title: Crystal structure of the yeast MATalpha2/MCM1/DNA ternary complex.
abstract: 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.
authors.affiliation: ETH-Zurich, Institut für Molekularbiologie und Biophysik, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Tan
authors.forename: T J
authors.initials: TJ
authors.lastname: Richmond
mesh_terms: D001665:Binding Sites; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000737:chemistry*; D005656:Fungal Proteins / Q000737:chemistry*; D018398:Homeodomain Proteins / Q000737:chemistry*; D026341:Minichromosome Maintenance 1 Protein; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D011487:Protein Conformation; D012097:Repressor Proteins / Q000737:chemistry*; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000737:chemistry*
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D018398:Homeodomain Proteins; C062928:MATA2 protein, S cerevisiae; D026341:Minichromosome Maintenance 1 Protein; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D004247:DNA