Ultracentrifugal analysis of the quaternary structure of the raf repressor from Escherichia coli.
The raf repressor from Escherichia coli regulates the expression of the plasmid-borne raf operon by switching between active and inactive conformational states. Ultracentrifugal analysis of the largely purified repressor proves the DNA-free protein to undergo concentration-dependent dissociation-association. High-speed sedimentation equilibria show that the 72 kDa dimer prevails under meniscus depletion conditions. At intracellular concentrations the 144 kDa dimer-of-dimers is the dominating species. It is suggested that the tetrameric structure of the raf repressor is involved in the recognition of the 18-basepair operator DNA.
Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, FRG.
R
R
Jaenicke
I
I
Muiznieks
C
C
Aslanidis
R
R
Schmitt
D001482:Base Composition; D004247:DNA / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000235:genetics / Q000302:isolation & purification; D004926:Escherichia coli / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D009876:Operon; D010957:Plasmids; D012097:Repressor Proteins / Q000235:genetics / Q000302:isolation & purification*; D014157:Transcription Factors / Q000302:isolation & purification*; D014158:Transcription, Genetic; D014461:Ultracentrifugation
D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D004247:DNA