title: Inducer and anti-inducer interactions with the lac repressor seen by nuclear magnetic resonance changes at tyrosines and tryptophans.
abstract: The effects of binding inducer and anti-inducer of the Escherichia coli lac operon to the lac repressor were examined by taking advantage of fluorine-19 NMR. The fluorine nucleus was biosynthetically incorporated into the lac repressor with either 5-fluorotryptophan or 3-fluorotyrosine. It is suggested that these small effector molecules influence the operator-binding properties of the tetrameric lac repressor by altering the intersubunit relationships in the protein.
mesh_terms: D004926:Escherichia coli / Q000235:genetics; D007763:Lac Operon; D009682:Magnetic Resonance Spectroscopy; D011485:Protein Binding; D011487:Protein Conformation; D012097:Repressor Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014364:Tryptophan / Q000031:analogs & derivatives / Q000032:analysis*; D014443:Tyrosine / Q000032:analysis*
chemical_list: D012097:Repressor Proteins; D014157:Transcription Factors; C026927:5-fluorotryptophan; D014443:Tyrosine; D014364:Tryptophan