title: Trp holorepressor-trp operator interaction studied by protein distribution analysis.
abstract: Trp repressor protein of Escherichia coli (Mr 24,700) undergoes a conformational change upon interaction with L-tryptophan that enables the resulting binary complex to bind with high specificity to several operator targets in double-stranded DNA. By protein distribution analysis it was shown that a significant fraction of Trp repressor is inert in operator binding. The equilibrium dissociation constant for Trp holorepressor-Trp operator interaction is 6.7 nM at 20 degrees in 0.05M NaCl, pH 7.4. The Trp holorepressor-trp operator complex consists of one molecule of each of the participating species, even at high molar ratios of protein to DNA.
mesh_terms: D001426:Bacterial Proteins; D004926:Escherichia coli / Q000378:metabolism; D007700:Kinetics; D008433:Mathematics; D008722:Methods; D009876:Operon; D011487:Protein Conformation; D012097:Repressor Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014364:Tryptophan / Q000378:metabolism; D029968:Escherichia coli Proteins
chemical_list: D001426:Bacterial Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D014364:Tryptophan; C027190:TRPR protein, E coli; D029968:Escherichia coli Proteins