The GCN4 basic region leucine zipper binds DNA as a dimer of uninterrupted alpha helices: crystal structure of the protein-DNA complex

Cell. 1992 Dec 24;71(7):1223-37. doi: 10.1016/s0092-8674(05)80070-4.

Abstract

The yeast transcriptional activator GCN4 is 1 of over 30 identified eukaryotic proteins containing the basic region leucine zipper (bZIP) DNA-binding motif. We have determined the crystal structure of the GCN4 bZIP element complexed with DNA at 2.9 A resolution. The bZIP dimer is a pair of continuous alpha helices that form a parallel coiled coil over their carboxy-terminal 30 residues and gradually diverge toward their amino termini to pass through the major groove of the DNA-binding site. The coiled-coil dimerization interface is oriented almost perpendicular to the DNA axis, giving the complex the appearance of the letter T. There are no kinks or sharp bends in either bZIP monomer. Numerous contacts to DNA bases and phosphate oxygens are made by basic region residues that are conserved in the bZIP protein family. The details of the bZIP dimer interaction with DNA can explain recognition of the AP-1 site by the GCN4 protein.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Crystallography
  • DNA-Binding Proteins / chemistry*
  • Fungal Proteins / chemistry*
  • Leucine Zippers
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation*
  • Protein Kinases / chemistry*
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Saccharomyces cerevisiae Proteins*
  • Sequence Alignment
  • Sequence Homology, Amino Acid

Substances

  • DNA-Binding Proteins
  • Fungal Proteins
  • Saccharomyces cerevisiae Proteins
  • Protein Kinases