteins appear to have a similar alpha-helical fold that binds DNA and evolved from a common precursor

J Mol Evol. 1983;19(2):109-14. doi: 10.1007/BF02300748.


Amino acid and DNA sequence comparisons suggest that many sequence-specific DNA-binding proteins have in common an homologous region of about 22 amino acids. This region corresponds to two consecutive alpha-helices that occur in both Cro and cI repressor proteins of bacteriophage lambda and in catabolite gene activator protein of Escherichia coli and are presumed to interact with DNA. The results obtained here suggest that this alpha-helical DNA-binding fold occurs in many proteins that regulate gene expression. It also appears that this DNA-binding unit evolved from a common evolutionary precursor.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Biological Evolution
  • DNA-Binding Proteins* / genetics
  • Models, Molecular
  • Protein Conformation
  • Repressor Proteins
  • Sequence Homology, Nucleic Acid
  • Transcription Factors* / genetics
  • Viral Proteins
  • Viral Regulatory and Accessory Proteins


  • DNA-Binding Proteins
  • Repressor Proteins
  • Transcription Factors
  • Viral Proteins
  • Viral Regulatory and Accessory Proteins
  • phage repressor proteins