An amino-terminal fragment of GAL4 binds DNA as a dimer

J Mol Biol. 1989 Oct 5;209(3):423-32. doi: 10.1016/0022-2836(89)90007-7.


GAL4 is a yeast transcriptional activator protein that binds to specific 2-fold rotationally symmetric sites on DNA and stimulates transcription of the genes required for galactose catabolism. The DNA binding region of the protein is located within the first 74 amino acids and contains a "zinc finger" sequence motif. We show that a polypeptide comprising the first 147 amino acids of GAL4, designated GAL4 (1-147), binds DNA as a dimer in vitro. Although a protein containing only the first 74 amino acids, designated GAL4 (1-74), binds DNA specifically, its affinity is reduced relative to GAL4 (1-147). Addition of the strong dimerization domain of lambda repressor to GAL4 (1-74) generates a protein that binds as tightly as GAL4 (1-147). GAL4 (1-147) makes rotationally symmetric contacts with its recognition site when assayed by DNase I, exonuclease III and hydroxyl radical footprinting and by phosphate ethylation interference. Binding of GAL4 (1-147) in vitro requires either zinc or cadmium.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids
  • Base Sequence
  • Binding Sites
  • DNA, Fungal / genetics
  • DNA, Fungal / metabolism
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Edetic Acid / metabolism
  • Fungal Proteins / genetics*
  • Fungal Proteins / metabolism
  • Molecular Sequence Data
  • Saccharomyces cerevisiae Proteins*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism


  • Amino Acids
  • DNA, Fungal
  • DNA-Binding Proteins
  • Fungal Proteins
  • GAL4 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • Edetic Acid