Crystal structure of the yeast MATalpha2/MCM1/DNA ternary complex

Nature. 1998 Feb 12;391(6668):660-6. doi: 10.1038/35563.


The structure of a complex containing the homeodomain repressor protein MATalpha2 and the MADS-box transcription factor MCM1 bound to DNA has been determined by X-ray crystallography at 2.25 A resolution. It reveals the protein-protein interactions responsible for cooperative binding of MATalpha2 and MCM1 to DNA. The otherwise flexible amino-terminal extension of the MATalpha2 homeodomain forms a beta-hairpin that grips the MCM1 surface through parallel beta-strand hydrogen bonds and close-packed, predominantly hydrophobic, side chains. DNA bending induced by MCM1 brings the two proteins closer together, facilitating their interaction. An unusual feature of the complex is that an eight-amino-acid sequence adopts an alpha-helical conformation in one of two copies of the MATalpha2 monomer and a beta-strand conformation in the other. This 'chameleon' sequence of MATalpha2 may be important for recognizing natural operator sites.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Crystallography, X-Ray
  • DNA / chemistry*
  • DNA-Binding Proteins / chemistry*
  • Fungal Proteins / chemistry*
  • Homeodomain Proteins / chemistry*
  • Minichromosome Maintenance 1 Protein
  • Models, Molecular
  • Nucleic Acid Conformation
  • Protein Binding
  • Protein Conformation
  • Repressor Proteins / chemistry*
  • Saccharomyces cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors / chemistry*


  • DNA-Binding Proteins
  • Fungal Proteins
  • Homeodomain Proteins
  • MATA2 protein, S cerevisiae
  • Minichromosome Maintenance 1 Protein
  • Repressor Proteins
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • DNA

Associated data

  • PDB/1APL
  • PDB/1MNM