title: Structure of a ternary transcription activation complex.
abstract: The cI protein of bacteriophage lambda (lambdacI) activates transcription by binding a DNA operator just upstream of the promoter and interacting with the RNA polymerase sigma subunit domain 4 (sigma(4)). We determined the crystal structure of the lambdacI/sigma(4)/DNA ternary complex at 2.3 A resolution. There are no conformational changes in either protein, which interact through an extremely small interface involving at most 6 amino acid residues. The interactions of the two proteins stabilize the binding of each protein to the DNA. The results provide insight into how activators can operate through a simple cooperative binding mechanism but affect different steps of the transcription initiation process.
authors.affiliation: The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
authors.forename: Deepti
authors.initials: D
authors.lastname: Jain
authors.forename: Bryce E
authors.initials: BE
authors.lastname: Nickels
authors.forename: Li
authors.initials: L
authors.lastname: Sun
authors.forename: Ann
authors.initials: A
authors.lastname: Hochschild
authors.forename: Seth A
authors.initials: SA
authors.lastname: Darst
mesh_terms: D000595:Amino Acid Sequence; D010582:Bacteriophage lambda / Q000235:genetics; D001483:Base Sequence; D016384:Consensus Sequence; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D020035:Holoenzymes / Q000737:chemistry / Q000378:metabolism; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012808:Sigma Factor / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation
chemical_list: D004268:DNA-Binding Proteins; D020035:Holoenzymes; D012808:Sigma Factor; D012321:DNA-Directed RNA Polymerases