How Trp repressor binds to its operator.
We propose that the generally accepted model of a single Trp repressor dimer binding to a center of symmetry in the natural trp operator (Otwinowski et al., 1988) is wrong. We show here that the Trp repressor binds to a sequence whose center is located four base pairs either to the right or to the left of the central axis of symmetry that was previously identified. We show that: (i) the oligonucleotide used by Otwinowski et al. is not retarded by the Trp repressor in a mobility shift assay under conditions wherein a shorter oligonucleotide carrying our consensus sequence is retarded, (ii) that methylation protection experiments on the full natural operator sequence and the short oligonucleotide protect similar patterns and (iii) that by varying every base in the shorter oligonucleotide, we can demonstrate an optimal sequence for Trp repressor binding.
Institut für Genetik der Universität zu Köln, FRG.
D
D
Staacke
B
B
Walter
B
B
Kisters-Woike
B
B
von Wilcken-Bergmann
B
B
Müller-Hill
D001426:Bacterial Proteins; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D008745:Methylation; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009875:Operator Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics*; D014364:Tryptophan / Q000378:metabolism; D029968:Escherichia coli Proteins
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012097:Repressor Proteins; D014157:Transcription Factors; D014364:Tryptophan; C027190:TRPR protein, E coli; D029968:Escherichia coli Proteins