Principles of protein-DNA recognition revealed in the structural analysis of Ndt80-MSE DNA complexes.
The Saccharomyces cerevisiae transcription factor Ndt80 selectively binds a DNA consensus sequence (the middle sporulation element [MSE]) to activate gene expression after the successful completion of meiotic recombination. Here we report the X-ray crystal structures of Ndt80 bound to ten distinct MSE variants. Comparison of these structures with the structure of Ndt80 bound to a consensus MSE reveals structural principles that determine the DNA binding specificity of this transcription factor. The 5' GC-rich end of the MSE contains distinct 5'-YpG-3' steps that are recognized by arginine side chains through a combination of hydrogen bonding and cation-pi interactions. The 3' AT-rich region is recognized via minor groove contacts that sterically exclude the N2 atom of GC base pairs. The conformation of the AT-rich region is fixed by interactions with the protein that favor recognition of poly(A)-poly(T) versus mixed AT sequences through an avoidance of major groove steric clashes at 5'-ApT-3' steps.
Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
Jason S
JS
Lamoureux
J N Mark
JN
Glover
D001482:Base Composition; D020029:Base Pairing; D001483:Base Sequence; D016384:Consensus Sequence; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D014644:Genetic Variation; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry; D011487:Protein Conformation; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics*; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics*
D004268:DNA-Binding Proteins; D050505:Mutant Proteins; C097071:NDT80 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D004247:DNA