title: Escherichia coli tryptophan repressor binds multiple sites within the aroH and trp operators.
abstract: DNase I footprinting and methylation protection studies have been used to analyze the binding of Escherichia coli Trp repressor to the trpR, aroH, and trp operators. The methylation protection assay shows that Trp repressor binds in two successive major grooves of the trpR operator, three successive major grooves of the aroH operator, and four successive major grooves of the trp operator. The simplest model that explains the difference in Trp repressor interaction at the three operators is that the aroH and trp operators are composed of multiple, helically stacked binding sites. When viewed in three dimensions, each site is positioned on a different face of the DNA, and together process up the surface of the DNA helix. Analysis of a deletion derivative of the trp operator supports this model.
authors.affiliation: Molecular Biology Institute, University of California, Los Angeles 90024.
authors.forename: A A
authors.initials: AA
authors.lastname: Kumamoto
authors.forename: W G
authors.initials: WG
authors.lastname: Miller
authors.forename: R P
authors.initials: RP
authors.lastname: Gunsalus
mesh_terms: D001426:Bacterial Proteins; D001483:Base Sequence; D001665:Binding Sites; D003850:Deoxyribonuclease I; D004926:Escherichia coli / Q000235:genetics*; D009154:Mutation; D009876:Operon; D010957:Plasmids; D011485:Protein Binding; D012097:Repressor Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D029968:Escherichia coli Proteins
chemical_list: D001426:Bacterial Proteins; D003850:Deoxyribonuclease I; D012097:Repressor Proteins; D014157:Transcription Factors; C027190:TRPR protein, E coli; D029968:Escherichia coli Proteins